Using Adobe LiveCycle Data Services ES2 Guide

Using Adobe LiveCycle Data Services ES2 Guide
Using
ADOBE® LIVECYCLE® DATA SERVICES ES2
Version 3.1
© 2010 Adobe Systems Incorporated. All rights reserved.
Copyright
Using Adobe® LiveCycle® Data Services ES2 version 3.1.
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Contents
Chapter 1: Getting started with LiveCycle Data Services
Introducing LiveCycle Data Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Building and deploying LiveCycle Data Services applications
........................................................... 9
Chapter 2: System architecture
Client and server architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Channels and endpoints
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Managing session data
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Data serialization
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Chapter 3: Controlling data traffic
Data throttling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Deserialization validators
Advanced data tuning
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Message delivery with adaptive polling
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Measuring message processing performance
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Chapter 4: RPC services
Using RPC services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Chapter 5: Message Service
Using the Message Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Connecting to the Java Message Service (JMS)
Chapter 6: Data Management Service
Introducing the Data Management Service
Data Management Service clients
Data paging
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Occasionally connected clients
Server push
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
Standard assemblers
Hierarchical data
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Data Management Service configuration
Custom assemblers
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Chapter 7: Model-driven applications
Building your first model-driven application
Building an offline-enabled application
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
Customizing client-side functionality
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
Customizing server-side functionality
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Generating database tables from a model
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Creating a client for an existing service destination
Configuring a data source
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
Configuring RDS on the server
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
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Building the client application
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372
Using server-side logging with the Model Assembler
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
Setting Hibernate properties for a model in a Hibernate configuration file
Configuring the model deployment service
Entity utility
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
Chapter 8: Edge Server
Connecting an Edge Server to a server in the application tier
Example application configuration
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
Creating a merged configuration for client compilation
Edge Server authentication and authorization
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
Restricting access from the Edge Server with white lists and black lists
Connecting Flex clients to an Edge Server
Handling missing Java types at the edge tier
JMX management
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Chapter 9: Generating PDF documents
About the PDF generation feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
Using the PDF generation feature
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
Chapter 10: Run-time configuration
About run-time configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Configuring components with a bootstrap service
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Configuring components with a remote object
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
Using assemblers with run-time configuration
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
Accessing dynamic components with a Flex client application
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
Chapter 11: Administering LiveCycle Data Services applications
Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
Security
Clustering
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
Integrating Flex applications with portal servers
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451
Chapter 12: Additional programming topics
The Ajax client library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460
Extending applications with factories
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
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Chapter 1: Getting started with LiveCycle
Data Services
Introducing LiveCycle Data Services
Adobe® LiveCycle® Data Services provides highly scalable remote access, messaging, and data management services for
use with client-side applications built in Adobe® Flex® or Adobe® AIR™.
LiveCycle Data Services overview
LiveCycle Data Services provides a set of services that lets you connect a client-side application to server-side data, and
pass data among multiple clients connected to the server. LiveCycle Data Services synchronizes data sharing among
clients, performs data push and data conflict management, and implements real-time messaging between clients.
A LiveCycle Data Services application consists of two parts: a client-side application and a server-side J2EE web
application. The following figure shows this architecture:
Web Server
J2EE Server
Client
Client
LiveCycle Data Services ES
Client
The client-side application
A LiveCycle Data Services client application is typically an Flex or AIR application. Flex and AIR applications use Flex
components to communicate with the LiveCycle Data Services server, including the RemoteObject, HTTPService,
WebService, Producer, Consumer, and DataService components. The HTTPService, WebService, Producer, and
Consumer components are part of the Flex Software Development Kit (SDK). To use the DataService component,
configure your development environment to use the LiveCycle Data Services SWC files. For more information, see
“Building and deploying LiveCycle Data Services applications” on page 9.
Although you typically use Flex or AIR to develop the client-side application, you can develop the client as a
combination of Flex, HTML, and JavaScript. Or, you can develop it in HTML and JavaScript by using the Ajax client
library to communicate with LiveCycle Data Services. For more information on using the Ajax client library, see “The
Ajax client library” on page 460.
The LiveCycle Data Services server
The LiveCycle Data Services server consists of a J2EE web application and a highly scalable socket server running on
a J2EE application server. The LiveCycle Data Services installer creates three web applications that you can use as the
basis of your application development. For more information on using these web applications, see “Building and
deploying LiveCycle Data Services applications” on page 9.
Configure an existing J2EE web application to support LiveCycle Data Services by performing the following steps:
1 Add the LiveCycle Data Services JAR files and dependent JAR files to the WEB-INF/lib directory.
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2 Edit the LiveCycle Data Services configuration files in the WEB-INF/flex directory.
3 Define MessageBrokerServlet and a session listener in WEB-INF/web.xml.
Versions of LiveCycle Data Services
You can download a free developer version of LiveCycle Data Services with certain restrictions on its use. For more
information, see the LiveCycle Enterprise Suite page on www.adobe.com.
LiveCycle Data Services features
The following figure shows the main features of LiveCycle Data Services:
LiveCycle Data Services ES
RPC Services
Service Adapters
Web Service
LiveCycle
HTTP Service
SQL
Remoting Service
Messaging Service
Hibernate
Publish & Subscribe
ColdFusion
Collaboration
Real Time Data push
JMS
Data Management Service
Data Synchronization
Java
Off-line Applications
Custom
Data Paging
Proxy Service
Portal Deployment
RIA-PDF Generation
LiveCycle Data Services core features
The LiveCycle Data Services core features include the RPC services, Message Service, and Data Management Service.
RPC services
The Remote Procedure Call (RPC) services are designed for applications in which a call and response model is a good
choice for accessing external data. RPC services let a client application make asynchronous requests to remote services
that process the requests and then return data directly to the client. You can access data through client-side RPC
components that include HTTP GET or POST (HTTP services), SOAP (web services), or Java objects (remote object
services).
Use RPC components when you want to provide enterprise functionality, such as proxying of service traffic from
different domains, client authentication, whitelists of permitted RPC service URLs, server-side logging, localization
support, and centralized management of RPC services. LiveCycle Data Services lets you use RemoteObject
components to access remote Java objects without configuring them as SOAP-compliant web services.
A client-side RPC component calls a remote service. The component then stores the response data from the service in
an ActionScript object from which you can easily obtain the data. The client-side RPC components are the
HTTPService, WebService, and RemoteObject components.
Note: You can use Flex SDK without the LiveCycle Data Services proxy service to call HTTP services or web services
directly. You cannot use RemoteObject components without LiveCycle Data Services or Adobe® ColdFusion®.
For more information, see “Using RPC services” on page 135.
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Message Service
The Message Service lets client applications communicate asynchronously by passing messages back and forth through
the server. A message defines properties such as a unique identifier, LiveCycle Data Services headers, any custom
headers, and a message body.
Client applications that send messages are called message producers. You define a producer in a Flex application by
using the Producer component. Client applications that receive messages are called message consumers. You define a
consumer in a Flex application by using the Consumer component. A Consumer component subscribes to a serverside destination and receives messages that a Producer component sends to that destination. For more information on
messaging, see “Using the Message Service” on page 190.
The Message Service also supports bridging to JMS topics and queues on an embedded or external JMS server by using
the JMSAdapter. Bridging lets Flex client applications exchange messages with Java client applications. For more
information, see “Connecting to the Java Message Service (JMS)” on page 214.
Data Management Service
The Data Management Service lets you create applications that work with distributed data. By using the Data
Management Service, you build applications that provide real-time data synchronization, data replication, on-demand
data paging, and occasionally connected application services. You can manage large collections of data and nested data
relationships, such as one-to-one and one-to-many relationships. You can also use data adapters to integrate with data
resources, such as a database.
Note: The Data Management Service is not available in BlazeDS.
A client-side DataService component calls methods on a server-side Data Management Service destination. Use this
component to perform activities such as filling client-side data collections with data from remote data sources and
synchronizing the client and server versions of data. Changes made to the data at the client side are tracked
automatically using property change events.
When the user is ready to submit their changes, the changes are sent to a service running on the server. This service
then passes the changes to a server-side adapter, which checks for conflicts and commits the changes. The adapter can
be an interface you write, or one of the supplied adapters that work with a standard persistence layer such as SQL or
Hibernate. After the changes are committed, the Data Management Service pushes these changes to any other clients
looking at the same data.
For more information, see “Introducing the Data Management Service” on page 221.
Service adapters
LiveCycle Data Services lets you access many different persistent data stores and databases including Hibernate, SQL,
JMS, and other data persistence mechanisms. A Service Adapter is responsible for updating the persistent data store
on the server in a manner appropriate to the specific data store type. The adapter architecture is customizable to let
you integrate with any type of messaging or back-end persistence system.
The message-based framework
LiveCycle Data Services uses a message-based framework to send data back and forth between the client and server.
LiveCycle Data Services uses two primary exchange patterns between server and client. In the first pattern, the requestresponse pattern, the client sends a request to the server to be processed. The server returns a response to the client
containing the processing outcome. The RPC services use this pattern.
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The second pattern is the publish-subscribe pattern where the server routes published messages to the set of clients
that have subscribed to receive them. The Message Service and Data Management Service use this pattern to push data
to interested clients. The Message Service and Data Management Service also use the request-response pattern to issue
commands, publish messages, and interact with data on the server.
Channels and endpoints
To send messages across the network, the client uses channels. A channel encapsulates message formats, network
protocols, and network behaviors to decouple them from services, destinations, and application code. A channel
formats and translates messages into a network-specific form and delivers them to an endpoint on the server.
Channels also impose an order to the flow of messages sent to the server and the order of corresponding responses.
Order is important to ensure that interactions between the client and server occur in a consistent, predictable fashion.
Channels communicate with Java-based endpoints on the server. An endpoint unmarshals messages in a protocolspecific manner and then passes the messages in generic Java form to the message broker. The message broker
determines where to send messages, and routes them to the appropriate service destination.
LiveCycle Data Services ES
Client
Channel
Endpoint
For more information on channels and endpoints, see “Client and server architecture” on page 27.
Channel types
LiveCycle Data Services includes several types of channels, including standard and secure Real Time Messaging
Protocol (RTMP) channels and channels that support binary Action Message Format (AMF) and its text-based XML
representation called AMFX. AMF and HTTP channels support non-polling request-response patterns and client
polling patterns to simulate real-time messaging. The RTMP channels and streaming AMF and HTTP channels
provide true data streaming for real-time messaging.
LiveCycle Data Services summary of features
The following table summarizes some of the main features of LiveCycle Data Services:
Feature
Description
Client-server
synchronization
Automatic and manual synchronization of a common set of data on multiple clients
and server-side data resources. Also supports offline client-side data persistence for
occasionally connected clients.
Removes the complexity and potential for error by providing a robust, highperformance data synchronization engine between client and server. It also can
easily integrate with existing persistence solutions to provide an end-to-end
solution.
Collaboration
Enables a client application to concurrently share data with other clients or servers.
This model enables new application concepts like "co-browsing" and synchronous
collaboration, which allow users to share experiences and work together in real time.
Data paging
Facilitates the paging of large data sets, enabling developers to focus on core
application business logic instead of worrying about basic data management
infrastructure.
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Feature
Description
Data push
Enables data to automatically be pushed to the client application without polling.
This highly scalable capability can push data to thousands of concurrent users to
provide up-to-the-second views of critical data. Examples include stock trader
applications, live resource monitoring, shop floor automation, and more.
Data traffic control
Provides a set of features for managing data traffic, such as data throttling,
deserialization validation, reliable messaging, message prioritization, message
filtering, and measuring message processing performance.
Model-driven development
Use Adobe application modeling technology to facilitate the development of datacentric applications.
Occasionally connected
client
Handles temporary disconnects, ensuring reliable delivery of data to and from the
client application. Provides support for the development of offline and occasionally
connected applications that run in the browser or on the desktop. LiveCycle Data
Services takes advantage of the scalable local SQLite database in AIR to store data,
synchronize it back to the server, and rationalize any changes or conflicts.
Portal service integration
Configure a Flex client applications as local portlets hosted on JBoss Portal, Oracle
WebLogic Portal, or IBM WebSphere Portal.
Proxy service
Enables communication between clients and domains that they cannot access
directly, due to security restrictions, allowing you to integrate multiple services with
a single application. By using the Proxy Service, you do not have to configure a
separate web application to work with web services or HTTP services.
Publish and subscribe
messaging
Provides a messaging infrastructure that integrates with existing messaging
systems such as JMS. This service enables messages to be exchanged in real time
between browser clients and the server. It allows Flex clients to publish and
subscribe to message topics with the same reliability, scalability, and overall quality
of service as traditional thick client applications.
RIA-to-PDF generation
Users can generate template-driven PDF documents that include graphical assets
from Flex applications, such as graphs and charts. The generated PDF documents
can be orchestrated with other LiveCycle services and policy-protected to ensure
only authorized access.
Software clustering
Handles failover when using stateful services and non-HTTP channels, such as RTMP,
to ensure that Flex applications continue running in the event of server failure. The
more common form of clustering using load balancers, usually in the form of
hardware, is supported without any feature implementation.
Example LiveCycle Data Services applications
The following example applications show client-side and server-side code that you can compile and deploy to get
started with LiveCycle Data Services. You typically use the following steps to build an application:
1 Configure a destination in the LiveCycle Data Services server used by the client application to communicate with
the server. A destination is the server-side code that you connect to from the client. Configure a destination in one
of the configuration files in the WEB-INF/flex directory of your web application.
2 Configure a channel used by the destination to send messages across the network. The channel encapsulates
message formats, network protocols, and network behaviors and decouples them from services, destinations, and
application code. Configure a channel in one of the configuration files in the WEB-INF/flex directory of your web
application.
3 Write the Flex client application in MXML or ActionScript.
4 Compile the client application into a SWF file by using Adobe® Flash® Builder™ or the mxmlc compiler.
5 Deploy the SWF file to your LiveCycle Data Services web application.
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Running the examples
The LiveCycle Data Services installer creates a directory structure on your computer that contains all of the resources
necessary to build applications. As part of the installation, the installer creates three web applications that you can use
as the basis of your development environment. The lcds-samples web application contains many LiveCycle Data
Services examples.
You can run the following examples if you compile them for the lcds-samples web application and deploy them to the
lcds-samples directory structure. For more information on building and running the examples, see “Building and
deploying LiveCycle Data Services applications” on page 9.
RPC service example
The Remoting Service is one of the RPC services included with LiveCycle Data Services. The Remoting Service lets
clients access methods of Plain Old Java Objects (POJOs) on the server.
In this example, you deploy a Java class, EchoService.java, on the server that echoes back a String passed to it from the
client. The following code shows the definition of EchoService.java:
package remoting;
public class EchoService
{
public String echo(String text) {
return "Server says: I received '" + text + "' from you";
}
}
The echo() method takes a String argument and returns it with additional text. After compiling EchoService.java,
place EchoService.class in the WEB-INF/classes/remoting directory. Notice that the Java class does not have to import
or reference any LiveCycle Data Services resources.
Define a destination, and reference one or more channels that transport the data. Configure EchoService.class as a
remoting destination by editing the WEB-INF/flex/remoting-config.xml file and adding the following code:
<destination id="echoServiceDestination" channels="my-amf">
<properties>
<source>remoting.EchoService</source>
</properties>
</destination>
The source element references the Java class, and the channels attribute references a channel called my-amf.
Define the my-amf channel in WEB-INF/flex/services-config.xml, as the following example shows:
<channel-definition id="my-amf" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://{server.name}:{server.port}/{context.root}/messagebroker/amf"
class="flex.messaging.endpoints.AMFEndpoint"/>
<properties>
<polling-enabled>false</polling-enabled>
</properties>
</channel-definition>
The channel definition specifies that the Flex client uses a non-polling AMFChannel to communicate with the
AMFEndpoint on the server. Restart the LiveCycle Data Services server after making this change.
Note: If you deploy this application on the lcds-samples web application installed with LiveCycle Data Services, servicesconfig.xml already contains a definition for the my-amf channel.
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The Flex client application uses the RemoteObject component to access EchoService. The RemoteObject component
uses the destination property to specify the destination. The user clicks the Button control to invoke the remote
echo() method:
<?xml version="1.0"?>
<!-- intro\intro_remoting.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
width="100%" height="100%">
<mx:Script>
<![CDATA[
import mx.rpc.events.FaultEvent;
import mx.rpc.events.ResultEvent;
// Send the message in response to a Button click.
private function echo():void {
var text:String = ti.text;
remoteObject.echo(text);
}
// Handle the recevied message.
private function resultHandler(event:ResultEvent):void {
ta.text += "Server responded: "+ event.result + "\n";
}
// Handle a message fault.
private function faultHandler(event:FaultEvent):void {
ta.text += "Received fault: " + event.fault + "\n";
}
]]>
</mx:Script>
<mx:RemoteObject id="remoteObject"
destination="echoServiceDestination"
result="resultHandler(event);"
fault="faultHandler(event);"/>
<mx:Label text="Enter a text for the server to echo"/>
<mx:TextInput id="ti" text="Hello World!"/>
<mx:Button label="Send" click="echo();"/>
<mx:TextArea id="ta" width="100%" height="100%"/>
</mx:Application>
Compile the client application into a SWF file by using Flash Builder or the mxmlc compiler, and then deploy it to your
web application.
Message Service example
The Message Service lets client applications send and receive messages from other clients. In this example, create a Flex
application that sends and receives messages from the same LiveCycle Data Services destination.
Define the messaging destination in WEB-INF/flex/messaging-config.xml, as the following example shows:
<destination id="MessagingDestination" channels="my-amf-poll"/>
Define the my-amf-poll channel in WEB-INF/flex/services-config.xml, as the following example shows:
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<channel-definition id="my-amf-poll" class="mx.messaging.channels.AMFChannel">
<endpoint
url="http://{server.name}:{server.port}/{context.root}/messagebroker/amfpoll"
class="flex.messaging.endpoints.AMFEndpoint"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-seconds>1</polling-interval-seconds>
</properties>
</channel-definition>
This channel definition creates a polling channel with a polling interval of 1 second. Therefore, the client sends a poll
message to the server every second to request new messages. Use a polling channel because it is the easiest way for the
client to receive updates. Other options include polling with piggybacking, long-polling, and streaming. Restart the
LiveCycle Data Services server after making this change.
The following Flex client application uses the Producer component to send a message to the destination, and the
Consumer component to receive messages sent to the destination. To send the message, the Producer first creates an
instance of the AsyncMessage class and then sets its body property to the message. Then, it calls the Producer.send()
method to send it. To receive messages, the Consumer first calls the Consumer.subscribe() method to subscribe to
messages sent to a specific destination.
<?xml version="1.0"?>
<!-- intro\intro_messaging.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
width="100%" height="100%"
creationComplete="consumer.subscribe();">
<mx:Script>
<![CDATA[
import mx.messaging.channels.AMFChannel;
import mx.messaging.ChannelSet;
import mx.messaging.events.MessageFaultEvent;
import mx.messaging.events.MessageEvent;
import mx.messaging.messages.AsyncMessage;
import mx.messaging.Producer;
import mx.messaging.Consumer;
// Send the message in response to a Button click.
private function sendMessage():void {
var msg:AsyncMessage = new AsyncMessage();
msg.body = "Foo";
producer.send(msg);
}
// Handle the received message.
private function messageHandler(event:MessageEvent):void {
ta.text += "Consumer received message: "+ event.message.body + "\n";
}
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// Handle a message fault.
private function faultHandler(event:MessageFaultEvent):void {
ta.text += "Received fault: " + event.faultString + "\n";
}
]]>
</mx:Script>
<mx:Producer id="producer"
destination="MessagingDestination"
fault="faultHandler(event);"/>
<mx:Consumer id="consumer"
destination="MessagingDestination"
fault="faultHandler(event);"
message="messageHandler(event);"/>
<mx:Button label="Send" click="sendMessage();"/>
<mx:TextArea id="ta" width="100%" height="100%"/>
</mx:Application>
Compile the client application into a SWF file by using Flash Builder or the mxmlc compiler, and then deploy it to your
web application.
Building and deploying LiveCycle Data Services
applications
Adobe LiveCycle Data Services applications consist of client-side code and server-side code. Client-side code is
typically is built with Flex in MXML and ActionScript and deployed as a SWF file. Server-side code is written in Java
and deployed as Java class files or Java Archive (JAR) files. Every LiveCycle Data Services application has client-side
code; however, you can implement an entire application without writing any server-side code.
For more information on the general application and deployment process for Flex applications, see the Flex
documentation.
Setting up your development environment
LiveCycle Data Services applications consist of two parts: client-side code and server-side code. Before you start
developing your application, configure your development environment, including the directory structure for your
client-side source code and for your server-side source code.
Installation directory structure
The LiveCycle Data Services installer creates a directory structure on your computer that contains all of the resources
necessary to build your application. As part of the installation, the installer creates three web applications that you can
use as the basis of your development environment.
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The following example shows the directory structure of the web applications installed with LiveCycle Data Services:
J2EE appplication server
root directory
lcds
WEB-INF
lcds-samples
WEB-INF
ds-console
WEB-INF
The installer gives you the option of installing the integrated Tomcat application server to host these web applications.
Alternatively, you can install LiveCycle Data Services without installing Tomcat. Instead, you deploy the LiveCycle
Data Services web application on your J2EE application server or servlet container.
The following table describes the directory structure of each web application:
Directory
Description
/lcds
The root directory of a web application. Contains the WEB-INF directory.
/lcds-samples
/ds-console
This directory also includes all files that must be accessible by the user’s web browser, such as
SWF files, JSP pages, HTML pages, Cascading Style Sheets, images, and JavaScript files. You can
place these files directly in the web application root directory or in arbitrary subdirectories that
do not use the reserved name WEB-INF.
/META-INF
Contains package and extension configuration data.
/WEB-INF
Contains the standard web application deployment descriptor (web.xml) that configures the
LiveCycle Data Services web application. This directory can also contain a vendor-specific web
application deployment descriptor.
/WEB-INF/classes
Contains Java class files and configuration files.
/WEB-INF/flex
Contains LiveCycle Data Services configuration files.
/WEB-INF/flex/libs
Contains SWC library files used when compiling a LiveCycle Data Services application.
/WEB-INF/flex/locale Contains localization resource files used when compiling a LiveCycle Data Services application.
/WEB-INF/lib
Contains LiveCycle Data Services JAR files.
/WEB-INF/src
(Optional) Contains Java source code used by the web application.
Accessing a web application
To access a web application and the services provided by LiveCycle Data Services, you need the URL and port number
associated with the web application. The following table describes how to access each web application assuming that
you install LiveCycle Data Services with the integrated Tomcat application server.
Note: If you install LiveCycle Data Services into the directory structure of your J2EE application server or servlet
container, modify the context root URL based on your development environment.
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Application
Context root URL for Tomcat
Description
Sample application
http://localhost:8400/lcds-samples/ A sample web application that includes many LiveCycle
Data Services examples. To start building your own
applications, start by editing these samples.
Template
application
http://localhost:8400/lcds/
A fully configured LiveCycle Data Services web application
that contains no application code. You can use this
application as a template to create your own web
application.
Console application
http://localhost:8400/ds-console/
A console application that lets you view information about
LiveCycle Data Services web applications.
If you install LiveCycle Data Services with the integrated Tomcat application server, you can also access the ROOT web
application by using the following URL: http://localhost:8400/.
Creating a web application
To get started writing LiveCycle Data Services applications, you can edit the samples in the lcds-samples web
application, add your application code to the lcds-samples web application, or add your application code to the empty
lcds web application.
However, Adobe recommends leaving the lcds web application alone, and instead copying its contents to a new web
application. That leaves the lcds web application empty so that you can use it as the template for creating web
applications.
If you base a new web application on the lcds web application, make sure you change the port numbers of the RTMP
and NIO channel definitions in the services-config.xml file of the new web application. Otherwise, the ports in the new
web application with conflict with those in the lcds web application. Make sure the new port numbers you use aren’t
already used in other web applications, such as the lcds-samples web application.
Defining the directory structure for client-side code
You develop LiveCycle Data Services client-side applications, and compile them in the same way that you compile
applications that use the Flex Software Development Kit (SDK). That means you can use the compiler built in to Flash
Builder, or the command line compiler, mxmlc, supplied with the Flex SDK.
When you develop applications, you have two choices for how you arrange the directory structure of your application:
• Define a directory structure on your computer outside any LiveCycle Data Services web application. Compile the
application into a SWF file, and then deploy it, along with any run-time assets, to a LiveCycle Data Services web
application.
• Define a directory structure in a LiveCycle Data Services web application. In this scenario, all of your source code
and assets are stored in the web application. When you deploy the application, make sure to deploy only the
application SWF file and run-time assets. Otherwise, you run the risk of deploying your source code on a
production server.
You define each application in its own directory structure, with the local assets for the application under the root
directory. For assets shared across applications, such as image files, you can define a directory that is accessible by all
applications.
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The following example shows two applications, appRoot1 and appRoot2. Each application has a subdirectory for local
MXML and ActionScript components, and can also reference a library of shared components:
base dir
appRoot1
myValidators
PriceValidator.mxml
AddressValidator.as
myFormatters
PriceFormatter.mxml
StringFormatter.as
appRoot2
myValidators
myFormatters
sharedLibrary
sharedValidators
SharedVal1.mxml
SharedVal2.as
sharedFormatters
SharedFormatter1.mxml
SharedFormatter2.as
Defining the directory structure for server-side code
You develop the server-side part of a LiveCycle Data Services application in Java. For example, the client-side
RemoteObject component lets you access the methods of server-side Java objects to return data to the client.
You also write Java classes to extend the functionality of the LiveCycle Data Services server. For example, a Data
Management Service destination references one or more message channels that transport messages, and contains
network- and server-related properties. The destination can also reference a data adapter, server-side code that lets the
destination work with data through a particular type of interface such as a Java object. An assembler class is a Java class
that interacts indirectly or directly with a data resource. For more information on assemblers, see “Standard
assemblers” on page 268.
When you develop server-side code, you have several choices for how you arrange the directory structure of your
application:
• Define a directory structure that corresponds to the package hierarchy of your Java source code outside any
LiveCycle Data Services web application. Compile the Java code, and then deploy the corresponding class files and
JAR files, along with any run-time assets, to a LiveCycle Data Services web application.
• Define a directory structure in a LiveCycle Data Services web application. In this scenario, all of your source code
and assets are stored in the web application. When you deploy the application, make sure to deploy only the class
and JAR files. Otherwise, you risk deploying source code on a production server.
The WEB-INF/classes and WEB-INF/lib directories are automatically included in the classpath of the web application.
When you deploy your server-side code, place the compiled Java class files in the WEB-INF/classes directory. Place
JAR files in the WEB-INF/lib directory.
Running the LiveCycle Data Services sample applications
When you install LiveCycle Data Services, the installer creates the lcds-samples web application that contains sample
applications, including the 30 Minute Test Drive application. The sample applications demonstrate basic capabilities
and best practices for developing LiveCycle Data Services applications.
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The samples use an HSQLDB database that is installed in the install_root/sampledb directory. You must start the
LiveCycle Data Services server and the samples database before you can run the LiveCycle Data Services samples. After
starting the server and database, access the main sample application page by opening the following URL in a browser:
http://localhost:8400/lcds-samples/
The objective of the 30 Minute Test Drive is to give you, in a very short time, an understanding of how the LiveCycle
Data Services works. Access the 30 Minute Test Drive application by opening the following URL in a browser:
http://localhost:8400/lcds-samples/testdrive.htm
The client-side source code for the samples is shipped in the lcds-samples/WEB-INF/flex-src/flex-src.zip file. To
modify the client-side code, extract the flex-src.zip file into the lcds-samples directory, and then edit, compile, and
deploy the modified examples. Editing the samples makes it easier to get started developing applications because you
only have to modify existing code, rather than creating it from scratch.
Extract the client-side source code
1 Open lcds-samples/WEB-INF/flex-src/flex-src.zip file.
2 Extract the ZIP file into the lcds-samples directory.
Expanding the ZIP file adds a src directory to each sample in the lcds-samples directory. For example, the source
code for the chat example, Chat.mxml, is written to the directory lcds-samples/testdrive-chat/src.
The server-side source code for these examples is shipped in the lcds-samples/WEB-INF/src/flex/samples directory.
These source files are not zipped, but shipped in an expanded directory structure. To modify the server-side code you
can edit and compile it in that directory structure, and then copy it to the lcds-samples directory to deploy it.
Run the sample applications
1 Change directory to install_root/sampledb.
2 Start the samples database by using the following command:
startdb
You can stop the database by using the command:
stopdb
3 Start LiveCycle Data Services.
How you start LiveCycle Data Services depends on your system.
4 Open the following URL in a browser:
http://localhost:8400/lcds-samples/
Building your client-side application
You write the client-side part of a LiveCycle Data Services application in Flex, and then use Flash Builder or the mxmlc
command line compiler to compile it.
Before you begin
Before you begin to develop your client-side code, determine the files required to perform the compilation. Ensure that
you configured your Flex installation to compile SWF files for LiveCycle Data Services applications.
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Add the LiveCycle Data Services SWC files to the Flex SDK
To compile an application, Flash Builder and mxmlc reference the SWC library files that ship with the Flex SDK in
subdirectories of the frameworks directory. In Flash Builder, the frameworks directories for different Flex SDK
versions are in the install_root/sdks/sdkversion directory.
LiveCycle Data Services ships the following additional sets of SWC files. You must reference the set of SWC files that
matches the Flex SDK you compile against.
• Flex 4 compatible SWC files in subdirectories of the install_root/resources/lcds_swcs/FlexSDK4/frameworks
directory.
• Flex 3 compatible SWC files in subdirectories of the install_root/resources/lcds_swcs/FlexSDK3/frameworks
directory.
Copy the files in the LiveCycle Data Services frameworks directory (including its subdirectories) to the corresponding
Flex SDK frameworks directory.
Note: Flex 3 compatible SWC files are also available in the WEB-INF/flex/libs directory of a LiveCycle Data Services web
application. By default, Flash Builder adds these files to the library-path of a project that uses LiveCycle Data Services.
However, the Flex 4 compatible versions of these files are not available in that location. You must add them manually
from the install_root/resources/lcds_swcs/FlexSDK4/frameworks directory.
LiveCycle Data Services provides the following SWC files:
• fds.swc and fiber.swc
The SWC library files that define LiveCycle Data Services. These SWC files must be included in the library path of
the compiler.
• airfds.swc and playerfds.swc
The SWC files required to build LiveCycle Data Services applications for Flash Player (playerfds.swc) or AIR
(airfds.swc). One of these SWC files must be included in the library path of the compiler.
For the default Flex SDK installation, playerfds.swc must be in the libs/player directory, and airfds.swc must be in
the libs/air directory. The airfds.swc and playerfds.swc files must not both be available at the time of compilation.
When you compile your application in Flash Builder, it automatically references the correct SWC file based on your
project settings.
When you compile an application using mxmlc, by default the compiler references the flex-config.xml
configuration file, which specifies to include the libs/player directory in the library path for Flash Player. When you
compile an application for AIR, use the load-config option to the mxmlc compiler to specify the air-config.xml
file, which specifies to include the libs/air directory in the library path.
• fds_rb.swc and fiber_rb.swc
The localized SWC files for LiveCycle Data Services. These SWC files must be in the library path of the compilation.
Specifying the services-config.xml file in a compilation
When you compile your Flex application, you typically specify the services-config.xml configuration file to the
compiler. This file defines the channel URLs that the client-side Flex application uses to communicate with the
LiveCycle Data Services server. Then the channel URLs are compiled into the resultant SWF file.
Both client-side and server-side code use the services-config.xml configuration file. If you change anything in servicesconfig.xml, you usually have to recompile your client-side applications and restart your server-side application for the
changes to take effect.
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In Flash Builder, the appropriate services-config.xml file is included automatically based on the LiveCycle Data
Services web application that you specified in the configuration of your Flash Builder project. When you use the mxmlc
compiler, use the services option to specify the location of the file.
Note: You can also create channel definitions on the client in ActionScript or MXML. In that case, you might be able to
omit the reference to the services-config.xml configuration file from the compiler. For more information, see “About
channels and endpoints” on page 38.
Specifying the context root in a compilation
The services-config.xml configuration file typically uses the context.root token to specify the context root of a web
application. At compile time, you use the compiler context-root option to specify that information.
During a compilation, Flash Builder automatically sets the value of the context.root token based on the LiveCycle
Data Services web application that you specified in the configuration of your project. When you use the mxmlc
compiler, use the context-root option to set it.
Using Flash Builder to compile client-side code
Flash Builder is an integrated development environment (IDE) for developing applications that use the Flex
framework, MXML, Adobe Flash Player, AIR, ActionScript, LiveCycle Data Services, and the Flex charting
components.
Flash Builder is built on top of Eclipse, an open-source IDE. It runs on Microsoft Windows, Apple Mac OS X, and
Linux, and is available in several versions. Installation configuration options let you install Flash Builder as a plug-in
to an existing Eclipse workbench installation, or to install it as a stand-alone application.
Using the stand-alone or plug-in configuration of Flash Builder
The Flash Builder installer provides the following two configuration options:
Plug-in configuration This configuration is for users who already use the Eclipse workbench, who already develop in
Java, or who want to add the Flash Builder plug-ins to their toolkit of Eclipse plug-ins. Because Eclipse is an open,
extensible platform, hundreds of plug-ins are available for many different development purposes. When you use the
plug-in configuration, you can create a combined Java and Flex Eclipse project; for more information, see “Creating a
combined Java and Flex project in Eclipse” on page 22.
Stand-alone configuration This configuration is a customized packaging of Eclipse and the Flash Builder plug-in
created specifically for developing Flex and ActionScript applications. The stand-alone configuration is ideal for new
users and users who intend to develop only Flex and ActionScript applications.
Both configurations provide the same functionality. You select the configuration when you install Flash Builder.
Most LiveCycle Data Services developers choose to use the Eclipse plug-in configuration. Then they develop the Java
code that runs on the server in the same IDE that they use to develop the MXML and ActionScript code for the client
Flex application.
Note: The stand-alone configuration of Flash Builder does not contain tools to edit Java code, however, you can install
them. Select Help > Software Updates > Find and Install menu command to open the Install/Update dialog box. Then
select Search For New Features To Install. In the results, select Europa Discovery Site, and then select the Java
Development package to install.
If you aren’t sure which configuration to use, follow these guidelines:
• If you already use and have Eclipse 3.11 (or later) installed, select the plug-in configuration. On Macintosh, Eclipse
3.2 is the earliest version.
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• If you don’t have Eclipse installed and your primary focus is on developing Flex and ActionScript applications,
select the stand-alone configuration. This configuration also lets you install other Eclipse plug-ins, so you can
expand the scope of your development work in the future.
Create a Flash Builder project
Use this procedure to create a Flash Builder project to edit one of the samples shipped with the Test Drive application.
The procedure for creating and configuring a new project is almost the same as the following procedure.
Note: When you use the plug-in configuration of Flash Builder, you can create a combined Java and Flex Eclipse project;
for more information, see “Creating a combined Java and Flex project in Eclipse” on page 22.
For more information on the Test Drive application, see “Running the LiveCycle Data Services sample applications”
on page 12.
1 Start Flash Builder.
2 Select File > New > Flex Project.
3 Enter a project name. You are editing an existing application, so use the exact name of the sample folder: testdrive-chat.
Note: If you are creating an empty project, you can name it anything that you want.
4 If you unzipped flex-src.zip in the lcds-samples directory, deselect the Use Default Location option, and specify the
directory as install_root/tomcat/webapps/lcds-samples/testdrive-chat, or wherever you unzipped the file on your
computer.
Note: By default, Flash Builder creates the project directory based on the project name and operating system. For
example, if you are using the plug-in configuration of Flash Builder on Microsoft Windows, the default project
directory is C:/Documents and Settings/USER_NAME/workspace/PROJECT_NAME.
5 Select the application type as Web (runs in Adobe® Flash® Player) to configure the application to run in the browser
as a Flash Player application.
If you are creating an AIR application, select Desktop (runs In Adobe AIR). However, make sure that you do not
have any server tokens in URLs in the configuration files. In the web application that ships with LiveCycle Data
Services, server tokens are used in the channel endpoint URLs in the WEB-INF/flex/services-config.xml file, as the
following example shows:
<endpoint
url="https://{server.name}:{server.port}/{context.root}/messagebroker/streamingamf"
class="flex.messaging.endpoints.StreamingAMFEndpoint"/>
You would change that line to the following:
<endpoint url="http://your_server_name:8400/lcds/messagebroker/streamingamf"
class="flex.messaging.endpoints.StreamingAMFEndpoint"/>
6 Select J2EE as the Application server type.
7 Select Use Remote Object Access.
8 Select LiveCycle Data Services.
9 Click Next.
10 Deselect Use Default Location For Local LiveCycle Data Services Server.
11 Set the root folder, root URL, and context root of your web application.
The root folder specifies the top-level directory of the web application (the directory that contains the WEB-INF
directory). The root URL specifies the URL of the web application, and the context root specifies the root of the web
application.
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If you are using the integrated Tomcat application server, set the properties as follows:
Root folder: C:\lcds\tomcat\webapps\lcds-samples\
Root URL: http://localhost:8400/lcds-samples/
Context root: /lcds-samples/
Modify these settings as appropriate if you are not using the Tomcat application server.
12 Make sure that your LiveCycle Data Services server is running, and click Validate Configuration to ensure that your
project is valid.
13 Clear the Output Folder field to set the directory of the compiled SWF file to the main project directory.
By default, Flash Builder writes the compiled SWF file to the bin-debug directory under the main project directory.
To use a different output directory, specify it in the Output Folder field.
14 Click Next.
15 Set the name of the main application file to Chat.mxml, and click Finish.
Edit, compile, and deploy a LiveCycle Data Services application in Flash Builder
1 Open src/Chat.mxml in your Flash Builder project.
2 Edit Chat.mxml to change the definition of the TextArea control so that it displays an initial text string when the
application starts:
<mx:TextArea id="log" width="100%" height="100%" text="My edited file!"/>
3 Save the file.
When you save the file, Flash Builder automatically compiles it. By default, the resultant SWF file is written to the
C:/lcds/tomcat/webapps/lcds-samples/testdrive-chat/bin-debug directory, or the location you set for the Output
directory for the project. You should have set the Output directory to the main project directory in the previous
procedure.
Note: If you write the Chat.SWF file to any directory other than lcds-samples\testdrive-chat, deploy the SWF file by
copying it to the lcds-samples\testdrive-chat directory.
4 Make sure that you have started the samples database and LiveCycle Data Services, as described in “Running the
LiveCycle Data Services sample applications” on page 12.
5 Select Run > Run Chat to run the application.
You can also request the application in a browser by using the URL http://localhost:8400/lcds-samples/testdrivechat/index.html.
Note: By default, Flash Builder creates a SWF file that contains debug information. When you are ready to deploy
your final application, meaning one that does not contain debug information, select File > Export > Release Build. For
more information, see Using Adobe Flash Builder 4.
6 Verify that your new text appears in the TextArea control.
Create a linked resource to the LiveCycle Data Services configuration files
While working on the client-side of your applications, you often look at or change the LiveCycle Data Services
configuration files. You can create a linked resource inside a Flash Builder project to make the LiveCycle Data Services
configuration files easily accessible.
1 Right-click the project name in the project navigation view.
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2 Select New > Folder in the pop-up menu.
3 Specify the name of the folder as it will appear in the navigation view. This name can be different from the name of
the folder in the file system. For example, type server-config.
4 Click the Advanced button.
5 Select the Link To Folder In The File System option.
6 Click the Browse button and select the flex folder under the WEB-INF directory of your web application. For
example, on a typical Windows installation that uses the Tomcat integrated server, select:
install_root/tomcat/webapps/lcds-samples/WEB-INF/flex.
7 Click Finish. The LiveCycle Data Services configuration files are now available in your Flash Builder project under
the server-config folder.
Note: If you change anything in the services-config.xml file, you usually have to recompile your client-side applications
and restart your server-side application for the changes to take effect.
Using mxmlc to compile client-side code
You use the mxmlc command line compiler to create SWF files from MXML, ActionScript, and other source files.
Typically, you pass the name of the MXML application file to the compiler. The output is a SWF file. The mxmlc
compiler ships in the bin directory of the Flex SDK. You run the mxmlc compiler as a shell script and executable file
on Windows and UNIX systems. For more information, see the Flex documentation set.
The basic syntax of the mxmlc utility is as follows:
mxmlc [options] target_file
The target file of the compile is required. If you use a space-separated list as part of the options, you can terminate the
list with a double hyphen before adding the target file.
mxmlc -option arg1 arg2 arg3 -- target_file.mxml
To see a list of options for mxmlc, use the helplist option, as the following example shows:
mxmlc -help list
To see a list of all options available for mxmlc, including advanced options, use the following command:
mxmlc -help list advanced
The default output of mxmlc is filename.swf, where filename is the name of the target file. The default output location
is in the same directory as the target, unless you specify an output file and location with the output option.
The mxmlc command line compiler does not generate an HTML wrapper. Create your own wrapper to deploy a SWF
file that the mxmlc compiler produced. The wrapper embeds the SWF object in the HTML tag. The wrapper includes
the <object> and <embed> tags, and scripts that support Flash Player version detection and history management. For
information about creating an HTML wrapper, see the Flex Help Resource Center.
Note: Flash Builder automatically generates an HTML wrapper when you compile your application.
Compiling LiveCycle Data Services applications
Along with the standard options that you use with the mxmlc compiler, use the following options to specify
information about your LiveCycle Data Services application.
•
services filename
Specifies the location of the services-config.xml file.
•
library-path context-path
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Sets the library path of the LiveCycle Data Services SWC files. Use the += syntax with the library-path option to add
the WEB-INF/flex/libs directory to the library path.
•
context-root context-path
Sets the value of the context root of the application. This value corresponds to the {context.root} token in the
services-config.xml file, which is often used in channel definitions. The default value is null.
Edit, compile, and deploy the Chat.mxml file
1 Unzip flex-src.zip in the lcds/tomcat/webapps/lcds-samples directory, as described in “Running the LiveCycle Data
Services sample applications” on page 12.
2 Open the file install_root/tomcat/webapps/lcds-samples/testdrive-chat/src/Chat.mxml in an editor. Modify this
path as necessary based on where you unzipped flex-src.zip.
3 Change the definition of the TextArea control so that it displays an initial text string when the application starts:
<mx:TextArea id="log" width="100%" height="100%" text="My edited file!"/>
4 Change the directory to install_root/tomcat/webapps/lcds-samples.
5 Use the following command to compile Chat.mxml:
Note: This command assumes that you added the mxmlc directory to your system path. The default location is
install_root/resources/flex_sdk/bin.
mxmlc -strict=true
-show-actionscript-warnings=true
-use-network=true
-services=WEB-INF/flex/services-config.xml
-library-path+=WEB-INF/flex/libs
-context-root=lcds-samples
-output=testdrive-chat/Chat.swf
testdrive-chat/src/Chat.mxml
The compiler writes the Chat.swf file to the lcds-samples/testdrive-chat directory.
6 Start the samples database and LiveCycle Data Services as described in “Running the LiveCycle Data Services
sample applications” on page 12.
7 Request the application by using the URL http://localhost:8400/lcds-samples/testdrive-chat/index.html.
8 Verify that your new text appears in the TextArea control.
Rather than keep your source code in your deployment directory, you can set up a separate directory, and then copy
Chat.swf to lcds-samples/testdrive-chat to deploy it.
Loading LiveCycle Data Services client applications as sub-applications
You can load sub-applications that use RPC services, the Message Service, or the Data Management Service into a
parent client application. For general information about sub-applications, see Creating and loading sub-applications
in the Flex documentation.
To load LiveCycle Data Services sub-applications into a parent application when using Flash Player 10.1 or later, use
the SWFLoader control with its loadForCompatibility property to true. There is a single class table per security
domain; setting the loadForCompatibility property to true lets you avoid class registration conflicts between subapplications by ensuring that each application has its own class table and its own security domain.
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There is a bug in Flash Player versions prior to version 10.1 where applications in a single physical domain also run in
the same security domain and therefore only have one class table even when SWFLoader loadForCompatibility is
set to true. For this reason, Adobe recommends that you use Flash Player 10.1 or later if your application is loading
more than one sub-application that uses LiveCycle Data Services functionality.
If you must support Flash Player versions prior to version 10.1, there are a couple of workarounds to this issue. One
workaround is to use the SWFLoader control with the loadForCompatibility property set to true, but load each
sub-application from a different domain. You can accomplish this in a production system by using different
subdomains for each SWF file, such as app1.domain.com/mylcdsapp.swf and app2.domain.com/mylcdsapp.swf,
where each subdomain resolves to the same server or host. Because each sub-application is loaded from a different
physical domain, Flash Player gives it a separate security domain.
The other workaround is to use the ModuleLoader control to load the sub-applications or use the SWFLoader control
with the loadForCompatibility property set to false. In either case, in the parent application you define all data
services and RPC classes as well as any strongly typed objects that your application uses. The following example shows
this workaround with the SWFLoader control. FDSClasses and RPCClasses are the class definitions required for data
services and RPC classes.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" xmlns="*"
backgroundColor="#FFFFFF">
<mx:SWFLoader loadForCompatibility="false" id="s1"
source="SampleDataService.swf"/>
<mx:SWFLoader loadForCompatibility="false" id="s2"
source="SampleDataService2.swf"/>
<mx:Script>
<![CDATA[
FDSClasses;
RPCClasses;
]]>
</mx:Script>
</mx:Application>
Building your server-side application
You write the server-side part of a LiveCycle Data Services application in Java, and then use the javac compiler to
compile it.
Creating a simple Java class to return data to the client
A common reason to create a server-side Java class is to represent data returned to the client. For example, the clientside RemoteObject component lets you access the methods of server-side Java objects to return data to the client.
The Test Drive sample application contains the Accessing Data Using Remoting sample where the client-side code
uses the RemoteObject component to access product data on the server. The Product.java class represents that data.
After starting the LiveCycle Data Services server and the samples database, view this example by opening the following
URL in a browser: http://localhost:8400/lcds-samples/testdrive-remoteobject/index.html.
The source code for Product.java is in the install_root/lcds-samples/WEB-INF/src/flex/samples/product directory.
For example, if you installed LiveCycle Data Services with the integrated Tomcat server on Microsoft Windows, the
directory is install_root/tomcat/webapps/lcds-samples/WEB-INF/src/flex/samples/product.
Modify, compile, and deploy Product.java on the lcds-sample server
1 Start the samples database.
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2 Start LiveCycle Data Services.
3 View the running example by opening the following URL in a browser:
http://localhost:8400/lcds-samples/testdrive-remoteobject/index.html
4 Click the Get Data button to download data from the server. Notice that the description column contains product
descriptions.
5 In an editor, open the file install_root/tomcat/webapps/lcds-samples/WEB-
INF/src//flex/samples/product/Product.java. Modify this path as necessary for your installation.
6 Modify the following getDescription() method definition so that it always returns the String "My description"
rather than the value from the database:
public String getDescription() {
return description;
}
The modified method definition appears as the following:
public String getDescription() {
return "My description.";
}
7 Change the directory to lcds-samples.
8 Compile Product.java by using the following javac command line:
javac -d WEB-INF/classes/ WEB-INF/src/flex/samples/product/Product.java
This command creates the file Product.class, and deploys it to the WEB-INF/classes/flex/samples/product
directory.
9 View the running example by opening the following URL in a browser:
http://localhost:8400/lcds-samples/testdrive-remoteobject/index.html
10 Click the Get Data button.
Notice that the description column now contains the String "My description" for each product.
Creating a Java class that extends a LiveCycle Data Services class
As part of developing your server-side code, you can create a custom assembler class, factory class, or other type of Java
class that extends the LiveCycle Data Services Java class library. For example, a data adapter is responsible for updating
the persistent data store on the server in a manner appropriate to the specific data store type.
You perform many of the same steps to compile a Java class that extends the LiveCycle Data Services Java class library
as you do for compiling a simple class. The major difference is to ensure that you include the appropriate LiveCycle
Data Services JAR files in the classpath of your compilation so that the compiler can locate the appropriate files.
The Test Drive sample application contains the Data Management Service sample, in which the server-side code uses
a custom assembler represented by the ProductAssembler.java class. To view the sample, start the LiveCycle Data
Services server and the samples database. Then open the following URL in a browser: http://localhost:8400/lcdssamples/testdrive-dataservice/index.html.
The source code for ProductAssembler.java is in the directory install_root/lcds-samples/WEBINF/src/flex/samples/product. For example, if you installed LiveCycle Data Services with the integrated Tomcat server
on Microsoft Windows, the directory is install_root/tomcat/webapps/lcds-samples/WEBINF/src/flex/samples/product.
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Compile and deploy ProductAssembler.java on the lcds-sample server
1 View the running example by opening the following URL in a browser:
http://localhost:8400/lcds-samples/testdrive-dataservice/index.html
2 Click the Get Data button to download data from the server.
3 In an editor, open the file install_root/tomcat/webapps/lcds-samples/WEB-
INF/src/flex/samples/product/ProductAssembler.java. Modify this path as necessary for your installation.
For more information on assemblers, see “Standard assemblers” on page 268.
4 Change the directory to install_root/tomcat/webapps/lcds-samples/WEB-INF/src.
5 Compile ProductAssembler.java by using the following javac command line:
javac
-sourcepath .
-d ..\classes
-classpath ..\lib\flex-messaging-common.jar;
..\lib\flex-messaging-core.jar;
..\lib\flex-messaging-data-req.jar;
..\lib\flex-messaging-data.jar;
..\lib\flex-messaging-opt.jar;
..\lib\flex-messaging-proxy.jar;
..\lib\flex-messaging-remoting.jar
flex\samples\product\ProductAssembler.java
Notice that the classpath contains many, but not all, of the JAR files in WEB-INF/lib. If you are compiling other
types of classes, you include additional JAR files in the classpath. These JAR files are also shipped in the
install_root/resources/lib directory.
This command creates the file ProductAssembler.class, and deploys it to the WEBINF/classes/flex/samples/product directory.
6 View the running example by opening the following URL in a browser:
http://localhost:8400/lcds-samples/testdrive-dataservice/index.html
7 Click the Get Data button to make sure that your code is working correctly.
Creating a combined Java and Flex project in Eclipse
If you use Eclipse for Java development, you can develop Java code in the same Eclipse project in which you develop
Flex client code. You toggle between the Java and Flash perspectives to work on Java or Flex code. This procedure
describes how to create a combined project. Another alternative is to use separate Eclipse projects for Java and Flex
development.
Note: To create a combined Java and Flex project, use a plug-in configuration of Flash Builder. You must have the Eclipse
Java perspective available in your installation.
1 Create a Java project in Eclipse.
2 When you create a Java project, you can optionally set the output location to be a linked directory in your LiveCycle
Data Services web application. For example, you can save compiled POJO classes to the WEB-INF/classes directory
of your web application.
Complete these steps to set the output location to a linked directory:
a When configuringa project in the New Java Project dialog, select the Allow Output Folders For Source Folders
option.
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b Click Browse to the right of the Default Output Folder field.
c Select the project directory in the Folder Selection dialog.
d Click Create New Folder.
e Select Advanced > Link To Folder In File System.
f
Browse to the directory where you want to save output and click OK.
g Click OK on the New Folder dialog.
h Click OK on the Folder Selection dialog.
i
Click Finish on the New Java Project dialog.
Similarly, if you plan to export your output to a JAR file, you can save the JAR file to the WEB-INF/lib directory of
your LiveCycle Data Services web application.
3 In the Package Explorer, right-click your new Java project and select Add/Change Project Type > Add Flex Project.
4 Set up your Flex project as described in “Using Flash Builder to compile client-side code” on page 15.
Debugging your application
If you encounter errors in your applications, you can use the debugging tools to perform the following:
• Set and manage breakpoints in your code
• Control application execution by suspending, resuming, and terminating the application
• Step into and over the code statements
• Select critical variables to watch
• Evaluate watch expressions while the application is running
Debugging Flex applications can be as simple as enabling trace() statements or as complex as stepping into a
source files and running the code, one line at a time. The Flash Builder debugger and the command line debugger,
fdb, let you step through and debug ActionScript files used by your Flex applications. For information on how to
use the Flash Builder debugger, see Using Adobe Flash Builder 4. For more information on the command line
debugger, fdb, see the Flex documentation set.
Using Flash Debug Player
To use the fdb command line debugger or the Flash Builder debugger, install and configure Flash Debug Player. To
determine whether you are running the Flash Debug Player or the standard version of Flash Player, open any Flex
application in Flash Player and right-click. If you see the Show Redraw Regions option, you are running Flash Debug
Player. For more information about installing Flash Debug Player, see the LiveCycle Data Services installation
instructions.
Flash Debug Player comes in ActiveX, Plug-in, and stand-alone versions for Microsoft Internet Explorer, Netscapebased browsers, and desktop applications. You can find Flash Debug Player installers in the following locations:
• Flash Builder: install_dir/Player/os_version
• Flex SDK: install_dir/runtimes/player/os_version/
Like the standard version of Adobe Flash Player 9, Flash Debug Player runs SWF files in a browser or on the desktop
in a stand-alone player. Unlike Flash Player, the Flash Debug Player enables you to do the following:
• Output statements and application errors to the local log file of Flash Debug Player by using the trace() method.
• Write data services log messages to the local log file of Flash Debug Player.
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• View run-time errors (RTEs).
• Use the fdb command line debugger.
• Use the Flash Builder debugging tool.
• Use the Flash Builder profiling tool.
Note: ADL logs trace() output from AIR applications.
Using logging to debug your application
One tool that can help in debugging is the logging mechanism. You can perform server-side and client-side logging of
requests and responses.
Client-side logging
For client-side logging, you directly write messages to the log file, or configure the application to write messages
generated by ­Flex to the log file. Flash Debug Player has two primary methods of writing messages to a log file:
• The global trace() method. The global trace() method prints a String to the log file. Messages can contain
checkpoint information to signal that your application reached a specific line of code, or the value of a variable.
• Logging API. The logging API, implemented by the TraceTarget class, provides a layer of functionality on top of
the trace() method. For example, you can use the logging API to log debug, error, and warning messages
generated by Flex while applications execute.
Flash Debug Player sends logging information to the flashlog.txt file. The operating system determines the location of
this file, as the following table shows:
Operating system
Location of log file
Windows 95/98/ME/2000/XP
C:/Documents and Settings/username/Application
Data/Macromedia/Flash Player/Logs
Windows Vista
C:/Users/username/AppData/Roaming/Macromedia/Flash
Player/Logs
Mac OS X
/Users/username/Library/Preferences/Macromedia/Flash
Player/Logs/
Linux
/home/username/.macromedia/Flash_Player/Logs/
Use settings in the mm.cfg text file to configure Flash Debug Player for logging. If this file does not exist, you can create
it when you first configure Flash Debug Player. The location of this file depends on your operating system. The
following table shows where to create the mm.cfg file for several operating systems:
Operating system
Location of mm.cfg file
Mac OS X
/Library/Application Support/Macromedia
Windows 95/98/ME
%HOMEDRIVE%/%HOMEPATH%
Windows 2000/XP
C:/Documents and Settings/username
Windows Vista
C:/Users/username
Linux
/home/username
The mm.cfg file contains many settings that you can use to control logging. The following sample mm.cfg file enables
error reporting and trace logging:
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ErrorReportingEnable=1
TraceOutputFileEnable=1
After you enable reporting and logging, call the trace() method to write a String to the flashlog.txt file, as the
following example shows:
trace("Got to checkpoint 1.");
Insert the following MXML line to enable the logging of all Flex-generated debug messages to flashlog.txt:
<mx:TraceTarget loglevel="2"/>
For information about client-side logging, see the Flex documentation set.
Server-side logging
You configure server-side logging in the logging section of the services configuration file, services-config.xml. By
default, output is sent to System.out.
You set the logging level to one of the following available levels:
•
All
•
Debug
•
Info
•
Warn
•
Error
•
None
You typically set the server-side logging level to Debug to log all debug messages, and also all info, warning, and error
messages. The following example shows a logging configuration that uses the Debug logging level:
<logging>
<!-- You may also use flex.messaging.log.ServletLogTarget. -->
<target class="flex.messaging.log.ConsoleTarget" level="Debug">
<properties>
<prefix>[Flex]</prefix>
<includeDate>false</includeDate>
<includeTime>false</includeTime>
<includeLevel>false</includeLevel>
<includeCategory>false</includeCategory>
</properties>
<filters>
<pattern>Endpoint</pattern>
<!--<pattern>Service.*</pattern>-->
<!--<pattern>Message.*</pattern>-->
</filters>
</target>
</logging>
For more information, see “Logging” on page 420.
Measuring application performance
As part of preparing your application for final deployment, you can test its performance to look for ways to optimize
it. One place to examine performance is in the message processing part of the application. To help you gather this
performance information, enable the gathering of message timing and sizing data.
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The mechanism for measuring the performance of message processing is disabled by default. When enabled,
information regarding message size, server processing time, and network travel time is captured. This information is
available to the client that pushed a message to the server, to a client that received a pushed message from the server,
or to a client that received an acknowledge message from the server in response a pushed message. A subset of this
information is also available for access on the server.
You can use this mechanism across all channel types, including polling and streaming channels, that communicate
with the server. However, this mechanism does not work when you make a direct connection to an external server by
setting the useProxy property to false for the HTTPService and WebService tags because it bypasses the LiveCycle
Data Services Proxy Server.
You use two parameters in a channel definition to enable message processing metrics:
•
<record-message-times>
•
<record-message-sizes>
Set these parameters to true or false; the default value is false. You can set the parameters to different values to
capture only one type of metric. For example, the following channel definition specifies to capture message timing
information, but not message sizing information:
<channel-definition id="my-streaming-amf"
class="mx.messaging.channels.StreamingAMFChannel">
<endpoint
url="http://{server.name}:{server.port}/{context.root}/messagebroker/streamingamf"
class="flex.messaging.endpoints.StreamingAMFEndpoint"/>
<properties>
<record-message-times>true</record-message-times>
<record-message-sizes>false</record-message-sizes>
</properties>
</channel-definition>
For more information, see “Measuring message processing performance” on page 121.
Deploying your application
Your production environment determines how you deploy your application. One option is to package your
application and assets in a LiveCycle Data Services web application, and then create a single WAR file that contains
the entire web application. You can then deploy the single WAR file on your production server.
Alternatively, you can deploy multiple LiveCycle Data Services applications on a single web application. In this case,
your production server has an expanded LiveCycle Data Services web application to which you add the directories that
are required to run your new application.
When you deploy your LiveCycle Data Services application in a production environment, ensure that you deploy all
the necessary parts of the application, including the following:
• The compiled SWF file that contains your client-side application
• The HTML wrapper generated by Flash Builder or created manually if you use the mxmlc compiler
• The compiled Java class and JAR files that represent your server-side application
• Any run-time assets required by your application
• A LiveCycle Data Services web application
• Updated LiveCycle Data Services configuration files that contain the necessary information to support your
application
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Chapter 2: System architecture
Client and server architecture
A LiveCycle Data Services application consists of a client application running in a web browser or Adobe AIR and a
J2EE web application on the server that the client application communicates with. The client application can be a Flex
application or it can be a combination of Flex, HTML, and JavaScript. When you use JavaScript, communication with
the LiveCycle Data Services server is accomplished using the JavaScript proxy objects provided in the Ajax Client
Library. For information about the Ajax Client Library, see “The Ajax client library” on page 460.
LiveCycle Data Services client architecture
LiveCycle Data Services clients use a message-based framework provided by LiveCycle Data Services to interact with
the server. On the client side of the message-based framework are channels that encapsulate the connection behavior
between the Flex client and the LiveCycle Data Services server. Channels are grouped together into channel sets that
are responsible for channel hunting and channel failover. For information about client class APIs, see the Adobe
LiveCycle ActionScript Reference.
The following illustration shows the LiveCycle Data Services client architecture:
LiveCycle Data Services ES Client Architecture
Flex Client
Web Server
SWF from MXML
J2EE Server
User Interface using Flex SDK
LiveCycle Data Services ES components
RemoteObject component
HTTPService/WebService components
Producer/Consumer components
HTTP/RTMP protocol
DataService component
LiveCycle Data
Services ES
AMF/AMFX encoding
Channel Set
AMFChannel
HTTPChannel
RTMPChannel
Flex components
The following Flex components interact with a LiveCycle Data Services server:
• RemoteObject
• HTTPService
• WebService
• Producer
• Consumer
• DataService
All of these components, except for the DataService component, are included in the Flex SDK in the rpc.swc
component library. The DataService component is included in the fds.swc component library provided in the
LiveCycle Data Services installation.
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Although the RemoteObject, Producer, and Consumer components are included with the Flex SDK, they require a
server that can interpret the messages that they send. The BlazeDS and LiveCycle Data Services servers are two
examples of such servers. A Flex application can also make direct HTTP service or web service calls to remote servers
without LiveCycle Data Services in the middle tier. However, going through the LiveCycle Data Services Proxy Service
is beneficial for several reasons; for more information, see “Using RPC services” on page 135.
Client-side components communicate with services on the LiveCycle Data Services server by sending and receiving
messages of the correct type. For more information about messages, see “Messages” on page 28.
Channels and channel sets
A Flex component uses a channel to communicate with a LiveCycle Data Services server. A channel set contains
channels; its primary function is to provide connectivity between the Flex client and the LiveCycle Data Services server.
A channel set contains channels ordered by preference. The Flex component tries to connect to the first channel in the
channel set and in the case where a connection cannot be established falls back to the next channel in the list. The Flex
component continues to go through the list of channels in the order in which they are specified until a connection can
be established over one of the channels or the list of channels is exhausted.
Channels encapsulate the connection behavior between the Flex components and the LiveCycle Data Services server.
Conceptually, channels are a level below the Flex components and they handle the communication between the Flex
client and the LiveCycle Data Services server. They communicate with their corresponding endpoints on the LiveCycle
Data Services server; for more information about endpoints, see “Endpoints” on page 29.
Flex clients can use several different channel types, such as the AMFChannel, HTTPChannel, and RTMPChannel.
Channel selection depends on a number of factors, including the type of application you are building. For example, if
HTTP is the only protocol allowed in your environment, you would use the AMFChannel or HTTPChannel; you
would not use the RTMPChannel, which uses the RTMP protocol. If non-binary data transfer is required, you would
use the HTTPChannel, which uses a non-binary format called AMFX (AMF in XML). For more information about
channels, see “Channels and endpoints” on page 38.
Messages
All communication between Flex client components and LiveCycle Data Services is performed with messages. Flex
components use several message types to communicate with their corresponding services in LiveCycle Data Services.
All messages have client-side (ActionScript) implementations and server-side (Java) implementations because the
messages are serialized and deserialized on both the client and the server. You can also create messages directly in Java
and have those messages delivered to clients using the server push API.
Some message types, such as AcknowledgeMessage and CommandMessage, are used across different Flex components
and LiveCycle Data Services services. For example, to have a Producer component send a message to subscribed
Consumer components, you create a message of type AsyncMessage and pass it to the send() method of the Producer
component.
In other situations, you do not write code for constructing and sending messages. For example, you simply use a
RemoteObject component to call the remote method from the Flex application. The RemoteObject component creates
a RemotingMessage to encapsulate the RemoteObject call. In response it receives an AcknowledgeMessage from the
server. The AcknowledgeMessage is encapsulated in a ResultEvent in the Flex application.
Sometimes you must create a message to send to the server. For example, you could send a message by creating an
AsyncMessage and passing it to a Producer.
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LiveCycle Data Services uses two patterns for sending and receiving messages: the request/reply pattern and the
publish/subscribe pattern. RemoteObject, HTTPService, and WebService components use the request/reply message
pattern, in which the Flex component makes a request and receives a reply to that request. Producer and Consumer
components use the publish/subscribe message pattern. In this pattern, the Producer publishes a message to a
destination defined on the LiveCycle Data Services server. All Consumers subscribed to that destination receive the
message.
LiveCycle Data Services server architecture
The LiveCycle Data Services server is a combination of a J2EE web application and a highly scalable network socket
server. A Flex client makes a request over a channel and the request is routed to an endpoint on the LiveCycle Data
Services server. From the endpoint, the request is routed through a chain of Java objects that includes the
MessageBroker object, a service object, a destination object, and finally an adapter object. The adapter fulfills the
request either locally, or by contacting a backend system or a remote server such as Java Message Service (JMS) server.
The following illustration shows the LiveCycle Data Services server architecture:
LiveCycle Data Services Server Architecture
MessageBrokerServlet
Servlet-based endpoints
Message
Broker
Service
Destination
RemotingService
RemotingDestination
Adapter
AMFEndpoint
JavaAdapter
HTTPEndpoint
HTTPProxyService
HTTPProxyDestination
StreamingAMFEndpoint
HTTPProxyAdapter
...
SOAPAdapter
MessageService
Flex client
MessageDestination
ActionScriptAdapter
Socket server
JMSAdapter
NIO-based endpoints
NIOAMFEndpoint
NIOHTTPEndpoint
RTMPEndpoint
DataService
DataDestination
ActionScriptObjectAdapter
JavaAdapter
...
Hibernate Assembler
SQLAssembler
Endpoints
LiveCycle Data Services has two types of endpoints: servlet-based endpoints and NIO-based endpoints.
Note: NIO-based endpoints are not available in BlazeDS.
NIO stands for Java New Input/Output. Servlet-based endpoints are inside the J2EE servlet container, which means
that the servlet handles the I/O and HTTP sessions for the endpoints. Servlet-based endpoints are bootstrapped by the
MessageBrokerServlet, which is configured in the web.xml file of the web application. In addition to the
MessageBrokerServlet, an HTTP session listener is registered with the J2EE server in the web application’s web.xml
file so that LiveCycle Data Services has HTTP session attribute and binding listener support.
NIO-based endpoints run in an NIO-based socket server. These endpoints can offer significant scalability gains
because they are not limited to one thread per connection and a single thread can manage multiple I/Os.
Flex client applications use channels to communicate with LiveCycle Data Services endpoints. There is a mapping
between the channels on the client and the endpoints on the server. It is important that the channel and the endpoint
use the same message format. A channel that uses the AMF message format, such as the AMFChannel, must be paired
with an endpoint that also uses the AMF message format, such as the AMFEndpoint or the NIOAMFEndpoint. A
channel that uses the AMFX message format such as the HTTPChannel cannot be paired with an endpoint that uses
the AMF message format. Also, a channel that uses streaming must be paired with an endpoint that uses streaming.
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You configure endpoints in the services-config.xml file in the WEB-INF/flex directory of your LiveCycle Data Services
web application. For more information on servlet-based and NIO-based endpoints, see “Channels and endpoints” on
page 38.
MessageBroker
The MessageBroker is responsible for routing messages to services and is at the core of f LiveCycle Data Services on
the server. After an endpoint initially processes the request, it extracts the message from the request and passes it to
the MessageBroker. The MessageBroker inspects the message's destination and passes the message to its intended
service. If the destination is protected by a security constraint, the MessageBroker runs the authentication and
authorization checks before passing the message along (see “Configuring security” on page 432). You configure the
MessageBroker in the services-config.xml file in he WEB-INF/flex directory of your LiveCycle Data Services web
application.
Services and destinations
Services and destinations are the next links in the message processing chain in the LiveCycle Data Services server. The
system includes four services and their corresponding destinations:
• RemotingService and RemotingDestination
• HTTPProxyService and HTTPProxyDestination
• MessageService and MessageDestination
• DataService and DataDestination
Note: DataService and DataDestination are not available in BlazeDS.
Services are the targets of messages from client-side Flex components. Think of destinations as instances of a service
configured in a certain way. For example, a RemoteObject component is used on the Flex client to communicate with
the RemotingService. In the RemoteObject component, you must specify a destination id property that refers to a
remoting destination with certain properties, such as the class you want to invoke methods on. The mapping between
client-side Flex components and LiveCycle Data Services services is as follows:
• HTTPService and WebService communicate with HTTPProxyService/HTTPProxyDestination
• RemoteObject communicates with RemotingService/RemotingDestination
• Producer and Consumer communicate with MessageService/MessageDestination
• DataService communicates with DataService/DataDestination
You can configure services and their destinations in the services-config.xml file, but it is best practice to put them in
separate files as follows:
• RemotingService configured in the remoting-config.xml file
• HTTPProxyService configured in the proxy-config.xml file
• MessageService configured in the messaging-config.xml file
• DataService configured in the data-management-config.xml file
More Help topics
“Using RPC services” on page 135
“Using the Message Service” on page 190
“Introducing the Data Management Service” on page 221
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Adapters and assemblers
Adapters, and optionally assemblers, are the last link in the message processing chain. When a message arrives at the
correct destination, it is passed to an adapter that fulfills the request either locally or by contacting a backend system
or a remote server such as a JMS server. Some adapters use yet another layer, called assemblers, to further break down
the processing. For example, a DataDestination can use JavaAdapter, and JavaAdapter could use HibernateAssembler
to communicate with Hibernate. LiveCycle Data Services uses the following mappings between destinations and
adapters/assemblers:
• RemotingDestination uses JavaAdapter
• HTTPProxyDestination uses HTTPProxyAdapter or SOAPAdapter
• MessageDestination uses ActionScriptAdapter or JMSAdapter
• DataDestination uses ASObjectAdapter or JavaAdapter
• JavaAdapter uses HibernateAssembler, SQLAssembler, or a custom assembler
Adapters and assemblers are configured along with their corresponding destinations in the same configuration files.
Although the LiveCycle Data Services server comes with a rich set of adapters and assemblers to communicate with
different systems, custom adapters and assemblers can be plugged into the server. Similarly, you do not have to create
all destinations in configuration files, but instead you can create them dynamically at server startup or when the server
is running; for more information, see “Run-time configuration” on page 411.
For information about the LiveCycle Data Services server-side classes, see the Javadoc API documentation.
About configuration files
You configure LiveCycle Data Services in the services-config.xml file. The default location of this file is the WEBINF/flex directory of your LiveCycle Data Services web application. You can set this location in the configuration for
the MessageBrokerServlet in the WEB-INF/web.xml file.
You can include files that contain service definitions by reference in the services-config.xml file. Your LiveCycle Data
Services installation includes the Remoting Service, Proxy Service, Message Service, and Data Management Service by
reference.
The following table describes the typical setup of the configuration files. Commented versions of these files are
available in the resources/config directory of the LiveCycle Data Services installation.
Filename
Description
services-config.xml
The top-level LiveCycle Data Services configuration file. This file usually contains
security constraint definitions, channel definitions, and logging settings that each
of the services can use. It can contain service definitions inline or include them by
reference. Generally, the services are defined in the remoting-config.xml, proxyconfig.xml, messaging-config.xml, and data-management-config.xml files.
remoting-config.xml
The Remoting Service configuration file, which defines Remoting Service
destinations for working with remote objects.
For information about configuring the Remoting Service, see “Using RPC services”
on page 135.
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Filename
Description
proxy-config.xml
The Proxy Service configuration file, which defines Proxy Service destinations for
working with web services and HTTP services (REST services).
For information about configuring the Proxy Service, see “Using RPC services” on
page 135.
messaging-config.xml
The Message Service configuration file, which defines Message Service
destinations for performing publish subscribe messaging.
For information about configuring the Message Service, see “Using the Message
Service” on page 190.
data-management-config.xml
The Data Management Service configuration file, which defines Data
Management Service destinations.
For information about configuring the Data Management Service, see “Data
Management Service configuration” on page 244.
When you include a file by reference, the content of the referenced file must conform to the appropriate XML structure
for the service. The file-path value is relative to the location of the services-config.xml file. The following example
shows service definitions included by reference:
<services>
<!-- REMOTING SERVICE -->
<service-include file-path="remoting-config.xml"/>
<!-- PROXY SERVICE -->
<service-include file-path="proxy-config.xml"/>
<!-- MESSAGE SERVICE -->
<service-include file-path="messaging-config.xml"/>
<!-- DATA MANAGEMENT SERVICE -->
<service-include file-path="data-management-config.xml"/>
</services>
Configuration tokens
The configuration files sometimes contain special {server.name} and {server.port} tokens. These tokens are
replaced with server name and port values based on the URL from which the SWF file is served when it is accessed
through a web browser from a web server. Similarly, a special {context.root} token is replaced with the actual
context root of a web application.
Note: If you use server tokens in a configuration file for an Adobe AIR application and you compile using that file, the
application will not be able to connect to the server. You can avoid this issue by configuring channels in ActionScript
rather than in a configuration file (see “Channels and endpoints” on page 38).
You can also use custom run-time tokens in service configuration files; for example, {messaging-channel} and
{my.token}. You specify values for these tokens in Java Virtual Machine (JVM) options. The server reads these JVM
options to determine what values are defined for them, and replaces the tokens with the specified values. If you have a
custom token for which a value cannot be found, an error is thrown. Because {server.name}, {server.port}, and
{context.root} are special tokens, no errors occur when these tokens are not specified in JVM options.
How you define JVM options depends on the application server you use. For example, in Apache Tomcat, you can
define an environment variable JAVA_OPTS that contains tokens and their values, as this code snippet shows:
JAVA_OPTS=-Dmessaging.channel=my-amf -Dmy.token=myValue
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Configuration elements
The following table describes the XML elements of the services-config.xml file. The root element is the servicesconfig element.
XML
element
Description
services
Contains definitions of individual data services or references to
other XML files that contain service definitions. It is a best practice
to use a separate configuration file for each type of standard service.
These services include the Proxy Service, Remoting Service,
Message Service, and Data Management Service.
The services element is declared at the top level of the
configuration as a child of the root element, services-config.
For information about configuring specific types of services, see the
following topics:
•
“Using RPC services” on page 135
•
“Using the Message Service” on page 190
•
“Data Management Service configuration” on page 244
Sets the application-level default channels to use for all services. The
default channels are used when a channel is not explicitly
referenced in a destination definition. The channels are tried in the
order in which they are included in the file. When one is unavailable,
the next is tried.
defaultchannels
Default channels can also be defined individually for each service, in
which case the application-level default channels are overwritten
by the service level default channels. Application-level default
channels are necessary when a dynamic component is created
using the run-time configuration feature and no channel set has
been defined for the component. In that case, application-level
default channels are used to contact the destination.
For more information about channels and endpoints, see “Channels
and endpoints” on page 38.
Specifies the full path to an XML file that contains the configuration
elements for a service definition.
serviceinclude
Attributes:
•
file-path Path to the XML file that contains a service definition.
Contains a service definition.
service
(Optional) You can use the service-include element to include
a file that contains a service definition by reference instead of inline
in the services-config.xml file.
In addition to standard data services, you can define custom
bootstrap services here for use with the run-time configuration
feature; bootstrap services dynamically create services,
destinations, and adapters at server startup. For more information,
see “Run-time configuration” on page 411.
properties Contains service properties.
adapters
Contains service adapter definitions that are referenced in a
destination to provide specific types of functionality.
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XML
element
Description
adapter-definition
Contains a service adapter definition. Each type of service has its
own set of adapters that are relevant to that type of service. For
example, Data Management Service destinations can use the Java
adapter or the ActionScript object adapter. An adapterdefinition has the following attributes:
defaultchannels
•
id Identifier of an adapter, which you use to reference the
adapter inside a destination definition.
•
class Fully qualified name of the Java class that provides the
adapter functionality.
•
default Boolean value that indicates whether this adapter is the
default adapter for service destinations. The default adapter is
used when you do not explicitly reference an adapter in a
destination definition.
Contains references to default channels. The default channels are
used when a channel is not explicitly referenced in a destination
definition. The channels are tried in the order in which they are
included in the file. When one is unavailable, the next is tried.
channel
Contains a reference to the id of a channel definition. A channel
element contains the following attribute:
•
ref The id value of a channel definition
For more information about channels and endpoints, see “Channels
and endpoints” on page 38.
destinatio Contains a destination definition.
n
adapter
Contains a reference to a service adapter. If this element is omitted,
the destination uses the default adapter.
properties
Contains destination properties.
The properties available depend on the type of service, which the
specified service class determines.
channels
Contains references to the channels that the service can use for data
transport. The channels are tried in the order in which they are
included in the file. When one is unavailable, the next is tried.
The channel child element contains references to the id value of a
channel. Channels are defined in the channels element at the top
level of the configuration as a child of the root element, servicesconfig.
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XML
element
Description
security
Contains a reference to a security constraint definition and login
command definitions that are used for authentication and
authorization.
This element can also contain complete security constraint
definitions instead of references to security constraints that are
defined globally in the top-level security element.
For more information, see “Security” on page 429.
The security-constraint child element contains references to
the id value of a security constraint definition or contains a security
constraint definition.
Attributes:
•
ref The id value of a security-constraint element defined
in the security element at the top level of the services
configuration.
•
id Identifier of a security constraint when you define the actual
security constraint in this element.
The login-command child element contains a reference to the id
value of a login command definition that is used for performing
authentication.
Attributes:
•
ref The id value of a login command definition.
Contains security constraint definitions and login command
definitions for authentication and authorization.
security
For more information, see “Security” on page 429.
channels
securityconstraint
Defines a security constraint.
logincommand
Defines a login command that is used for custom authentication.
Attributes:
•
class Fully qualified class name of a login command class.
•
server Application server on which custom authentication is
performed.
•
per-client-authentication You can only set this attribute
to true for a custom login command and not an appicationserver-based login command. Setting it to true allows multiple
clients sharing the same session to have distinct authentication
states. For example, two windows of the same web browser could
authenticate users independently. This attribute is set to false
by default.
Contains the definitions of message channels that are used to
transport data between the server and clients.
For more information about channels and endpoints, see “Channels
and endpoints” on page 38.
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XML
element
Description
Defines a message channel that can be used to transport data.
channeldefinition
Attributes:
endpoint
•
id Identifier of the channel definition.
•
class Fully qualified class name of a channel class.
Specifies the endpoint URI and the endpoint class of the channel
definition.
Attributes:
•
•
uri Endpoint URI
class Fully qualified name of the channel class used on the
client.
properties Contains the properties of a channel definition. The properties
available depend on the type of channel specified.
Contains cluster definitions, which configure software clustering
across multiple hosts.
clusters
For more information, see “Clustering” on page 442.
flexclient
reliablereconnectdurationmillis
Idle timeout for FlexClient state at the server, including reliable
messaging sequences. To support reliable reconnects consistently
across all supported channels and endpoints, this value must be
defined and greater than 0.
Any active sessions/connections keep idle FlexClient instances
alive. This timeout only applies to instances that have no currently
active associated sessions/connections.
heartbeatintervalmillis
Optional setting that controls whether the client application issues
periodic heartbeat requests to the server to keep an idle connection
alive and to detect loss of connectivity. Use this setting to keep
sessions alive.
The default value of 0 disables this functionality. If the application
sets this value, it should use a longer rather than shorter interval to
avoid placing unnecessary load on the remote host.
As an illustrative example, low-level TCP socket keep-alives
generally default to an interval of 2 hours. That is a longer interval
than most applications that enable heartbeats would likely want to
use, but it serves as a clear precedent to prefer a longer interval over
a shorter interval.
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XML
element
Description
Each Flex application that connects to the server triggers the
creation of a FlexClient instance that represents the remote client
application. I the value of the timeout-minutes element is left
undefined or set to 0 (zero), FlexClient instances on the server are
shut down when all associated FlexSessions (corresponding to
connections between the client and server) are shut down. If this
value is defined, FlexClient instances are kept alive for this amount
of idle time.
timeoutminutes
FlexClient instances that have an associated RTMP
connection/session open, are kept alive even if they are idle
because the open connection indicates the remote client
application is still running.
For HTTP connections/sessions, if the remote client application is
polling, the FlexClient is kept alive.
If the remote client is not polling and a FlexClient instance is idle for
this amount of time. it is shut down even if an associated
HttpSession is still valid. This is because multiple Flex client
applications can share a single HttpSession. A valid HttpSession
does not indicate that a specific client application instance is still
running.
Contains server-side logging configuration. For more information,
see “Logging” on page 420.
logging
Specifies the logging target class and the logging level.
target
Attributes:
•
class Fully qualified logging target class name.
•
level The logging level.
System-wide settings that do not fall into a previous category. In
addition to locale information, it also contains redeployment and
watch file settings.
system
enforceendpointvalidation
(Optional) Default value is false. When a destination is accessed
over a channel, the message broker validates that the destination
accepts requests over that channel. However, the client can disable
this validation if the client has a null id value for its channel. When
this setting is true, the message broker performs the endpoint
validation even if the client channel has a null id value.
locale
(Optional) Locale string; for example, "en", "de", "fr", and "es"
are valid locale strings.
defaultlocale
The default locale string.
If no default-locale element is provided, a base set of English
error messages is used.
Support for web application redeployment when configuration files
are updated. This feature works with J2EE application server web
application redeployment.
redeploy
The touch-file value is the file used by your application server to
force web redeployment.
Check the application server to confirm what the touch-file
value should be.
enabled
Boolean value that indicates whether redeployment is enabled.
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XML
element
Description
watchinterval
Number of seconds to wait before checking for changes to
configuration files.
watch-file A data services configuration file watched for changes. The watchfile value must start with {context.root} or be an absolute
path. The following example uses {context.root}:
{context.root}/WEB-INF/flex/data-managementconfig.xml
touch-file The file that the application server uses to force redeployment of a
web application. The value of the touch-file element must start
with {context.root} or be an absolute path. Check the
application server documentation to determine the touch-file
value. For Tomcat, the touch-file value is the web.xml file, as the
following example shows:
{context.root}/WEB-INF/web.xml
Channels and endpoints
Channels are the client-side representation of the connection to a service, while endpoints are the server-side
representation.
About channels and endpoints
Channels are client-side objects that encapsulate the connection behavior between Flex components and the LiveCycle
Data Services server or the Edge Server. Channels communicate with corresponding endpoints on the LiveCycle Data
Services server. You configure the properties of a channel and its corresponding endpoint in the services-config.xml
file.
For more information on the Edge Server, see “Edge Server” on page 391.
How channels are assigned to a Flex component
Flex components use channel sets, which contain one or more channels, to contact the server. You can automatically
or manually create and assign a channel set to a Flex component. The channel allows the component to contact the
endpoint, which forwards the request to the destination.
If you compile an MXML file using the MXML compiler option -services pointing to the services-config.xml file,
the component (RemoteObject, HTTPService, and so on) is automatically assigned a channel set that contains one or
more appropriately configured channel instances. The configuration is based on the channel definition assigned to a
destination in a configuration file. Alternatively, if you do not compile your application with the -services option
or want to override the compiled-in behavior, you can create a channel set in MXML or ActionScript, populate it with
one or more channels, and then assign the channel set to the Flex component.
Application-level default channels are especially important when you want to use dynamically created destinations
and you do not want to create and assign channel sets to your Flex components that use the dynamic destination. In
that case, application-level default channels are used. For more information, see “Assigning channels and endpoints
to a destination” on page 42.
When you compile a Flex client application with the MXML compiler-services option, it contains all of the
information from the configuration files that is needed for the client to connect to the server.
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Configuring channels and endpoints
You can configure channels in channel definitions in the services-config.xml file or on the Flex client.
Configuring channels on the server
The channel definition in the following services-config.xml file snippet creates an AMFChannel that communicates
with an AMFEndpoint on the server:
<channels>
...
<channel-definition id="samples-amf"
type="mx.messaging.channels.AMFChannel">
<endpoint url="http://servername:8400/myapp/messagebroker/amf" port="8700"
type="flex.messaging.endpoints.AMFEndpoint"/>
</channel-definition>
</channels>
The channel-definition element specifies the following information:
•
id and channel class type of the client-side channel that the Flex client uses to contact the server
•
remote attribute that specifies that the endpoint as remote. In that case, the endpoint is not started on this server
and it is assumed that the client will connect to a remote endpoint on another server. This is useful when the client
is compiled against this configuration but some of the endpoints are on a remote server.
•
endpoint element that contains the URL and endpoint class type of the server-side endpoint
•
properties element that contains channel and endpoint properties
•
server element, which when using an NIO-based channel and endpoint optionally refers to a shared NIO server
configuration
The endpoint URL is the specific network location that the endpoint is exposed at. The channel uses this value to
connect to the endpoint and interact with it. The URL must be unique across all endpoints exposed by the server. The
url attribute can point to the MessageBrokerServlet or an NIO server if you are using an NIO-based endpoint.
Configuring channels on the client
To create channels at runtime in Flex code, you create your own channel set in MXML or ActionScript, add channels
to it, and then assign the channel set to a component. This process is common in the following situations:
• You do not compile your MXML file using the -services MXML compiler option. This is useful when you do not
want to hard code endpoint URLs into your compiled SWF files on the client. It is also useful when you want to use
a remote server when developing an application in Flash Builder.
• You want to use a dynamically created destination (the destination is not in the services-config.xml file) with the
run-time configuration feature. For more information, see “Run-time configuration” on page 411.
• You want to control in your client code the order of channels that a Flex component uses to connect to the server.
When you create and assign a channel set on the client, the client requires the correct channel type and endpoint URL
to contact the server. The client does not specify the endpoint class that handles that request, but there must be a channel
definition in the services-config.xml file that specifies the endpoint class to use with the specified endpoint URL.
The following example shows a RemoteObject component that defines a channel set and channel inline in MXML:
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...
<RemoteObject id="ro" destination="Dest">
<mx:channelSet>
<mx:ChannelSet>
<mx:channels>
<mx:AMFChannel id="myAmf"
uri="http://myserver:2000/myapp/messagebroker/amf"/>
</mx:channels>
</mx:ChannelSet>
</mx:channelSet>
</RemoteObject>
...
The following example shows ActionScript code that is equivalent to the MXML code in the previous example:
...
private function run():void {
ro = new RemoteObject();
var cs:ChannelSet = new ChannelSet();
cs.addChannel(new AMFChannel("myAmf",
"http://myserver:2000/eqa/messagebroker/amf"));
ro.destination = "Dest";
ro.channelSet = cs;
}
...
Important: When you create a channel on the client, you still must include a channel definition that specifies an endpoint
class in the services-config.xml file. Otherwise, the message broker cannot pass a Flex client request to an endpoint.
To further externalize configuration, you can pass the endpoint URL value to the client at runtime. One way to do this
is by reading a configuration file with an HTTPService component at application startup. The configuration file
includes the information to programmatically create a channel set at runtime. You can use E4X syntax to get
information from the configuration file.
The following MXML application shows this configuration file technique:
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<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
applicationComplete="configSrv.send()">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.messaging.channels.AMFChannel;
import mx.messaging.ChannelSet;
import mx.rpc.events.ResultEvent;
private var channelSet:ChannelSet;
private function configResultHandler(event:ResultEvent):void
{
var xml:XML = event.result as XML;
var amfEndpoint:String = "" + xml..channel.(@id=="amf")[email protected];
if (amfEndpoint == "")
{
Alert.show("amf channel not configured", "Error");
}
else
{
channelSet = new ChannelSet();
var channel:AMFChannel = new AMFChannel("my-amf", amfEndpoint);
channelSet.addChannel(channel);
ro.channelSet = channelSet;
ro.getProducts();
}
}
]]>
</mx:Script>
<mx:HTTPService id="configSrv" url="config.xml" resultFormat="e4x"
result="configResultHandler(event)"/>
<mx:RemoteObject id="ro" destination="product"/>
<mx:DataGrid dataProvider="{ro.getProducts.lastResult}" width="100%" height="100%"/>
</mx:Application>
The MXML application reads the following configuration file:
<?xml version="1.0" encoding="utf-8"?>
<config>
<channels>
<channel id="amf" endpoint="http://localhost:8400/lcds-samples/messagebroker/amf"/>
</channels>
</config>
Configuring a Flash Builder project with client-configured channels
When you create a new LiveCycle Data Services or BlazeDS project in Flash Builder, you typically select J2EE as the
Application Server Type and then check Use Remote Object Access Service. This adds an MXML compiler argument
that points to the services-config.xml file. If you check the Flex Compiler properties of your Flash Builder project, you
see something like this:
-services "c:\lcds\tomcat\webapps\samples\WEB-INF\flex\services-config.xml"
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When you compile the application, the required values of the services-config.xml are included in the SWF file. The
services-config.xml file is read at compile time and not at runtime as you might assume. You can use tokens such as
{server.name}, {server.port}, and {context.root} in the services-config.xml file. The {context.root} token is substituted
at compile time. The {server.name} and {server.port} are replaced at runtime with the server name and port number
of the server the SWF is loaded from; you can’t use these tokens for AIR applications.
When you configure channels on the client, you can avoid dependency on the services-config.xml file. You can create
a new Flex project with no Application Server Type settings because the channels are configured at runtime in the SWF
file. For existing LiveCycle Data Services or BlazeDS projects, you can remove the services-config.xml compiler
argument.
Assigning channels and endpoints to a destination
Settings in the LiveCycle Data Services configuration files determine the channels and endpoints from which a
destination can accept messages, invocations, or data, except when you use the run-time configuration feature. The
channels and endpoints are determined in one of the following ways:
• If most of the destinations across all services use the same channels, you can define application-level default
channels in the services-config.xml file, as the following example shows.
Note: Using application-level default channels is a best practice whenever possible.
<services-config ...>
...
<default-channels>
<channel ref="my-http"/>
<channel ref="my-amf"/>
</default-channels>
...
In this case, all destinations that do not define channels use a default channel. You can override the default channel
setting by specifying a channel at the destination level or service level.
• If most of the destinations in a service use the same channels, you can define service-level default channels, as the
following example shows:
<service ...>
...
<default-channels>
<channel ref="my-http"/>
<channel ref="my-amf"/>
</default-channels>
...
In this case, all destinations in the service that do not explicitly specify their own channels use the default channel.
• The destination definition can reference a channel inline, as the following example shows:
<destination id="sampleVerbose">
<channels>
<channel ref="my-secure-amf"/>
</channels>
...
</destination>
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Fallback and failover behavior
The primary reason that channels are contained in a channel set is to provide a fallback mechanism from one channel
to the next listed in the channel set, and so on, in case the first choice is unable to establish a connection to the server.
For example, you could define a channel set that falls back from a StreamingAMFChannel to an AMFChannel with
polling enabled to work around network components such as web server connectors, HTTP proxies, or reverse proxies
that could buffer chunked responses incorrectly. You can also use this functionality to provide different protocol
options so that a client can first try to connect using RTMP and if that fails, can fall back to HTTP.
The connection process involves searching for the first channel and trying to connect to it. In addition to the fallback
behavior that the channel set provides, the channel defines a failoverURIs property. This property lets you configure
a channel in ActionScript that causes failover across this array of endpoint URLs when it tries to connect to its
destination. If the channel defines failover URIs, each is attempted before the channel gives up and the channel set
searches for the next available channel. If no channel in the set can connect, any pending unsent messages generate
faults on the client.
If the channel was successfully connected before experiencing a fault or disconnection, it attempts a pinned
reconnection to the same endpoint URL once. If this immediate reconnection attempt fails, the channel falls back to
its previous failover strategy and attempts to fail over to other server nodes in the cluster or fall back to alternate
channel protocols.
Choosing an endpoint
The two types of endpoints in LiveCycle Data Services are servlet-based endpoints and NIO-based endpoints that use
Java New I/O APIs.
Note: NIO-based endpoints are not available in BlazeDS.
The J2EE servlet container manages networking, IO, and HTTP session maintenance for the servlet-based endpoints.
NIO-based endpoints are outside the servlet container and run inside an NIO-based socket server. NIO-based
endpoints can offer significant scalability gains. Because they are NIO-based, they are not limited to one thread per
connection. Far fewer threads can efficiently handle high numbers of connections and IO operations. If the web
application is not servicing general servlet requests, you can configure the servlet container to bind non-standard
HTTP and HTTPS ports. Ports 80 and 443 are then free for your NIO-based endpoints to use.
You can also deploy an Edge Server in your DMZ to forward client requests to a LiveCycle Data Services server in the
application tier. In this configuration, clients communicate with the Edge Server in the DMZ, and not directly with the
LiveCycle Data Services server inside the internal firewall. This configuration gives you more options for the endpoints
you can use and the ports those endpoints can listen over. For more information about the Edge Server, see “Edge
Server” on page 391.
The servlet-based endpoints are part of both BlazeDS and LiveCycle Data Services. Reasons to use servlet-based
endpoints when you have LiveCycle Data Services are that you must include third-party servlet filter processing of
requests and responses or you must access data structures in the application server HttpSession.
The NIO-based endpoints include RTMP endpoints as well as NIO-based AMF and HTTP endpoints that use the
same client-side channels as their servlet-based counterparts.
The following situations prevent the NIO socket server used with NIO-based endpoints from creating a real-time
connection between client and server in a typical deployment of a rich Internet application:
• The only client access to the Internet is through a proxy server.
• The application server on which LiveCycle Data Services is installed can only be accessed from behind the web tier
in the IT infrastructure.
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Servlet-based streaming endpoints and long polling are good alternatives when NIO-based streaming is not an
option. In the worst case, the client falls back to simple polling. The main disadvantages of polling are increased
overhead on client and server machines, and increased network latency.
Servlet-based channel and endpoint combinations
LiveCycle Data Services provides the following servlet-based channel and endpoint combinations. A secure version of
each of these channels/endpoints transports data over a secure HTTPS connection. The names of the secure channels
and endpoints all start with the text "Secure"; for example, SecureAMFChannel and SecureAMFEndpoint.
Servlet-based channel/endpoint classes
Description
AMFChannel/AMFEndpoint
A simple channel/endpoint that transports data over HTTP in the
binary AMF format in an asynchronous call and response model. Use
for RPC requests/responses with RPC-style Flex components such as
RemoteObject, HTTPService, and WebService. You can also
configure a channel that uses this endpoint to repeatedly poll the
endpoint for new messages. You can combine polling with a long
wait interval for long polling, which handles near real-time
communication.
For more information, see “Simple channels and endpoints” on
page 47.
HTTPChannel/HTTPEndpoint
Provides the same behavior as the AMF channel/endpoint, but
transports data in the AMFX format, which is the text-based XML
representation of AMF. Transport with this endpoint is not as fast as
with the AMFEndpoint because of the overhead of text-based XML.
Use when binary AMF is not an option in your environment.
For more information, see “Simple channels and endpoints” on
page 47.
StreamingAMFChannel/StreamingAMFEndp Streams data in real time over the HTTP protocol in the binary AMF
oint
format. Use for real-time data services, such as the Data
Management Service and the Message Service where streaming
data is critical to performance.
For more information, see “Streaming AMF and HTTP channels” on
page 52.
StreamingHTTPChannel/StreamingHTTPEnd Provides the same behavior model as the streaming AMF
point
channel/endpoint, but transports data in the AMFX format, which is
the text-based XML representation of AMF. Transport with this
endpoint is not as fast as with the StreamingAMFEndpoint because
of the overhead of text-based XML. Use when binary AMF is not an
option in your environment.
For more information, see “Streaming AMF and HTTP channels” on
page 52.
NIO-based channel and endpoint combinations
The NIO-based endpoints include RTMP endpoints as well as NIO-based AMF and HTTP endpoints that use the
same client-side channels as their servlet-based counterparts.
Note: NIO-based endpoints are not available in BlazeDS.
LiveCycle Data Services provides the following NIO-based channels/endpoints. A secure version of the RTMP
channel/endpoint transports data over an RTMPS connection. A secure version of each of the HTTP and AMF
channels/endpoints transports data over an HTTPS connection. The names of the secure channels and endpoints all
start with the text "Secure"; for example, SecureAMFChannel and SecureNIOAMFEndpoint.
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NIO-based channel/endpoint classes
Description
RTMPChannel/RTMPEndpoint
Streams data in real time over the TCP-based RTMP protocol in
the binary AMF format. Use for real-time data services, such as
the Data Management Service and the Message Service where
streaming data is critical to performance.
The RTMP channel/endpoint uses an NIO server to support
scaling up to thousands of connections. It uses a single duplex
socket connection to the server and gives the server the best
notification of Flash Player being shut down. If the direct
connect attempt fails, Flash Player attempts a CONNECT tunnel
through an HTTP proxy if the browser defines one (resulting in a
direct, tunneled duplex socket connection to the server). In the
worst case, Flash Player falls back to adaptive polling of HTTP
requests that tunnel RTMP data back and forth between client
and server, or it fails to connect entirely.
When you define an RTMP endpoint with a URI that starts with
rtmp: and specifies no port, the endpoint automatically binds
ports 1935 and 80 when the server starts.
When you define an RTMP endpoint with a URI that starts with
rtmpt: and specifies no port, the endpoint will automatically
bind port 80 when the server starts.
When you define a secure RTMP endpoint that specifies no port,
the endpoint automatically binds port 443 when the server
starts.
A defined (hardcoded) port value in the channel/endpoint URI
overrides these defaults, and a bind-port configuration
setting overrides these as well. When using a defined port in the
URI or bind-port the endpoint binds just that single port at
startup.
For more information, see “Configuring channels with NIObased endpoints” on page 55.
AMFChannel/NIOAMFEndpoint
NIO-based version of the AMF channel/endpoint. Uses an NIO
server and a minimal HTTP stack to support scaling up to
thousands of connections.
StreamingAMFChannel/
NIOStreamingAMFEndpoint
NIO-based version of streaming AMF channel/ endpoint. Uses
an NIO server and a minimal HTTP stack to support scaling up to
thousands of connections.
HTTPChannel/NIOHTTPEndpoint
NIO-based version of HTTP channel/endpoint. Uses an NIO
server and a minimal HTTP stack to support scaling up to
thousands of connections.
StreamingHTTPChannel/StreamingNIOHTTPEnd
point
NIO-based version of streaming HTTP channel/endpoint. Uses
an NIO server and a minimal HTTP stack to support scaling up to
thousands of connections.
Choosing a channel
Depending on your application requirements, you can use simple AMF or HTTP channels without polling or with
piggybacking, polling, or long polling. You can also use streaming RTMP, AMF, or HTTP channels. The difference
between AMF and HTTP channels is that AMF channels transport data in the binary AMF format and HTTP channels
transport data in AMFX, the text-based XML representation of AMF. Because AMF channels provide better
performance, use an HTTP channel instead of an AMF channel only when you have auditing or compliance
requirements that preclude the use of binary data over your network or when you want the contents of messages to be
easily readable over the network (on the wire).
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Non-polling AMF and HTTP channels
You can use AMF and HTTP channels without polling for remote procedure call (RPC) services, such as remoting
service calls, proxied HTTP service calls and web service requests, or Data Management Service requests without
automatic synchronization. These scenarios do not require the client to poll for messages or the server to push
messages to the client.
Piggybacking on AMF and HTTP channels
The piggybacking feature enables the transport of queued messages along with responses to any messages the client
sends to the server over the channel. By default, piggybacking is disabled. You can set it to true in the piggybackingenabled property of a channel definition in the services-config.xml file or in the piggybackingEnabled property of
a Channel instance when you create a channel in ActionScript.
Piggybacking provides lightweight pseudo polling, where rather than the client channel polling the server on a fixed
or adaptive interval, when the client sends a non-command message to the server (using a Producer, RemoteObject,
or DataService object), the server sends any pending data for client messaging or data management subscriptions along
with the response to the client message.
Piggybacking can also be used on a channel that has polling enabled but on a wide interval like 5 seconds or 10 seconds
or more, in which case the application appears more responsive if the client is sending messages to the server. In this
mode, the client sends a poll request along with any messages it sends to the server between its regularly scheduled poll
requests. The channel piggybacks a poll request along with the message being sent, and the server piggybacks any
pending messages for the client along with the acknowledge response to the client message.
Polling AMF and HTTP channels
AMF and HTTP channels support simple polling mechanisms that clients can use to request messages from the server
at set intervals. A polling AMF or HTTP channel is useful when other options such as long polling or streaming
channels are not acceptable and also as a fallback channel when a first choice, such as a streaming channel, is
unavailable at run time.
Long polling AMF and HTTP channels
You can use AMF and HTTP channels in long polling mode to get pushed messages to the client when the other more
efficient and real-time mechanisms are not suitable. This mechanism uses the normal application server HTTP request
processing logic and works with typical J2EE deployment architectures.
You can establish long polling for any channel that uses a non-streaming AMF or HTTP endpoint by setting the
polling-enabled, polling-interval-millis, wait-interval-millis, and client-wait-interval-millis
properties in a channel definition; for more information, see “Simple channels and endpoints” on page 47.
Streaming channels
For streaming, you can use RTMP channels, or streaming AMF or HTTP channels. Streaming channels must be paired
with corresponding streaming endpoints that are NIO-based or servlet-based. Streaming AMF and HTTP channels
work with servlet-based streaming AMF or HTTP endpoints or NIO-based streaming AMF or HTTP endpoints.
RTMP channels work with NIO-based RTMP endpoints.
For more information about endpoints, see “Choosing an endpoint” on page 43.
Configuring channels with servlet-based endpoints
The servlet-based endpoints are part of both BlazeDS and LiveCycle Data Services.
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Simple channels and endpoints
The AMFEndpoint and HTTPEndpoint are simple servlet-based endpoints. You generally use channels with these
endpoints without client polling for RPC service components, which require simple call and response communication
with a destination. When working with the Message Service or Data Management Service, you can use these channels
with client polling to constantly poll the destination on the server for new messages, or with long polling to provide
near real-time messaging when using a streaming channel is not an option in your network environment.
Property
Description
polling-enabled
Optional channel property. Default value is false.
polling-interval-millis
Optional channel property. Default value is 3000. This
parameter specifies the number of milliseconds the client
waits before polling the server again. When pollinginterval-millis is 0, the client polls as soon as it receives
a response from the server with no delay.
wait-interval-millis
Optional endpoint property. Default value is 0. This
parameter specifies the number of milliseconds the server
poll response thread waits for new messages to arrive when
the server has no messages for the client at the time of poll
request handling. For this setting to take effect, you must use
a nonzero value for the max-waiting-poll-requests
property.
A value of 0 means that server does not wait for new
messages for the client and returns an empty
acknowledgment as usual. A value of -1 means that server
waits indefinitely until new messages arrive for the client
before responding to the client poll request.
The recommended value is 60000 milliseconds (one
minute).
client-wait-interval-millis
Optional channel property. Default value is 0. Specifies the
number of milliseconds the client will wait after it receives a
poll response from the server that involved a server wait
(wait-interval-millis is set to a non-zero value).
A value of 0 means the client uses its configured pollinginterval-millis value to determine the wait until its
next poll. Otherwise, this value overrides the default polling
interval of the client.
Setting this value to 1 allows clients that poll the server with
wait (wait-interval-millis is set to a non-zero value) to poll
immediately upon receiving a poll response from the server,
providing a real-time message stream from the server to the
client.
Clients that poll the server and are not serviced with a server
wait (wait-interval-millis is not set to a non-zero value) use
the polling-interval-millis value.
max-waiting-poll-requests
Optional endpoint property. Default value is 0. Specifies the
maximum number of server poll response threads that can
be in wait state. When this limit is reached, the subsequent
poll requests are treated as having zero wait-intervalmillis.
piggybacking-enabled
Optional endpoint property. Default value is false. Enable
to support piggybacking of queued messaging and data
management subscription data along with responses to any
messages the client sends to the server over this channel.
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Property
Description
login-after-disconnect
Optional channel property. Default value is false. Setting
to true causes clients to automatically attempt to
reauthenticate themselves with the server when they send a
message that fails because credentials have been reset due
to server session timeout. The failed messages are resent
after reauthentication, making the session timeout
transparent to the client with respect to authentication.
login-after-disconnect functionality only works for
requests (messages) that fault due to an authentication error
for a client that was previously authenticated but is no
longer authenticated. The destination or service must be
protected with a security constraint. The login-afterdisconnect setting is not used if a message faults for any
other reason.
flex-client-outbound-queue-processor
Optional channel property. Use to manage messaging
quality of service for subscribers. Every client that subscribes
to the server over this channel is assigned a unique instance
of the specified outbound queue processor implementation
that manages the flow of messages to the client. This can
include message conflation, filtering, scheduled delivery and
load shedding. You can define configuration properties, and
if so, they are used to configure each new queue processor
instance that is created. The following example shows how
to provide a configuration property:
<flex-client-outbound-queue-processor
class="my.company.QoSQueueProcessor">
<properties>
<custom-property>5000</custom-property>
</properties>
</flex-client-outbound-queue-processor>
serialization
Optional serialization properties on endpoint. For more
information, see “Configuring AMF serialization on a
channel” on page 84.
connect-timeout-seconds
Optional channel property. Default value is 0. Use to limit the
client channel's connect attempt to the specified time
interval.
invalidate-session-on-disconnect
Optional endpoint property. Disabled by default. If enabled,
when a disconnect message is received from a client
channel, the corresponding server session is invalidated. If
the client is closed without first disconnecting its channel, no
disconnect message is sent, and the server session is
invalidated when its idle timeout elapses.
add-no-cache-headers
Optional endpoint property. Default value is true. HTTPS
requests on some browsers do not work when pragma nocache headers are set. By default, the server adds headers,
including pragma no-cache headers to HTTP responses to
stop caching by the browsers.
Non-polling AMF and HTTP channels
The simplest types of channels are AMF and HTTP channels in non-polling mode, which operate in a single requestreply pattern. The following example shows AMF and HTTP channel definitions configured for no polling:
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<!-- Simple AMF -->
<channel-definition id="samples-amf"
type="mx.messaging.channels.AMFChannel">
<endpoint url="http://{server.name}:8100/myapp/messagebroker/amf"
type="flex.messaging.endpoints.AmfEndpoint"/>
</channel-definition>
<!-- Simple secure AMF -->
<channel-definition id="my-secure-amf"
class="mx.messaging.channels.SecureAMFChannel">
<endpoint url="https://{server.name}:9100/dev/messagebroker/
amfsecure" class="flex.messaging.endpoints.SecureAMFEndpoint"/>
</channel-definition>
<!-- Simple HTTP -->
<channel-definition id="my-http"
class="mx.messaging.channels.HTTPChannel">
<endpoint url="http://{server.name}:8100/dev/messagebroker/http"
class="flex.messaging.endpoints.HTTPEndpoint"/>
</channel-definition>
<!-- Simple secure HTTP -->
<channel-definition id="my-secure-http" class="mx.messaging.channels.SecureHTTPChannel">
<endpoint url=
"https://{server.name}:9100/dev/messagebroker/
httpsecure"
class="flex.messaging.endpoints.SecureHTTPEndpoint"/>
</channel-definition>
Polling AMF and HTTP channels
You can use an AMF or HTTP channel in polling mode to repeatedly poll the endpoint to create client-pull message
consumers. The interval at which the polling occurs is configurable on the channel. You can also manually poll by
calling the poll() method of a channel for which polling is enabled; for example, you want set the polling interval to
a high number so that the channel does not automatically poll, and call the poll() method to poll manually based on
an event, such as a button click.
When you use a polling AMF or HTTP channel, you set the polling property to true in the channel definition. You
can also configure the polling interval in the channel definition.
Note: You can also use AMF and HTTP channels in long polling mode to get pushed messages to the client when the other
more efficient and real-time mechanisms are not suitable. For information about long polling, see “Long polling AMF
and HTTP channels” on page 50.
The following example shows AMF and HTTP channel definitions configured for polling:
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<!-- AMF with polling -->
<channel-definition id="samples-polling-amf"
class="mx.messaging.channels.AMFChannel">
<endpoint url="http://{server.name}:8700/dev/messagebroker/amfpolling"
type="flex.messaging.endpoints.AMFEndpoint"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-millis>8000</polling-interval-millis>
</properties>
</channel-definition>
<!-- HTTP with polling -->
<channel-definition id="samples-polling-http"
class="mx.messaging.channels.HTTPChannel">
<endpoint url="http://{server.name}:8700/dev/messagebroker/httppolling"
type="flex.messaging.endpoints.HTTPEndpoint"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-millis>8000</polling-interval-millis>
</properties>
</channel-definition>
Note: You can also use secure AMF or HTTP channels in polling mode.
Long polling AMF and HTTP channels
In the default configuration for a polling AMF or HTTP channel, the endpoint does not wait for messages on the
server. When the poll request is received, it checks whether any messages are queued for the polling client and if so,
those messages are delivered in the response to the HTTP request. You configure long polling in the same way as
polling, but you also must set the wait-interval-millis, max-waiting-poll-requests, and client-waitinterval-millis properties.
To achieve long polling, you set the following properties in the properties section of a channel definition in the
services-config.xml file:
•
polling-enabled
•
polling-interval-millis
•
wait-interval-millis
•
max-waiting-poll-requests.
•
client-wait-interval-millis
The following example shows AMF and HTTP channel definitions configured for long polling:
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<!-- Long polling AMF -->
<channel-definition id="my-amf-longpoll" class="mx.messaging.channels.AMFChannel">
<endpoint
url="http://servername:8700/contextroot/messagebroker/myamflongpoll"
class="flex.messaging.endpoints.AMFEndpoint"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-millis>0</polling-interval-millis>
<wait-interval-millis>60000</wait-interval-millis>
<client-wait-interval-millis>3000</client-wait-interval-millis>
<max-waiting-poll-requests>100</max-waiting-poll-requests>
</properties>
</channel-definition>
<!-- Long polling HTTP -->
<channel-definition id="my-http-longpoll" class="mx.messaging.channels.HTTPChannel">
<endpoint
url="http://servername:8700/contextroot/messagebroker/myhttplongpoll"
class="flex.messaging.endpoints.HTTPEndpoint"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-millis>0</polling-interval-millis>
<wait-interval-millis>60000</wait-interval-millis>
<client-wait-interval-millis>3000</client-wait-interval-millis>
<max-waiting-poll-requests>100</max-waiting-poll-requests>
</properties>
</channel-definition>
Note: You can also use secure AMF or HTTP channels in polling mode.
The caveat for using the wait-interval-millis is the utilization of available application server threads. Because this
channel ties up one application server request handling thread for each parked poll request, this mechanism can have
an impact on server resources and performance. Modern JVMs can typically support about 200 threads comfortably
if given enough heap space. Check the maximum thread stack size (often 1 or 2 megabytes per thread) and make sure
that you have enough memory and heap space for the number of application server threads you configure. This
limitation does not apply to NIO-based endpoints.
To ensure that Flex clients using channels with wait-interval-millis do not lock up your application server,
LiveCycle Data Services requires that you set the max-waiting-poll-requests property, which specifies the
maximum number of waiting connections that LiveCycle Data Services should manage. This number must be set to a
number smaller than the number of HTTP request threads your application server is configured to use. For example,
you configure the application server to have at most 200 threads and allow at most 170 waiting poll requests. This
setting would ensure that you have at least 30 application server threads to use for handling other HTTP requests. Your
free application server threads should be large enough to maximize parallel opportunities for computation.
Applications that are I/O heavy can require a large number of threads to ensure all I/O channels are utilized
completely. Multiple threads are useful for the following operations:
Using different settings for these properties results in different behavior. For example, setting the wait-intervalmillis property to 0 (zero) and setting the polling-interval-millis property to a nonzero positive value results
in normal polling. Setting the wait-interval-millis property to a high value reduces the number of poll messages
that the server must process, but the number of request handling threads on the server limits the total number of
parked poll requests.
• Simultaneously writing responses to clients behind slow network connections
• Executing database queries or updates
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• Performing computation on behalf of user requests
Another consideration for using wait-interval-millis is that LiveCycle Data Services must avoid monopolizing
the available connections that the browser allocates for communicating with a server. The HTTP 1.1 specification
recommends that browsers allocate at most two connections to the same server when the server supports HTTP 1.1.
To avoid using more that one connection from a single browser, LiveCycle Data Services allows only one waiting
thread for a given application server session at a time. If more than one Flash Player instance within the same browser
process attempts to interact with the server using long polling, the server forces them to poll on the default interval
with no server wait to avoid busy polling.
Streaming AMF and HTTP channels
The streaming AMF and HTTP channels are HTTP-based streaming channels that the LiveCycle Data Services server
can use to push updates to clients using a technique called HTTP streaming. These channels give you the option of
using standard HTTP for real-time messaging. This capability is supported for HTTP 1.1, but is not available for HTTP
1.0. There are also a number of proxy servers still in use that are not compliant with HTTP 1.1. When using a streaming
channel, make sure that the channel has connect-timeout-seconds defined and the channel set has a channel to fall
back to, such as an AMF polling channel.
LiveCycle Data Services gives you the additional option of using NIO-based endpoints with streaming AMF and HTTP
channels. For more information about using NIO-based endpoints, see “Configuring channels with NIO-based
endpoints” on page 55.
Using streaming AMF or HTTP channels/endpoints is like setting a long polling interval on a standard AMF or HTTP
channel/endpoint, but the connection is never closed even after the server pushes the data to the client. By keeping a
dedicated connection for server updates open, network latency is greatly reduced because the client and the server do
not continuously open and close the connection. Unlike polling channels, because streaming channels keep a constant
connection open, they can be adversely affected by HTTP connectors, proxies, reverse proxies or other network
components that can buffer the response stream.
The following table describes the channel and endpoint configuration properties in the services-config.xml file that are
specific to streaming AMF and HTTP channels/endpoints. The table includes the default property values as well as
considerations for specific environments and applications.
Property
Description
connect-timeout-seconds
Using a streaming connection that passes through an HTTP 1.1 proxy server
that incorrectly buffers the response sent back to the client hangs the
connection. For this reason, you must set the connect-timeoutseconds property to a relatively short timeout period and specify a
fallback channel such as an AMF polling channel.
idle-timeout-minutes
Optional channel property. Default value is 0. Specifies the number of
minutes that a streaming channel is allowed to remain idle before it is
closed. Setting the idle-timeout-minutes property to 0 disables the
timeout completely, but it is a potential security concern.
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Property
Description
max-streaming-clients
Optional endpoint property. Default value is 10. Limits the number of Flex
clients that can open a streaming connection to the endpoint. To
determine an appropriate value, consider the number of threads available
on your application server because each streaming connection open
between a FlexClient and the streaming endpoints uses a thread on the
server. Use a value that is lower than the maximum number of threads
available on the application server.
This value is for the number of Flex client application instances, which can
each contain one or more MessageAgents (Producer or Consumer
components).
server-to-client-heartbeatmillis
Optional endpoint property. Default value is 5000. Number of milliseconds
that the server waits before writing a single byte to the streaming
connection to make sure that the client is still available. This is important to
determine when a client is no longer available so that its resources
associated with the streaming connection can be cleaned up. A nonpositive value disables this functionality.
Note that this functionality does not keep the session alive. To keep a
session alive, add a heartbeat-interval-millis property to the
flex-client settings in the services-config.xml file. For more
information, see “Configuration elements” on page 33.
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Property
Description
user-agent-settings
Optional endpoint property. Use user agents to customize a long-polling or
streaming endpoints for specific browsers. Long-polling and streaming
endpoints require persistent HTTP connections which are limited
differently by different browsers per session. A single long-poll connection
requires two browser HTTP connections in order to send data in both
directions: one for the streamed response from the server to the client that
the channel hangs on to, and a second transient connection, drawn from
the browser pool only when data needs to be sent to the server and this
second transient connection is then immediately released back to the
browser's connection pool. For client applications to function properly, the
number of HTTP connections made by all clients running in the same
session must stay within the limit established by the browser.
The max-persistent-connections-per-session setting lets you
limit the number of long-polling or streaming connections that can be
made from clients in the same browser session. The kickstart-bytes
setting indicates a certain number of bytes must be written before the
endpoint can reliably use a streaming connection.
There is a browser-specific limit to the number of connections allowed per
session. By default, LiveCycle Data Services uses 1 as the value for maxstreaming-connections-per-session. You can add browserspecific limits by specifying user-agent elements with a match-on value
for specific browser user agents.
The special match string "*" defines a default to be used if no string
matches. The match strings "MSIE" and "Firefox" are always defined
and must be specified explicitly to override the default settings. Specifying
"*" does not do so. If you are using streaming channels, you should
configure both the streaming and polling channels to the same values
The following example shows default user agent values:
<user-agent-settings>
<!-- MSIE 5, 6, 7 limit is 2.
<user-agent match-on="MSIE" max-persistent-connectionsper-session="1" kickstart-bytes="2048"/>
-->
<!-- MSIE 8 limit is 6.
<user-agent match-on="MSIE 8" max-persistentconnections-per-session="5" kickstart-bytes="2048"/>
-->
<!-- Firefox 1, 2 limit is 2.
<user-agent match-on="Firefox" max-persistentconnections-per-session="1"/>
-->
<!-- Firefox 3 limit is 6.
<user-agent match-on="Firefox/3" max-persistentconnections-per-session="5"/>
-->
<!-- Safari 3, 4 limit is 4.
<user-agent match-on="Safari" max-persistentconnections-per-session="3"/>
-->
<!-- Chrome 0, 1, 2 limit is 6.
<user-agent match-on="Chrome" max-persistentconnections-per-session="5"/>
-->
<!-- Opera 7, 9 limit is 4.
<user-agent match-on="Opera" max-persistentconnections-per-session="3"/>
-->
<!-- Opera 8 limit is 8.
<user-agent match-on="Opera 8" max-persistentconnections-per-session="7"/>
-->
<!-- Opera 10 limit is 8.
<user-agent match-on="Opera/9.8" max-persistentconnections-per-session="7"/>
-->
</user-agent-settings>
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The following example shows streaming AMF and HTTP channel definitions:
<!-- AMF with streaming -->
<channel-definition id="my-amf-stream"
class="mx.messaging.channels.StreamingAMFChannel">
<endpoint url="http://servername:2080/myapp/messagebroker/streamingamf"
class="flex.messaging.endpoints.StreamingAMFEndpoint"/>
</channel-definition>
<!-- Secure AMF with streaming -->
<channel-definition id="my-secure-amf-stream"
class="mx.messaging.channels.SecureStreamingAMFChannel">
<endpoint url="http://servername:2080/myapp/messagebroker/securestreamingamf"
class="flex.messaging.endpoints.SecureStreamingAMFEndpoint"/>
</channel-definition>
<!-- HTTP with streaming -->
<channel-definition id="my-http-stream"
class="mx.messaging.channels.StreamingHTTPChannel">
<endpoint url="http://servername:2080/myapp/messagebroker/streaminghttp"
class="flex.messaging.endpoints.StreamingHTTPEndpoint"/>
</channel-definition>
<!-- Secure HTTP with streaming -->
<channel-definition id="my-secure-http-stream"
class="mx.messaging.channels.SecureStreamingHTTPChannel">
<endpoint url="https://servername:2080/myapp/messagebroker/securestreaminghttp"
class="flex.messaging.endpoints.SecureStreamingHTTPEndpoint"/>
</channel-definition>
Configuring channels with NIO-based endpoints
Note: NIO-based endpoints are not available in BlazeDS.
AMF and HTTP (AMFX) channels offer long-polling and streaming channel support over HTTP. They are a good
alternative to simple polling and approximate real-time push. However, in LiveCycle Data Services 2.5 they relied on
servlet-based AMF and HTTP endpoints on the server. The servlet API requires a request-handler thread for each
long-polling or streaming connection. A thread is not available to service other requests while it is servicing a longpoll parked on the server, or while it is servicing a streaming HTTP response. Therefore, the servlet implementation
does not scale well for a large number of long-polling or streaming connections.
NIO-based AMF and HTTP endpoints address this scalability limitation by providing identical transport functionality
from the client perspective, while avoiding the requirement of using one thread for each long-polling or streaming
connection. NIO-based endpoints use the Java NIO API to service a large number of client connections in a nonblocking, asynchronous fashion.
Note: Like servlet-based endpoints, NIO-based AMF and HTTP endpoints return a session id to inject into the client
channel URL in the first response that is returned from the server. This allows client-server interaction to work when the
client has cookies disabled. NIO endpoints also return a stand-in representation of a javax.servlet.HttpServletRequest
object even though these endpoints do not use the Servlet API in any way. This stand-in object supports a subset of the
full HttpServletRequest API. For more information, see the flex.messaging.io.http.StandInHttpServletRequest class the
Javadoc API documentation.
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Configuring a shared socket server for NIO-based endpoints
You can configure one or more socket servers for use with NIO-based endpoints. The only reason to define more than
one socket server is if you want to use both secure and insecure NIO endpoints. An underlying server either supports
secure (SSL or TLS) connections or insecure connections, not both.
Do not define more than one socket server unless you need both secure and insecure support in the same application.
When you do define more than one socket server, you can specify which server the endpoint of a channel definition
uses. You use the server element in the services-config.xml file to create the server definition. The servers element
can contain one or more server elements, as the following example shows:
<servers>
<server id="my-nio-server" class="flex.messaging.socketserver.SocketServer">
</server>
<server id="secure-nio-server" class="flex.messaging.socketserver.SocketServer">
<properties>
<keystore-file>d:\keystores\localhoststore</keystore-file>
<keystore-file>{context.root}/WEB-INF/flex/localhost.keystore</keystore-file>
<keystore-password>changeit</keystore-password>
<alias>lh</alias>
</properties>
</server>
</servers>
NIO-based endpoints within a channel definition reference a <server> definition by using the <server ref="..."/>
property, as the following example shows:
<channel-definition id="my-nio-amf" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://localhost:2080/mynioamf"
class="flex.messaging.endpoints.NIOAMFEndpoint"/>
<server ref="my-nio-server"/>
</channel-definition>
Note: One reason to share a server definition among multiple endpoint definitions is that a single port cannot be bound
by more than one server definition. For example, if your application must define both a regular NIOAMFEndpoint as
well as a StreamingNIOAMFEndpoint, you want clients to be able to reach either endpoint over the same port so these
endpoints must reference a common server. If you do not require a shared server, you can configure socket server
properties inside channel definitions.
An NIO-based endpoint can implicitly define and use an internal server definition by omitting the <server ref="..."/>
property, and instead including any server configuration properties directly within its <properties> element. For
example, if you define only a single NIO-based AMF or HTTP endpoint, omit the <server ref="…"/> element and
define any desired properties within the endpoint definition. However, if a <server ref="..."/> property is included in
the channel definition, any server-related configuration properties in the endpoint definition are ignored and must
instead be defined directly for the server itself.
If you configure more than one NIO-based AMF or HTTP endpoint that is not secure, they should all reference a
shared unsecured server definition. If you define more than one secure NIO-based AMF or HTTP endpoint, they
should all reference a secured shared <server> definition. This configuration lets all insecure endpoints share the
same insecure port, and lets all the secure endpoints share a separate, secure port.
Note: A server definition accepts either standard or secure connections based on whether it is configured to use a
keystore. A server definition cannot service both standard and secure connections concurrently.
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The endpoint uses the class attribute to register the protocol-specific connection implementation classes with the
server. For information on the NIO HTTP implementation classes, see “Defining channels and NIO-based endpoints”
on page 57.
Secure server definition
A secure server definition requires a digital certificate, and contains child elements for specifying a keystore filename
and password. You can create public and private key pairs and self-signed certificates with the Java keytool utility. The
common name (CN) of self-signed certificates must be set to localhost or the IP address on which the RTMPS
endpoint is available. For information about key and certificate creation and management, see the Java keytool
documentation at http://java.sun.com.
Optionally, you can store a keystore password in a separate file, possibly on removable media. Specify only one
keystore-password or keystore-password-file. The following example shows a keystore-password-file element:
<keystore-password-file>a:\password</keystore-password-file>
Compatibility with previous versions of LiveCycle Data Services
The NIO-based AMF and HTTP endpoints are functionally equivalent to the existing servlet-based AMF and HTTP
endpoints as far as the client is concerned. You should be able to run your existing applications, using the existing
configuration files, when migrating your application to LiveCycle Data Services 2.6.
NIO-based endpoints do not support the following configuration options:
•
max-waiting-poll-requests
NIO-based polling endpoints do not have the threading limitation that the servlet API imposes, so they do not
require nor support the max-waiting-poll-requests property.
•
max-streaming-clients
NIO-based streaming endpoints do not have the threading limitation that the servlet API imposes, so they do not
require nor support the max-streaming-clients property.
Defining channels and NIO-based endpoints
When defining NIO-based endpoints, you specify one of the following classes to define the protocol-specific
connection implementation There is also a secure version of each of these endpoints that transports data over a secure
connection. The names of the secure endpoints all start with the text "Secure"; for example, SecureRTMPEndpoint.
• RTMPEndpoint
• NIOAMFEndpoint
• StreamingNIOAMFEndpoint
• NIOHTTPEndpoint
• StreamingNIOHTTPEndpoint
The NIO-based AMF and HTTP endpoints implement part of the HttpServletRequest interface to expose headers and
cookies in requests to custom LoginCommands or for other uses. You can access the HttpServletRequest instance by
using the FlexContext.getHttpRequest() method. These endpoints do not implement the HttpServletResponse
interface; therefore, the FlexContext.getHttpResponse() method returns null.
Supported methods from the HttpServletRequest interface include the following:
•
getCookies()
•
getDateHeader()
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•
getHeader()
•
getHeaderNames()
•
getHeaders()
•
getIntHeader()
Calling an unsupported method of the HttpServletRequest interface throws an UnsupportedOperationException
exception.
Configuring RTMP endpoints
You use RTMP channels to connect to an RTMP endpoint that supports real-time messaging and data. You can also
configure these channels for long polling.
RTMPT connections are HTTP connections from the client to the server over which RTMP data is tunneled. When a
direct RTMP connection is unavailable, the standard and secure channels automatically attempt to use RTMPT and
tunneled RTMPS connections, respectively, on the RTMP endpoint with no additional configuration required.
Note: You cannot use server.port tokens in an RTMP endpoint configuration. You can use the server.name token, but not
when using clustering. If you have a firewall in place, you must open the port that you assign to the RTMP endpoint to
allow RTMP traffic.
RTMP is a protocol that is primarily used to stream data, audio, and video over the Internet to Flash Player clients.
RTMP maintains a persistent connection with an endpoint and allows real-time communication. You can make an
RTMP connection in one of the following ways depending upon the network setup of the clients:
• Direct socket connection.
• Tunneled socket connection through an HTTP proxy server using the CONNECT method.
• Active, adaptive polling using the browser HTTP stack. This mechanism does place additional computational load
on the RTMP server and so reduces the scalability of the deployment.
RTMP direct socket connection
RTMP in its most direct form uses a simple TCP socket connection from the client machine directly to the RTMP
server.
RTMPT Tunnelling with HTTP Proxy Server Connect
This connection acts like a direct connection but uses the proxy server support for the CONNECT protocol if
supported. If this connection is not supported, the server falls back to using HTTP requests with polling.
RTMPT Tunnelling with HTTP requests
In this mode, the client uses an adaptive polling mechanism to implement two-way communication between the
browser and the server. This mechanism is not configurable and is designed to use at most one connection between
the client and server at a time to ensure that Flash Player does not consume all of the connections the browser allows
to one server.
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Connecting RTMP from the web tier to the application server tier
Currently, all RTMP connections must be made from the browser, or an HTTP proxy server in the case of a
CONNECT-based tunnel connection, directly to the RTMP server. Because the NIO server is embedded in the
application server tier with access to the database, in some server environments it is not easy to expose it directly to
web clients. There are a few ways to address this problem in your configuration:
• You can expose a firewall and load balancer to web clients that can implement a TCP pass-through mode to the
LiveCycle Data Services server.
• You can place a proxy server on the web tier that supports the HTTP CONNECT protocol so it can proxy
connections from the client to the RTMP server. This provides real-time connection support by passing the web
tier. The proxy server configuration can provide control over which servers and ports can use this protocol so it is
more secure than opening up the RTMP server directly to clients. For an RTMP CONNECT tunnel to work, the
client browser must be configured to use a specific HTTP proxy server.
• You can place a reverse proxy server on the web tier which proxies simple HTTP requests to the NIO server. This
approach only works in RTMPT polling mode.
• You can deploy an Edge Server in your DMZ. Clients connect to the Edge Server over RTMP, and the Edge Server
then forwards the client requests to a LiveCycle Data Services server in the application tier. Because the Edge Server
is running in the DMZ, you are not exposing the secure application tier of your internal network.
Configuring a standard RTMPChannel/RTMPEndpoint
Use a standard RTMPChannel/RTMPEndpoint only when transmitting data that does not require security. The
following example shows an RTMP channel definition:
<channel-definition id="my-rtmp"
class="mx.messaging.channels.RTMPChannel">
<endpoint url="rtmp://{server.name}:2035"
class="flex.messaging.endpoints.RTMPEndpoint"/>
<properties>
<idle-timeout-minutes>20</idle-timeout-minutes>
</properties>
</channel-definition>
You can use the optional rtmpt-poll-wait-millis-on-client element when clients are connected over RTMPT
while performing adaptive polling. After receiving a server response, clients wait for an absolute time interval before
issuing the next poll request rather than using an exponential back-off up to a maximum poll wait time of 4 seconds.
Allowed values are integers in the range of 0 to 4000, for example:
<rtmpt-poll-wait-millis-on-client>0</rtmpt-poll-wait-millis-on-client>
You can set the optional block-rtmpt-polling-clients element to true to allow the server to be configured to
drop the inefficient polling connection. This action triggers the client to fall back to the next channel in its channel set.
The default value is false.
When an RTMPChannel internally falls back to tunneling, it sends its HTTP requests to the same domain/port that is
used for regular RTMP connections and these requests must be sent over a standard HTTP port so that they make it
through external firewalls that some clients could be behind. For RTMP to work, you must bind your server-side
RTMP endpoint for both regular RTMP connections and tunneled connections to port 80. When the client channel
falls back to tunneling, it always goes to the domain/port specified in the channel endpoint URI.
If you have a switch or load balancer that supports virtual IPs, you can use a deployment as the following table shows,
using a virtual IP (and no additional NIC on the LiveCycle Data Services server) where client requests first hit a load
balancer that routes them back to a backing LiveCycle Data Services server:
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Public Internet
Load balancer
LiveCycle Data Services
Browser client makes HTTP request
my.domain.com:80 Servlet container bound to port 80
Browser client uses RTMP/T
rtmp.domain.com:
80 (virtual IP
address)
RTMPEndpoint bound to any port; for example, 2037
The virtual IP/port in this example (rtmp.domain.com:80) is configured to route back to port 2037 or whatever port
the RTMPEndpoint is configured to use on the LiveCycle Data Services server. In this approach, the RTMPEndpoint
does not have to bind to a standard port because the load balancer publicly exposes the endpoint via a separate virtual
IP address on a standard port.
If you do not have a switch or load balancer that supports virtual IPs, you need a second NIC to allow the
RTMPEndpoint to bind port 80 on the same server as the servlet container that binds to port 80 on the primary NIC,
as the following table shows:
Public Internet
LiveCycle Data Services
NICs
LiveCycle Data Services
Browser client makes
HTTP request
my.domain.com:80
Servlet container bound to port 80 on primary NIC using
primary domain/IP address
Browser client uses
RTMP/T
rtmp.domain.com:80
RTMPEndpoint bound to port 80 on a second NIC using a
separate domain/IP address
In this approach the physical LiveCycle Data Services server has two NICs, each with its own static IP address. The
servlet container binds port 80 on the primary NIC and the RTMPEndpoint binds port 80 on the secondary NIC. This
allows traffic to and from the server to happen over a standard port (80) regardless of the protocol (HTTP or RTMP).
The key take away is that for the RTMPT fallback to work smoothly, the RTMPEndpoint must be exposed to Flex
clients over port 80, which is the standard HTTP port that generally allows traffic (unlike nonstandard RTMP ports
like 2037, which are usually closed by IT departments).
To bind the RTMPEndpoint to port 80, one of the approaches above is required. For secure RTMPS (direct or
tunneled) connections, the information above is the same but you would use port 443. If an application requires both
secure and non-secure RTMP connections with tunneling fallback, you do not need three NICs; you need only two.
The first NIC services regular HTTP/HTTPS traffic on the primary IP address at ports 80 and 443, and the second NIC
services RTMP and RTMPS connections on the secondary IP at ports 80 and 443. If a load balancer is in use, it is the
same as the first option above where LiveCycle Data Services has a single NIC and the different IP/port combinations
are defined at the load balancer.
Configuring NIO-based AMF and HTTP endpoints
The NIO-based AMF and HTTP endpoint classes support simple polling, long-polling, and streaming requests. Like
the socket server configuration options, these endpoints support the existing configuration options defined for the
RTMPEndpoint, AMFEndpoint and HTTPEndpoint classes, and the following additional configuration options:
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Option
Description
session-cookie-name
(Optional) Default value is AMFSessionId. The name used for the session cookie
set by the endpoint.
If you define multiple NIO-based endpoints and specify a custom cookie name, it
must be the same for all NIO-based AMF and HTTP endpoints.
session-timeoutminutes
(Optional) Default value is 15 minutes. The session timeout for inactive NIO HTTP
sessions, in minutes. Long-poll requests or streaming connections that uses
server-to-client-heartbeat-millis keep the session alive, as will any
request from the client.
If you define multiple NIO-based endpoint and specify a custom session timeout,
it must be the same for all NIO-based AMF and HTTP endpoints.
max-request-line-size
(Optional) Default value is 8192 characters. Requests that contain request or
header lines that exceed this value are dropped and the connection is closed.
max-request-body-size
(Optional) Default is 5 MB. The maximum POST body size, in bytes, that the
endpoint accepts. Requests that exceed this limit are dropped and the connection
is closed.
Channels that use NIO-based endpoints
The following channel definition defines an RTMP channel for use with RTMP endpoints.
<!-- NIO RTMP -->
<channel-definition id="my-rtmp" class="mx.messaging.channels.RTMPChannel">
<endpoint url="rtmp://servername:2038"
class="flex.messaging.endpoints.RTMPEndpoint"/>
<properties>
<idle-timeout-minutes>0</idle-timeout-minutes>
<bind-address>10.132.64.63</bind-address>
<bind-port>2035</bind-port>
</properties>
</channel-definition>
The following channel definitions define AMF channels for use with NIO-based AMF endpoints.
<!-- NIO RTMP -->
<channel-definition id="my-rtmp" class="mx.messaging.channels.RTMPChannel">
<endpoint url="rtmp://servername:2038"
class="flex.messaging.endpoints.RTMPEndpoint"/>
<properties>
<idle-timeout-minutes>0</idle-timeout-minutes>
<bind-address>10.132.64.63</bind-address>
<bind-port>2035</bind-port>
</properties>
</channel-definition>
<!-- NIO AMF -->
<channel-definition id="my-nio-amf" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://servername:2080/nioamf"
class="flex.messaging.endpoints.NIOAMFEndpoint"/>
<server ref="my-nio-server"/>
<properties>
<polling-enabled>false</polling-enabled>
</properties>
</channel-definition>
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<!-- NIO AMF with polling -->
<channel-definition id="my-nio-amf-poll" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://servername:2080/nioamfpoll"
class="flex.messaging.endpoints.NIOAMFEndpoint"/>
<server ref="my-nio-server"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-millis>3000</polling-interval-millis>
</properties>
</channel-definition>
<!-- NIO AMF with long polling -->
<channel-definition id="my-nio-amf-longpoll" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://servername:2080/nioamflongpoll"
class="flex.messaging.endpoints.NIOAMFEndpoint"/>
<server ref="my-nio-server"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-millis>0</polling-interval-millis>
<wait-interval-millis>-1</wait-interval-millis>
</properties>
</channel-definition>
<!-- NIO AMF with streaming -->
<channel-definition id="my-nio-amf-stream"
class="mx.messaging.channels.StreamingAMFChannel">
<endpoint url="http://servername:2080/nioamfstream"
class="flex.messaging.endpoints.StreamingNIOAMFEndpoint"/>
<server ref="my-nio-server"/>
<properties>
<server-to-client-heartbeat-millis>10000</server-to-client-heartbeat-millis>
<user-agent-settings>
<user-agent match-on="MSIE"
kickstart-bytes="2048" max-streaming-connections-per-session="1"/>
<user-agent match-on="Firefox"
kickstart-bytes="0" max-streaming-connections-per-session="1"/>
</user-agent-settings>
</properties>
</channel-definition>
<!-- Secure NIO AMF -->
<channel-definition id="secure-nio-amf" class="mx.messaging.channels.SecureAMFChannel">
<endpoint url="https://servername:2443/securenioamf"
class="flex.messaging.endpoints.SecureNIOAMFEndpoint"/>
<server ref="secure-nio-server"/>
<properties>
<polling-enabled>false</polling-enabled>
</properties>
</channel-definition>
The following channel definitions define HTTP channels for use with NIO-based HTTP endpoints:
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<!-- NIO HTTP -->
<channel-definition id="my-nio-http" class="mx.messaging.channels.HTTPChannel">
<endpoint url="http://servername:2080/niohttp"
class="flex.messaging.endpoints.NIOHTTPEndpoint"/>
<server ref="my-nio-server"/>
<properties>
<polling-enabled>false</polling-enabled>
</properties>
</channel-definition>
<!-- NIO HTTP with streaming -->
<channel-definition id="my-nio-http-stream"
class="mx.messaging.channels.StreamingHTTPChannel">
<endpoint url="http://servername:2080/niohttpstream"
class="flex.messaging.endpoints.StreamingNIOHTTPEndpoint"/>
<server ref="my-nio-server"/>
</channel-definition>
<!-- Secure NIO HTTP -->
<channel-definition id="secure-nio-http" class="mx.messaging.channels.SecureHTTPChannel">
<endpoint url="https://servername:2443/secureniohttp"
class="flex.messaging.endpoints.SecureNIOHTTPEndpoint"/>
<server ref="secure-nio-server"/>
<properties>
<polling-enabled>false</polling-enabled>
</properties>
</channel-definition>
Monitoring an NIO-based endpoint through a proxy service
You can use a proxy service to monitor traffic to and from an NIO-based endpoint. To do so, set the url property of
the endpoint element in a channel definition to use the port on which you want the proxy service to listen. The client
uses the url property of the endpoint element. Set the bind-port property of the NIO server to the port that the
server endpoint should listen on.
For the following channel definition, you would configure your proxy service to listen for requests on port 9999 and
forward requests to port 2081:
<channel-definition
class="mx.messaging.channels.StreamingAMFChannel" id="qa-nio-amf-stream-proxy">
<endpoint class="flex.messaging.endpoints.StreamingNIOAMFEndpoint"
url="http://yourserver:9999/nioamfstreamproxy"/>
<server ref="nio-server"/>
<properties>
<bind-port>2081</bind-port>
<server-to-client-heartbeat-millis>5000</server-to-client-heartbeat-millis>
</properties>
</channel-definition>
Configuring the socket server
You configure one or more socket server definitions in the services-config.xml file. Once defined, you can specify
which server a channel definition uses.
Note: You can optionally set any of the socket server properties directly in a channel definition for situations where you
are not sharing the same socket server for more than one endpoint.
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Use a secure channel definition to connect to the endpoint over Transport Layer Security (TLS) for RTMP-based
endpoints or SSL for servlet-based endpoints. When using RTMP, the channel falls back to tunneled RTMPS when a
direct connection is unavailable.
The following table describes the configuration options for the socket server:
Option
Description
Security Related Options
max-connection-count
(Optional) The total number of open connections that the server
accepts. Clients that attempt to connect beyond this limit are
rejected. Setting max-connection-count to 0, the default,
disables this limitation.
Note that this is a potential security concern.
connection-idle-timeout-minutes
(Optional) The number of minutes that a streaming channel is
allowed to remain idle before it is closed. Setting idle-timeoutminutes to 0, the default value, disables the timeout.
Note that this is a potential security concern.
idle-timeout-minutes
Supported but deprecated. See connection-idle-timeoutminutes above.
whitelist
(Optional) Contains client IP addresses that are permitted to connect
to the server. When defined, client IPs must satisfy this filter to
connect. The blacklist option takes precedence over the
whitelist option if the client IP is a member of both sets.
Define a whitelist by creating a list of ip-address and ipaddress-pattern elements. The ipaddress- element supports
simple IP matching, allowing you to use a wildcard symbol, *, for
individual bytes in the address. The ip-address-pattern element
supports regular-expression pattern matching of IP addresses to
support range-based IP filtering, as the following example shows:
<whitelist>
<ip-address>10.132.64.63</ip-address>
<ip-address-pattern>240.*</ip-address-pattern>
</whitelist>
blacklist
(Optional) Contains client IPs that are restricted from accessing the
server. The blacklist option takes precedence over the
whitelist option if the client IP is a member of both sets.
Blacklists take a list of ip-address and ip-address-pattern
elements, as the following example shows:
<blacklist>
<ip-address>10.132.64.63</ip-address>
<ip-address-pattern>240.63.*</ip-address-pattern>
</blacklist>
For more information on the ip-address and ip-addresspattern elements, see the whitelist option.
cross-domain-path
Path to a cross domain policy file. For more information, see “Using
cross domain policy files with the NIO server” on page 68.
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Option
Description
enabled-cipher-suites
A cipher suite is a set of encryption algorithms. Secure NIO socket
server definitions or secure NIO (RTMP, AMF, or HTTP) endpoint
definitions can define a restricted set of cipher suites to use with
secure connections, as the following examples shows:
<enabled-cipher-suites>
<cipher-suite>SSL_RSA_WITH_128_MD5</cipher-suite>
<ciphersuite>TLS_DHE_DSS_WITH_AES_128_CBC_SHA</ciphersuite>
</enabled-cipher-suites>
If left undefined, the default set of cipher suites for the security
provider implementation of the Java virtual machine (JVM) are used
for secure connection handshaking. If an unsupported cipher suite is
defined, an error occurs and a ConfigurationException exception is
thrown when the server starts.
General Server Options
bind-address
(Optional) Binds the server to a specific network interface. If left
unspecified, the server binds to all local network interfaces on
startup.
bind-port
(Optional) Binds the server to a port that differs from the public port
that clients connect to. This allows clients to connect to a public port
on a firewall or load balancer that forwards traffic to this internal port.
reuse-address-enabled
(Optional) When set to false disables address reuse by the socket
server. This causes the SocketServer to not start when it cannot bind
to a port because the port is in a TIME_WAIT state. The default value
is true, which allows the socket server to start if the port is in a
TIME_WAIT state.
Connection Configuration Options
connection-buffer-type
(Optional) Controls the type of byte buffers that connections use to
read and write from the network. Supported values include:
•
heap (default) specifies to use heap-allocated ByteBuffers.
•
direct specifies to use DirectByteBuffers.
Performance varies depending upon JRE and operating system.
connection-read-buffer-size
(Optional) Default value is 8192 (8 KBytes). Size, in bytes, for the read
buffer for connections.
connection-write-buffer-size
(Optional) Default value is 8192 (8 KBytes). Size, in bytes, for the write
buffer for connections.
Control the threading behavior of the
server in the absence of a WorkManager.
websphere-workmanager-jndi-name
(Optional) For IBM WebSphere deployment, the WorkManager
configured and referenced as the worker thread pool for the server.
A WorkManager must be referenced to support JTA, which the Data
Management Service uses.
max-worker-threads
(Optional) The upper bound on the number of worker threads that
the server uses to service connections. Defaults to unbounded with
idle threads being reaped based upon the idle-worker-threadtimeout-millis value. Ignored if the server is using a
WorkManager.
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Option
Description
min-worker-threads
(Optional) A nonzero, lower bound on the number of worker threads
that the server uses to service connections. Defaults to 0. If nonzero,
on server start up this number of worker threads is prestarted.
Ignored if the server is using a WorkManager.
idle-worker-thread-timeoutmillis
(Optional) Time, in minutes, that a worker thread must be idle before
it is released. Defaults to 1. Ignored if the server is using a
WorkManager.
worker-thread-priority
(Optional) Desired priority for the server threads. Defaults to
Thread.NORM_PRIORITY. Ignored if the server is using a
WorkManager.
Accept or and Reactor Configuration
Options
accept-backlog
(Optional) The suggested size of the accept queue for the server
socket to buffer new connect requests when the server is too busy to
handshake immediately. Default is the platform default value for a
server socket.
accept-thread-priority
(Optional) Allows the priority for accepting new connections to be
adjusted either above or below the general server priority for
servicing existing connections. Default is the thread priority of the
worker thread pool or the WorkManager (whichever is used).
reactor-count
(Optional) Splits IO read/write readiness selection for all existing
connections to the server out across all available processors and
divides the total readiness selection set by the number of reactors to
avoid having a single Selector manage the state for all connections.
Default is the number of available physical processors on the
machine.
TLS/SSL Configuration Options
keystore-type
(Optional) Default value is JKS. Specifies the keystore type. The
supported values include: JKS and PKCS12.
keystore-file
Points to the actual keystore file on the running server. The path to
the file may be specified as an absolute path, as in:
<keystore-file>C:\keystore.jks</keystore-file>
Or as a relative to the WEB-APP directory using the
{context.root} token, as in:
<keystore-file>{context.root}/WEBINF/certs/keystore.jks</keystore-file>
keystore-password
The keystore password.
keystore-password-file
Path to a text file on external or removable media that contains the
password value. Ignored if keystore-password is specified.
keystore-password-obfuscated
(Optional) Default value is false. Set to true if an obfuscated value is
stored in the configuration file and a password deobfuscator has
been registered for use.
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Option
Description
password-deobfuscator
(Optional) The class name of a password deobfuscator used to
handle obfuscated passwords safely at run time.
A password deobfuscator implements the
flex.messaging.util.PasswordDeobfuscator interface, which contains
a deobfuscate() and a destroy() method. The
flex.messaging.util.AbstactPasswordDeobfuscator class is an
abstract class that implements the destroy() method. Your
deobfuscator class can extend this class, and just implement a
deobfuscate() method. The deobfuscate() method takes a
string that contains the obfuscated password and returns a char[]
containing the deobfuscated password.
For more information, see the JavaDoc for the
flex.messaging.util.PasswordDeobfuscator interface and the
flex.messaging.util.AbstractPasswordDeobfuscator abstract base
class.
algorithm
(Optional) Only configure this option when using a third-party
security provider implementation. Defaults to the current default
JVM algorithm. The default JVM algorithm can be controlled by
setting the ssl.KeyManagerFactory.algorithm security
property.
Example usage:
•
<algorithm>Default</algorithm> - Explicitly uses the
default JVM algorithm.
•
<algorithm>SunX509</algorithm> - Uses Sun algorithm;
requires the Sun secuity provider.
•
<algorithm>IbmX509</algorithm> - Uses IBM algorithm;
requires the IBM security provider.
alias
(Optional) If a keystore is used that contains more than one server
certificate, use this property to define which certificate to use to
authenticate the server end of SSL/TLS connections.
protocol
(Optional) Default value is TLS. The preferred protocol for secure
connections.
Socket Configuration Options (for
accepted sockets)
socket-keepalive-enabled
(Optional) Enables/Disables SO_KEEPALIVE for sockets the server
uses.
socket-oobinline-enabled
(Optional) Enables/Disables OOBLINE (receipt of TCP urgent data).
Defaults to false, which is the JVM default.
socket-receive-buffer-size
(Optional) Sets the SO_RCVBUF option for sockets to this value,
which is a hint for the size of the underlying network I/O buffer to use.
socket-send-buffer-size
(Optional) Sets the SO_SNDBUF option for sockets to this value,
which is a hint for the size of the underlying network I/O buffer to use.
socket-linger-seconds
(Optional) Enables/Disables SO_LINGER for sockets the server uses
where the value indicates the linger time for a closing socket in
seconds. A value of -1 disables socket linger.
socket-tcp-no-delay-enabled
(Optional) Enables/Disables TCP_NODELAY, which enables or
disables the use of the Nagle algorithm by the sockets.
socket-traffic-class
(Optional) Defines the traffic class for the socket.
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Using cross domain policy files with the NIO server
By default, the Flash Player security sandbox only allows a SWF file to make requests back to the same domain that the
SWF file originated from. You use a cross domain policy file to deal with this security restriction. If a SWF file makes
a request to a domain that is different than the one from which it originated, Flash Player makes a request to the new
domain for a cross domain policy file that can provide the SWF file with additional permissions to communicate with
the domain.
For servlet-based endpoints, LiveCycle Data Services depends on the application server for cross domain policy file
handling. For NIO-based AMF and HTTP endpoints, LiveCycle Data Services must depend on the NIO server for
cross domain policy file handling and not the application server itself. This is because the NIO server listens for
requests on a different port than the application server.
If your application makes a request to an AMF or HTTP endpoint at the
http://domainA:8400/lcds/messagebroker/amfpolling and domainA is not the same domain the SWF file was
downloaded from, Flash Player makes a cross domain policy file request to http://domainA:8400. To allow the
application to make the request to the AMF endpoint, you must place a cross domain policy file in the root directory
of your application server. For example, with a typical installation of Tomcat, this would be the
TOMCAT_HOME\webapps\ROOT directory.
If your application makes a request to an NIO-based AMF or HTTP endpoint at the
http://domainA:1234/nioamfpolling and domainA is not the same domain the SWF file was downloaded from, Flash
Player makes a cross domain policy file request to http://domainA:1234. Since this request goes directly to the NIO
server and not to the application server, you must configure the NIO server to serve the cross domain policy file. To
do this, you add a cross-domain-path property to your NIO server settings in your services-config.xml file as the
following example shows:
<server id="my-nio-server" class="flex.messaging.socketserver.SocketServer">
<properties>
<http>
<cross-domain-path>crossdomain.xml</cross-domain-path>
</http>
</properties>
</server>
Because this setting only applies to NIO-based AMF and HTTP endpoints it goes in the http section of configuration
settings. The NIO server expects cross domain policy files to be under the WEB-INF/flex directory of the LiveCycle
Data Services web application. In the previous example, you would place a file called crossdomain.xml with your cross
domain policy settings in the WEB-INF/flex directory of your LiveCycle Data Services web application.
You can also place cross domain files in subdirectories under WEB-INF/flex. This lets you have cross domain policy
files for individual NIO-based endpoints. For example, if you want a cross domain policy file that only applies to your
NIO-based AMF endpoint at http://domainA:1234/nioamfpolling, you would configure your application as follows:
• Use a cross-domain-path of /nioamfpolling, which causes the NIO server to search for a cross domain policy file
under /WEB-INF/flex/nioamfpolling.
• The cross domain path must match the cross domain policy request. This means that to use the cross domain policy
file under /WEB-INF/flex/nioamfpolling, the request must be made to
http://domainA:1234/nioamfpolling/crossdomain.xml.
• By default, the cross domain policy request is made to the root of the application; for example,
http://domainA:1234/crossdomain.xml. To override this behavior in your application, you must use the
Security.loadPolicyFile() method; in your application, before you make the request to the endpoint, you would add
the following line of code.
Security.loadPolicyFile("http://domainA:1234/nioamfpolling/crossdomain.xml");
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This causes Flash Player to attempt to load a cross domain policy file with the supplied URL. In this case, the NIO
server returns a cross domain policy file from the WEB-INF/flex/nioamfpolling directory and the permissions in
the policy file are applied to requests to the http://domainA:1234/nioamfpolling endpoint only.
Channel and endpoint recommendations
The NIO-based AMF and HTTP endpoints use the same client-side channels as their servlet-based endpoint
counterparts. The main advantage that NIO-based endpoints have over servlet-based endpoints is that they scale
better. If a web application is not servicing general servlet requests, you can configure the servlet container to bind
non-standard HTTP and HTTPS ports, leaving ports 80 and 443 free for your NIO-based endpoints. You still have
access to the servlet-based endpoints if you want to use them instead.
Note: The LiveCycle Data Services installation includes an NIO load testing tool with sample test driver classes and a
readme file in the install_root/resources/load-testing-tool directory. You can use this tool in a Java client application to
load test LiveCycle Data Services NIO-based channels/endpoints running in a LiveCycle Data Services web application.
Use the servlet-based endpoints when you must include third-party servlet filter processing of requests and responses
or when you must access data structures in the application server HttpSession. NIO -based AMF and HTTP endpoints
are not part of the servlet pipeline, so, although they provide a FlexSession in the same manner that RTMP connections
do, these session instances are disjoint from the J2EE HttpSession.
If you are only using remote procedure calls or using the Data Management Service without auto synchronization, you
can use the AMFChannel.
Note: The HTTPChannel is the same as the AMFChannel behaviorally, but serializes data in an XML format called
AMFX. This channel only exists for customers who require all data sent over the wire to be non-binary for auditing
purposes. There is no other reason to use this channel instead of the AMFChannel for RPC-based applications.
The process for using real-time data push to web clients is not as simple as the RPC scenario. There are a variety of
trade-offs, and benefits and disadvantages to consider. Although the answer is not simple, it is prescriptive based on
the requirements of your application.
If your application uses both real-time data push as well as RPC, you do not need to use separate channels. All of the
channels listed can send RPC invocations to the server. Use a single channel set, possibly containing just a single
channel, for all of your RPC, messaging and data management components.
Servlet-based endpoints
Some servlet-based channel/endpoint combinations are preferred over others, depending on your application
environment. Each combination is listed here in order of preference. Although servlet-based channels/endpoints are
listed first, the equivalent NIO-based versions are preferred when NIO is available and acceptable in your application
environment.
1. AMFChannel/Endpoint configured for long polling (no fallback needed)
The channel issues polls to the server in the same way as simple polling, but if no data is available to return immediately
the server parks the poll request until data arrives for the client or the configured server wait interval elapses.
The client can be configured to issue its next poll immediately following a poll response making this channel
configuration feel like real-time communication.
A reasonable server wait time would be one minute. This eliminates the majority of busy polling from clients without
being so long that you’re keeping server sessions alive indefinitely or running the risk of a network component between
the client and server timing out the connection.
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Benefits
Disadvantages
Valid HTTP request/response
pattern over standard ports that
nothing in the network path will
have trouble with.
When many messages are being pushed to the client, this configuration has
the overhead of a poll round trip for every pushed message or small batch of
messages queued between polls. Most applications are not pushing data so
frequently for this to be a problem.
The Servlet API uses blocking IO, so you must define an upper bound for the
number of long poll requests parked on the server at any single instant. If your
number of clients exceeds this limit, the excess clients devolve to simple
polling on the default 3- second interval with no server wait. For example, if
you server request handler thread pool has a size of 500, you could set the
upper bound for waited polls to 250, 300, or 400 depending on the relative
amount of non-poll requests you expect to service concurrently.
2. StreamingAMFChannel/Endpoint (in a channel set followed by the polling AMFChannel for fallback)
Because HTTP connections are not duplex, this channel sends a request to open an HTTP connection between the
server and client, over which the server writes an infinite response of pushed messages. This channel uses a separate
transient connection from the browser connection pool for each send it issues to the server. The streaming connection
is used purely for messages pushed from the server down to the client. Each message is pushed as an HTTP response
chunk (HTTP 1.1 Transfer-Encoding: chunked).
Benefits
Disadvantages
No polling overhead associated
with pushing messages to the
client.
Holding onto the open request on the server and writing an infinite response
is not typical HTTP behavior. HTTP proxies that buffer responses before
forwarding them can effectively consume the stream. Assign the channel’s
‘connect-timeout-seconds’ property a value of 2 or 3 to detect this and trigger
fallback to the next channel in your channel set.
Uses standard HTTP ports so
firewalls do not interfere and all
requests/responses are HTTP so
packet inspecting proxies won’t
drop the packets.
No support for HTTP 1.0 client. If the client is 1.0, the open request is faulted
and the client falls back to the next channel in its channel set.
The Servlet API uses blocking IO so as with long polling above, you must set a
configured upper bound on the number of streaming connections you allow.
Clients that exceed this limit are not able to open a streaming connection and
will fall back to the next channel in their channel set.
3. AMFChannel/Endpoint with simple polling and piggybacking enabled (no fallback needed)
This configuration is the same as simple polling support but with piggybacking enabled. When the client sends a
message to the server between its regularly scheduled poll requests, the channel piggybacks a poll request along with
the message being sent, and the server piggybacks any pending messages for the client along with the response.
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Benefits
Disadvantages
Valid HTTP request/response
pattern over standard ports that
nothing in the network path will
have trouble with.
Less real-time behavior than long polling or streaming. Requires client
interaction with the server to receive pushed data faster than the channel's
configured polling interval.
User experience feels more realtime than with simple polling on
an interval.
Does not have thread resource
constraints like long polling and
streaming due to the blocking IO
of the Servlet API.
NIO-based endpoints
Some NIO-based channel/endpoint combinations are preferred over others, depending on your application
environment. Each combination is listed here in order of preference.
1. RTMPChannel/Endpoint (in a channel set with fallback to NIO AMFChannel configured to long poll)
The RTMPChannel creates a single duplex socket connection to the server and gives the server the best notification of
Flash Player being shut down. If the direct connect attempt fails, the player attempts a CONNECT tunnel through an
HTTP proxy if one is defined by the browser, resulting in a direct, tunneled duplex socket connection to the server. In
the worst case, the channel falls back to adaptive HTTP requests that tunnel RTMP data back and forth between client
and server, or it fails to connect entirely.
Benefits
Disadvantages
Single, stateful duplex socket that
gives clean, immediate
notification when a client is closed.
The NIO-based AMF and HTTP
channels/endpoints generally do
not receive notification of a client
going away until the HTTP session
on the server times out. That is not
optimal for a call center
application where you must know
whether representatives are
online or not.
RTMP generally uses a non-standard port so it is often blocked by client
firewalls. Network components that use stateful packet inspection might also
drop RTMP packets, killing the connection. Fallback to HTTP CONNECT
through a proxy or adaptive HTTP tunnel requests is difficult in deployment
scenarios within a Java servlet container which generally already has the
standard HTTP ports bound. This requires a non-trivial networking
configuration to route these requests to the RTMPEndpoint.
By using an Edge Server in the DMZ to forward requests to a LiveCycle Data
Services server in the application tier, you can avoid or work around some of
these issues. For more information about the Edge Server see “Edge Server” on
page 391.
The Flash Player internal fallback
to HTTP CONNECT to traverse an
HTTP proxy if one is configured in
the browser gives the same
benefit as above, and is a
technique that is not possible from
ActionScript or JavaScript.
2. NIO AMFChannel/Endpoint configured for long polling (no fallback needed)
This configuration is behaviorally the same as the servlet-based AMFChannel/AMFEndpoint but uses an NIO server
and minimal HTTP stack to support scaling up to thousands of connections.
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Benefits
Disadvantages
The same benefits as mentioned
for RTMPChannel/Endpoint, along
with much better scalability and
no configured upper bound on the
number of parked poll requests.
Because the servlet pipeline is not used, this endpoint requires more network
configuration to route requests to it on a standard HTTP port if you must
concurrently service HTTP servlet requests. However, it can share the same
port as any other NIO- based AMF or HTTP endpoint for the application.
3. NIO StreamingAMFChannel/Endpoint (in a channel set followed by the polling AMFChannel for fallback)
This configuration is behaviorally the same as the servlet-based StreamingAMFChannel/Endpoint but uses an NIO
server and minimal HTTP stack to support scaling up to thousands of connections.
Benefits
Disadvantages
The same benefits as mentioned
for NIO AMFChannel/Endpoint
configured for Long Polling, along
with much better scalability and
no configured upper bound on the
number of streaming connections.
Because the servlet pipeline is not being used, this endpoint requires more
network configuration to route requests to it on a standard HTTP port. It must
concurrently service HTTP servlet requests. However, it can share the same
port as any other NIO-based AMF or HTTP endpoint for the application.
Unlike RTMP, which provides a full duplex socket connection, this scenario
requires one connection for regular HTTP requests and responses, and another
connection for server-to-client updates.
4. NIO AMFChannel/Endpoint with simple polling enabled (no long polling) and piggybacking enabled (no
fallback needed)
Behaviorally the same as the equivalent servlet-based configuration, but uses an NIO server and minimal HTTP stack
to support scaling up to thousands of connections.
Benefits
Disadvantages
Same benefits as the servlet-based
piggybacking configuration.
Shares the same FlexSession as
other NIO-based AMF and HTTP
endpoints
Same disadvantages as the servlet-based piggybacking configuration.
Because the servlet pipeline is not being used, this endpoint requires more
network configuration to route requests to it on a standard HTTP port if you
need to concurrently service HTTP servlet requests. However, it can share the
same port as any other NIO-based AMF or HTTP endpoint for the application.
Using LiveCycle Data Services clients and servers behind a firewall
Because servlet-based endpoints use standard HTTP requests, communicating with clients inside firewalls usually
works, as long as the client-side firewall has the necessary ports open. Using the standard HTTP port 80 and HTTPS
port 443 is recommended because many firewalls block outbound traffic over non-standard ports.
When working with NIO-based endpoints, using AMF and HTTP endpoints instead of RTMP endpoints when clients
are inside a firewall allows the clients to connect to the server through their client-side firewall without running into a
blocked port. This method also allows packets to traverse stateful proxies that drop packets that they do not recognize,
but this requires that you expose the NIO-based AMF and HTTP endpoints on the standard HTTP port 80 and the
standard HTTPS port 443.
You can use load balancers with the NIO-based AMF and HTTP endpoints. You must configure the load balancer to
do sticky sessions based on the session cookie AMFSessionId, or based upon the session id embedded in request URLs
that match the format of J2EE-encoded URLs but use an AMFSessionId token rather than the J2EE jsessionid
token. For RTMP endpoints, you should apply TCP round-robin connectivity to the load-balanced RTMP port.
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You must configure server-side firewalls the same way you would to allow access to servlet-based AMF and HTTP
endpoints. Be aware of the following potential issues when using web servers/connectors in front of NIO-based AMF
and HTTP endpoints:
• The web server/connector could buffer streamed chunks in the response, interfering with real-time streaming. This
is not an issue for polling or long-polling, where a complete HTTP response is returned whenever data is sent to
the client.
• The web server/connector may not use asynchronous IO, in which case a single webserver or connector most likely
will not scale up to thousands of persistent concurrent HTTP connections.
The protocols that the various client channels use are hard coded. For example, the AMFChannel always uses HTTP,
while the SecureAMFChannel always uses HTTPS. One thing to watch for when using a
SecureAMFChannel/SecureAMFEndpoint combination is an issue with Internet Explorer related to no-cache
response headers and HTTPS. By default, no-cache response headers are enabled on HTTP-based endpoints. This
causes problems for Internet Explorer browsers. You can suppress these response headers by adding the following
configuration property to your endpoint:
<add-no-cache-headers>false</add-no-cache-headers>
When you have a firewall/reverse HTTP proxy in your deployment that handles SSL for you, you must mix and match
your channel and endpoint. You need the client to use a secure channel and the server to use an insecure endpoint, as
the following example shows:
<channel-definition id="secure-amf" class="mx.messaging.channels.SecureAMFChannel">
<endpoint url="https://<<firewall ip:port>>/{context.root}/messagebroker/amf"
class="flex.messaging.endpoints.AMFEndpoint"/>
<properties>
<add-no-cache-headers>false</add-no-cache-headers>
...
The channel class uses HTTPS to hit the firewall/proxy, and the endpoint URL must point at the firewall/proxy.
Because SSL is handled in the middle, you want the endpoint class used by LiveCycle Data Services to be the insecure
AMFEndpoint and your firewall/proxy must hand back requests to the HTTP port of the LiveCycle Data Services
server, not the HTTPS port.
Testing channel and endpoint performance under load
Use the LiveCycle Data Services load testing tool in a Java client application to load test LiveCycle Data Services NIOand servlet-based channels/endpoints running in a LiveCycle Data Services web application.
The LiveCycle Data Services installation includes the load testing tool with sample test driver classes and a readme file
in the install_root/resources/load-testing-tool directory.
Managing session data
Instances of the FlexClient, MessageClient, and FlexSession classes on the LiveCycle Data Services server represent a
Flex application and its connections to the server. You can use these objects to manage synchronization between a Flex
application and the server.
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FlexClient, MessageClient, and FlexSession objects
The FlexClient object
Every Flex application, written in MXML or ActionScript, is eventually compiled into a SWF file. When the SWF file
connects to the LiveCycle Data Services server, a flex.messaging.client.FlexClient object is created to represent that
SWF file on the server. SWF files and FlexClient instances have a one-to-one mapping. In this mapping, every
FlexClient instance has a unique identifier named id, which the LiveCycle Data Services server generates. An
ActionScript singleton class, mx.messaging.FlexClient, is also created for the Flex application to access its unique
FlexClient id.
The MessageClient object
If a Flex application contains a Consumer component (flex.messaging.Consumer), the server creates a corresponding
flex.messaging.MessageClient instance that represents the subscription state of the Consumer component. Every
MessageClient has a unique identifier named clientId. The LiveCycle Data Services server can automatically
generate the clientId value, but the Flex application can also set the value in the Consumer.clientId property
before calling the Consumer.subscribe() method.
The FlexSession object
A FlexSession object represents the connection between the Flex application and the LiveCycle Data Services server.
Its life cycle depends on the underlying protocol, which is determined by the channels and endpoints used on the client
and server, respectively.
If you use an RTMP channel in the Flex application, the FlexSession on the LiveCycle Data Services server is scoped to
the underlying RTMP connection from the single SWF file. The server is immediately notified when the underlying
SWF file is disconnected because RTMP provides a duplex socket connection between the SWF file and the LiveCycle
Data Services server. RTMP connections are created for individual SWF files, so when the connection is closed, the
associated FlexSession is invalidated.
If an HTTP-based channel, such as AMFChannel or HTTPChannel, is used in the Flex application, the FlexSession on
the LiveCycle Data Services server is scoped to the browser and wraps an HTTP session. If the HTTP-based channel
connects to a servlet-based endpoint, the underlying HTTP session is a J2EE HttpSession object. If the channel
connects to an NIO-based endpoint, the underlying HTTP session supports the FlexSession API, but it is disjointed
from the application server HttpSession object.
The relationship between FlexClient, MessageClient, and FlexSession classes
A FlexClient object can have one or more FlexSession instances associated with it depending on the channels that the
Flex application uses. For example, if the Flex application uses one HTTPChannel, one FlexSession represents the
HTTP session created for that HTTPChannel on the LiveCycle Data Services server. If the Flex application uses an
HTTPChannel and an RTMPChannel, two FlexSessions are created; one represents the HTTP session and the other
represents the RTMP session.
A FlexSession can also have one or more FlexClients associated with it. For example, when a SWF file that uses an
HTTPChannel is opened in two tabs, two FlexClient instances are created in the LCDS server (one for each SWF file),
but there is only one FlexSession because two tabs share the same underlying HTTP session.
In terms of hierarchy, FlexClient and FlexSession are peers whereas there is a parent-child relationship between
FlexClient/FlexSession and MessageClient. A MessageClient is created for every Consumer component in the Flex
application. A Consumer must be contained in a single SWF file and it must subscribe over a single channel. Therefore,
each MessageClient is associated with exactly one FlexClient and one FlexSession.
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If either the FlexClient or the FlexSession is invalidated on the server, it invalidates the MessageClient. This behavior
matches the behavior on the client. If you close the SWF file, the client subscription state is invalidated. If you
disconnect the channel or it loses connectivity, the Consumer component is unsubscribed.
Event listeners for FlexClient, MessageClient, and FlexSession
The LiveCycle Data Services server provides the following set of event listener interfaces that allow you to execute
custom business logic as FlexClient, FlexSession, and MessageClient instances are created and destroyed and as their
state changes:
Event listener
Description
FlexClientListener
FlexClientListener supports listening for life cycle events
for FlexClient instances.
FlexClientAttributeListener
FlexClientAttributeListener supports notification when
attributes are added, replaced, or removed from
FlexClient instances.
FlexClientBindingListener
FlexClientBindingListener supports notification when
the implementing class is bound or unbound as an
attribute to a FlexClient instance.
FlexSessionListener
FlexSessionListener supports listening for life cycle
events for FlexSession instances.
FlexSessionAttributeListener
FlexSessionAttributeListener supports notification when
attributes are added, replaced, or removed from
FlexSession instances.
FlexSessionBindingListener
FlexSessionBindingListener supports notification when
the implementing class is bound or unbound as an
attribute to a FlexSession instance.
MessageClientListener
MessageClientListener supports listening for life cycle
events for MessageClient instances representing
Consumer subscriptions.
For more information about these classes, see the Javadoc API documentation.
Log categories for FlexClient, MessageClient, and FlexSession classes
The following server-side log filter categories can be used to track creation, destruction, and other relevant information
for FlexClient, MessageClient, and FlexSession:
• Client.FlexClient
• Client.MessageClient
• Endpoint.FlexSession
Using the FlexContext class with FlexSession and FlexClient attributes
The flex.messaging.FlexContext class is a utility class that exposes the current execution context on the LiveCycle Data
Services server. It provides access to FlexSession and FlexClient instances associated with the current message being
processed. It also provides global context by accessing MessageBroker, ServletContext, and ServletConfig instances.
The following example shows a Java class that calls FlexContext.getHttpRequest() to get an HTTPServletRequest
object and calls FlexContext.getFlexSession() to get a FlexSession object. Exposing this class as a remote object
makes it accessible to a Flex client application. Place the compiled class in the WEB_INF/classes directory or your
LiveCycle Data Services web application.
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package myROPackage;
import
import
import
import
import
flex.messaging.*;
java.io.*;
java.util.*;
javax.servlet.*;
javax.servlet.http.*;
public class SessionRO {
public HttpServletRequest request;
public FlexSession session;
public SessionRO() {
request = FlexContext.getHttpRequest();
session = FlexContext.getFlexSession();
}
public String getSessionId() throws Exception {
String s = new String();
s = (String) session.getId();
return s;
}
public String getHeader(String h) throws Exception {
String s = new String();
s = (String) request.getHeader(h);
return h + "=" + s;
}
}
The following example shows a Remoting Service destination definition that exposes the SessionRO class as a remote
object. You add this destination definition to your Remoting Service configuration file.
...
<destination id="myRODestination">
<properties>
<source>myROPackage.SessionRO</source>
</properties>
</destination>
...
The following example shows an ActionScript snippet for calling the remote object from a Flex client application. You
place this code inside a method declaration.
...
ro = new RemoteObject();
ro.destination = "myRODestination";
ro.getSessionId.addEventListener("result", getSessionIdResultHandler);
ro.getSessionId();
...
When you use an RTMP channel/endpoint, you can call the getClientInfo() method of the FlexSession instance to
get the IP address of the remote RTMP client and determine if the connection is an SSL connection, as the
getClientIp() method in the following example shows. You must cast the FlexSession instance to its
RTMPFlexSession subclass.
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package features.remoting;
import features.dataservice.paging.Employee;
import flex.messaging.FlexContext;
import flex.messaging.FlexSession;
import flex.messaging.MessageBroker;
import flex.messaging.endpoints.rtmp.ClientInfo;
import flex.messaging.endpoints.rtmp.RTMPFlexSession;
import flex.messaging.messages.AsyncMessage;
import flex.messaging.util.UUIDUtils;
import javax.servlet.http.HttpServletRequest;
public class EchoService
{
public String getClientIp()
{
FlexSession session = FlexContext.getFlexSession();
if (session instanceof RTMPFlexSession)
{
ClientInfo clientInfo = ((RTMPFlexSession)session).getClientInfo();
return "Client ip: " + clientInfo.getIp() + " isSecure? " + clientInfo.isSecure();
}
return null;
}
}
For more information about FlexContext, see the Javadoc API documentation.
Session life cycle
If you use an RTMP channel in the Flex application, the server is immediately notified when the SWF file is
disconnected because RTMP provides a duplex socket connection between the SWF file and the LiveCycle Data
Services server. RTMP channels connect to individual SWF files, so when the connection is closed, the associated
FlexSession is invalidated. This is not the case with HTTP-based channels because HTTP is a stateless protocol.
However, you can use certain techniques in your code to disconnect from HTTP-based channels and invalidate HTTP
sessions.
Disconnecting from an HTTP-based channel
Because HTTP is a stateless protocol, when a SWF file is disconnected, notification on the server depends on when the
HTTP session times out on the server. When you want a Flex application to notify the LiveCycle Data Services server
that it is closing, you call the disconnectAll() method on the ChannelSet from JavaScript.
In your Flex application, expose a function for JavaScript to call, as the following example shows:
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<mx:Application creationComplete="init();">
...
<mx:Script>
<![CDATA[
import flash.external.ExternalInterface;
private function init():void
{
if (ExternalInterface.available)
{
ExternalInterface.addCallback("disconnectAll", disconnectAll);
}
}
// This function will be called by JavaScript
private function disconnectAll():void
{
// Here you get channelSet of your component and call disconnectAll.
// For example: producer.channelSet.disconnectAll();
}
...
</mx:Script>
</mx:Application>
Next, in the body element of the HTML file that wraps your SWF file, you specify an onunload() function, as the
following example shows:
<body ... onunload="disconnectAll()" ..>
Finally, you define the JavaScript disconnectAll() function that calls the ActionScript disconnectAll() method,
as the following example shows:
<script langugage='javascript' ..>
function disconnectAll()
{
var answer = confirm("Disconnect All?")
if (answer)
{
// Here you'll need to provide the id of your Flex swf
document.getElementById("yourFlexSwfId").disconnectAll();
// And it is important that you have some alert or confirm
// here to make sure disconnectAll is called before the
// browser window is closed.
alert("Disconnected!")
}
}
</script>
Invalidating an HTTP session
Another complication with using the HTTP protocol is that multiple SWF files share the same HTTP session. When
one SWF file disconnects, LiveCycle Data Services cannot invalidate the HTTP session. In this scenario, the default
behavior on the server is to leave the current session in place for other applications or pages that are using the HTTP
session. However, you can use the optional invalidate-session-on-disconnect configuration property in a
channel definition in the services-config.xml file to invalidate the session, as the following example shows:
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<channel-definition id="my-amf" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://servername:port/contextroot/messagebroker/amf"
class="flex.messaging.endpoints.AMFEndpoint"/>
<properties>
<invalidate-session-on-disconnect>true</invalidate-session-on-disconnect>
</properties>
</channel>
Data serialization
LiveCycle Data Services and Flex provide functionality for serializing data to and from ActionScript objects on the
client and Java objects on the server, as well as serializing to and from ActionScript objects on the client and SOAP and
XML schema types. Basic types are automatically serialized and deserialized. When working with the Data
Management Service or Remoting Service, you can explicitly map custom ActionScript types to custom Java types.
Serialization between ActionScript and Java
LiveCycle Data Services and Flex let you serialize data between ActionScript (AMF 3) and Java in both directions.
Data conversion from ActionScript to Java
When method parameters send data from a Flex application to a Java object, the data is automatically converted from
an ActionScript data type to a Java data type. When LiveCycle Data Services searches for a suitable method on the Java
object, it uses further, more lenient conversions to find a match.
Simple data types on the client, such as Boolean and String values, typically exactly match a remote API. However, Flex
attempts some simple conversions when searching for a suitable method on a Java object.
An ActionScript Array can index entries in two ways. A strict Array is one in which all indices are Numbers. An
associative Array is one in which at least one index is based on a String. It is important to know which type of Array
you are sending to the server, because it changes the data type of parameters that are used to invoke a method on a Java
object. A dense Array is one in which all numeric indices are consecutive, with no gap, starting from 0 (zero). A sparse
Array is one in which there are gaps between the numeric indices; the Array is treated like an object and the numeric
indices become properties that are deserialized into a java.util.Map object to avoid sending many null entries.
The following table lists the supported ActionScript (AMF 3) to Java conversions for simple data types:
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ActionScript type (AMF 3) Deserialization to Java
Supported Java type binding
Array (dense)
java.util.Collection, Object[ ] (native array)
java.util.List
If the type is an interface, it is mapped to the following
interface implementations
•
List becomes ArrayList
•
SortedSet becomes TreeSet
•
Set becomes HashSet
•
Collection becomes ArrayList
A new instance of a custom Collection implementation is
bound to that type.
Array (sparse)
java.util.Map
java.util.Map
Boolean
java.lang.Boolean
Boolean, boolean, String
String of "true" or
"false"
flash.utils.ByteArray
byte []
flash.utils.IExternalizable
java.io.Externalizable
Date
java.util.Date
(formatted for
Coordinated Universal
Time (UTC))
java.util.Date, java.util.Calendar, java.sql.Timestamp,
java.sql.Time, java.sql.Date
int/uint
java.lang.Integer
java.lang.Double, java.lang.Long, java.lang.Float,
java.lang.Integer, java.lang.Short, java.lang.Byte,
java.math.BigDecimal, java.math.BigInteger, String,
primitive types of double, long, float, int, short, byte
null
null
primitives
Number
java.lang.Double
java.lang.Double, java.lang.Long, java.lang.Float,
java.lang.Integer, java.lang.Short, java.lang.Byte,
java.math.BigDecimal, java.math.BigInteger, String, 0
(zero) if null is sent, primitive types of double, long, float,
int, short, byte
Object (generic)
java.util.Map
If a Map interface is specified, creates a new
java.util.HashMap for java.util.Map and a new
java.util.TreeMap for java.util.SortedMap.
String
java.lang.String
java.lang.String, java.lang.Boolean, java.lang.Number,
java.math.BigInteger, java.math.BigDecimal, char[],
enum, any primitive number type
typed Object
typed Object
typed Object
when you use
[RemoteClass]
metadata tag that
specifies remote class
name. Bean type must
have a public no args
constructor.
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ActionScript type (AMF 3) Deserialization to Java
Supported Java type binding
undefined
null
null for Object, default values for primitives
XML
org.w3c.dom.Document
org.w3c.dom.Document
XMLDocument
org.w3c.dom.Document
org.w3c.dom.Document
(legacy XML type)
You can enable legacy XML support for the
XMLDocument type on any channel defined in the
services-config.xml file. This setting is only important for
sending data from the server back to the client; it controls
how org.w3c.dom.Document instances are sent to
ActionScript. For more information, see “Configuring AMF
serialization on a channel” on page 84.
Primitive values cannot be set to null in Java. When passing Boolean and Number values from the client to a Java
object, Flex interprets null values as the default values for primitive types; for example, 0 for double, float, long, int,
short, byte, \u0000 for char, and false for boolean. Only primitive Java types get default values.
LiveCycle Data Services handles java.lang.Throwable objects like any other typed object. They are processed with rules
that look for public fields and bean properties, and typed objects are returned to the client. The rules are like normal
bean rules except they look for getters for read-only properties. This lets you get more information from a Java
exception. If you require legacy behavior for Throwable objects, you can set the legacy-throwable property to true
on a channel; for more information, see “Configuring AMF serialization on a channel” on page 84.
You can pass strict Arrays as parameters to methods that expect an implementation of the java.util.Collection or native
Java Array APIs.
A Java Collection can contain any number of Object types, whereas a Java Array requires that entries are the same type
(for example, java.lang.Object[ ], and int[ ]).
LiveCycle Data Services also converts ActionScript strict Arrays to appropriate implementations for common
Collection API interfaces. For example, if an ActionScript strict Array is sent to the Java object method public void
addProducts(java.util.Set products), LiveCycle Data Services converts it to a java.util.HashSet instance before
passing it as a parameter, because HashSet is a suitable implementation of the java.util.Set interface. Similarly,
LiveCycle Data Services passes an instance of java.util.TreeSet to parameters typed with the java.util.SortedSet
interface.
LiveCycle Data Services passes an instance of java.util.ArrayList to parameters typed with the java.util.List interface
and any other interface that extends java.util.Collection. Then these types are sent back to the client as
mx.collections.ArrayCollection instances. If you require normal ActionScript Arrays sent back to the client, you must
set the legacy-collection element to true in the serialization section of a channel-definition's properties; for
more information, see “Configuring AMF serialization on a channel” on page 84.
Explicitly mapping ActionScript and Java objects
For Java objects that LiveCycle Data Services does not handle implicitly, LiveCycle Data Services uses value objects,
also known as transfer objects, to send data between client and server. For Java objects on the server side, values found
in public bean properties with get/set methods and public variables are sent to the client as properties on an Object.
Private properties, constants, static properties, and read-only properties are not serialized. For ActionScript objects on
the client side, public properties defined with the get/set accessors and public variables are sent to the server.
LiveCycle Data Services uses the standard Java class, java.beans.Introspector, to get property descriptors for a Java bean
class. It also uses reflection to gather public fields on a class. It uses bean properties in preference to fields. The Java
and ActionScript property names should match. Native Flash Player code determines how ActionScript classes are
introspected on the client.
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In the ActionScript class, you use the [RemoteClass(alias=" ")] metadata tag to create an ActionScript object that
maps directly to the Java object. The ActionScript class to which data is converted must be used or referenced in the
MXML file for it to be linked into the SWF file and available at run time. A good way to do this is by casting the result
object, as the following example shows:
var result:MyClass = MyClass(event.result);
The class itself should use strongly typed references so that its dependencies are also linked.
The following example shows the source code for an ActionScript class that uses the [RemoteClass(alias=" ")]
metadata tag:
package samples.contact {
[Bindable]
[RemoteClass(alias="samples.contact.Contact")]
public class Contact {
public var contactId:int;
public var firstName:String;
public var lastName:String;
public var address:String;
public var city:String;
public var state:String;
public var zip:String;
}
}
You can use the [RemoteClass] metadata tag without an alias if you do not map to a Java object on the server, but
you do send back your object type from the server. Your ActionScript object is serialized to a special Map object when
it is sent to the server, but the object returned from the server to the clients is your original ActionScript type.
To restrict a specific property from being sent to the server from an ActionScript class, use the [Transient] metadata
tag above the declaration of that property in the ActionScript class.
Data conversion from Java to ActionScript
An object returned from a Java method is converted from Java to ActionScript. LiveCycle Data Services also handles
objects found within objects. LiveCycle Data Services implicitly handles the Java data types in the following table.
Java type
ActionScript type (AMF 3)
enum (JDK 1.5)
String
java.lang.String
String
java.lang.Boolean, boolean
Boolean
java.lang.Integer, int
int
If value < 0xF0000000 || value > 0x0FFFFFFF, the value is promoted to
Number due to AMF encoding requirements.
java.lang.Short, short
int
If i < 0xF0000000 || i > 0x0FFFFFFF, the value is promoted to Number.
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Java type
ActionScript type (AMF 3)
java.lang.Byte, byte[]
int
If i < 0xF0000000 || i > 0x0FFFFFFF, the value is promoted to Number.
java.lang.Byte[]
flash.utils.ByteArray
java.lang.Double, double
Number
java.lang.Long, long
Number
java.lang.Float, float
Number
java.lang.Character, char
String
java.lang.Character[], char[]
String
java. math.BigInteger
String
java.math.BigDecimal
String
java.util.Calendar
Date
Dates are sent in the Coordinated Universal Time (UTC) time zone. Clients
and servers must adjust time accordingly for time zones.
java.util.Date
Date
Dates are sent in the UTC time zone. Clients and servers must adjust time
accordingly for time zones.
java.util.Collection (for example,
java.util.ArrayList)
mx.collections.ArrayCollection
java.lang.Object[]
Array
java.util.Map
Object (untyped). For example, a java.util.Map[] is converted to an Array (of
Objects).
java.util.Dictionary
Object (untyped)
org.w3c.dom.Document
XML object
null
null
java.lang.Object (other than
previously listed types)
Typed Object
Objects are serialized using Java bean introspection rules and also include
public fields. Fields that are static, transient, or nonpublic, as well as bean
properties that are nonpublic or static, are excluded.
Note: You can enable legacy XML support for the flash.xml.XMLDocument type on any channel that is defined in the
services-config.xml file. In Flex 1.5, java.util.Map was sent as an associative or ECMA Array. This is no longer a
recommended practice. You can enable legacy Map support to associative Arrays, but Adobe recommends against doing this.
The following table contains type mappings between types that are specific to Apache Axis and ActionScript types for
RPC-encoded web services:
Apache Axis type
ActionScript type
Map
Object
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Apache Axis type
ActionScript type
RowSet
Can only receive RowSets; can’t send them.
Document
Can only receive Documents; can’t send them.
Element
flash.xml.XMLNode
Configuring AMF serialization on a channel
You can support legacy AMF type serialization used in earlier versions of Flex and configure other serialization
properties in channel definitions in the services-config.xml file.
The following table describes the properties that you can set in the <serialization> element of a channel definition:
Property
Description
enable-small-messages
Default value is true. If enabled, messages are sent using an alternative
smaller form if one is available and the endpoint supports it. When you set
the value of this property to false, messages include headers including
messageId, timestamp, correlationId, and destination, which can be useful
for debugging. When you disable small messages, enable debug logging to
include messages in server logs. For information, see “Server-side logging”
on page 25.
ignore-property-errors
Default value is true. Determines if the endpoint should throw an error
when an incoming client object has unexpected properties that cannot be
set on the server object.
include-read-only
Default value is false. Determines if read-only properties should be
serialized back to the client.
log-property-errors
Default value is false. When true, unexpected property errors are logged.
legacy-collection
Default value is false. When true, instances of java.util.Collection are
returned to the client as ActionScript Array objects instead of
mx.collections.ArrayCollection objects. When true, during client to server
deserialization, instances of ActionScript Array objects are deserialized into
Java List objects instead of Java Object arrays.
legacy-map
Default value is false. When true, java.util.Map instances are serialized as
an ECMA Array or associative array instead of an anonymous Object.
legacy-xml
Default value is false. When true, org.w3c.dom.Document instances are
serialized as flash.xml.XMLDocument instances instead of intrinsic XML (E4X
capable) instances.
legacy-throwable
Default value is false. When true, java.lang.Throwable instances are
serialized as AMF status-info objects (instead of normal bean serialization,
including read-only properties).
legacy-externalizable
Default value is false. When true, java.io.Externalizable types (that extend
standard Java classes like Date, Number, String) are not serialized as custom
objects (for example, MyDate is serialized as Date instead of MyDate). Note
that this setting overwrites any other legacy settings. For example, if
legacy-collection is true but the collection implements
java.io.Externalizable, the collection is returned as custom object without
taking the legacy-collection value into account.
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Property
Description
type-marshaller
Specifies an implementation of flex.messaging.io.TypeMarshaller that
translates an object into an instance of a desired class. Used when invoking
a Java method or populating a Java instance and the type of the input object
from deserialization (for example, an ActionScript anonymous Object is
always deserialized as a java.util.HashMap) doesn't match the destination
API (for example, java.util.SortedMap). Thus, the type can be marshalled into
the desired type.
The flex.messaging.io.amf.translator.ASTranslator class is an
implementation of TypeMarshaller that you can use as an example for your
own TypeMarshaller implementations.
restore-references
Default value is false. An advanced switch to make the deserializer keep
track of object references when a type translation has to be made; for
example, when an anonymous Object is sent for a property of type
java.util.SortedMap, the Object is first deserialized to a java.util.Map as
normal, and then translated to a suitable implementation of SortedMap
(such as java.util.TreeMap). If other objects pointed to the same anonymous
Object in an object graph, this setting restores those references instead of
creating SortedMap implementations everywhere. Notice that setting this
property to true can slow down performance significantly for large
amounts of data.
instantiate-types
Default value is true. Advanced switch that when set to false stops the
deserializer from creating instances of strongly typed objects and instead
retains the type information and deserializes the raw properties in a Map
implementation, specifically flex.messaging.io.ASObject. Notice that any
classes under flex.* package are always instantiated.
Using custom serialization between ActionScript and Java
If the standard mechanisms for serializing and deserializing data between ActionScript on the client and Java on the
server do not meet your needs, you can write your own serialization scheme. You implement the ActionScript-based
flash.utils.IExternalizable interface on the client and the corresponding Java-based java.io.Externalizable interface on
the server.
A typical reason to use custom serialization is to avoid passing all of the properties of either the client-side or serverside representation of an object across the network tier. When you implement custom serialization, you can code your
classes so that specific properties that are client-only or server-only are not passed over the wire. When you use the
standard serialization scheme, all public properties are passed back and forth between the client and the server.
On the client side, the identity of a class that implements the flash.utils.IExternalizable interface is written in the
serialization stream. The class serializes and reconstructs the state of its instances. The class implements the
writeExternal() and readExternal() methods of the IExternalizable interface to get control over the contents and
format of the serialization stream, but not the class name or type, for an object and its supertypes. These methods
supersede the native AMF serialization behavior. These methods must be symmetrical with their remote counterpart
to save the state of the class.
On the server side, a Java class that implements the java.io.Externalizable interface performs functionality that is
analogous to an ActionScript class that implements the flash.utils.IExternalizable interface.
Note: You should not use types that implement the IExternalizable interface with the HTTPChannel if precise byreference serialization is required. When you do this, references between recurring objects are lost and appear to be cloned
at the endpoint.
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Client-side Product class
The following example shows the complete source code for the client (ActionScript) version of a Product class that
maps to a Java-based Product class on the server. The client Product class implements the IExternalizable interface and
the server Product class implements the Externalizable interface.
// Product.as
package samples.externalizable {
import flash.utils.IExternalizable;
import flash.utils.IDataInput;
import flash.utils.IDataOutput;
[RemoteClass(alias="samples.externalizable.Product")]
public class Product implements IExternalizable {
public function Product(name:String=null) {
this.name = name;
}
public
public
public
public
var
var
var
var
id:int;
name:String;
properties:Object;
price:Number;
public function readExternal(input:IDataInput):void {
name = input.readObject() as String;
properties = input.readObject();
price = input.readFloat();
}
public function writeExternal(output:IDataOutput):void {
output.writeObject(name);
output.writeObject(properties);
output.writeFloat(price);
}
}
}
The client Product class uses two kinds of serialization. It uses the standard serialization that is compatible with the
java.io.Externalizable interface and AMF 3 serialization. The following example shows the writeExternal() method
of the client Product class, which uses both types of serialization:
public function writeExternal(output:IDataOutput):void {
output.writeObject(name);
output.writeObject(properties);
output.writeFloat(price);
}
As the following example shows, the writeExternal() method of the server Product class is almost identical to the
client version of this method:
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject(name);
out.writeObject(properties);
out.writeFloat(price);
}
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In the writeExternal() method of the client Product class, the flash.utils.IDataOutput.writeFloat()
method is an example of standard serialization methods that meet the specifications for the Java
java.io.DataInput.readFloat() methods for working with primitive types. This method sends the price
property, which is a Float, to the server Product.
The examples of AMF 3 serialization in the writeExternal() method of the client Product class is the call to the
flash.utils.IDataOutput.writeObject() method, which maps to the java.io.ObjectInput.readObject()
method call in the server Product class readExternal() method. The flash.utils.IDataOutput.writeObject()
method sends the properties property, which is an Object, and the name property, which is a String, to the server
Product. This is possible because the AMFChannel endpoint has an implementation of the java.io.ObjectInput
interface that expects data sent from the writeObject() method to be formatted as AMF 3.
In turn, when the readObject() method is called in the server Product's readExternal() method, it uses AMF 3
deserialization; this is why the ActionScript version of the properties value is assumed to be of type Map and name
is assumed to be of type String.
Server-side Product class
The following example shows the complete source code of the server Product class:
// Product.java
package samples.externalizable;
import
import
import
import
import
java.io.Externalizable;
java.io.IOException;
java.io.ObjectInput;
java.io.ObjectOutput;
java.util.Map;
/**
* This Externalizable class requires that clients sending and
* receiving instances of this type adhere to the data format
* required for serialization.
*/
public class Product implements Externalizable {
private String inventoryId;
public String name;
public Map properties;
public float price;
public Product()
{
}
/**
* Local identity used to track third party inventory. This property is
* not sent to the client because it is server-specific.
* The identity must start with an 'X'.
*/
public String getInventoryId() {
return inventoryId;
}
public void setInventoryId(String inventoryId) {
if (inventoryId != null && inventoryId.startsWith("X"))
{
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this.inventoryId = inventoryId;
}
else
{
throw new IllegalArgumentException("3rd party product
inventory identities must start with 'X'");
}
}
/**
* Deserializes the client state of an instance of ThirdPartyProxy
* by reading in String for the name, a Map of properties
* for the description, and
* a floating point integer (single precision) for the price.
*/
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
// Read in the server properties from the client representation.
name = (String)in.readObject();
properties = (Map)in.readObject();
price = in.readFloat();
setInventoryId(lookupInventoryId(name, price));
}
/**
* Serializes the server state of an instance of ThirdPartyProxy
* by sending a String for the name, a Map of properties
* String for the description, and a floating point
* integer (single precision) for the price. Notice that the inventory
* identifier is not sent to external clients.
*/
public void writeExternal(ObjectOutput out) throws IOException {
// Write out the client properties from the server representation
out.writeObject(name);
out.writeObject(properties);
out.writeFloat(price);
}
private static String lookupInventoryId(String name, float price) {
String inventoryId = "X" + name + Math.rint(price);
return inventoryId;
}
}
The following example shows the readExternal() method of the server Product class:
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
// Read in the server properties from the client representation.
name = (String)in.readObject();
properties = (Map)in.readObject();
price = in.readFloat();
setInventoryId(lookupInventoryId(name, price));
}
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The writeExternal() method of the client Product class does not send the id property to the server during
serialization because it is not useful to the server version of the Product object. Similarly, the writeExternal()
method of the server Product class does not send the inventoryId property to the client because it is a server-specific
property.
Notice that the names of a Product properties are not sent during serialization in either direction. Because the state of
the class is fixed and manageable, the properties are sent in a well-defined order without their names, and the
readExternal() method reads them in the appropriate order.
Remote object class
The following example shows the source code of the Java class, ProductRegistry, which is called with the RemoteObject
component on the client:
package example.externalizable;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* A simple registry to manage instances of Product for an example of the
* Externalizable API for custom serialization.
*/
public class ProductRegistry
{
public ProductRegistry()
{
registry = Collections.synchronizedMap(new HashMap());
Product p = new Product();
p.name = "Example Widget";
p.description = "The right widget for any problem.";
p.price = 350;
registerProduct(p);
p = new Product();
p.name = "Example Gift";
p.description = "The perfect gift for any occasion.";
p.price = 225;
registerProduct(p);
}
public void registerProduct(Product product)
{
registry.put(product.getId(), product);
}
public Collection getProducts()
{
return registry.values();
}
private Map registry;
}
Destination configuration
The following XML snippet shows the ProductRegistry destination in the remoting-config.xml file:
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<destination id="ProductRegistry">
<properties>
<source>example.externalizable.ProductRegistry</source>
<scope>application</scope>
</properties>
</destination>
MXML application code
The following example shows the MXML application that calls the ProductRegistry destination on the server:
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.controls.Alert;
import mx.rpc.events.FaultEvent;
import mx.rpc.events.ResultEvent;
import example.externalizable.Product;
[Bindable]
public var products:ArrayCollection
// Create a compile time dependency on Product class.
private static var dep:Product;
public function resultHandler(event:ResultEvent):void
{
products = event.result as ArrayCollection;
}
public function faultHandler(event:FaultEvent):void
{
Alert.show("Fault", event.fault.toString());
}
]]>
</mx:Script>
<mx:RemoteObject id="remoteObject" destination="ProductRegistry"
fault="faultHandler(event)"
result="resultHandler(event)" />
<mx:Panel title="Externalizable Example" height="400" width="600"
paddingTop="10" paddingLeft="10" paddingRight="10">
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<mx:DataGrid id="grid" width="100%" rowCount="5" dataProvider="{products}">
<mx:columns>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="price" headerText="Price"/>
</mx:columns>
</mx:DataGrid>
<mx:Form width="100%">
<mx:FormItem label="Name">
<mx:Label text="{grid.selectedItem.name}"/>
</mx:FormItem>
<mx:FormItem label="Price">
<mx:Label text="{grid.selectedItem.price}"/>
</mx:FormItem>
<mx:FormItem label="Description">
<mx:TextArea text="{grid.selectedItem.description}"/>
</mx:FormItem>
</mx:Form>
<mx:Button label="Get Products" click="remoteObject.getProducts()" />
</mx:Panel>
</mx:Application>
Serialization between ActionScript and web services
Default encoding of ActionScript data
The following table shows the default encoding mappings from ActionScript 3 types to XML schema complex types.
XML schema definition
Supported ActionScript 3
types
Notes
Object
If input value is null, encoded output is set with
the xsi:nil attribute.
Object
Input value is ignored and fixed value is used
instead.
Object
If input value is null, this default value is used
instead.
Object
Input value is ignored and omitted from encoded
output.
Top-level elements
xsd:element
nillable == true
xsd:element
fixed != null
xsd:element
default != null
Local elements
xsd:element
maxOccurs == 0
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xsd:element
Object
Input value is processed as a single entity. If the
associated type is a SOAP-encoded array, then
arrays and mx.collection.IList
implementations pass through intact and are
handled as a special case by the SOAP encoder for
that type.
Object
Input value should be iterable (such as an array or
mx.collections.IList implementation),
although noniterable values are wrapped before
processing. Individual items are encoded as
separate entities according to the definition.
Object
If input value is undefined or null, encoded
output is omitted.
maxOccurs == 1
xsd:element
maxOccurs > 1
xsd:element
minOccurs == 0
The following table shows the default encoding mappings from ActionScript 3 types to XML schema built-in types.
XML schema type
Supported ActionScript 3
types
Notes
xsd:anyType
Object
Boolean -> xsd:boolean
ByteArray -> xsd:base64Binary
xsd:anySimpleType
Date -> xsd:dateTime
int -> xsd:int
Number -> xsd:double
String -> xsd:string
uint -> xsd:unsignedInt
xsd:base64Binary
flash.utils.ByteArray
mx.utils.Base64Encoder is used (without
line wrapping).
Boolean
Always encoded as true or false.
Number
Number == 1 then true, otherwise false.
Object
Object.toString() == "true" or "1" then
true, otherwise false.
xsd:byte
Number
String first converted to Number.
xsd:unsignedByte
String
xsd:date
Date
Date UTC accessor methods are used.
Number
Number used to set Date.time.
String
String assumed to be preformatted and encoded
as is.
Date
Date UTC accessor methods are used.
Number
Number used to set Date.time.
String
String assumed to be preformatted and encoded
as is.
Number
Number.toString() is used. Note that Infinity,
xsd:boolean
xsd:dateTime
xsd:decimal
String
-Infinity, and NaN are invalid for this type.
String first converted to Number.
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XML schema type
Supported ActionScript 3
types
Notes
xsd:double
Number
Limited to range of Number.
String
String first converted to Number.
xsd:duration
Object
Object.toString() is called.
xsd:float
Number
Limited to range of Number.
String
String first converted to Number.
Date
Date.getUTCDate() is used.
Number
Number used directly for day.
String
String parsed as Number for day.
Date
Date.getUTCMonth() is used.
Number
Number used directly for month.
String
String parsed as Number for month.
Date
Date.getUTCMonth() and
Date.getUTCDate() are used.
xsd:gDay
xsd:gMonth
xsd:gMonthDay
String
String parsed for month and day portions.
xsd:gYear
xsd:gYearMonth
Date
Date.getUTCFullYear() is used.
Number
Number used directly for year.
String
String parsed as Number for year.
Date
Date.getUTCFullYear() and
Date.getUTCMonth() are used.
String
String parsed for year and month portions.
xsd:hexBinary
flash.utils.ByteArray
mx.utils.HexEncoder is used.
xsd:integer
Number
Limited to range of Number.
and derivatives:
String
String first converted to Number.
xsd:int
Number
String first converted to Number.
xsd:unsignedInt
String
xsd:long
Number
xsd:unsignedLong
String
xsd:short
Number
xsd:unsignedShort
String
xsd:negativeInteger
xsd:nonNegativeInteger
xsd:positiveInteger
xsd:nonPositiveInteger
String first converted to Number.
String first converted to Number.
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XML schema type
Supported ActionScript 3
types
Notes
xsd:string
Object
Object.toString() is invoked.
Date
Date UTC accessor methods are used.
Number
Number used to set Date.time.
String
String assumed to be preformatted and encoded
as is.
null
If the corresponding XML schema element
definition has minOccurs > 0, a null value is
encoded by using xsi:nil; otherwise the element is
omitted entirely.
and derivatives:
xsd:ID
xsd:IDREF
xsd:IDREFS
xsd:ENTITY
xsd:ENTITIES
xsd:language
xsd:Name
xsd:NCName
xsd:NMTOKEN
xsd:NMTOKENS
xsd:normalizedString
xsd:token
xsd:time
xsi:nil
The following table shows the default mapping from ActionScript 3 types to SOAP-encoded types.
SOAPENC type
Supported ActionScript 3
types
Notes
soapenc:Array
Array
SOAP-encoded arrays are special cases and are supported only
with RPC-encoded web services.
mx.collections.IList
soapenc:base64
flash.utils.ByteArray
Encoded in the same manner as xsd:base64Binary.
soapenc:*
Object
Any other SOAP-encoded type is processed as if it were in the
XSD namespace based on the localName of the type's QName.
Default decoding of XML schema and SOAP to ActionScript 3
The following table shows the default decoding mappings from XML schema built-in types to ActionScript 3 types.
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XML schema type
Decoded ActionScript 3
types
Notes
xsd:anyType
String
If content is empty -> xsd:string.
xsd:anySimpleType
Boolean
If content cast to Number and value is NaN; or
Number
if content starts with "0" or "-0", or
if content ends with "E":
then, if content is "true" or "false" -> xsd:boolean
otherwise -> xsd:string.
Otherwise content is a valid Number and thus ->
xsd:double.
xsd:base64Binary
flash.utils.ByteArray
mx.utils.Base64Decoder is used.
xsd:boolean
Boolean
If content is "true" or "1" then true, otherwise
false.
xsd:date
Date
If no time zone information is present, local time is
assumed.
xsd:dateTime
Date
If no time zone information is present, local time is
assumed.
xsd:decimal
Number
Content is created via Number(content) and is
thus limited to the range of Number.
Number.NaN, Number.POSITIVE_INFINITY and
Number.NEGATIVE_INFINITY are not allowed.
xsd:double
Number
Content is created via Number(content) and is
thus limited to the range of Number.
xsd:duration
String
Content is returned with whitespace collapsed.
xsd:float
Number
Content is converted through Number(content)
and is thus limited to the range of Number.
xsd:gDay
uint
Content is converted through uint(content).
xsd:gMonth
uint
Content is converted through uint(content).
xsd:gMonthDay
String
Content is returned with whitespace collapsed.
xsd:gYear
uint
Content is converted through uint(content).
xsd:gYearMonth
String
Content is returned with whitespace collapsed.
xsd:hexBinary
flash.utils.ByteArray
mx.utils.HexDecoder is used.
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XML schema type
Decoded ActionScript 3
types
Notes
xsd:integer
Number
Content is decoded via parseInt().
Number.NaN, Number.POSITIVE_INFINITY and
Number.NEGATIVE_INFINITY are not allowed.
and derivatives:
xsd:byte
xsd:int
xsd:long
xsd:negativeInteger
xsd:nonNegativeInteger
xsd:nonPositiveInteger
xsd:positiveInteger
xsd:short
xsd:unsignedByte
xsd:unsignedInt
xsd:unsignedLong
xsd:unsignedShort
String
The raw content is simply returned as a string.
xsd:time
Date
If no time zone information is present, local time is
assumed.
xsi:nil
null
xsd:string
and derivatives:
xsd:ID
xsd:IDREF
xsd:IDREFS
xsd:ENTITY
xsd:ENTITIES
xsd:language
xsd:Name
xsd:NCName
xsd:NMTOKEN
xsd:NMTOKENS
xsd:normalizedString
xsd:token
The following table shows the default decoding mappings from SOAP-encoded types to ActionScript 3 types.
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SOAPENC type
Decoded ActionScript
type
Notes
soapenc:Array
Array
SOAP-encoded arrays are special cases. If
makeObjectsBindable is true, the result is wrapped in
an ArrayCollection; otherwise a simple array is returned.
mx.collections.Ar
rayCollection
soapenc:base64
flash.utils.ByteA
rray
Decoded in the same manner as xsd:base64Binary.
soapenc:*
Object
Any other SOAP-encoded type is processed as if it were in
the XSD namespace based on the localName of the
type's QName.
The following table shows the default decoding mappings from custom data types to ActionScript 3 data types.
Custom type
Decoded ActionScript 3 type
Notes
Apache Map
Object
SOAP representation of java.util.Map. Keys
must be representable as strings.
http://xml.apache.o
rg/xml-soap:Map
Apache Rowset
Array of objects
http://xml.apache.o
rg/xml-soap:Rowset
ColdFusion QueryBean
Array of objects
http://rpc.xml.cold
fusion:QueryBean
mx.collections.ArrayColl
ection of objects
If makeObjectsBindable is true, the resulting
array is wrapped in an ArrayCollection.
XML Schema element support
The following XML schema structures or structure attributes are only partially implemented in Flex 3:
<choice>
<all>
<union
The following XML Schema structures or structure attributes are ignored and are not supported in Flex 3:
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<attribute use="required"/>
<element
substitutionGroup="..."
unique="..."
key="..."
keyref="..."
field="..."
selector="..."/>
<simpleType>
<restriction>
<minExclusive>
<minInclusive>
<maxExclusiv>
<maxInclusive>
<totalDigits>
<fractionDigits>
<length>
<minLength>
<maxLength>
<enumeration>
<whiteSpace>
<pattern>
</restriction>
</simpleType>
<complexType
final="..."
block="..."
mixed="..."
abstract="..."/>
<any
processContents="..."/>
<annotation>
Customizing web service type mapping
When consuming data from a web service invocation, Flex usually creates untyped anonymous ActionScript objects
that mimic the XML structure in the body of the SOAP message. If you want Flex to create an instance of a specific
class, you can use an mx.rpc.xml.SchemaTypeRegistry object and register a QName object with a corresponding
ActionScript class.
For example, suppose you have the following class definition in a file named User.as:
package
{
public class User
{
public function User() {}
public var firstName:String;
public var lastName:String;
}
}
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Next, you want to invoke a getUser operation on a web service that returns the following XML:
<tns:getUserResponse xmlns:tns="http://example.uri">
<tns:firstName>Ivan</tns:firstName>
<tns:lastName>Petrov</tns:lastName>
</tns:getUserResponse>
To make sure you get an instance of your User class instead of a generic Object when you invoke the getUser operation,
you need the following ActionScript code inside a method in your Flex application:
SchemaTypeRegistry.getInstance().registerClass(new QName("http://example.uri",
"getUserResponse"), User);
SchemaTypeRegistry.getInstance() is a static method that returns the default instance of the type registry. In
most cases, that is all you need. However, this registers a given QName with the same ActionScript class across all web
service operations in your application. If you want to register different classes for different operations, you need the
following code in a method in your application:
var qn:QName = new QName("http://the.same", "qname");
var typeReg1:SchemaTypeRegistry = new SchemaTypeRegistry();
var typeReg2:SchemaTypeRegistry = new SchemaTypeRegistry();
typeReg1.registerClass(qn, someClass);
myWS.someOperation.decoder.typeRegistry = typeReg1;
typeReg2.registerClass(qn, anotherClass);
myWS.anotherOperation.decoder.typeRegistry = typeReg2;
Using custom web service serialization
There are two approaches to take full control over how ActionScript objects are serialized into XML and how XML
response messages are deserialized. The recommended approach is to work directly with E4X.
If you pass an instance of XML as the only parameter to a web service operation, it is passed on untouched as the child
of the <SOAP:Body> node in the serialized request. Use this strategy when you need full control over the SOAP
message. Similarly, when deserializing a web service response, you can set the operation’s resultFormat property to
e4x. This returns an XMLList object with the children of the <SOAP:Body> node in the response message. From there,
you can implement the necessary custom logic to create the appropriate ActionScript objects.
The second and more tedious approach is to provide your own implementations of mx.rpc.soap.ISOAPDecoder and
mx.rpc.soap.ISOAPEncoder. For example, if you have written a class called MyDecoder that implements
ISOAPDecoder, you can have the following in a method in your Flex application:
myWS.someOperation.decoder = new MyDecoder();
When invoking someOperation, Flex calls the decodeResponse() method of the MyDecoder class. From that point
on it is up to the custom implementation to handle the full SOAP message and produce the expected ActionScript
objects.
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Data throttling
Both BlazeDS and LiveCycle Data Services provide data throttling features that give you control over aspects of the
server’s underlying messaging system.
You use data throttling to limit the number of server-to-client and client-to-server messages that a Message Service or
Data Management Service destination can process per second. You can also set absolute limits for the number of
client-to-server and server-to-client messages allowed per second. Without data throttling, the server pushes messages
to clients without any indication on how fast the clients are processing messages. Similarly, a high number of messages
from Flex clients can overwhelm a server. Throttling is useful when the server could overwhelm slow clients with a
high number of messages that they cannot process or the server could be overwhelmed with messages from clients.
For server-to-client messages in LiveCycle Data Services, you can use adaptive throttling to message frequency limits
based on the message processing rates of clients. You can also set policies that determine what happens to messages
that exceed the specified maximum message limits.
Note: In addition to these standard throttling features, a set of advanced capabilities are available in LiveCycle Data
Service only. For more information, see “Advanced data tuning” on page 106.
Message frequency limits
Control the rate at which a Message Service or Data Management Service destination on the server sends messages to
or accepts messages from Flex clients in the following ways:
Message frequency
limit
Description
Destination-level
frequency
In a destination definition on the server, you can specify server-to-client and client-to-server
message frequency limits in the throttle-outbound and throttle-inbound elements,
respectively. There are separate settings for controlling message frequency globally and on
a per-client basis.
Client-level
On the Flex client side, you can set the maxFrequency property of a Consumer,
MultiTopicConsumer, or DataService component to limit the maximum number of
messages that the component prefers to receive from the server. If possible, the server
accommodates this setting. For MultiTopic Consumer and DataService components, which
allow multiple subscriptions, you can set the maxFrequency property on a per subscription
basis.
Adaptive
Advanced feature not available in BlazeDS. See “Advanced data throttling” on page 109.
Destination-level message frequency
You specify client-to-server and server-to-client message frequency limits for a destination in the destination’s
throttle-inbound and throttle-outbound elements. Use the max-frequency attribute to set the maximum
number of client-to-server or server-to-client messages per second that the destination can process. Use the maxclient-frequency attribute to set the maximum number of client-to-server or server-to-client messages per second
that the destination can process to or from individual clients.
The following example shows throttle-outbound and throttle-inbound elements with max-frequency and maxclient-frequency attributes:
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...
<destination id="MyTopic">
<properties>
<network>
<throttle-outbound policy="ERROR"
max-frequency="100" max-client-frequency="10"/>
<throttle-inbound policy="IGNORE"
max-frequency="100" max-client-frequency="10"/>
...
The max-frequency attribute of the throttle-outbound element indicates that the destination sends a maximum of
100 messages per second to the entire pool of Flex clients. The max-client-frequency attribute indicates that the
destination sends a maximum of ten messages per second to individual Flex clients.
The max-frequency element of the throttle-inbound element indicates that the destination processes a maximum
of 100 client-to-server messages per second from the entire pool of Flex clients. The max-client-frequency attribute
indicates that the destination processes a maximum of ten messages per second from individual Flex clients.
Client-level message frequency
The maxFrequency property of a client-side Consumer, MultiTopicConsumer, or DataService component lets you
limit the number of messages the component receives from a destination. The server read this information and ensures
that it limits the messages it sends to the maximum number of messages per second specified. The server sends up to
the limit, but can send fewer messages depending on how many messages are available on the server to send. The
maxFrequency property is set when the Consumer, MutiTopicConsumer, or DataService component subscribes.
The following example sets the maxFrequency property of a Consumer component that you create in ActionScript:
...
<mx:Script>
<![CDATA[
var consumer:Consumer = new Consumer();
consumer.destination = "chat";
consumer.maxFrequency = 40;
consumer.subscribe();
]]>
</mx:Script>
...
You can also set the maxFrequency property of a Consumer, MultiTopicConsumer, or DataService component that
you create in MXML as the following example shows:
...
<mx:Consumer id="consumer" destination="chat" maxFrequency="40"/>
...
MultiTopicConsumer message frequency
Unlike the standard Consumer component, the MultiTopicConsumer component supports multiple subscriptions.
You can set a default value for the maxFrequency property of a MultiTopicConsumer component, and also set
separate values for individual subscriptions. The following example shows a MultiTopicConsumer with a default
maxFrequency value of 40 messages per second. One of its two subscriptions uses the default value, while the other
uses a different maxFrequency value specified in the third parameter of the addSubscription() method. The first
two parameters of the addSubscription() method specify the subtopic and selector, respectively. The selector value
is null in this case.
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...
<mx:Script>
<![CDATA[
var consumer:MultiTopicConsumer = new MultiTopicConsumer();
...
consumer.maxFrequency = 40;
// For this subscription, use the default maxFrequency of 40.
consumer.addSubscription("chat.subtopic1");
// Only for this subscription, overwrite the maxFrequency to 20.
consumer.addSubscription("chat.subtopic2", null, 20);
consumer.subscribe();
]]>
</mx:Script>
...
For more information about the MultiTopicConsumer component, see “Multitopic producers and consumers” on
page 205.
DataService message frequency
For the DataService component, you specify the default value of the maxFrequency property as the following example
shows:
...
<mx:Script>
<![CDATA[
...
var ds:DataService = new DataService("Meeting");
ds.maxFrequency = 20;
...
]]>
</mx:Script>
...
When you use a DataService component in manual routing mode (manual synchronization of messages), you can
specify multiple subscriptions and subscription-level values for the maxFrequency property as the following example
shows. As with the MultiTopicConsumer.addSubscription() method, the
manualSync.consumerAdSubscription() method takes subtopic, selector, and maxFrequency in its three
parameters.
...
<mx:Script>
<![CDATA[
...
var ds:DataService = new DataService("Meeting");
ds.autoSyncEnabled = false;
ds.manualSync.producerSubtopics.addItem("flex-room");
// Set the subscription level frequency to 10.
ds.manualSync.consumerAddSubscription("flex-room", null, 10);
ds.manualSync.consumerSubscribe();
ds.fill(…);
...
]]>
</mx:Script>
...
For more information about manual routing, see “Manually routing data messages” on page 234.
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Adaptive client message frequency
When you enable adaptive client message frequency, the server adjusts the frequency of messages sent from server to
client while taking the client’s actual message processing rate into account. You specify the maximum number of
messages per second that the frequency is incrementally increased or decreased.
Add something about fact that the calculations the server does are different depending the type of endpoint you are
using. For example, RTMP versus long polling AMF.
To use adaptive client message frequency, you configure the adaptive-frequency property of the flex-clientoutbound-queue-processor element in the flex-client section of the services-config.xml, as follows:
1 Set the flex-client-queue-processorclass value to
"flex.messaging.client.AdvancedOutboundQueueProcessor".
2 Set the value of the adaptive-frequency property to true.
3 Set the value of the frequency-step-size property to the number of messages per second that you want to
incrementally increase the message frequency, depending on the server’s calculation. This setting is useful when
you want to gradually increase the number of messages sent per second.
The following example shows an advanced outbound queue processor configured for adaptive message frequency:
...
<flex-client>
<flex-client-outbound-queue-processor
class="flex.messaging.client.AdvancedOutboundQueueProcessor">
<properties>
<adaptive-frequency>true</adaptive-frequency>
<frequency-step-size>10</frequency-step-size>
</properties>
</flex-client-outbound-queue-processor>
</flex-client>
...
You can also configure an outbound queue processor for a particular endpoint in a channel definition. Such an
endpoint-specific configuration overrides the global one in the services-config.xml file.
Data throttling policies
Data throttling policies determine what happens to Message Service and Data Management Service messages that
exceed the specified maximum message limits.
Destinations can use the following throttling policies:
policy
Description
NONE
No data throttling is performed when the maximum message frequency is
reached. This setting is equivalent to setting the maximum frequency to 0 (zero).
ERROR
Applies to client-to-server (inbound) messages only.
When the maximum frequency limit is exceeded, the server drops the message
and sends an error to the client.
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policy
Description
IGNORE
When the maximum message frequency is exceeded, the server drops the
message but no error is sent to the client.
BUFFER
Advanced feature not available in BlazeDS. See “Advanced data throttling” on
page 109.
CONFLATE
Advanced feature not available in BlazeDS.See “Advanced data throttling” on
page 109.
Deserialization validators
You can validate AMF and AMFX deserialization of client-to-server messages when you create an instance of a Java
class and set the values of the object’s properties. Validation lets you ensure that the server creates only specific types
of objects and that only specific values are allowed on an object’s properties.
Using deserialization validators
Deserialization validator classes must implement the flex.messaging.validators.DeserializationValidator interface,
which contains the following methods:
•
•
boolean validateCreation(Class<?> c), which validates the creation of a class.
boolean validateAssignment(Object instance, int index, Object value), which validates the
assignment of a value to an index of an Array or List instance.
•
boolean validateAssignment(Object instance, String propertyName, Object value), which validates
the assignment of a property of an instance of a class to a value.
For more information about the DeserializionValidator interface, see the LiveCycle Data Services Javadoc
documentation.
Note: If a deserialization validator maintains internal state, guard access and modification of that state with a lock.
There is a single deserialization validator per message broker and multiple threads could access the same validator.
You can assign deserialization validators at the top level of the services-config.xml file, as the following example shows:
<?xml version="1.0" encoding="UTF-8"?>
<services-config>
...
<validators>
<validator class="mycompany.myvalidators.TestDeserializationValidator"/>
</validators>
...
</services-config>
You can also use the runtime configuration feature to dynamically create deserialization validators in a bootstrap
service class at server startup. Create a MessageBroker and a validator instance in a Java class, and then call the
MessageBroker’s setDeserializationValidator() method to use the validator. The following example shows this
approach:
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...
MessageBroker broker = MessageBroker.get MessageBroker(null);
TestDeserializationValidator validator = new TestDeserializationValidator();
validator.
// Next, you can call specific add/remove methods on the validator
// for allowed/disallowed classes.
...
broker.setDeserializationValidator(validator);
...
The default validator, flex.messaging.validators.ClassDeserializationValidator, lets you explicitly allow or disallow
specific class types. For more information about this class, see the LiveCycle Data Services Javadoc documentation.
To use the ClassDerializationValidator, you specify disallowed and allowed classes within disallow-classes and
allow-classes elements as the following example shows. You can use fully qualified class names or wildcard
expressions in class name values.
<?xml version="1.0" encoding="UTF-8"?>
<services-config>
...
<validators>
<validator class="flex.messaging.validators.ClassDeserializationValidator">
<properties>
<disallow-classes>
</disallow-classes>
<allow-classes>
<class name="java.*"/>
<class name="\[Ljava.*"/>
<class name="flex.*"/>
<class name="\[B*"/>
</allow-classes>
</properties>
</validator>
</validators>
...
</services-config>
To help determine which class types are deserialized on the server, you can use the sample
features.validators.deserialization.ClassLoggingDeserializationValidator class. Registering this validator in a
development environment lets you capture to the server log all required types that the application uses. When a class
is encountered for the first time, an info-level log message that lists the class name is printed to the
Endpoint.Deserialization.Creation log category. By default, log messages are sent to the console. You can use this
information to configure a ClassDeserializationValidator instance that disallows creation of all non-required types in
the production environment.
The source code for the ClassLoggingDeserialization class is in the resources/samples/validators directory of your
LiveCycle Data Services installation. Unlike the ClassSerializationValidator validator, the configuration for this
validator does not use any properties. You only need to specify the class name of the validator in a validator element.
For more information about the DeserializionValidator interface, see the LiveCycle Data Services Javadoc
documentation.
More Help topics
“Run-time configuration” on page 411
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Advanced data tuning
LiveCycle Data Services provides a set of advanced data tuning features that give you greater control over the server’s
data delivery capabilities.
Note: Advanced data tuning features are not available in BlazeDS.
Advanced data tuning includes the following features:
Feature
Description
Reliable messaging
Improves the quality of message delivery between Flex clients and the LiveCycle Data
Services server. For more information, see “Reliable messaging” on page 107.
Advanced data
throttling
Includes adaptive throttling and the BUFFER and CONFLATE throttling policies. For more
information, see “Advanced data throttling” on page 109.
Message priority
Lets you set the priority of server-to-client messages when using the Message Service or
Data Management Service. For more information, see “Message priority” on page 111.
Message filtering
Lets you pre-process incoming messages and post-process reply messages and pushed
messages. For more information, see “Message filtering” on page 112.
Advanced messaging support
To use most advanced data tuning features, you enable advanced messaging support on the server. The
AdvancedMessagingSupport service enables reliable messaging support as the server starts up and handles
interactions with client-side AdvancedChannelSet objects at runtime.
The following example shows the text you must add to the services section of the services-config.xml file:
...
<services>
...
<service id="AdvancedMessagingSupport"
class="flex.messaging.services.AdvancedMessagingSupport"/>
...
</services>
...
Suppose you have MXML applications in which you create ChannelSet objects manually and you want to use the listed
advanced data tuning features. In this case, modify your applications to use the AdvancedChannelSet class in the
fds.swc file rather than the base ChannelSet class in the rpc.swc file.
The following example shows the difference between using the standard ChannelSet object and the
AdvancedChannelSet object:
...
// Existing base ChannelSet.
var channelSet:ChannelSet = new ChannelSet();
...
// New AdvancedChannelSet.
var channelSet:ChannelSet = new AdvancedChannelSet();
...
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Reliable messaging
The reliable messaging feature improves the quality of message delivery between clients and destinations on the
LiveCycle Data Services server.
Reliable messaging provides the following benefits above what is provided with standard messaging:
Benefit
Description
No message loss
No messages are lost when transient network failures occur if the AdvancedChannelSet
object's immediate reliable reconnect attempt succeeds.
If this single attempt fails the reliable sequence is closed and the client proceed to regular
channel failover and channel set hunting.
Ordered message
delivery
Reliable messaging ensures the delivery of correctly ordered messages when using AMF or
HTTP channels/endpoints that use more than one TCP socket concurrently to send or
receive messages. Message order is ensured even if the intended order differs from the
order in which the messages are received from the network.
When you use RTMP channels/endpoints, messages are delivered in the correct order
whether you use reliable messaging.
No duplicate message There is no duplicate processing of messages even when messages for reliable destination
processing
are automatically sent following a disconnect and reconnect.
Reconnection to
server following
unexpected
connection loss
For deployments where network connections are forced to close periodically, reliable
messaging allows the client to seamlessly reconnect to the same server. The client resumes
exactly where it left off, as long as the server has not crashed, or exited.
A single reliable reconnection is attempted immediately following connection loss. This
reconnection attempt allows the reliable connection to survive due to an idle timeout or
when firewalls, proxies, or other network components force a TCP connection to close
periodically. If this single attempt fails, the reliable sequence is closed and the client
proceeds to regular channel failover and channel set hunting. The feature currently does
not support repeated reliable reconnect attempts.
Note: To use reliable messaging, you enable advanced messaging support.
To enable reliable messaging, you set the reliable property to true in the network properties section of the
destination definition, as the following example shows:
...
<destination id="trade-settlement">
<properties>
<network>
<reliable>true</reliable>
</network>
</properties>
</destination>
...
By default, if a channel was successfully connected before experiencing a fault or disconnection, it attempts a pinned
reconnection to the same endpoint URL once. If this immediate reconnection attempt fails, the channel falls back to
its previous failover strategy and attempts to fail over to other server nodes in the cluster or fall back to alternate
channel protocols. To support IP mobility use cases, the AdvancedChannelSet object provides the following property
that you can assign in ActionScript code to extend the time duration for reliable reconnect attempts to continue. One
such use case is undocking a laptop and waiting several seconds for its wireless modem to start up and acquire network
connectivity and a new IP address.
advancedChannelSet.reliableReconnectDuration = 60000; // In milliseconds.
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The default value is 0. The default behavior is to try a single, immediate reliable reconnection. By assigning a value
larger than 0, you give the AdvancedChannelSet more time to attempt to reconnect reliably more than once.
You can also set this value statically in the services-config.xml file within the flex-client section, as the following
example shows:
...
<flex-client>
<reliable-reconnect-duration-millis>60000</reliable-reconnect-duration-millis>
<!-- Idle timeout for FlexClient state at the server, including reliable messaging sequences.
In order to support reliable reconnects consistently across all supported channels and
endpoints, this value must be defined and greater than 0.
Note: Any active sessions/connections keep idle FlexClient instances alive. This timeout
only applies to instances that have no currently active associated sessions/connections.
-->
<timeout-minutes>1</timeout-minutes>
</flex-client>
...
Note: If you do not define an explicit FlexClient timeoutand at least one RTMP endpoint is registered with the message
broker, the server uses a default timeout of 5 seconds for FlexClient timeout. This allows reliable messaging over RTMP
to work with no configuration other than setting destinations as reliable. If you want to use a longer reliable reconnect
interval, use the optional timeout-minutes and reliable-reconnect-duration-millis elements within the
flex-client section of services-config.xml file.
Standard behavior without reliable messaging
RTMP channels use a single TCP connection and never deliver messages to the server out of order whether you enable
reliable messaging. However, standard AMF channels do not guarantee in-order delivery of sent messages. Server-toclient AMF messages are rolled up into a batch and sent as binary body content in an HTTP POST when Flash Player
is able to issue a request. Within a batch, AMF messages are guaranteed to be delivered for processing on the server in
order. However, there is a slim chance that clients on slow networks could put themselves into a conflict state
unintentionally due to separate HTTP requests that contain individual batches of AMF messages arriving at the server
out of order. Nothing in Flash Player or in standard AMF channels prevents sending more than one HTTP request
containing a batch of AMF messages at a time. Standard HTTP channels use a unique URLLoader for each message
sent, but they serialize the flow of sent messages and only send a subsequent message after an ack (acknowledgement)
or fault for the previous message is received. These channels lack the efficiency introduced by the batching behavior
of the AMF channels, but they do guarantee in-order message delivery during regular operation.
RTMP channels use a single TCP connection and never receive messages from the server out of order whether you
enable reliable messaging. However, standard AMF and HTTP channels sometimes issue concurrent HTTP requests
over multiple TCP connections. Polling or streaming, which simulates a duplex connection by overlapping of
concurrent HTTP requests more of the time sometimes exacerbates this situation. Standard AMF and HTTP channels
provide no guarantee for delivery order across reply messages and pushed messages because data arrives at the client
over separate connections concurrently.
Received messages are either replies (acknowledgements/results/faults) for sent messages or they are pushed messages
generated by other clients, backend processes, or the server directly. All reliable messages traveling from the server to
the client's AdvancedChannelSet object belong to a common sequence. As messages are received, the
AdvancedChannelSet object uses a reliable receive buffer to re-order them if necessary, and any in-order messages are
removed from the buffer and dispatched to application code. Reply messages are dispatched to the acknowledgment
or fault handler of the component that sent the correlated request message. Pushed messages are dispatched to any
listeners that have registered for MessageEvents.
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Regardless of the runtime message ordering behavior for the various standard channels discussed here, none of these
channels can seamlessly survive a transient network disconnect event on its own. By enabling reliable messaging, the
channel and server endpoint enforce a guarantee of in-order, once-and-only-once message delivery between the client
and server that survives any transient disconnect followed by a successful reconnect to the same server.
Important: There is a trade-off between quickly detecting that clients have disconnected versus supporting long reliable
reconnect durations. For applications where timely server detection of clients disconnecting is important, leave the
reliable reconnect duration at its default setting or use a short duration value based on the requirements of your
application. For applications where you want to favor reliable reconnections, you can tune this value higher.
Advanced data throttling
For server-to-client messages, you can use adaptive throttling, which changes message frequency limits based on the
actual message processing rates of clients. You can also set policies that determine what happens to messages that
exceed the specified maximum message limits.
Note: To use advanced throttling features, you must enable advanced messaging support.
Adaptive client message frequency
When you enable adaptive client message frequency, the server automatically adjusts the frequency of messages sent
from server to client while taking the client's actual message processing rate into account. You specify the maximum
number of messages per second that the frequency is incrementally increased or decreased.
Add something about fact that the calculations the server does are different depending the type of endpoint you are
using. For example, RTMP versus long polling AMF.
To use adaptive client message frequency, you configure the adaptive-frequency property of the flex-clientoutbound-queue-processor element in the flex-client section of the services-config.xml, as follows:
1 Set the flex-client-queue-processorclass value to
"flex.messaging.client.AdvancedOutboundQueueProcessor".
2 Set the value of the adaptive-frequency property to true.
3 You can set the value of the frequency-step-size property to the number of messages per second that you want
to incrementally increase the message frequency, depending on the server’s calculation. This setting is useful when
you want to gradually increase the number of messages sent per second.
The following example shows an advanced outbound queue processor configured for adaptive message frequency:
...
<flex-client>
<flex-client-outbound-queue-processor
class="flex.messaging.client.AdvancedOutboundQueueProcessor">
<properties>
<adaptive-frequency>true</adaptive-frequency>
<frequency-step-size>10</frequency-step-size>
</properties>
</flex-client-outbound-queue-processor>
</flex-client>
...
You can also configure an outbound queue processor for a particular endpoint in a channel definition. Such an
endpoint-specific configuration overrides the global one in the services-config.xml file.
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Advanced data throttling policies
Destinations can use the following advanced throttling policies. For information about standard throttling policies, see
“Data throttling policies” on page 103.
policy
Description
BUFFER
Buffers messages to the client without dropping or conflating them and without
pushing more to the client than the maximum frequency limit. The buffered
messages are processed before any newer messages.
You can use BUFFER in combination with a maximum message queue size to limit
the number of buffered messages that a client can have in its outbound queue.
For more information, see “Maximum outbound message queue size” on
page 110.
CONFLATE
Applies to the Data Management Service only.
Merges messages to the client when the maximum frequency limit is exceeded.
This is an advanced BUFFER policy, in which messages are added to a buffer queue
but while they are in the queue, they will be merged if possible.
You can use CONFLATE in combination with a maximum message queue size to
limit the number of buffered messages that a client can have in its outbound
queue. For more information, see “Maximum outbound message queue size” on
page 110.
The CONFLATE policy applies to the following two scenarios:
•
Conflation merges DataMessage.UPDATE_OPERATION messages for a single
item. These are operations generated when properties of an item are updated.
For example, one message might contain an update to the firstname
property of an item while another message contains an update to the
lastname property. In this case, both changes are merged into a single
message. Another example is several updates to the stockprice property, the
update message are merged to one and only the latest price is sent, saving
unnecessary network traffic and application overhead.
•
Conflation cancels out a DataMessage.CREATE_OPERATION message followed
by a DataMessage.DELETE_OPERATION. This avoids sending two messages
unnecessarily.
Maximum outbound message queue size
You can configure the maximum number of messages that a Flex client can have in its outbound queue on the server.
The default value of -1 indicates there is no limit on the size of the outbound queue. When the queue is full, the
maxQueueSizeReached() method of the AdvancedOutboundQueueProcessor class is called and the default
implementation unsubscribes the client.
To use a maximum message queue size, you configure the max-queue-size property of the flex-client-outboundqueue-processor element in the flex-client section of the services-config.xml, as follows:
1 Set the flex-client-queue-processorclass value to
"flex.messaging.client.AdvancedOutboundQueueProcessor".
2 Set the value of the max-queue-size property to the maximum number of messages to store in the queue.
The following example shows an advanced outbound queue processor configured for adaptive message frequency
and maximum outbound message queue size:
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...
<flex-client>
<flex-client-outbound-queue-processor
class="flex.messaging.client.AdvancedOutboundQueueProcessor">
<properties>
<max-queue-size>50</max-queue-size>
</properties>
</flex-client-outbound-queue-processor>
</flex-client>
...
You can also configure an outbound queue processor for a particular endpoint in a channel definition. Such an
endpoint-specific configuration overrides the global one in the services-config.xml file.
Message priority
To ensure that messages reach clients in order of importance, you can specify the priority of server-to-client messages
when using the Message Service or Data Management Service. Message priority is based on a scale from 0 (zero) to 9,
where 0 is the lowest priority and 9 is the highest. The server sends higher priority messages before lower priority
messages.
Message prioritization is most useful in situations where messages are queued, such as when you use polling channels
or the BUFFER or CONFLATE throttling policy. When you use a polling channel, the server sends the messages that
accumulate on the server between polling requests in order of priority. When you use message buffering or conflation,
the server sends the messages in the outbound message queue in order of priority.
When you use RTMP or NIO-based HTTP channels, the server sends any messages that accumulate, due to resource
constraints or other issues, in order of priority.
By default, messages have a priority of 4. You can override the global default priority by specifying a destination-level
default priority. For finer grained control, you can set the default message priority on the client-side Producer or
DataService. For still finer grained control, you can set the priority on the priority header of an individual message.
Destination-level message priority
Use destination-level message priority to apply the default priority level to all server-to-client messages sent from a
particular destination on the server. This setting overrides the global default priority level.
In the destination definition, set the value of the message-priority server property, as the following example shows:
...
<destination id="MyTopic">
<properties>
<server>
<message-priority>4</message-priority>
...
Producer-level or DataService-level message priority
Use Producer-level or DataService-level message priority to set the default priority to all messages that a Producer or
DataService component in a Flex client application create. This setting overrides global and destination-level priority
levels.
In ActionScript, set the value of the Producer.priority property or DataService.priority property, as the
following example shows:
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...
<mx:Script>
<![CDATA[
var producer:Producer = new Producer();
...
producer.priority = 2;
...
var ds:DataService = new DataService();
...
ds.priority = 2;
]]>
</mx:Script>
...
In MXML, set the value of the priority attribute of a Producer or DataService component, as the following example
shows:
...
<mx:Producer id="producer" destination="chat" priority="2"/>
..
<mx:DataService id="ds" destination="meeting" priority="2"/>
...
Message-level priority
You can override the default priority of a message at send time by setting the priority header of the message to the
desired value. You can set the priority header in ActionScript when a message is created and sent from a Producer or
DataService component on the client to the server. Or, set the priority header in Java when a message is sent directly
from the server directly to a client (for example, from a remote object class).
The following example shows a message-level priority header set in ActionScript:
...
<mx:Script>
<![CDATA[
var msg:AsyncMessage = new AsyncMessage();
msg.body = "Foo";
msg.headers[AbstractMessage.PRIORITY_HEADER] = 4;
]]>
</mx:Script>
...
The following example shows a message-level priority header set in a Java class:
...
AsyncMessage msg = new AsyncMessage();
msg.setBody("Foo");
msg.setHeader(Message.PRIORITY_HEADER, 4);
...
Message filtering
You use custom message filter classes to pre-process incoming messages and post-process reply messages, and postprocess pushed messages that have been flushed from per-client outbound message queues. You configure message
filters in the services-config.xml file or for run-time configuration in a Java class. You can apply multiple message
filters by chaining them together in your configuration.
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Message filter classes must subclass either the flex.messaging.filters.BaseAsyncMessageFilter class or the
flex.messaging.filters.BaseSyncMessageFilter. Subclass BaseSyncMessageFilter when using servlet-based endpoints
and BaseAsyncMessageFilter when using NIO-based endpoints. To write a filter that works for either type of endpoint,
create two separate classes ideally with common code factored out into a helper/utility class that both filter
implementations use internally.
As a first step, you would do what the Base* classes do. For more information, see the LiveCycle Data Services Javadoc
API documentation.
Asynchronous message filter
The following example shows a simple asynchronous message filter:
package features.messaging.filters;
import flex.messaging.MessageContext;
import flex.messaging.client.FlexClient;
import flex.messaging.endpoints.Endpoint;
import flex.messaging.filters.BaseAsyncMessageFilter;
import flex.messaging.messages.AsyncMessage;
import flex.messaging.messages.Message;
/**
* An asynchronous message filter that works with NIO-based endpoints. You can
* configure this message filter in services-config.xml as follows:
*
* <async-message-filters>
*
<filter id="SampleAsyncFilter" class="features.messaging.filters.SampleAsyncFilter"/>
* </async-message-filters>
*/
public class SampleAsyncFilter extends BaseAsyncMessageFilter
{
/**
* Filter incoming messages that are marked as heartbeat.
*/
public void in(final MessageContext context)
{
Message message = context.getRequestMessage();
if (message instanceof HeartbeatMessageExt)
{
context.doOut(getPrev()); // Don't process the message further.
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return;
}
super.in(context);
}
/**
* Filter outgoing messages here.
*/
public void out(final MessageContext context)
{
super.out(context);
}
/**
* Filter push messages here.
*/
public AsyncMessage filterPush(final AsyncMessage message, final FlexClient recipient,
final Endpoint endpoint)
{
return super.filterPush(message, recipient, endpoint);
}
}
Synchronous message filter
The following example shows a simple synchronous message filter:
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package features.messaging.filters;
import flex.messaging.client.FlexClient;
import flex.messaging.endpoints.Endpoint;
import flex.messaging.filters.BaseSyncMessageFilter;
import flex.messaging.filters.SyncMessageFilterContext;
import flex.messaging.messages.AsyncMessage;
import flex.messaging.messages.Message;
/**
* A synchronous message filter that works with Servlet-based endpoints. You can
* configure this message filter in services-config.xml as follows:
*
* <sync-message-filters>
*
<filter id="SampleSyncFilter" class="features.messaging.filters.SampleSyncFilter"/>
* </sync-message-filters>
*/
public class SampleSyncFilter extends BaseSyncMessageFilter
{
/**
* Filter incoming messages that are marked as heartbeat.
*/
public AsyncMessage filterRequest(final Message message, final Endpoint endpoint, final
SyncMessageFilterContext context)
{
return (message instanceof HeartbeatMessageExt)? null : context.filterRequest(message,
endpoint);
}
/**
* Filter push messages here.
*/
public void filterPush(final AsyncMessage message, final FlexClient recipient, final
Endpoint endpoint, final SyncMessageFilterContext context)
{
context.filterPush(message, recipient, endpoint);
}
}
Message filter configuration
You can assign message filters at the top level of the services-config.xml file. The following example shows the
configuration for an asynchronous message filter and a synchronous message filter:
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<?xml version="1.0" encoding="UTF-8"?>
<services-config>
...
<!-- Asynchronous message filters pre-process incoming messages in "in" method
and post-process reply messages in "out" method, as well as filtering pushed
messages in "filterPush" method that travel through all asynchronous
(NIO-based) endpoints.
-->
<async-message-filters>
<filter id="asyncFilter" class="my.custom.filters.TestAsyncFilter"/>
</async-message-filters>
<!-- Synchronous message filters pre-process incoming messages and post-process
reply messages and pushed messages that travel through all synchronous
(Servlet-based) endpoints.
-->
<sync-message-filters>
<filter id="syncFilter" class="my.custom.filters.TestSyncFilter"/>
</sync-message-filters>
...
</services-config>
Message delivery with adaptive polling
The adaptive polling capability lets you write custom logic to control how messages are queued for delivery to Adobe®
Flex™ client applications on a per-client basis.
Adaptive polling
The adaptive polling capability provides a per-client outbound message queue API. You can use this API in custom
Java code to manage per-client messaging quality of service based on your criteria for determining and driving quality
of service. To use this capability, you create a custom queue processor class and register it in a channel definition in
the services-config.xml file.
Using a custom queue processor, you can do such things as conflate messages (combine a new message with an existing
message in the queue), order messages according to arbitrary priority rules, filter out messages based on arbitrary rules,
and manage flushing (sending) messages to the network layer explicitly. You have full control over the delivery rate of
messages to clients on a per-client basis, and the ability to define the order and contents of delivered messages on a
per-client basis.
Instances of the flex.messaging.client.FlexClient class on the server maintain the state of each client application. You
provide adaptive polling for individual client instances by extending the
flex.messaging.client.FlexClientOutboundQueueProcessor class. This class provides an API to manage adding
messages to an outbound queue and flushing messages in an outbound queue to the network.
When a message arrives at a destination on the server and it matches a specific client subscription, represented by an
instance of the flex.messaging.MessageClient class, the message is routed to an instance of FlexClient where it is added
to the queue for the channel/endpoint that the MessageClient subscription was created over. An instance of the
flex.messaging.MessageClient class represents a specific client subscription. When a message arrives at a destination
on the server, and it matches a client subscription, the message is routed to an instance of the FlexClient class. Then
the message is added to the queue for the channel/endpoint that the MessageClient subscription was created over.
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The default flush behavior depends on the channel/endpoint that you use. If you use polling channels, a flush is
attempted when a poll request is received. If you use direct push channels, a flush is attempted after each new message
is added to the outbound queue. You can write Java code to return a flex.messaging.FlushResult instance that contains
the list of messages to hand off to the network layer, which are sent to the client, and specify an optional wait time to
delay the next flush.
For polling channels, a next flush wait time results in the client waiting the specified length of time before issuing its
next poll request. For direct push channels, until the wait time is over, the addition of new messages to the outbound
queue does not trigger an immediate invocation of flush; when the wait time is up, a delayed flush is invoked
automatically. This lets you write code to drive adaptive client polling and adaptive writes over direct connections. You
could use this functionality to shed load (for example, to cause clients to poll a loaded server less frequently), or to
provide tiered message delivery rates on a per-client basis to optimize bandwidth usage (for example, gold customers
could get messages immediately, while bronze customers only receive messages once every 5 minutes).
If an outbound queue processor must adjust the rate of outbound message delivery, it can record its own internal
statistics to do so. This could include total number of messages delivered, rate of delivery over time, and so forth.
Queue processors that only perform conflation or filtering do not require the overhead of collecting statistics.
The FlexClientOutboundQueueProcessor, FlexClient, MessageClient, and FlushResult classes are documented in the
public LiveCycle Data Services Javadoc API documentation.
Using a custom queue processor
To use a custom queue processor, you must create a queue processor class, compile it, add it to the class path, and then
configure it. The examples in this topic are part of the adaptive polling sample application included in the LiveCycle
Data Services samples web application.
Creating a custom queue processor
To create a custom queue processor class, you must extend the FlexClientOutboundQueueProcessor class. This class
is documented in the public LiveCycle Data Services Javadoc API documentation. It provides the methods described
in the following table:
Method
Description
initialize(ConfigMap
properties)
Initializes a new queue processor instance after it is associated with its
corresponding FlexClient, but before any messages are enqueued.
add(List queue, Message message) Adds the message to the queue at the desired index, conflates it with
an existing message, or ignores it entirely.
FlushResult flush(List queue)
Removes messages from the queue to be flushed out over the network.
Can contain an optional wait time before the next flush is invoked.
FlushResult flush(MessageClient
messageClient, List queue)
Removes messages from the queue for a specific MessageClient
subscription. Can contain an optional wait time before the next flush is
invoked.
The following example shows the source code for a custom queue processor class that sets the delay time between
flushes in its flush(List outboundQueue) method.
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package flex.samples.qos;
import java.util.ArrayList;
import java.util.List;
import
import
import
import
import
flex.messaging.client.FlexClient;
flex.messaging.client.FlexClientOutboundQueueProcessor;
flex.messaging.client.FlushResult;
flex.messaging.config.ConfigMap;
flex.messaging.MessageClient;
/**
* Per client queue processor that applies custom quality of
* service parameters (in this case: delay).
* Custom quality of services parameters are read from the client FlexClient
* instance.
* In this sample, these parameters are set in the FlexClient instance by
* the client application using the flex.samples.qos.FlexClientConfigService
* remote object class.
* This class is used in the per-client-qos-polling-amf channel definition.
*
*/
public class CustomDelayQueueProcessor extends FlexClientOutboundQueueProcessor
{
/**
* Used to store the last time this queue was flushed.
* Starts off with an initial value of the construct time for the
* instance.
*/
private long lastFlushTime = System.currentTimeMillis();
/**
* Driven by configuration, this is the configurable delay time between
* flushes.
*/
private int delayTimeBetweenFlushes;
public CustomDelayQueueProcessor()
{}
/**
* Sets up the default delay time between flushes. This default is used
* if a client-specific
* value has not been set in the FlexClient instance.
*
* @param properties A ConfigMap containing any custom initialization
* properties.
*/
public void initialize(ConfigMap properties)
{
delayTimeBetweenFlushes = properties.getPropertyAsInt("flush-delay",-1);
if (delayTimeBetweenFlushes < 0)
throw new RuntimeException("Flush delay time forDelayedDeliveryQueueProcessor
must be a positive value.");
}
/**
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* This flush implementation delays flushing messages from the queue
* until 3 seconds have passed since the last flush.
*
* @param outboundQueue The queue of outbound messages.
* @return An object containing the messages that have been removed
* from the outbound queue
* to be written to the network and a wait time for the next flush
* of the outbound queue
* that is the default for the underlying Channel/Endpoint.
*/
public FlushResult flush(List outboundQueue)
{
int delay = delayTimeBetweenFlushes;
// Read custom delay from client's FlexClient instance
System.out.println("***"+getFlexClient());
FlexClient flexClient = getFlexClient();
if (flexClient != null)
{
Object obj = flexClient.getAttribute("market-data-delay");
if (obj != null)
{
try {
delay = Integer.parseInt((String) obj);
} catch (Exception e) {
}
}
}
long currentTime = System.currentTimeMillis();
System.out.println("Flush?" + (currentTime - lastFlushTime) + "<" +delay);
if ((currentTime - lastFlushTime) < delay)
{
// Delaying flush. No messages will be returned at this point
FlushResult flushResult = new FlushResult();
// Don't return any messages to flush.
// And request that the next flush doesn't occur until 3 secondssince the previous.
flushResult.setNextFlushWaitTimeMillis((int)(delay (currentTime - lastFlushTime)));
return flushResult;
}
else // OK to flush.
{
// Flushing. All queued messages will now be returned
lastFlushTime = currentTime;
FlushResult flushResult = new FlushResult();
flushResult.setNextFlushWaitTimeMillis(delay);
flushResult.setMessages(new ArrayList(outboundQueue));
outboundQueue.clear();
return flushResult;
}
}
public FlushResult flush(MessageClient client, List outboundQueue) {
return super.flush(client, outboundQueue);
}
}
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A Flex client application calls the following remote object to set the delay time between flushes on
CustomDelayQueueProcessor:
package flex.samples.qos;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import flex.messaging.FlexContext;
import flex.messaging.client.FlexClient;
public class FlexClientConfigService
{
public void setAttribute(String name, Object value)
{
FlexClient flexClient = FlexContext.getFlexClient();
flexClient.setAttribute(name, value);
}
public List getAttributes()
{
FlexClient flexClient = FlexContext.getFlexClient();
List attributes = new ArrayList();
Enumeration attrNames = flexClient.getAttributeNames();
while (attrNames.hasMoreElements())
{
String attrName = (String) attrNames.nextElement();
attributes.add(new Attribute(attrName, flexClient.getAttribute(attrName)));
}
return attributes;
}
public class Attribute {
private String name;
private Object value;
public Attribute(String name, Object value) {
this.name = name;
this.value = value;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Object getValue() {
return value;
}
public void setValue(Object value) {
this.value = value;
}
}
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Configuring a custom queue processor
You register custom implementations of the FlexClientOutboundQueueProcessor class on a per-channel/endpoint
basis. To register a custom implementation, you configure a flex-client-outbound-queue property in a channel
definition in the services-config.xml file, as the following example shows:
<channel-definition id="per-client-qos-polling-amf"
class="mx.messaging.channels.AMFChannel">
<endpoint url="http://localhost:8400/lcds-samples/messagebroker/qosamfpolling"
class="flex.messaging.endpoints.AMFEndpoint"/>
<properties>
<polling-enabled>true</polling-enabled>
<polling-interval-millis>500</polling-interval-millis>
<flex-client-outbound-queue-processor
class="flex.samples.qos.CustomDelayQueueProcessor">
<properties>
<flush-delay>5000</flush-delay>
</properties>
</flex-client-outbound-queue-processor>
</properties>
</channel-definition>
This example shows how you can also specify arbitrary properties to be passed into the initialize() method of your
queue processor class after it has been constructed and has been associated with its corresponding FlexClient instance,
but before any messages are enqueued. In this case, the flush-delay value is passed into the initialize() method.
This is the default value that is used if a client does not specify a flush delay value.
You then specify the channel in your message destination, as the bold text in the following example shows:
<destination id="market-data-feed">
<properties>
<network>
<subscription-timeout-minutes>0</subscription-timeout-minutes>
</network>
<server>
<message-time-to-live>0</message-time-to-live>
<durable>true</durable>
<allow-subtopics>true</allow-subtopics>
<subtopic-separator>.</subtopic-separator>
</server>
</properties>
<channels>
<channel ref="per-client-qos-rtmp"/>
</channels>
</destination>
Measuring message processing performance
As part of preparing your application for final deployment, you can test its performance to look for ways to optimize
it. One place to examine performance is in the message processing part of the application. To help you gather this
performance information, enable the gathering of message timing and sizing data.
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About measuring message processing performance
The mechanism for measuring message processing performance is disabled by default. When enabled, information
regarding message size, server processing time, and network travel time is available to the client that pushed a message
to the server, to a client that received a pushed message from the server, or to a client that received an acknowledge
message from the server in response a pushed message. A subset of this information is also available for access on the
server.
You can use this mechanism across all channel types, including polling and streaming channels, that communicate
with the LiveCycle Data Services server. However, this mechanism does not work when you make a direct connection
to an external server by setting the useProxy property to false for the HTTPService and WebService tags because it
bypasses the LiveCycle Data Services Proxy Server.
The MessagePerformanceUtils class defines the available message processing metrics. When a consumer receives a
message, or a producer receives an acknowledge message, the consumer or producer extracts the metrics into an
instance of the MessagePerformanceUtils class, and then accesses the metrics as properties of that class. For a complete
list of the available metrics, see “Available message processing metrics” on page 123.
Measuring performance for different channel types
The types of metrics that are available and their calculations, depend on the channel configuration over which a
message is sent from or received by the client.
Producer acknowledge scenario
In the producer acknowledge scenario, a producer sends a message to a server over a specific channel. The server then
sends an acknowledge message back to the producer.
The following image shows the producer acknowledge scenario:
Client
M
Server
Message producer
A
M. Message sent to server A. Acknowledge message
If you enable the gathering of message processing metrics, the producer adds information to the message before
sending it to the server, such as the send time and message size. The server copies the information from the message
to the acknowledge message. Then the server adds additional information to the acknowledge message, such as the
response message size and server processing time. When the producer receives the acknowledge message, it uses all of
the information in the message to calculate the metrics defined by the MessagePerformanceUtils class.
Message polling scenario
In a message polling scenario, a consumer polls a message channel to determine if a message is available on the server.
On receiving the polling message, the server pushes any available message to the consumer.
The following image shows the polling scenario:
Client
P
Server
Pushed message queue
Message producer
M
M
P. Polling message sent. M. Message pushed to client from server.
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If you enable the gathering of message processing metrics in this scenario, the consumer obtains performance metrics
about the poll-response transaction, such as the response message size and server processing time. The metrics also
include information about the message returned by the server. This information lets the consumer determine how long
the message was waiting before it was pushed. However, the metric information does not identify the client that
originally pushed the message onto the server.
Message streaming scenario
In the streaming scenario, the server pushes a message to a consumer when a message is available; the consumer itself
does not initiate the transaction.
The following image shows this scenario:
Client
Server
M
Message producer
A
Pushed message queue
M
Client
M
Message consumer
Message streaming scenario.
In this scenario, the message producer pushes a message, and then receives an acknowledge message. The producer
can obtain metric information as described in “Producer acknowledge scenario” on page 122.
When the server pushes the message to the consumer, the message contains information from the original message
from the producer, and the metric information that the server added. The consumer can then examine the metric data,
including the time from when the producer pushed the message until the consumer received it.
Measuring message processing performance for streaming and RTMP channels
For streaming and RTMP channels, a pushed message is sent to a consumer without the client first sending a polling
message. In this case, the following metrics are not available to the consumer for the pushed message, but instead are
set to 0:
•
networkRTT
•
serverPollDelay
•
totalTime
Available message processing metrics
The following table lists the available message processing metrics defined by the MessagePerformanceUtils class:
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Property
Description
clientReceiveTime
The number of milliseconds since the start of the UNIX epoch, January 1, 1970,
00:00:00 GMT, to when the client received a response message from the server.
messageSize
The size of the original client message, in bytes, as measured during
deserialization by the server endpoint.
networkRTT
The duration, in milliseconds, from when a client sent a message to the server until
it received a response, excluding the server processing time. This value is
calculated as totalTime - serverProcessingTime.
If a pushed message is using a streaming or RTMP channel, the metric is
meaningless because the client does not initiate the pushed message; the server
sends a message to the client whenever a message is available. Therefore, for a
message pushed over a streaming or RTMP channel, this value is 0. However, for
an acknowledge message sent over a streaming or RTMP channel, the metric
contains a valid number.
originatingMessageSentTime
The timestamp, in milliseconds since the start of the UNIX epoch on January 1,
1970, 00:00:00 GMT, to when the client that caused a push message sent its
message.
Only populated for a pushed message, but not for an acknowledge message.
originatingMessageSize
Size, in bytes, of the message that originally caused this pushed message.
Only populated for a pushed message, but not for an acknowledge message.
pushedMessageFlag
Contains true if the message was pushed to the client but is not a response to a
message that originated on the client. For example, when the client polls the
server for a message, pushedMessageFlag is false. When you are using a
streaming channel, pushedMessageFlag is true. For an acknowledge message,
pushedMessageFlag is false.
pushOneWayTime
Time, in milliseconds, from when the server pushed the message until the client
received it.
Note: This value is only relevant if the server and receiving client have
synchronized clocks.
Only populated for a pushed message, but not for an acknowledge message.
responseMessageSize
The size, in bytes, of the response message sent to the client by the server as
measured during serialization at the server endpoint.
serverAdapterExternalTime
Time, in milliseconds, spent in a module invoked from the adapter associated with
the destination for this message, before either the response to the message was
ready or the message had been prepared to be pushed to the receiving client. This
value corresponds to the message processing time on the server.
serverAdapterTime
Processing time, in milliseconds, of the message by the adapter associated with
the destination before the response to the message was ready or the message was
prepared to be pushed to the receiving client. The processing time corresponds to
the time that your code on the server processed the message, not when LiveCycle
Data Services processed the message.
serverNonAdapterTime
Server processing time spent outside the adapter associated with the destination
of this message. Calculated as serverProcessingTime serverAdapterTime.
serverPollDelay
Time, in milliseconds, that this message sat on the server after it was ready to be
pushed to the client but before it was picked up by a poll request.
For a streaming or RTMP channel, this value is always 0.
serverPrePushTime
Time, in milliseconds, between the server receiving the client message and the
server beginning to push the message out to other clients.
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Property
Description
serverProcessingTime
Time, in milliseconds, between server receiving the client message and either the
time the server responded to the received message or has the pushed message
ready to be sent to a receiving client.
For example, in the producer-acknowledge scenario, this value is the time from
when the server receives the message and sends the acknowledge message back
to the producer. In a polling scenario, it is the time between the arrival of the
polling message from the consumer and any message returned in response to the
poll.
serverSendTime
The number of milliseconds since the start of the UNIX epoch, January 1, 1970,
00:00:00 GMT, to when the server sent a response message back to the client.
totalPushTime
Time, in milliseconds, from when the originating client sent a message and the
time that the receiving client received the pushed message.
Note: This value is only relevant if the two clients have synchronized clocks.
Only populated for a pushed message, but not for an acknowledge message.
totalTime
Time, in milliseconds, between this client sending a message and receiving a
response from the server.
This property contains 0 for a streaming or RTMP channel.
Considerations when measuring message processing performance
The mechanism that measures message processing performance attempts to minimize the overhead required to collect
information so that all timing information is as accurate as possible. However, take into account the following
considerations when you use this mechanism.
Synchronize the clocks on different computers
The metrics defined by the MessagePerformanceUtils class include the totalPushTime. The totalPushTime is a
measure of the time from when the originating message producer sent a message until a consumer receives the
message. This value is determined from the timestamp added to the message when the producer sends the message,
and the timestamp added to the message when the consumer receives the message. However, to calculate a valid value
for the totalPushTime metric, the clocks on the message-producing computer and on the message-consuming
computer must be synchronized.
Another metric, pushOneWayTime, contains the time from when the server pushed the message until the consumer
received it. This value is determined from the timestamp added to the message when the server sends the message, and
the timestamp added to the message when the consumer receives the message. To calculate a valid value for the
pushOneWayTime metric, the clocks on the message consuming computer and on the server must be synchronized.
One option is to perform your testing in a lab environment where you can ensure that the clocks on all computers are
synchronized. For the totalPushTime metric, you can ensure that the clocks for the producer and consumer
applications are synchronized by running the applications on the same computer. Or, for the pushOneWayTime metric,
you can run the consumer application and server on the same computer.
Perform different tests for message timing and sizing
The mechanism for measuring message processing performance lets you enable the tracking of timing information, of
sizing information, or both. The gathering of timing-only metrics is minimally intrusive to your overall application
performance. The gathering of sizing metrics involves more overhead time than gathering timing information.
Therefore, you can run your tests twice: once for gathering timing information and once for gathering sizing
information. In this way, the timing-only test can eliminate any delays caused by calculating message size. You can
then combine the information from the two tests to determine your final results.
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Measuring message processing performance
The mechanism for measuring message processing performance is disabled by default. When you enable it, you can
use the MessagePerformanceUtils class to access the metrics from a message received by a client.
Enabling message processing metrics
You use two parameters in a channel definition to enable message processing metrics:
•
<record-message-times>
•
<record-message-sizes>
Set these parameters to true or false; the default value is false. You can set the parameters to different values to
capture only one type of metric. For example, the following channel definition specifies to capture message timing
information, but not message sizing information:
<channel-definition id="my-streaming-amf"
class="mx.messaging.channels.StreamingAMFChannel">
<endpoint
url="http://{server.name}:{server.port}/{context.root}/messagebroker/streamingamf"
class="flex.messaging.endpoints.StreamingAMFEndpoint"/>
<properties>
<record-message-times>true</record-message-times>
<record-message-sizes>false</record-message-sizes>
</properties>
</channel-definition>
Using the MessagePerformanceUtils class
The MessagePerformanceUtils class is a client-side class that you use to access the message processing metrics. You
create an instance of the MessagePerformanceUtils class from a message pushed to the client by the server or from an
acknowledge message.
The following example shows a message producer that uses the acknowledge message to display in a TextArea control
the metrics for a message pushed to the server:
<?xml version="1.0"?>
<!-- mpi\ChatACK.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import
import
import
import
mx.messaging.messages.AsyncMessage;
mx.messaging.messages.IMessage;
mx.messaging.events.MessageEvent;
mx.messaging.messages.MessagePerformanceUtils;
// Event handler to send the message to the server.
private function send():void
{
var message:IMessage = new AsyncMessage();
message.body.chatMessage = msg.text;
producer.send(message);
msg.text = "";
}
// Event handler to write metrics to the TextArea control.
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private function ackHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils =
new MessagePerformanceUtils(event.message);
myTAAck.text = "totalTime = " + String(mpiutil.totalTime);
myTAAck.text = myTAAck.text + "\n" + "messageSize= " +
String(mpiutil.messageSize);
}
]]>
</mx:Script>
<mx:Producer id="producer" destination="chat" acknowledge="ackHandler(event)"/>
<mx:Label text="Acknowledge metrics"/>
<mx:TextArea id="myTAAck" width="100%" height="20%"/>
<mx:Panel title="Chat" width="100%" height="100%">
<mx:TextArea id="log" width="100%" height="100%"/>
<mx:ControlBar>
<mx:TextInput id="msg" width="100%" enter="send()"/>
<mx:Button label="Send" click="send()"/>
</mx:ControlBar>
</mx:Panel>
</mx:Application>
In this example, you write an event handler for the acknowledge event to display the metrics. The event handler
extracts the metric information from the acknowledge message, and then displays the
MessagePerformanceUtils.totalTime and MessagePerformanceUtils.messageSize metrics in a TextArea
control.
You can also use the MessagePerformanceUtils.prettyPrint() method to display the metrics. The
prettyPrint() method returns a formatted String that contains nonzero and non-null metrics. The following
example modifies the event handler for the previous example to use the prettyPrint() method:
// Event handler to write metrics to the TextArea control.
private function ackHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils = new MessagePerformanceUtils(event.message);
myTAAck.text = mpiutil.prettyPrint();
}
The following example shows the output from the prettyPrint() method that appears in the TextArea control:
Original message size(B): 509
Response message size(B): 562
Total time (s): 0.016
Network Roundtrip time (s): 0.016
A message consumer can write an event handler for the message event to display metrics, as the following example
shows:
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<?xml version="1.0"?>
<!-- mpi\ChatConsume.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="consumer.subscribe();">
<mx:Script>
<![CDATA[
import
import
import
import
mx.messaging.messages.AsyncMessage;
mx.messaging.messages.IMessage;
mx.messaging.events.MessageEvent;
mx.messaging.messages.MessagePerformanceUtils;
// Event handler to send the message to the server.
private function send():void
{
var message:IMessage = new AsyncMessage();
message.body.chatMessage = msg.text;
producer.send(message);
msg.text = "";
}
// Event handler to write metrics to the TextArea control.
private function ackHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils =
new MessagePerformanceUtils(event.message);
myTAAck.text = mpiutil.prettyPrint();
}
// Event handler to write metrics to the TextArea control for the message consumer.
private function messageHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils =
new MessagePerformanceUtils(event.message);
myTAMess.text = mpiutil.prettyPrint();
}
]]>
</mx:Script>
<mx:Producer id="producer" destination="chat" acknowledge="ackHandler(event)"/>
<mx:Consumer id="consumer" destination="chat" message="messageHandler(event)"/>
<mx:Label text="ack metrics"/>
<mx:TextArea id="myTAAck" width="100%" height="20%" text="ack"/>
<mx:Label text="receive metrics"/>
<mx:TextArea id="myTAMess" width="100%" height="20%" text="rec"/>
<mx:Panel title="Chat" width="100%" height="100%">
<mx:TextArea id="log" width="100%" height="100%"/>
<mx:ControlBar>
<mx:TextInput id="msg" width="100%" enter="send()"/>
<mx:Button label="Send" click="send()"/>
</mx:ControlBar>
</mx:Panel>
</mx:Application>
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In this example, you use the prettyPrint() method to write the metrics for the received message to a TextArea
control. The following example shows this output:
Response message size(B): 560
PUSHED MESSAGE INFORMATION:
Total push time (s): 0.016
Push one way time (s): 0.016
Originating Message size (B): 509
You can gather metrics for HTTPService and WebService tags when they use the Proxy Service, as defined by setting
the useProxy property to true for the HTTPService and WebService tags. The following example gathers metrics for
an HTTPService tag:
<?xml version="1.0" encoding="utf-8"?>
<!-- mpi\main.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
backgroundColor="#FFFFFF">
<mx:Script>
<![CDATA[
import mx.messaging.events.MessageEvent;
import mx.messaging.messages.MessagePerformanceUtils;
// Event handler to write metrics to the TextArea control for the message consumer.
private function messageHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils =
new MessagePerformanceUtils(event.message);
myTAMess.text = mpiutil.prettyPrint();
}
]]>
</mx:Script>
<mx:Label text="Message metrics"/>
<mx:TextArea id="myTAMess" width="100%" height="20%"/>
<mx:HTTPService id="srv"
destination="catalog"
useProxy="true"
result="messageHandler(event);"/>
<mx:DataGrid dataProvider="{srv.lastResult.catalog.product}"
width="100%" height="100%"/>
<mx:Button label="Get Data" click="srv.send()"/>
</mx:Application>
When using LiveCycle Data Services Data Management Service, you can use event handlers on the DataService class
to handle metrics, as the following example shows:
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<mx:Script>
<![CDATA[
import mx.messaging.events.MessageEvent;
import mx.messaging.messages.MessagePerformanceUtils;
// Event handler to write metrics to the TextArea control.
private function messageHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils = new MessagePerformanceUtils(event.message);
myTAMess.text = mpiutil.prettyPrint();
}
]]>
</mx:Script>
<mx:DataService id="ds" destination="inventory" result="messageHandler(event);"/>
<mx:Label text="receive metrics"/>
<mx:TextArea id="myTAMess" width="100%" height="20%" text="rec"/>
<mx:Button label="Get Data" click="ds.fill(products)"/>
Using the server-side classes to gather metrics
For managed endpoints, you can access the total number of bytes serialized and deserialized by using the following
methods of the flex.management.runtime.messaging.endpoints.EndpointControlMBean interface:
•
getBytesDeserialized()
Returns the total number of bytes deserialized by this endpoint during its lifetime.
•
getBytesSerialized()
Returns the total number of bytes serialized by this endpoint during its lifetime.
The flex.management.runtime.messaging.endpoints.EndpointControlMBean class implements these methods.
Writing messaging metrics to the log files
You can write messaging metrics to the client-side log file if you enable the metrics. To enable the metrics, set the
<record-message-times> or <record-mssage-sizes> parameter to true, and the client-side log level to DEBUG.
Messages are written to the log when a client receives an acknowledgment for a pushed message, or a client receives a
pushed message from the server. The metric information appears immediately following the debug information for
the received message.
The following example initializes logging and sets the log level to DEBUG:
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<?xml version="1.0"?>
<!-- mpi\ChatEverything.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="consumer.subscribe();initLogging();">
<mx:Script>
<![CDATA[
import
import
import
import
import
import
import
import
mx.messaging.messages.AsyncMessage;
mx.messaging.messages.IMessage;
mx.messaging.events.MessageEvent;
mx.messaging.messages.MessagePerformanceUtils;
mx.controls.Alert;
mx.collections.ArrayCollection;
mx.logging.targets.*;
mx.logging.*;
// Event handler to send the message to the server.
private function send():void
{
var message:IMessage = new AsyncMessage();
message.body.chatMessage = msg.text;
producer.send(message);
msg.text = "";
}
// Event handler to write metrics to the TextArea control.
private function ackHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils =
new MessagePerformanceUtils(event.message);
myTAAck.text = mpiutil.prettyPrint();
}
// Event handler to write metrics to the TextArea control for the message consumer.
private function messageHandler(event:MessageEvent):void {
var mpiutil:MessagePerformanceUtils =
new MessagePerformanceUtils(event.message);
myTAMess.text = mpiutil.prettyPrint();
}
// Initialize logging and set the log level to DEBUG.
private function initLogging():void {
// Create a target.
var logTarget:TraceTarget = new TraceTarget();
// Log all log levels.
logTarget.level = LogEventLevel.DEBUG;
// Add date, time, category, and log level to the output.
logTarget.includeDate = true;
logTarget.includeTime = true;
logTarget.includeCategory = true;
logTarget.includeLevel = true;
// Begin logging.
Log.addTarget(logTarget);
}
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]]>
</mx:Script>
<mx:Producer id="producer" destination="chat" acknowledge="ackHandler(event)"/>
<mx:Consumer id="consumer" destination="chat" message="messageHandler(event)"/>
<mx:Label text="ack metrics"/>
<mx:TextArea id="myTAAck" width="100%" height="20%" text="ack"/>
<mx:Label text="receive metrics"/>
<mx:TextArea id="myTAMess" width="100%" height="20%" text="rec"/>
<mx:Panel title="Chat" width="100%" height="100%">
<mx:TextArea id="log" width="100%" height="100%"/>
<mx:ControlBar>
<mx:TextInput id="msg" width="100%" enter="send()"/>
<mx:Button label="Send" click="send()"/>
</mx:ControlBar>
</mx:Panel>
</mx:Application>
For more information on logging, see the Flex documentation set.
By default, on Microsoft Windows the log file is written to the file C:\Documents and
Settings\USERNAME\Application Data\Macromedia\Flash Player\Logs\flashlog.txt. The following excerpt is from
the log file for the message "My test message":
2/14/2008 11:20:18.806 [DEBUG] mx.messaging.Channel 'my-rtmp' channel got connect attempt
status. (Object)#0
code = "NetConnection.Connect.Success"
description = "Connection succeeded."
details = (null)
DSMessagingVersion = 1
id = "D46A822C-962B-4651-6F2A-DCB41130C4CF"
level = "status"
objectEncoding = 3
2/14/2008 11:20:18.837 [INFO] mx.messaging.Channel 'my-rtmp' channel is connected.
2/14/2008 11:20:18.837 [DEBUG] mx.messaging.Channel 'my-rtmp' channel sending message:
(mx.messaging.messages::CommandMessage)
body=(Object)#0
clientId=(null)
correlationId=""
destination="chat"
headers=(Object)#0
messageId="E2F6B35E-42CD-F088-4B7A-18BF1515F142"
operation="subscribe"
timeToLive=0
timestamp=0
2/14/2008 11:20:18.868 [INFO] mx.messaging.Consumer 'consumer' consumer connected.
2/14/2008 11:20:18.868 [INFO] mx.messaging.Consumer 'consumer' consumer acknowledge for
subscribe. Client id 'D46A82C3-F419-0EBF-E2C8-330F83036D38' new timestamp 1203006018867
2/14/2008 11:20:18.884 [INFO] mx.messaging.Consumer 'consumer' consumer acknowledge of
'E2F6B35E-42CD-F088-4B7A-18BF1515F142'.
2/14/2008 11:20:18.884 [DEBUG] mx.messaging.Consumer Original message size(B): 626
Response message size(B): 562
2/14/2008 11:20:25.446 [INFO] mx.messaging.Producer 'producer' producer sending message
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'CF89F532-A13D-888D-D929-18BF2EE61945'
2/14/2008 11:20:25.462 [INFO] mx.messaging.Producer 'producer' producer connected.
2/14/2008 11:20:25.477 [DEBUG] mx.messaging.Channel 'my-rtmp' channel sending message:
(mx.messaging.messages::AsyncMessage)#0
body = (Object)#1
chatMessage = "My test message"
clientId = (null)
correlationId = ""
destination = "chat"
headers = (Object)#2
messageId = "CF89F532-A13D-888D-D929-18BF2EE61945"
timestamp = 0
timeToLive = 0
2/14/2008 11:20:25.571 [DEBUG] mx.messaging.Channel 'my-rtmp' channel got message
(mx.messaging.messages::AsyncMessageExt)#0
body = (Object)#1
chatMessage = "My test message"
clientId = "D46A82C3-F419-0EBF-E2C8-330F83036D38"
correlationId = ""
destination = "chat"
headers = (Object)#2
DSMPIO = (mx.messaging.messages::MessagePerformanceInfo)#3
infoType = "OUT"
messageSize = 575
overheadTime = 0
pushedFlag = true
receiveTime = 1203006025556
recordMessageSizes = false
recordMessageTimes = false
sendTime = 1203006025556
serverPostAdapterExternalTime = 0
serverPostAdapterTime = 0
serverPreAdapterExternalTime = 0
serverPreAdapterTime = 0
serverPrePushTime = 0
DSMPIP = (mx.messaging.messages::MessagePerformanceInfo)#4
infoType = (null)
messageSize = 506
overheadTime = 0
pushedFlag = false
receiveTime = 1203006025556
recordMessageSizes = true
recordMessageTimes = true
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sendTime = 1203006025556
serverPostAdapterExternalTime = 1203006025556
serverPostAdapterTime = 1203006025556
serverPreAdapterExternalTime = 0
serverPreAdapterTime = 1203006025556
serverPrePushTime = 1203006025556
messageId = "CF89F532-A13D-888D-D929-18BF2EE61945"
timestamp = 1203006025556
timeToLive = 0
2/14/2008 11:20:25.696 [DEBUG] mx.messaging.Channel Response message size(B): 575
PUSHED MESSAGE INFORMATION:
Originating Message size (B): 506
2/14/2008 11:20:25.712 [INFO] mx.messaging.Producer 'producer' producer acknowledge of
'CF89F532-A13D-888D-D929-18BF2EE61945'.
2/14/2008 11:20:25.712 [DEBUG] mx.messaging.Producer Original message size(B): 506
Response message size(B): 562
Total time (s): 0.156
Network Roundtrip time (s): 0.156
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Chapter 4: RPC services
Using RPC services
Remote Procedure Call (RPC) components let a client application make calls to operations and services across a
network. The three RPC components are the RemoteObject, HTTPService, and WebService components. Your Flex
client code uses these components to access remote object services, web services, and HTTP services.
When you use HTTPService and WebService components with LiveCycle Data Services or BlazeDS, you go through
the Proxy Service on the server, which proxies your requests so you do not need a cross domain policy file. When you
use the Proxy Service, you can also secure access to services. When you use RemoteObject components with LiveCycle
Data Services or BlazeDS, you go through the Remoting Service, which exposes plain old Java objects (POJOs) as
service destinations that your client-side RemoteObject components can access on the server.
Client-side RPC components
The RPC components are designed for client applications in which a call and response model is a good choice for
accessing external data. These components let the client make asynchronous requests to remote services that process
the requests, and then return data to your Flex application.
The RPC components call a remote service, and then store response data from the service in an ActionScript or XML
object from which you obtain the data. You can use the RPC components in the client application to work with three
types of RPC services: remote object services with the RemoteObject component, web services with the WebService
component, and HTTP services with the HTTPService component.
When you use LiveCycle Data Services or BlazeDS, the client typically contacts a destination, which is an RPC service
that has a corresponding server-side configuration. The following diagram shows how the RPC components in a Flex
client application interact with LiveCycle Data Services services:
LiveCycle Data Services server
Endpoints
Message
Broker
Service
Destination
HTTPProxyService
HTTPProxyDestination
Flex client
Adapter
HTTPProxyAdapter
Servlet-based
SOAPAdapter
Channel
Remote
HTTP or
Web service
NIO-based
RemotingService
RemotingDestination
JavaAdapter
Server-side services, destinations, and adapters
The server-side services, destinations, and adapters that you use depend on the RPC component, as the following table
shows:
Component
Service
Destination
Adapter
HTTPService
HTTPProxyService
HTTPProxyDestination
HTTPProxyAdapter
WebService
HTTPProxyService
HTTPProxyDestination
SOAPAdapter
RemoteObject
RemotingService
RemotingDestination
JavaAdapter
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RPC channels
With RPC services, you often use an AMFChannel on the client that calls a destination (endpoint) on the server. The
AMFChannel uses binary AMF encoding over HTTP. If binary data is not allowed, then you can use an
HTTPChannel, which is AMFX (AMF in XML) over HTTP. For more information on channels, see “Client and server
architecture” on page 27.
Types of client-side RPC components
Use RPC components to add enterprise functionality, such as proxying of service traffic from different domains, client
authentication, whitelists of permitted RPC service URLs, security, server-side logging, localization support, and
centralized management of RPC services.
Note: You can use the HTTPService and WebService components to call HTTP services or web services directly, without
going through the server-side proxy service. For more information, see “Using HTTPService and WebService without a
destination” on page 145.
By default, Adobe Flash Player blocks access to any host that is not exactly equal to the one used to load an application.
Therefore, if you do not use LiveCycle Data Services to proxy requests, an HTTP or web service must either be on the
server hosting your application, or the remote server that hosts the HTTP or web service must define a
crossdomain.xml file. A crossdomain.xml file is an XML file that provides a way for a server to indicate that its data and
documents are available to SWF files served from certain domains, or from all domains. The crossdomain.xml file
must be in the web root of the server that the Flex application is contacting.
Use RemoteObject components to access remote Java objects on the LiveCycle Data Services server without
configuring them as SOAP-compliant web services. You cannot use RemoteObject components without LiveCycle
Data Services or ColdFusion.
HTTPService component
HTTPService components let you send HTTP GET, POST, HEAD, OPTIONS, PUT, TRACE or DELETE requests,
and include data from HTTP responses in a Flex application. Flex does not support mulitpart form POST requests.
However, when you do not go through the HTTPProxyService, you can use only HTTP GET or POST methods.
An HTTP service can be any HTTP URI that accepts HTTP requests and sends responses. Another common name for
this type of service is a REST-style web service. REST stands for Representational State Transfer and is an architectural
style for distributed hypermedia systems. For more information about REST, see
www.ics.uci.edu/~fielding/pubs/dissertation/rest_arch_style.htm.
HTTPService components are a good option when you cannot expose the same functionality as a SOAP web service
or a remote object service. For example, you can use HTTPService components to interact with JavaServer Pages
(JSPs), servlets, and ASP pages that are not available as web services or Remoting Service destinations.
Use an HTTPService component for CGI-like interaction in which you use HTTP GET, POST, HEAD, OPTIONS,
PUT, TRACE, or DELETE to send a request to a specified URI. When you call the HTTPService object's send()
method, it makes an HTTP request to the specified URI, and an HTTP response is returned. Optionally, you can pass
arguments to the specified URI.
WebService component
WebService components let you access web services, which are software modules with methods. Web service methods
are commonly referred to as operations. Web service interfaces are defined by using XML. Web services provide a
standards-compliant way for software modules that are running on a variety of platforms to interact with each other.
For more information about web services, see the web services section of the World Wide Web Consortium website at
www.w3.org/2002/ws/.
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RPC services
Flex applications can interact with web services that define their interfaces in a Web Services Description Language
(WSDL) document, which is available as a URL. WSDL is a standard format for describing the messages that a web
service understands, the format of its responses to those messages, the protocols that the web service supports, and
where to send messages.
Flex supports WSDL 1.1, which is described at www.w3.org/TR/wsdl. Flex supports both RPC-encoded and
document-literal web services.
Flex applications support web service requests and results that are formatted as SOAP messages and are transported
over HTTP. SOAP provides the definition of the XML-based format that you can use for exchanging structured and
typed information between a web service client, such as a Flex application, and a web service.
You can use a WebService component to connect to a SOAP-compliant web service when web services are an
established standard in your environment. WebService components are also useful for objects that are within an
enterprise environment, but not necessarily available on the sourcepath of the Flex web application.
RemoteObject component
RemoteObject components let you access the methods of server-side Java objects, without manually configuring the
objects as web services. You can use RemoteObject components in MXML or ActionScript.
You can use RemoteObject components with a stand-alone LiveCycle Data Services web application or ColdFusion.
When using a LiveCycle Data Services web application, you configure the objects that you want to access as Remoting
Service destinations in a LiveCycle Data Services configuration file or by using LiveCycle Data Services run-time
configuration. For information on using RemoteObject components with ColdFusion, see the ColdFusion
documentation.
Use a RemoteObject component instead of a WebService component when objects are not already published as web
services, web services are not used in your environment, or you would rather use Java objects than web services. You
can use a RemoteObject component to connect to a local Java object that is in the LiveCycle Data Services or
ColdFusion web application sourcepath.
When you use a RemoteObject tag, data is passed between your application and the server-side object in the binary
Action Message Format (AMF) format.
Using an RPC component
The following example shows MXML code for a WebService component. This example connects to a LiveCycle Data
Services destination, calls the getProducts() operations of the web service in response to the click event of a Button
control, and displays the result data in a DataGrid control.
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<?xml version="1.0"?>
<!-- ds\rpc\RPCIntroExample.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.rpc.events.ResultEvent;
import mx.rpc.events.FaultEvent;
import mx.controls.Alert;
public function handleResult(event:ResultEvent):void {
// Handle result by populating the DataGrid control.
// The operation returns an Array containing product ID, name, and price.
myDG.dataProvider=event.result;
}
public function handleFault(event:FaultEvent):void {
// Handle fault.
Alert.show(event.fault.faultString, "Fault");
}
]]>
</mx:Script>
<!-- Define a WebService component and connect to a service destination. -->
<mx:WebService
id="adbe_news"
useProxy="true"
destination="ws-catalog"
result="handleResult(event);"
fault="handleFault(event);"/>
<!-- Call the getProducts() operation of the web service.
The operation takes no parameters. -->
<mx:Button label="Get Data" click="adbe_news.getProducts();"/>
<!-- Define a DataGrid control to diplay the results of the web service. -->
<mx:DataGrid id="myDG" width="100%" height="100%">
<mx:columns>
<mx:DataGridColumn dataField="productId" headerText="Product Id"/>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="price" headerText="Price"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
This example shows the basic process for using any RPC control, including the following:
• Defines the component in MXML. You can also define a component in ActionScript. For more information, see
“HTTP services and web services” on page 140.
• Specifies the LiveCycle Data Services destination that the RPC component connects to. For more information, see
“Using destinations” on page 140.
• Invokes the getProducts() operation in response to a Button click event. In this example, the getProducts()
operation takes no parameters. For more information on parameter passing, see “Passing parameters to a service”
on page 149.
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• Defines event handlers for the result event and for the fault event. Calls to an RPC service are asynchronous.
After you invoke an asynchronous call, your application does not block execution and wait for immediate response,
but continues to execute. Components use events to signal that the service has completed. In this example, the
handler for the result event populates the DataGrid control with the results of the operation. For more
information, see “Handling service events” on page 171.
RPC components versus other technologies
The way that Flex works with data sources and data is different from other web application environments, such as JSP,
ASP, and ColdFusion.
Client-side processing and server-side processing
Unlike a set of HTML templates created using JSPs and servlets, ASP, or CFML, the files in a Flex application are
compiled into a binary SWF file that is sent to the client. When a Flex application makes a request to an external
service, the SWF file is not recompiled and no page refresh is required.
The following example shows MXML code for calling a web service. When a user clicks the Button control, client-side
code calls the web service, and result data is returned into the binary SWF file without a page refresh. The result data
is then available to use as dynamic content within the application.
<?xml version="1.0"?>
<!-- ds\rpc\RPCIntroExample2.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<!-- Declare a WebService component (the specified WSDL URL is not functional). -->
<mx:WebService id="WeatherService"
destination="wsDest"/>
<mx:Button label="Get Weather"
click="WeatherService.GetWeather(input.text);"/>
<mx:TextInput id="input"/>
</mx:Application>
The following example shows JSP code for calling a web service using a JSP custom tag. When a user requests this JSP,
the web service request is made on the server instead of on the client, and the result is used to generate content in the
HTML page. The application server regenerates the entire HTML page before sending it back to the browser.
<%@ taglib prefix="web" uri="webservicetag" %>
<% String str1="BRL";
String str2="USD";%>
<!-- Call the web service. -->
<web:invoke
url="http://www.itfinity.net:8008/soap/exrates/default.asp"
namespace="http://www.itfinity.net/soap/exrates/exrates.xsd"
operation="GetRate"
resulttype="double"
result="myresult">
<web:param name="fromCurr" value="<%=str1%>"/>
<web:param name="ToCurr" value="<%=str2%>"/>
</web:invoke>
<!-- Display the web service result. -->
<%= pageContext.getAttribute("myresult") %>
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Data source access
Another difference between Flex and other web application technologies is that you never communicate directly with
a data source in Flex. You use a Flex service component to connect to a server-side service that interacts with the data
source.
The following example shows one way to access a data source directly in a ColdFusion page:
<CFQUERY DATASOURCE="Dsn"
NAME="myQuery">
SELECT * FROM table
</CFQUERY>
To get similar functionality in Flex, use an HTTPService, a WebService, or a RemoteObject component to call a serverside object that returns results from a data source.
HTTP services and web services
You define an HTTPService or WebService component in MXML or ActionScript. After defining the component, use
the component to call a destination defined on the server and process any results.
Using destinations
You typically connect an RPC component to a destination defined in the services-config.xml file or a file that it
includes by reference, such as the proxy-config.xml file. A destination definition is a named service configuration that
provides server-proxied access to an RPC service. A destination is the actual service or object that you want to call.
Destination definitions provide centralized administration of RPC services. They also enable you to use basic or
custom authentication to secure access to destinations. You can choose from several different transport channels,
including secure channels, for sending data to and from destinations. Additionally, you can use the server-side logging
capability to log RPC service traffic.
You have the option of omitting the destination and connecting to HTTP and web services directly by specifying the
URL of the service. For more information, see “Using HTTPService and WebService without a destination” on
page 145. However, you must define a destination when using the RemoteObject component.
You configure HTTP services and web services as HTTPProxyService destinations. The following example shows a
HTTPProxyService destination definition for an HTTP service in the proxy-config.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<service id="proxy-service" class="flex.messaging.services.HTTPProxyService">
...
<destination id="myHTTPService">
<properties>
<!-- The endpoint available to the http proxy service -->
<url>http://www.mycompany.com/services/myservlet</url>
<!-- Wildcard endpoints available to the http proxy services -->
<dynamic-url>http://www.mycompany.com/services/*</dynamic-url>
</properties>
</destination>
</service>
Using an RPC component with a server-side destination
The destination property of an RPC component references a destination configured in the proxy-config.xml file. A
destination specifies the RPC service class or URL, the transport channel to use, the adapter with which to access the
RPC service, and security settings.
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To declare a connection to a destination in MXML, set the id and destination properties in the RPC component.
The id property is required for calling the services and handling service results. The following example shows
HTTPService and WebService component declarations in MXML:
<?xml version="1.0"?>
<!-- ds\rpc\RPCMXML.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:HTTPService
id="yahoo_web_search"
useProxy="true"
destination="catalog"/>
<mx:WebService
id="adbe_news"
useProxy="true"
destination="ws-catalog"/>
</mx:Application>
When you use a destination with an HTTPService or WebService component, you set its useProxy property to true
to configure it to use the HTTPProxyService. The HTTPProxyService and its adapters provide functionality that lets
applications access HTTP services and web services on different domains. Additionally, the HTTPProxyService lets
you limit access to specific URLs and URL patterns, and provide security.
Note: Setting the destination property of the HTTPService or WebService component automatically sets the useProxy
property to true.
When you do not have LiveCycle Data Services or do not require the functionality provided by the HTTPProxyService,
you can bypass it. You bypass the proxy by setting the useProxy property of an HTTPService or WebService
component to false, which is the default value. Also set the HTTPService.url property to the URL of the HTTP
service, or set the WebService.wsdl property to the URL of the WSDL document. The RemoteObject component
does not define the useProxy property; you always use a LiveCycle Data Services destination with the RemoteObject
component.
Configuring a destination
You configure a destination in a service definition in the proxy-config.xml file. The following example shows a basic
server-side configuration for a WebService component in the proxy-config.xml file:
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<?xml version="1.0" encoding="UTF-8"?>
<service id="proxy-service" class="flex.messaging.services.HTTPProxyService">
<properties>
<connection-manager>
<max-total-connections>100</max-total-connections>
<default-max-connections-per-host>2</default-max-connections-per-host>
</connection-manager>
<allow-lax-ssl>true</allow-lax-ssl>
</properties>
<!-- Channels are typically defined in the services-config.xml file. -->
<default-channels>
<channel ref="my-http"/>
<channel ref="my-amf"/>
</default-channels>
<!-- Define the adapters used by the different destinations. -->
<adapters>
<adapter-definition id="http-proxy"
class="flex.messaging.services.http.HTTPProxyAdapter"
default="true"/>
<adapter-definition id="soap-proxy"
class="flex.messaging.services.http.SOAPProxyAdapter"/>
</adapters>
<!-- HTTPService destination uses the default adapter. -->
<destination id="catalog">
<properties>
<url>/{context.root}/testdrive-httpservice/catalog.jsp</url>
</properties>
</destination>
<!-- WebService destination uses the SOAPAdapter. -->
<destination id="ws-catalog">
<properties>
<wsdl>http://livecycledata.org/services/ProductWS?wsdl</wsdl>
<soap>http://livecycledata.org/services/ProductWS/*</soap>
</properties>
<adapter ref="soap-proxy"/>
</destination>
</service>
HTTPService and WebService components connect to HTTPProxyService destinations. Therefore, the class
attribute of the <service> tag specifies the HTTPProxyService class.
The adapter is server-side code that interacts with the remote service. Specify the HTTPProxyAdapter with a
destination defined for the HTTPService component, and the SOAPAdapter for the WebService component.
This destination uses an HTTP or an Action Message Format (AMF) message channel for transporting data.
Optionally, it could use one of the other supported message channels. Message channels are defined in the
services-config.xml file, in the channels section under the services-config element. For more information, see
“Channels and endpoints” on page 38.
You use the url and dynamic-url elements to configure HTTP service URLs in a destination. These elements define
which URLs are permitted for a destination. The following table describes those elements:
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Element
Description
url
(Optional) Default URL.
The HTTPService URL could be at a domain that is different from the one hosting your SWF file and
therefore cannot be requested directly from Adobe Flash Player due to the sandbox security
restrictions the player enforces. When that is the case, you can use the Proxy Service to proxy the
request. You establish a set of URLs that you permit it to proxy for you. In a Proxy Service
destination you configure the URL in the url property to instruct the Proxy Service to allow requests
to be proxied to this URL.The url property also lets you avoid hard coding the WSDL URL into your
MXML file by by specifying the destination name instead of the WSDL URL.
dynamic-url
(Optional) HTTP service URL patterns. You can use more than one dynamic-url entry to specify
multiple URL patterns. Flex matches these values against url property values that you specify in
client-side service tags or ActionScript code.
You use the wsdl and soap elements to configure web service URLs in a destination. These elements define which
URLs are permitted for a destination. The following table describes those elements:
Element
Description
wsdl
(Optional) Default WSDL URL.
When you use a WebService component in a Flex application, the first thing that happens is an HTTP
GET request is made to a URL to load the WSDL document for the web service. The URL could be at
a domain that is different from the one hosting your SWF file and therefore cannot be requested
directly from Adobe Flash Player due to the sandbox security restrictions the player enforces. When
that is the case, you can use the Proxy Service to proxy the request. You establish a set of URLs that
you permit it to proxy for you. In a Proxy Service destination you configure the WSDL URL in the
wsdl property to instruct the Proxy Service to allow requests to be proxied to this URL.The wsdl
property also lets you avoid hard coding the WSDL URL into your MXML file by by specifying the
destination name instead of the WSDL URL.
soap
SOAP endpoint URL patterns that would typically be defined for each operation in the WSDL
document.
In a WSDL document, there is a port section, usually at the end of the file, that describes the location
of the SOAP endpoints to handle web service requests. These URLs are used in subsequent HTTP
POST requests that send SOAP-formatted requests and corresponding SOAP-formatted responses.
You add these URLs using the soap properties in the destination configuration. You typically use a
soap property to define a SOAP endpoint URL pattern for each operation in a WSDL document. You
use more than one soap entry to specify multiple SOAP endpoint patterns.
You can use wildcards in these URLs because in more complex WSDLs you can have multiple
services, multiple ports, and therefore multiple SOAP address locations.
Example:
<soap>http://www.weather.gov/forecasts/xml/SOAP_server/*</soap>
Using a <soap>*</soap> element on an unprotected destination is not a good idea because you
are effectively setting up a public anonymous relay. If you do want to use a very lenient wildcard,
you can set a role-based J2EE security restriction and require authentication on the message broker
so that only authenticated requests are processed.
Note: If you use endpointURI property values in client-side service tags or ActionScript code, Flex
matches the values specified in soap properties against those.
Using HTTPService and WebService with a default destination
In the following situation, a component uses a default destination:
• You set the useProxy property to true
• You do not set the destination property
• You set the HTTPService.url property or the WebService.wsdl property
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The default destinations are named DefaultHTTP and DefaultHTTPS. The DefaultHTTPS destination is used when
your url or wsdl property specifies an HTTPS URL.
By setting the url or wsdl property, you let the component specify the URL of the remote service, rather than
specifying it in the destination. However, since the request uses the default destination, you can take advantage of
LiveCycle Data Services. Therefore, you can use basic or custom authentication to secure access to the destination. You
can choose from several different transport channels, including secure channels, for sending data to and from
destinations. Additionally, you can use the server-side logging capability to log remote service traffic.
Configure the default destinations in the proxy-config.xml file. Use one or more dynamic-url parameters to specify
URL patterns for the HTTP service, or one or more soap parameters to specify URL patterns for the WSDL of the web
service. The value of the url or wsdl property of the component must match the specified pattern.
The following example shows a default destination definition that specifies a dynamic-url value:
<service id="proxy-service" class="flex.messaging.services.HTTPProxyService">
...
<destination id="DefaultHTTP">
<channels>
<channel ref="my-amf"/>
</channels>
<properties>
<dynamic-url>http://mysite.com/myservices/*</dynamic-url>
</properties>
...
</destination>
</service>
Therefore, set the HTTPService.url property to a URL that begins with the pattern http://mysite.com/myservices/.
Setting the HTTPService.url property to any other value causes a fault event.
The following table describes elements that you use to configure the default destinations:
Parameter
Description
dynamic-url Specifies the URL pattern for the HTTP service. You can use one or more dynamic-url parameters
to specify multiple patterns. Any request from the client must match one of the patterns.
soap
Specifies the URL pattern for a WSDL or the location of a web service. You can use one or more soap
parameters to specify multiple patterns. The URL of the WSDL, or the URL of the web service, must
match one of the patterns. If you specify a URL for the wsdl property, the URL must match a
pattern,
Configuring the Proxy Service
Configure the Proxy Service by using the proxy-config.xml file. The service parameter contains a properties
element that you use to configure the Apache connection manager, self-signed certificates for SSL, and external
proxies. The following table describes elements that you use to configure the Proxy Service:
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Element
Description
connection-manager Contains the max-total-connections and default-max-connections-perhost elements.
The max-total-connections element controls the maximum total number of
concurrent connections that the proxy supports. If the value is greater than 0, LiveCycle
Data Services uses a multithreaded connection manager for the underlying Apache
HttpClient proxy.
The default-max-connections-per-host element sets the default number of
connections allowed for each host in an environment that uses hardware clustering.
content-chunked
Specifies whether to use chunked content. The default value is false. Flash Player does
not support chunked content.
allow-lax-ssl
Set to true when using SSL to allow self-signed certificates. Do not set to true in a
production environment.
external-proxy
Specifies the location of an external proxy, as well as a user name and a password, when
the Proxy Service must contact an external proxy before getting access to the Internet.
The properties of external-proxy depend on the external proxy and the underlying
Apache HttpClient proxy. For more information on the Apache HttpClient, see the Apache
website.
The following example shows a Proxy Service configuration:
<service id="proxy-service" class="flex.messaging.services.HTTPProxyService">
<!-- Define channels and destinations. -->
<properties>
<connection-manager>
<max-total-connections>100</max-total-connections>
<default-max-connections-per-host>2
</default-max-connections-per-host>
</connection-manager>
<!-- Allow self-signed certificates. Do not use in production -->
<allow-lax-ssl>true</allow-lax-ssl>
<!-- Connection settings for an external proxy. -->
<external-proxy>
<server>10.10.10.10</server>
<port>3128</port>
<nt-domain>mycompany</nt-domain>
<username>flex</username>
<password>flex</password>
</external-proxy>
</properties>
</service>
Using HTTPService and WebService without a destination
You can connect to HTTP services and web services without configuring a destination. To do so, you set the
HTTPService.url property or the WebService.wsdl property instead of setting the destination property.
Additionally, set the useProxy property of the component to false to bypass the HTTPProxyService. When the
useProxy property is set to false, the component communicates directly with the service based on the url or wsdl
property value.
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When you set the useProxy property to true for the HTTPService component, you can use the HTTP HEAD,
OPTIONS, TRACE, and DELETE methods. However, when you do not go through the HTTPProxyService, you can
use only HTTP GET or POST methods. By default, the HTTPService method uses the GET method.
Note: If you bypass the proxy, and the status code of the HTTP response is not a success code from 200 through 299, Flash
Player cannot access any data in the body of the response. For example, a server sends a response with an error code of
500 with the error details in the body of the response. Without a proxy, the body of the response is inaccessible by the Flex
application.
Connecting to a service in this manner requires that at least one of the following is true:
• The service is in the same domain as your Flex application.
• A crossdomain.xml (cross-domain policy) file is installed on the web server hosting the RPC service that allows
access from the domain of the application. For more information, see the Flex documentation.
The following examples show MXML tags for declaring HTTPService and WebService components that directly
reference RPC services. The id property is required for calling the services and handling service results. In these
examples, the useProxy property is not set in the tags. Therefore, the components use the default useProxy value of
false and contact the services directly:
<?xml version="1.0"?>
<!-- ds\rpc\RPCNoServer.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:HTTPService
id="yahoo_web_search"
url="http://api.search.yahoo.com/WebSearchService/V1/webSearch"/>
<mx:WebService
id="macr_news"
wsdl="http://ws.invesbot.com/companysearch.asmx?wsdl"/>
</mx:Application>
Defining and invoking an HTTPService component
Use the HTTPService components in your client-side application to make an HTTP request to a URL. The following
examples show HTTPService component declarations in MXML and in ActionScript. Regardless of how you define
the component, you send a request to the destination by calling the HTTPService.send() method. To handle the
results, you use the result and fault event handlers:
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<?xml version="1.0"?>
<!-- ds\rpc\HttpService.mxml. -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="useHttpService();">
<mx:Script>
<![CDATA[
import
import
import
import
mx.controls.Alert;
mx.rpc.http.mxml.HTTPService;
mx.rpc.events.ResultEvent;
mx.rpc.events.FaultEvent;
private var asService:HTTPService
// Define the HTTPService component in ActionScript.
public function useHttpService():void {
asService = new HTTPService();
asService.method = "POST";
asService.useProxy = true;
asService.destination = "catalog";
asService.addEventListener("result", httpResult);
asService.addEventListener("fault", httpFault);
}
public function httpResult(event:ResultEvent):void {
//Do something with the result.
}
public function httpFault(event:FaultEvent):void {
var faultstring:String = event.fault.faultString;
Alert.show(faultstring);
}
]]>
</mx:Script>
<!-- Define the HTTPService component in MXML. -->
<mx:HTTPService
id="mxmlService"
method="POST"
useProxy="true"
destination="catalog"
result="httpResult(event);"
fault="httpFault(event);"/>
<mx:Button label="MXML" click="mxmlService.send();"/>
<mx:Button label="AS" click="asService.send();"/>
</mx:Application>
Defining and invoking a WebService component
Use the WebService components in your client-side application to make a SOAP request. The following example
defines a WebService component in MXML and ActionScript:
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<?xml version="1.0"?>
<!-- ds\rpc\WebServiceExample.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="useWebService();">
<mx:Script>
<![CDATA[
import
import
import
import
mx.controls.Alert;
mx.rpc.soap.mxml.WebService;
mx.rpc.events.ResultEvent;
mx.rpc.events.FaultEvent;
private var asService:WebService;
// Define the WebService component in ActionScript.
public function useWebService():void {
asService = new WebService();
asService.destination = "ws-catalog";
asService.addEventListener("result", wsResult);
asService.addEventListener("fault", wsFault);
asService.loadWSDL();
}
public function wsResult(event:ResultEvent):void {
//Do something with the result.
}
public function wsFault(event:FaultEvent):void {
var faultstring:String = event.fault.faultString;
Alert.show(faultstring);
}
]]>
</mx:Script>
<!-- Define the WebService component in MXML. -->
<mx:WebService
id="mxmlService"
destination="ws-catalog"
result="wsResult(event);"
fault="wsFault(event);"/>
<mx:Button label="MXML" click="mxmlService.getProducts();"/>
<mx:Button label="AS" click="asService.getProducts();"/>
</mx:Application>
The destination specifies the WSDL associated with this web service. A web service can expose multiple methods,
corresponding to multiple operations. In this example, you directly call the getProducts() operation of the web
service in response to a click event of a Button control.
Important: Notice that the ActionScript version of the WebService component calls the WebService.loadWSDL()
method to load the WSDL. This is required when you create the WebService component in ActionScript. This method is
called automatically when you define the component in MXML.
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Using an Operation object with the WebService component
Because a single WebService component can invoke multiple operations on the web service, the component requires
a way to represent information specific to each operation. Therefore, for every operation, the component creates an
mx.rpc.soap.mxml.Operation object.
The name of the Operation object corresponds to the name of the operation. From the example shown in “Defining
and invoking a WebService component” on page 147, access the Operation object that corresponds to the
getProducts() operation by accessing the Operation object named getProducts, as the following code shows:
// The Operation object has the same name as the operation, without the trailing parentheses.
var myOP:Operation = mxmlService.getProducts;
The Operation object contains properties that you use to set characteristics of the operation, such as the arguments
passed to the operation, and to hold any data returned by the operation. You access the returned data by using the
Operation.lastResult property.
Invoke the operation by referencing it relative to the WebService component, as the following example shows:
mxmlService.getProducts();
Alternatively, invoke an operation by calling the Operation.send() method, as the following example shows:
mxmlService.getProducts.send();
Defining multiple operations for the WebService component
When a web service defines multiple operations, you define multiple operations for the WebService component and
specify the attributes for each operation, as the following example shows:
<mx:WebService
id="mxmlService"
destination="ws-catalog"
result="wsResult(event);">
<mx:operation name="getProducts" fault="getPFault(event);"/>
<mx:operation name="updateProdcut" fault="updatePFault(event);"/>
<mx:operation name="deleteProduct" fault="deletePFault(event);"/>
</mx:WebService>
The name property of an <mx:operation> tag must match one of the web service operation names. The WebService
component creates a separate Operation object for each operation.
Each operation can rely on the event handlers and characteristics defined by the WebService component. However,
the advantage of defining the operations separately is that each operation can specify its own event handlers, its own
input parameters, and other characteristics. In this example, the WebService component defines the result handler for
all three operations, and each operation defines its own fault handler. For more information, see “Handling service
events” on page 171 and “Passing parameters to a service” on page 149.
Passing parameters to a service
Flex provides two ways to pass parameters to a service call: explicit parameter passing and parameter binding. With
explicit parameter passing, pass properties in the method that calls the service. With parameter binding, use data
binding to populate the parameters.
Using explicit parameter passing
When you use explicit parameter passing, you provide input to a service in the form of parameters to an ActionScript
function. This way of calling a service closely resembles the way that you call methods in Java.
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Explicit parameter passing with HTTPService components
When you use explicit parameter passing with an HTTPService component, you specify an object that contains namevalue pairs as an argument to the send() method. A send() method parameter must be a simple base type such as
Object. You cannot use complex nested objects because there is no generic way to convert them to name-value pairs.
The following examples show two ways to call an HTTP service using the send() method with a parameter.
<?xml version="1.0"?>
<!-- ds\rpc\RPCSend.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
public function callService():void {
var params:Object = new Object();
params.param1 = 'val1';
myService.send(params);
}
]]>
</mx:Script>
<mx:HTTPService
id="myService"
destination="catalog"
useProxy="true"/>
<!-- HTTP service call with a send() method that takes
a variable as its parameter. The value of the variable is an Object. -->
<mx:Button label="send() with variable" click="myService.send({param1: 'val1'});"/>
<!-- HTTP service call with an object as a send() method parameter
that provides query parameters. -->
<mx:Button label="send() with query params" click="callService();"/>
</mx:Application>
Explicit parameter passing with WebService components
When using the WebService component, you call a service by directly calling the service method, or by calling the
Operation.send() method of the Operation object that represents the operation. When you use explicit parameter
passing, you specify the parameters as arguments to the method that you use to invoke the operation.
The following example shows MXML code for declaring a WebService component and calling a service using explicit
parameter passing in the click event listener of a Button control. A ComboBox control provides data to the service, and
event listeners handle the service-level result and fault events:
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<?xml version="1.0"?>
<!-- ds\rpc\RPCParamPassingWS.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
]]>
</mx:Script>
<mx:WebService
id="employeeWS"
destination="SalaryManager"/>
<mx:ComboBox id="dept" width="150">
<mx:dataProvider>
<mx:ArrayCollection>
<mx:source>
<mx:Object label="Engineering" data="ENG"/>
<mx:Object label="Product Management" data="PM"/>
<mx:Object label="Marketing" data="MKT"/>
</mx:source>
</mx:ArrayCollection>
</mx:dataProvider>
</mx:ComboBox>
<mx:Button label="Get Employee List"
click="employeeWS.getList(dept.selectedItem.data);"/>
</mx:Application>
Using data binding to pass parameters
Parameter binding lets you copy data from user interface controls or models to request parameters. You typically
declare data bindings in MXML. However, you can also define them in ActionScript. For more information about data
binding, see the Flex documentation.
Binding with HTTPService components
Parameters to an HTTPService component correspond to query parameters of the requested URL. When an HTTP
service takes query parameters, you can specify them by using the request property. The request property takes an
Object of name-value pairs used as parameters to the URL. The names of the properties must match the names of the
query parameters that the service expects. If the HTTPService.contentType property is set to application/xml, the
request property must be an XML document.
When you use parameter binding, you call a service by using the send() method but specify no arguments to the
method. The HTTPService component automatically adds the parameters specified by the request property to the
request.
Note: If you do not specify a parameter to the send() method, the HTTPService component uses any query parameters
specified in an <mx:request> tag.
The following example binds the selected data of a ComboBox control to the request property:
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<?xml version="1.0"?>
<!-- ds\rpc\HttpServiceParamBind.mxml. Compiles -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:HTTPService
id="employeeSrv"
destination="catalog">
<mx:request>
<deptId>{dept.selectedItem.data}</deptId>
</mx:request>
</mx:HTTPService>
<mx:HBox>
<mx:Label text="Select a department:"/>
<mx:ComboBox id="dept" width="150">
<mx:dataProvider>
<mx:ArrayCollection>
<mx:source>
<mx:Object label="Engineering" data="ENG"/>
<mx:Object label="Product Management" data="PM"/>
<mx:Object label="Marketing" data="MKT"/>
</mx:source>
</mx:ArrayCollection>
</mx:dataProvider>
</mx:ComboBox>
<mx:Button label="Get Employee List" click="employeeSrv.send();"/>
</mx:HBox>
<mx:DataGrid dataProvider="{employeeSrv.lastResult.employees.employee}"
width="100%">
<mx:columns>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="phone" headerText="Phone"/>
<mx:DataGridColumn dataField="email" headerText="Email"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
Binding with WebService components
When you use parameter binding with a WebService component, you typically declare an operation by using the
operation property. Each operation property corresponds to an instance of the Operation class, which defines a
request property that contains the XML nodes that the operation expects.
The following example binds the data of a selected ComboBox item to the getList() operation. When you use
parameter binding, you call a service by using the send() method with no arguments:
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<?xml version="1.0"?>
<!-- ds\rpc\WebServiceParamBind.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.utils.ArrayUtil;
import mx.controls.Alert;
]]>
</mx:Script>
<mx:ArrayCollection
id="employeeAC"
source="{ArrayUtil.toArray(employeeWS.getList.lastResult)}"/>
<mx:WebService
id="employeeWS"
destination="wsDest"
showBusyCursor="true"
fault="Alert.show(event.fault.faultString);">
<mx:operation name="getList">
<mx:request>
<deptId>{dept.selectedItem.data}</deptId>
</mx:request>
</mx:operation>
</mx:WebService>
<mx:HBox>
<mx:Label text="Select a department:"/>
<mx:ComboBox id="dept" width="150">
<mx:dataProvider>
<mx:ArrayCollection>
<mx:source>
<mx:Object label="Engineering" data="ENG"/>
<mx:Object label="Product Management" data="PM"/>
<mx:Object label="Marketing" data="MKT"/>
</mx:source>
</mx:ArrayCollection>
</mx:dataProvider>
</mx:ComboBox>
<mx:Button label="Get Employee List" click="employeeWS.getList.send();"/>
</mx:HBox>
<mx:DataGrid dataProvider="{employeeAC}" width="100%">
<mx:columns>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="phone" headerText="Phone"/>
<mx:DataGridColumn dataField=" to email" headerText="Email"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
You can manually specify an entire SOAP request body in XML with all of the correct namespace information defined
in the request property. Set the value of the format attribute of the request property to xml, as the following
example shows:
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<?xml version="1.0"?>
<!-- ds\rpc\WebServiceSOAPRequest.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" verticalGap="10">
<mx:WebService id="ws" wsdl="http://api.google.com/GoogleSearch.wsdl"
useProxy="true">
<mx:operation name="doGoogleSearch" resultFormat="xml">
<mx:request format="xml">
<ns1:doGoogleSearch xmlns:ns1="urn:GoogleSearch"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<key xsi:type="xsd:string">XYZ123</key>
<q xsi:type="xsd:string">Balloons</q>
<start xsi:type="xsd:int">0</start>
<maxResults xsi:type="xsd:int">10</maxResults>
<filter xsi:type="xsd:boolean">true</filter>
<restrict xsi:type="xsd:string"/>
<safeSearch xsi:type="xsd:boolean">false</safeSearch>
<lr xsi:type="xsd:string" />
<ie xsi:type="xsd:string">latin1</ie>
<oe xsi:type="xsd:string">latin1</oe>
</ns1:doGoogleSearch>
</mx:request>
</mx:operation>
</mx:WebService>
</mx:Application>
Using capabilities specific to WebService components
Flex applications can interact with web services that define their interfaces in a Web Services Description Language 1.1
(WSDL 1.1) document, which is available as a URL. WSDL is a standard format for describing the messages that a web
service understands, the format of its responses to those messages, the protocols that the web service supports, and
where to send messages. The Flex web service API generally supports SOAP 1.1, XML Schema 1.0 (versions 1999, 2000
and 2001), and WSDL 1.1 rpc-encoded, and rpc-literal, document-literal (bare and wrapped style parameters). The
two most common types of web services use RPC-encoded or document-literal SOAP bindings; the terms encoded and
literal indicate the type of WSDL-to-SOAP mapping that a service uses.
Note: Flex does not support the following XML schema types: union, default, or list. Flex also does not support the
following data types: duration, gMonth, gYear, gYearMonth, gDay, gMonthDay, Name, Qname, NCName, anyURI, or
language. These data types are treated as Strings and not validated. Flex supports any URL but treats it like a String.
Flex applications support web service requests and results that are formatted as Simple Object Access Protocol (SOAP)
messages. SOAP provides the definition of the XML-based format that you can use for exchanging structured and
typed information between a web service client, such as a Flex application, and a web service.
Adobe Flash Player operates within a security sandbox that limits what Flex applications and other Flash Player
applications can access over HTTP. Flash Player applications are only allowed HTTP access to resources on the same
domain and by the same protocol from which they were served. This restriction presents a problem for web services,
because they are typically accessed from remote locations. The Proxy Service, available in LiveCycle Data Services,
intercepts requests to remote web services, redirects the requests, and then returns the responses to the client.
If you are not using LiveCycle Data Services, you can access web services in the same domain as your Flex application.
Or, a crossdomain.xml file that allows access from the domain of the application must be installed on the web server
hosting the RPC service. For more information, see the Adobe Flex 3 documentation.
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Note: If you are using Flash Player version 9,0,124,0 or later, the crossdomain.xml file has a new tag called <allow-httprequest-headers-from> that you use to set header-sending rights. For web services, make sure to set the headers attribute
of the <allow-http-request-headers-from> tag to SOAPAction. For more information, see
http://www.adobe.com/devnet/flashplayer/articles/flash_player9_security_update.html and
http://kb.adobe.com/selfservice/viewContent.do?externalId=kb403185&sliceId=2.
Reading WSDL documents
View a WSDL document in a web browser, a simple text editor, an XML editor, or a development environment such
as Adobe Dreamweaver, which contains a built-in utility for displaying WSDL documents in an easy-to-read format.
For a complete description of the format of a WSDL document, see http://www.w3.org/TR/wsdl.
RPC-oriented operations and document-oriented operations
A WSDL file can specify either remote procedure call-oriented (RPC) or document-oriented (document/literal)
operations. Flex supports both operation styles.
When calling an RPC-oriented operation, a Flex application sends a SOAP message that specifies an operation and its
parameters. When calling a document-oriented operation, a Flex application sends a SOAP message that contains an
XML document.
In a WSDL document, each <port> tag has a binding property that specifies the name of a particular
<soap:binding> tag, as the following example shows:
<binding name="InstantMessageAlertSoap" type="s0:InstantMessageAlertSoap">
<soap:binding transport="http://schemas.xmlsoap.org/soap/http"
style="document"/>
The style property of the associated <soap:binding> tag determines the operation style. In this example, the style
is document.
Any operation in a service can specify the same style or override the style that is specified for the port associated with
the service, as the following example shows:
<operation name="SendMSN">
<soap:operation soapAction="http://www.bindingpoint.com/ws/imalert/
SendMSN"style="document"/>
Stateful web services
LiveCycle Data Services can maintain the state of web service endpoints. If the web service uses cookies to store session
information, LiveCycle Data Services uses Java server sessions to maintain the state of the web service. This capability
acts as an intermediary between Flex applications and web services. It adds the identity of an endpoint to whatever the
endpoint passes to a Flex application. If the endpoint sends session information, the Flex application receives it. This
capability requires no configuration; it is not supported for destinations that use the RTMP channel when using the
HTTPProxyService.
Working with SOAP headers
A SOAP header is an optional tag in a SOAP envelope that usually contains application-specific information, such as
authentication information.
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Adding SOAP headers to web service requests
Some web services require that you pass a SOAP header when you call an operation. Add a SOAP header to all web
service operations or individual operations by calling the addHeader() or addSimpleHeader() method of the
WebService or Operation object.
When you use the addHeader() method, you first create SOAPHeader and QName objects separately. The
addHeader() method has the following signature:
addHeader(header:mx.rpc.soap.SOAPHeader):void
To create a SOAPHeader object, you use the following constructor:
SOAPHeader(qname:QName, content:Object)
The content parameter of the SOAPHeader() constructor is a set of name-value pairs based on the following format:
{name1:value1, name2:value2}
To create the QName object in the first parameter of the SOAPHeader() method, you use the following constructor:
QName(uri:String, localName:String)
The addSimpleHeader() method is a shortcut for a single name-value SOAP header. When you use the
addSimpleHeader() method, you create SOAPHeader and QName objects in parameters of the method. The
addSimpleHeader() method has the following signature:
addSimpleHeader(qnameLocal:String, qnameNamespace:String, headerName:String,
headerValue:Object):void
The addSimpleHeader() method takes the following parameters:
•
qnameLocal is the local name for the header QName.
•
qnameNamespace is the namespace for the header QName.
•
headerName is the name of the header.
•
headerValue is the value of the header. This value can be a String if it is a simple value, an Object that undergoes
basic XML encoding, or XML if you want to specify the header XML yourself.
The following calls to the addSimpleHeader() and addSimpleHeader() methods are equivalent:
addHeader(new Qname(qNs,qLocal), {name:val});
addSimpleHeader(qLocal, qNs, name, val);
Both methods add a SOAPHeader object to a collection of headers. Each SOAPHeader is encoded as follows:
<qnamePrefix:qnameLocal>
content
</qnamePrefix:qnameLocal>
If the content parameter contains simple data, its String representation is used. If it contains an Object, its structure
is converted to XML. For example, if the content parameter passed to the method contains the following data:
{name:value}
The SOAPHeader is encoded as follows:
<qnamePrefix:qnameLocal>
<headerName>headerValue</headerName>
</qnamePrefix:qnameLocal>
If the content parameter contains a property with the same name as qnameLocal, the value of that property is used
as the header content. Therefore, if qnameLocal equals headerName, the SOAPHeader object is encoded as follows:
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<qnamePrefix:headerName>
headerValue
</qnamePrefix:headerName>
The code in the following example shows how to use the addHeader() method and the addSimpleHeader() method
to add a SOAP header. The methods are called in the headers() function, and the event listener is assigned in the
load property of an WebService component:
<?xml version="1.0"?>
<!-- ds\rpc\WebServiceAddHeader.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.rpc.soap.SOAPHeader;
private var header1:SOAPHeader;
private var header2:SOAPHeader;
public function headers():void {
// Create QName and SOAPHeader objects.
var q1:QName = new QName("http://soapinterop.org/xsd", "Header1");
header1 = new SOAPHeader(q1, {string:"bologna",int:"123"});
header2 = new SOAPHeader(q1, {string:"salami",int:"321"});
// Add the header1 SOAP Header to all web service requests.
ws.addHeader(header1);
// Add the header2 SOAP Header to the getSomething operation.
ws.getSomething.addHeader(header2);
// Within the addSimpleHeader method,
// which adds a SOAP header to web
//service requests, create SOAPHeader and QName objects.
ws.addSimpleHeader("header3", "http://soapinterop.org/xsd", "foo", "bar");
}
]]>
</mx:Script>
<mx:WebService id="ws"
destination="wsDest"
load="headers();"/>
</mx:Application>
Clearing SOAP headers
Use the clearHeaders() method of a WebService or Operation object to remove SOAP headers that you added to
the object, as the following example shows:
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<?xml version="1.0"?>
<!-- ds\rpc\WebServiceClearHeader.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<!-- The value
and is not
<mx:Script>
<![CDATA[
import
import
of the destination property is for demonstration only
a real destination. -->
mx.rpc.*;
mx.rpc.soap.SOAPHeader;
private function headers():void {
// Create QName and SOAPHeader objects.
var q1:QName = new QName("Header1", "http://soapinterop.org/xsd");
var header1:SOAPHeader = new SOAPHeader(q1, {string:"bologna",int:"123"});
var header2:SOAPHeader = new SOAPHeader(q1, {string:"salami",int:"321"});
// Add the header1 SOAP Header to all web service request.
ws.addHeader(header1);
// Add the header2 SOAP Header to the getSomething operation.
ws.getSomething.addHeader(header2);
// Within the addSimpleHeader method, which adds a SOAP header to all
// web service requests, create SOAPHeader and QName objects.
ws.addSimpleHeader("header3","http://soapinterop.org/xsd", "foo", "bar");
}
// Clear SOAP headers added at the WebService and Operation levels.
private function clear():void {
ws.clearHeaders();
ws.getSomething.clearHeaders();
}
]]>
</mx:Script>
<mx:WebService id="ws"
destination="wsDest"
load="headers();"/>
<mx:HBox>
<mx:Button label="Clear headers and run again"
click="clear();"/>
</mx:HBox>
</mx:Application>
Redirecting a web service to a different URL
Some web services require that you change to a different endpoint URL after you process the WSDL and make an
initial call to the web service. For example, suppose you want to use a web service that requires you to pass security
credentials. After you call the web service to send login credentials, it accepts the credentials and returns the actual
endpoint URL that is required to use the business operations. Before calling the business operations, change the
endpointURI property of your WebService component.
The following example shows a result event listener that stores the endpoint URL that a web service returns in a
variable, and then sets the endpoint URL for subsequent requests:
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public function onLoginResult(event:ResultEvent):void {
//Extract the new service endpoint from the login result.
var newServiceURL = event.result.serverUrl;
// Redirect all service operations to the URL received in the login result.
serviceName.endpointURI=newServiceURL;
}
A web service that requires you to pass security credentials can also return an identifier that you must attach in a SOAP
header for subsequent requests; for more information, see “Working with SOAP headers” on page 155.
Remote objects
You declare RemoteObject components in MXML or ActionScript to connect to remote services.
Note: This documentation describes how to connect to Java classes in conjunction with Livecycle Data Services. For
information about connecting to PHP or ColdFusion, see the Flex and ColdFusion documentation.
A destination for a RemoteObject component is a Java class defined as the source of a Remoting Service destination.
Destination definitions provide centralized administration of remote services. They also enable you to use basic or
custom authentication to secure access to destinations. You can choose from several different transport channels,
including secure channels, for sending data to and from destinations. Additionally, you can use the server-side logging
capability to log remote service traffic.
You can also use RemoteObject components with PHP and .NET objects in conjunction with third-party AMF
implementations.
Remoting Service channels
With the Remoting Service, you often use an AMFChannel. The AMFChannel uses binary AMF encoding over HTTP.
If binary data is not allowed, then you can use an HTTPChannel, which is AMFX (AMF in XML) over HTTP. Message
channels are typically defined in the services-config.xml file, in the channels section under the services-config
element. For more information on channels, see “Client and server architecture” on page 27.
Using a RemoteObject component
The following example shows a RemoteObject component that connects to a destination, sends a request to the data
source in the click event of a Button control, and displays the result data in the text property of a TextArea control:
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<?xml version="1.0"?>
<!-- ds\rpc\RPCIntroExample1.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.rpc.events.ResultEvent;
import mx.rpc.events.FaultEvent;
import mx.controls.Alert;
public function handleResult(event:ResultEvent):void {
// Handle result by populating the TextArea control.
outputResult.text=remoteService.getData.lastResult.prop1;
}
public function handleFault(event:FaultEvent):void {
// Handle fault.
Alert.show(event.fault.faultString, "Fault");
}
]]>
</mx:Script>
<!-- Connect to a service destination.-->
<mx:RemoteObject id="remoteService"
destination="census"
result="handleResult(event);"
fault="handleFault(event);"/>
<!-- Provide input data for calling the service. -->
<mx:TextInput id="inputText"/>
<!-- Call the web service, use the text in a TextInput control as input data.-->
<mx:Button click="remoteService.getData(inputText.text)"/>
<!-- Display results data in the user interface. -->
<mx:TextArea id="outputResult"/>
</mx:Application>
Defining remote Java objects
One difference between Remoting Service destinations and HTTP service and web service destinations is that in
Remoting Service destinations you host the remote Java object in your LiveCycle Data Services web application and
reference it by using a destination. With HTTP service and web service destinations, you typically configure the
destination to access a remote service, external to the web application. A developer is responsible for writing and
compiling the Java class and adding it to the web application classpath by placing it in the WEB-INF\classes or WEBINF\lib directory.
You can use any plain old Java object (POJO) that is available in the web application classpath as the source of the
Remoting Service destination. The class must have a zero-argument constructor so that LiveCycle Data Services can
construct an instance.
The following example shows a Remoting Service destination definition in the remoting-config.xml file. The source
element specifies the fully qualified name of a class in the classpath of the web application.
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<destination id="census">
<properties>
<source>flex.samples.census.CensusService</source>
</properties>
</destination>
The following example shows the corresponding source code of the Java class that is referenced in the destination
definition:
package flex.samples.census;
import
import
import
import
import
import
java.util.ArrayList;
java.util.List;
java.sql.Connection;
java.sql.PreparedStatement;
java.sql.ResultSet;
java.sql.SQLException;
import flex.samples.ConnectionHelper;
public class CensusService
{
public List getElements(int begin, int count)
{
long startTime = System.currentTimeMillis();
Connection c = null;
List list = new ArrayList();
String sql = "SELECT id, age, classofworker, education, maritalstatus, race,
sex FROM census WHERE id > ? AND id <= ? ORDER BY id ";
try {
c = ConnectionHelper.getConnection();
PreparedStatement stmt = c.prepareStatement(sql);
stmt.setInt(1, begin);
stmt.setInt(2, begin + count);
ResultSet rs = stmt.executeQuery();
while (rs.next()) {
CensusEntryVO ce = new CensusEntryVO();
ce.setId(rs.getInt("id"));
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ce.setAge(rs.getInt("age"));
ce.setClassOfWorker(rs.getString("classofworker"));
ce.setEducation(rs.getString("education"));
ce.setMaritalStatus(rs.getString("maritalstatus"));
ce.setRace(rs.getString("race"));
ce.setSex(rs.getString("sex"));
list.add(ce);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
c.close();
} catch (Exception ignored) {
}
}
return list;
}
}
Placing Java objects in the classpath
The Remoting Service lets you access stateless and stateful objects that are in the classpath of the LiveCycle Data
Services web application. Place class files in the WEB-INF\classes directory to add them to the classpath. Place Java
Archive (JAR) files in the WEB-INF\lib directory to add them to the classpath.
Specify the fully qualified class name in the source property of a Remoting Service destination in the
remoting-config.xml file. The class also must define a constructor that takes no arguments.
Converting ActionScript data to and from Java data
When you send data from a Flex application to a Java object, the data is automatically converted from an ActionScript
data type to a Java data type. An object returned from a Java method is converted from Java to ActionScript. For a
complete description of how data is converted, see “Data serialization” on page 79.
Reserved method names for the RemoteObject component
If a remote method has the same name as a method defined by the RemoteObject class, or by any of its parent classes,
then you cannot call the remote method directly. The RemoteObject class defines the following method names; do not
use these names as method names in your Java class:
disconnect()
getOperation()
hasOwnProperty()
initialized()
isPrototypeOf()
logout()
propertyIsEnumerable()
setCredentials()
setPropertyIsEnumerable()
setRemoteCredentials()
toString()
valueOf()
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Do not begin Java method names with the underscore (_) character. If a remote method name matches a reserved
method name, you can use the following ActionScript method with a RemoteObject or WebService component to
return an Operation object that represents the method:
public function getOperation(name:String):Operation
For example, if a remote method is called hasOwnProperty(), create an Operation object, as the following example
shows:
public var myRemoteObject:RemoteObject = new RemoteObject();
myRemoteObject.destination = "ro-catalog";
public var op:Operation = myRemoteObject.getOperation("hasOwnProperty");
Invoke the remote method by using the Operation.send() method, as the following example shows:
op.send();
RemoteObject endpoint property
The RemoteObject endpoint property lets you quickly specify an endpoint for a RemoteObject destination without
referring to a services configuration file at compile time or programmatically creating a ChannelSet. It also overrides
an existing ChannelSet if one is set for the RemoteObject service.
If the endpoint URL starts with https, a SecureAMFChannel is used. Otherwise, an AMFChannel is used. You can
use two special tokens, {server.name} and {server.port}, in the endpoint URL to specify that the channel should
use the server name and port that was used to load the SWF.
Note: The endpoint property is required for AIR applications that use the RemoteObject component.
Configuring a destination
You configure Remoting Service destinations in the Remoting Service definition in the remoting-config.xml file. The
following example shows a basic server-side configuration for a Remoting Service in the remoting-config.xml file:
<service id="remoting-service"
class="flex.messaging.services.RemotingService">
<adapters>
<adapter-definition id="java-object"
class="flex.messaging.services.remoting.adapters.JavaAdapter"
default="true"/>
</adapters>
<default-channels>
<channel ref="samples-amf"/>
</default-channels>
<destination id="restaurant">
<properties>
<source>samples.restaurant.RestaurantService</source>
<scope>application</scope>
</properties>
</destination>
</service>
The class attribute of the <service> tag specifies the RemotingService class. RemoteObject components connect to
RemotingService destinations.
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The adapter is server-side code that interacts with the Java class. Because you set the JavaAdapter as the default adapter,
all destinations use it unless the destination explicitly specifies another adapter.
Use the source and scope elements of a Remoting Service destination definition to specify the Java object that the
destination uses. Additionally, specify whether the destination is available in the request scope (stateless), the
application scope, or the session scope. The following table describes these properties:
Element
Description
source
Fully qualified class name of the Java object (remote object).
scope
Indicates whether the object is available in the request scope, the application scope, or the
session scope. Use the request scope when you configure a Remoting Service destination to
access stateless objects. With the request scope, the server creates an instance of the Java class
on each request. Use the request scope if you are storing the object in the application or session
scope causes memory problems.
When you use the session scope, the server creates an instance of the Java object once on the
server for the session. For example, multiple tabs in the same web browser share the same session.
If you open a Flex application in one tab, any copy of that application running in another tab
accesses the same Java object.
When you use the application scope, the server creates an instance of the Java object once on
the server for the entire application.
The default value is request.
For Remoting Service destinations, you can declare destinations that only allow invocation of methods that are
explicitly included in an include list. Any attempt to invoke a method that is not in the include-methods list results
in a fault. For even finer grained security, you can assign a security constraint to one or more of the methods in the
include-methods list. If a destination-level security constraint is defined, it is tested first. Following that, the methodlevel constraints are checked. For more information, see “Configuring a destination to use a security constraint” on
page 434.
Calling a service
Define the RemoteObject components in your client-side Flex application in MXML or ActionScript. The following
example defines a RemoteObject component using both techniques:
<?xml version="1.0"?>
<!-- ds\rpc\ROInAS.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="useRemoteObject();">
<mx:Script>
<![CDATA[
import
import
import
import
mx.controls.Alert;
mx.rpc.remoting.mxml.RemoteObject;
mx.rpc.events.ResultEvent;
mx.rpc.events.FaultEvent;
public var asService:RemoteObject;
public function useRemoteObject():void {
asService = new RemoteObject();
asService.destination = "ro-catalog";
asService.getList.addEventListener("result", getListResultHandler);
asService.addEventListener("fault", faultHandler);
asService.getList();
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}
public function getListResultHandler(event:ResultEvent):void {
// Handle the result by accessing the event.result property.
}
public function faultHandler (event:FaultEvent):void {
// Deal with event.fault.faultString, etc.
Alert.show(event.fault.faultString, 'Error');
}
]]>
</mx:Script>
<!-- Define the RemoteObject component in MXML. -->
<mx:RemoteObject
id="mxmlService"
destination="ro-catalog"
result="getListResultHandler(event);"
fault="faultHandler(event);"/>
<mx:Button label="MXML" click="mxmlService.getList();"/>
<mx:Button label="AS" click="asService.getList();"/>
</mx:Application>
The destination specifies the Java class associated with the remote service. A Java class can expose multiple methods,
corresponding to multiple operations. In this example, you directly call the getList() operation in response to a
click event of a Button control.
Using the Operation class with the RemoteObject component
Because a single RemoteObject component can invoke multiple operations, the component requires a way to represent
information specific to each operation. Therefore, for every operation, the component creates an
mx.rpc.remoting.mxml.Operation object.
The name of the Operation object corresponds to the name of the operation. From the example shown above, you
access the Operation object that corresponds to the getList() operation by accessing the Operation object named
getList, as the following code shows:
// The Operation object has the same name as the operation, without the trailing parentheses.
var myOP:Operation = mxmlService.getList;
The Operation object contains properties that you use to set characteristics of the operation, such as the arguments
passed to the operation, and to hold any data returned by the operation. You access the returned data by using the
Operation.lastResult property.
Invoke the operation by referencing it relative to the RemoteObject component, as the following example shows:
mxmlService.getList();
Alternatively, invoke an operation by calling the Operation.send() method, as the following example shows:
mxmlService.getList.send();
Defining multiple operations for the RemoteObject component
When a service defines multiple operations, you define multiple methods for the RemoteObject component and
specify the attributes for each method, as the following example shows:
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<mx:RemoteObject
id="mxmlService"
destination="ro-catalog"
result="roResult(event);">
<mx:method name="getList" fault="getLFault(event);"/>
<mx:method name="updateList" fault="updateLFault(event);"/>
<mx:method name="deleteListItem" fault="deleteLIFault(event);"/>
</mx:RemoteObject>
The name property of an <mx:method> tag must match one of the operation names. The RemoteObject component
creates a separate Operation object for each operation.
Each operation can rely on the event handlers and characteristics defined by the RemoteObject component. However,
the advantage of defining the methods separately is that each operation can specify its own event handlers, its own
input parameters, and other characteristics. In this example, the RemoteObject component defines the result handler
for all three operations, and each operation defines its own fault handler. For an example that defines input parameters,
see “Using parameter binding to pass parameters to the RemoteObject component” on page 167.
Note: The Flex compiler defines the method property of the RemoteObject class; it does not correspond to an actual
property of the RemoteObject class.
Setting the concurrency property
The concurrency property of the <mx:method> tag indicates how to handle multiple calls to the same method. By
default, making a new request to an operation or method that is already executing does not impact the existing request.
The following values of the concurrency property are permitted:
multiple Existing requests are not impacted and the developer is responsible for ensuring the consistency of
returned data by carefully managing the event stream. The default value is multiple.
single Making only one request at a time is allowed on the method; additional requests made while a request is
outstanding are immediately faulted on the client and are not sent to the server.
last Making a request causes the client to ignore a result or fault for any current outstanding request. Only the result
or fault for the most recent request is dispatched on the client. This can simplify event handling in the client
application, but be careful to only use this mode when you can safely ignore results or faults for requests.
Note: The request referred to here is not the HTTP request. It is the method invocation request. If the transport between
the client and server is HTTP, invocation requests are sent to the server within the body of HTTP requests and are
processed on by the server. The last invocation request is not necessarily the last to be received by the server because in
rare cases separate HTTP requests can travel over different routes through the network to the server, arriving in a different
order than they were issued by the client.
Passing parameters
Flex provides two ways to pass parameters to a service call: explicit parameter passing and parameter binding. With
explicit parameter passing, pass properties in the method that calls the service. With parameter binding, use data
binding to populate the parameters from user interface controls or models.
Explicit parameter passing with the RemoteObject component
The following example shows MXML code for declaring a RemoteObject component and calling a service using
explicit parameter passing in the click event listener of a Button control. A ComboBox control provides data to the
service.
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<?xml version="1.0"?>
<!-- ds\rpc\RPCParamPassing.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
[Bindable]
public var empList:Object;
]]>
</mx:Script>
<mx:RemoteObject
id="employeeRO"
destination="SalaryManager"
result="empList=event.result;"
fault="Alert.show(event.fault.faultString, 'Error');"/>
<mx:ComboBox id="dept" width="150">
<mx:dataProvider>
<mx:ArrayCollection>
<mx:source>
<mx:Object label="Engineering" data="ENG"/>
<mx:Object label="Product Management" data="PM"/>
<mx:Object label="Marketing" data="MKT"/>
</mx:source>
</mx:ArrayCollection>
</mx:dataProvider>
</mx:ComboBox>
<mx:Button label="Get Employee List"
click="employeeRO.getList(dept.selectedItem.data);"/>
</mx:Application>
Using parameter binding to pass parameters to the RemoteObject component
Parameter binding lets you copy data from user interface controls or models to request parameters. When you use
parameter binding with RemoteObject components, you always declare operations in a RemoteObject component's
<mx:method> tag. You then declare <mx:arguments> tags under an <mx:method> tag.
The order of the <mx:arguments> tags must match the order of the method parameters of the service. You can name
argument tags to match the actual names of the corresponding method parameters as closely as possible, but it is not
necessary.
Note: Defining multiple argument tags with the same name in an <mx:arguments> tag creates the argument as an Array
with the specified name. The service call fails if the remote method is not expecting an Array as the only input parameter.
No warning about this situation occurs when the application is compiled.
The following example uses parameter binding in a RemoteObject component's <mx:method> tag to bind the data of
a selected ComboBox item to the employeeRO.getList operation when the user clicks a Button control. When you
use parameter binding, you call a service by using the send() method with no parameters.
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<?xml version="1.0"?>
<!-- ds\rpc\ROParamBind2.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.utils.ArrayUtil;
]]>
</mx:Script>
<mx:ArrayCollection id="employeeAC"
source="{ArrayUtil.toArray(employeeRO.getList.lastResult)}"/>
<mx:RemoteObject
id="employeeRO"
destination="roDest"
showBusyCursor="true"
fault="Alert.show(event.fault.faultString, 'Error');">
<mx:method name="getList">
<mx:arguments>
<deptId>{dept.selectedItem.data}</deptId>
</mx:arguments>
</mx:method>
</mx:RemoteObject>
<mx:HBox>
<mx:Label text="Select a department:"/>
<mx:ComboBox id="dept" width="150">
<mx:dataProvider>
<mx:ArrayCollection>
<mx:source>
<mx:Object label="Engineering" data="ENG"/>
<mx:Object label="Product Management" data="PM"/>
<mx:Object label="Marketing" data="MKT"/>
</mx:source>
</mx:ArrayCollection>
</mx:dataProvider>
</mx:ComboBox>
<mx:Button label="Get Employee List" click="employeeRO.getList.send();"/>
</mx:HBox>
<mx:DataGrid dataProvider="{employeeAC}" width="100%">
<mx:columns>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="phone" headerText="Phone"/>
<mx:DataGridColumn dataField="email" headerText="Email"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
If you are unsure whether the result of a service call contains an Array or an individual object, use the toArray()
method of the mx.utils.ArrayUtil class to convert it to an Array, as this example shows. If you pass the toArray()
method an individual object, it returns an Array with that object as the only Array element. If you pass an Array to the
method, it returns the same Array. For information about working with ArrayCollection objects, see the Flex
documentation.
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Accessing EJBs and other objects in JNDI
Access Enterprise JavaBeans (EJBs) and other objects stored in the Java Naming and Directory Interface (JNDI) by
calling methods on a destination that is a service facade class that looks up an object in JNDI and calls its methods.
You can use stateless or stateful objects to call the methods of Enterprise JavaBeans and other objects that use JNDI.
For an EJB, you can call a service facade class that returns the EJB object from JNDI and calls a method on the EJB.
In your Java class, you use the standard Java coding pattern, in which you create an initial context and perform a JNDI
lookup. For an EJB, you also use the standard coding pattern in which your class contains methods that call the EJB
home object's create() method and the resulting business methods of the EJB.
The following example uses a method called getHelloData() on a facade class destination:
<mx:RemoteObject id="Hello" destination="roDest">
<mx:method name="getHelloData"/>
</mx:RemoteObject>
On the Java side, the getHelloData() method could easily encapsulate everything necessary to call a business method
on an EJB. The Java method in the following example performs the following actions:
• Creates new initial context for calling the EJB
• Performs a JNDI lookup that gets an EJB home object
• Calls the EJB home object's create() method
• Calls the sayHello() method of the EJB
public void getHelloData() {
try
{
InitialContext ctx = new InitialContext();
Object obj = ctx.lookup("/Hello");
HelloHome ejbHome = (HelloHome)
PortableRemoteObject.narrow(obj, HelloHome.class);
HelloObject ejbObject = ejbHome.create();
String message = ejbObject.sayHello();
}
catch (Exception e);
}
Calling Remoting Service destinations from Flash or Java applications
The NetConnection API of Flash Player provides a way to call Remoting Service destinations from a standard (nonFlex) Flash application or from ActionScript in a Flex application if desired. The AMFConnection API in LiveCycle
Data Services gives you a Java API patterned on the NetConnection API but for calling Remoting Service destinations
from a Java application. You can use either of these APIs with LiveCycle Data Services, BlazeDS, or third-party
remoting implementations.
Call a destination from a Flash application
You can use the Flash Player flash.net.NetConnection API to call a Remoting Service destination from a Flash
application. You use the NetConnection.connect() method to connect to a destination and the
NetConnection.call() method to call the service. The following MXML code example shows this way of making
Remoting Service calls with NetConnection instead of RemoteObject:
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<?xml version="1.0"?>
<!-- ds\rpc\NetCon.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
width="100%" height="100%"
creationComplete="creationCompleteHandler();">
<mx:Script>
<![CDATA[
import flash.net.NetConnection;
import flash.net.ObjectEncoding;
import flash.net.Responder;
private var nc:NetConnection
private function creationCompleteHandler():void {
// Create the connection.
nc = new NetConnection();
nc.objectEncoding = ObjectEncoding.AMF0;
// Connect to the remote URL.
nc.connect("http://[server]:[port]/yourapp/messagebroker/amf" );
}
private function echo():void {
// Call the echo method of a destination on the server named remoting_AMF.
nc.call( "remoting_AMF.echo", new Responder( resultHandler, faultHandler ),
ti.text );
}
private function resultHandler(result:Object):void {
ta.text += "Server responded: "+ result + "\n";
}
private function faultHandler(fault:Object):void {
ta.text += "Received fault: " + fault + "\n";
}
]]>
</mx:Script>
<mx:Panel id="mainPanel" height="100%" width="100%">
<mx:HBox>
<mx:Label text="Enter a text for the server to echo"/>
<mx:TextInput id="ti" text="Hello World!"/>
<mx:Button label="Send" click="echo()"/>
<mx:Button label="Clear" click='ta.text = ""'/>
</mx:HBox>
<mx:TextArea id="ta" width="100%" height="100%"/>
</mx:Panel>
</mx:Application>
Call a destination from a Java application
The AMFConnection API is a Java client API in the flex-messaging-core.jar file that makes it possible to work with
Remoting Service destinations from a Java application. To compile Java classes that use the AMFConnection API, you
must have both the flex-messaging-core.jar and flex-messaging-common.jar files in your class path.
The AMFConnection API is similar to the Flash Player flash.net.NetConnection API, but uses typical Java coding
pattern rather than ActionScript coding pattern. The classes are in the flex.messaging.io.amf.client* package in the
flex-messaging-amf.jar file. The primary class is the AMFConnection class. You connect to remote URLs with the
AMFConnection.connect() method and call the service with the AMFConnection.call() method. You catch
ClientStatusException and ServerStatusException exceptions when there are errors. Here is an example of how you
can use AMFConnection to call a Remoting Service destination from a method in a Java class:
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public void callRemoting()
{
// Create the AMF connection.
AMFConnection amfConnection = new AMFConnection();
// Connect to the remote URL.
String url = "http://[server]:[port]/yourapp/messagebroker/amf";
try
{
amfConnection.connect(url);
}
catch (ClientStatusException cse)
{
System.out.println(cse);
return;
}
// Make a remoting call and retrieve the result.
try
{
// Call the echo method of a destination on the server named remoting_AMF.
Object result = amfConnection.call("remoting_AMF.echo", "echo me1");
}
catch (ClientStatusException cse)
{
System.out.println(cse);
}
catch (ServerStatusException sse)
{
System.out.println(sse);
}
// Close the connection.
amfConnection.close();
}
The AMFConnection API automatically handles cookies similarly to the way in which web browsers do, so there is no
need for custom cookie handling.
Handling service events
Calls to a remote service are asynchronous. After you invoke an asynchronous call, your application does not wait for
the result, but continues to execute. Therefore, you typically use events to signal that the service call has completed.
When a service call completes, the WebService and HTTPService components dispatch one of the following events:
• A result event indicates that the result is available. A result event generates an mx.rpc.events.ResultEvent object.
You can use the result property of the ResultEvent object to access the data returned by the service call.
• A fault event indicates that an error occurred. A fault event generates an mx.rpc.events.FaultEvent object. You
can use the fault property of the FaultEvent object to access information about the failure.
You can also handle the invoke event, which is broadcast when an RPC component makes the service call. This
event is useful if operations are queued and invoked at a later time.
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You can handle these events at three different levels in your application:
• Handle events at the component level. Specify event handlers for the fault and result events for the component.
By default, these event handlers are invoked for all service calls.
• For WebService and RemoteObject components, handle events at the operation level. These event handlers
override any event handler specified at the component level. The HTTPService component does not support
multiple operations, so you use this technique only with the WebService component.
• Handle them at the call level. The send() method returns an AsyncToken object. You can assign event handlers to
the AsyncToken object to define event handlers for a specific service call.
Handling events at the component level
Handle events at the component level by using the fault and result properties of the component to specify the event
handlers, as the following example shows:
<?xml version="1.0"?>
<!-- ds\rpc\RPCIntroExample.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.rpc.events.ResultEvent;
import mx.rpc.events.FaultEvent;
import mx.controls.Alert;
public function handleResult(event:ResultEvent):void {
// Handle result by populating the DataGrid control.
// The operation returns an Array containing product ID, name, and price.
myDG.dataProvider=event.result;
}
public function handleFault(event:FaultEvent):void {
// Handle fault.
Alert.show(event.fault.faultString, "Fault");
}
]]>
</mx:Script>
<!-- Define a WebService component and connect to a service destination. -->
<mx:WebService
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id="adbe_news"
useProxy="true"
destination="ws-catalog"
result="handleResult(event);"
fault="handleFault(event);"/>
<!-- Call the getProducts() operation of the web service.
The operation takes no parameters. -->
<mx:Button label="Get Data" click="adbe_news.getProducts();"/>
<!-- Define a DataGrid control to diplay the results of the web service. -->
<mx:DataGrid id="myDG" width="100%" height="100%">
<mx:columns>
<mx:DataGridColumn dataField="productId" headerText="Product Id"/>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="price" headerText="Price"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
In this example, all operations that you invoke through the WebService component use the same event handlers.
Handling events at the operation level for the WebService and RemoteObject component
For the WebService component, you can handle events at the operation level. These event handlers override any event
handler specified at the component level. When you do not specify event listeners for an operation, the events are
passed to the component level.
In the following MXML example, the WebService component defines default event handlers, and the operation
specifies its own handlers:
<?xml version="1.0"?>
<!-- ds\rpc\RPCResultFaultMXML.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import
import
import
import
mx.rpc.soap.SOAPFault;
mx.rpc.events.ResultEvent;
mx.rpc.events.FaultEvent;
mx.controls.Alert;
public function getProductsResult(event:ResultEvent):void {
// Handle result.
}
public function getProductsFault(event:FaultEvent):void {
// Handle operation fault.
Alert.show(event.fault.faultString, "Error");
}
public function defaultResult(event:ResultEvent):void {
// Handle result.
}
public function defaultFault(event:FaultEvent):void {
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// Handle service fault.
if (event.fault is SOAPFault) {
var fault:SOAPFault=event.fault as SOAPFault;
var faultElement:XML=fault.element;
// You could use E4X to traverse the raw fault element
// returned in the SOAP envelope.
}
Alert.show(event.fault.faultString, "Error");
}
]]>
</mx:Script>
<mx:WebService id="WeatherService"
destination="ws-catalog"
result="defaultResult(event);"
fault="defaultFault(event);">
<mx:operation name="getProducts"
fault="getProductsFault(event);"
result="getProductsResult(event);">
</mx:operation>
</mx:WebService>
<mx:Button label="Get Weather"
click="WeatherService.getProducts.send();"/>
</mx:Application>
Handling events at the call level
Sometimes, an application requires different event handlers for calls to the same service. For example, a service call
uses one event handler at application startup, and a different handler for calls during application execution.
To define event handlers for a specific service call, you can use the AsyncToken object returned by the send() method.
You then register event handlers on the AsyncToken object, rather than on the component, as the following
ActionScript code shows:
<?xml version="1.0"?>
<!-- ds\rpc\RPCAsynchEventHandler.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import
import
import
import
import
import
mx.rpc.soap.SOAPFault;
mx.rpc.events.ResultEvent;
mx.rpc.events.FaultEvent;
mx.controls.Alert;
mx.rpc.AsyncToken;
mx.rpc.AsyncResponder;
// Define an instance of the AsyncToken class.
public var serviceToken:AsyncToken;
// Call the service, and then
// assign the event handlers to the AsyncToken object.
public function setCustomHandlers():void {
// send() returns an instance of AsyncToken.
serviceToken = WeatherService.getProducts.send();
var asynchRes:AsyncResponder =
new AsyncResponder(getProductsResult, getProductsFault);
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serviceToken.addResponder(asynchRes);
}
// Use the token argument to pass additional information to the handler.
public function getProductsResult(event:ResultEvent, token:Object = null):void {
// Handle result.
}
// Use the token argument to pass additional information to the handler.
public function getProductsFault(event:FaultEvent, token:Object = null):void {
// Handle operation fault.
Alert.show(event.fault.faultString, "Error");
}
public function defaultResult(event:ResultEvent):void {
// Handle result.
}
public function defaultFault(event:FaultEvent):void {
// Handle service fault.
if (event.fault is SOAPFault) {
var fault:SOAPFault=event.fault as SOAPFault;
var faultElement:XML=fault.element;
// You could use E4X to traverse the raw fault element
// returned in the SOAP envelope.
}
Alert.show(event.fault.faultString, "Error");
}
]]>
</mx:Script>
<mx:WebService id="WeatherService"
destination="ws-catalog"
result="defaultResult(event);"
fault="defaultFault(event);">
<mx:operation name="getProducts"/>
</mx:WebService>
<!-- Call the service using the default event handlers. -->
<mx:Button label="Use Default Handlers"
click="WeatherService.getProducts.send();"/>
<!-- Call the service using the custom event handlers. -->
<mx:Button label="Use Custom Handlers"
click="setCustomHandlers();"/>
</mx:Application>
Notice that some properties are assigned to the token after the call to the remote service is made. In a multi-threaded
language, there would be a race condition where the result comes back before the token is assigned. This situation is
not a problem in ActionScript because the remote call cannot be initiated until the currently executing code finishes.
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Handling service results
Most service calls return data to the application. The way to access that data depends on which component you use:
• HTTPService and WebService
Access the data by using the HTTPService.lastResult property, or in a result event by using the
ResultEvent.result property.
The WebService component creates an Operation object for each operation supported by the associated web
service. Access the data by using the Operation.lastResult property for the specific operation, or in a result
event by using the ResultEvent.result property.
By default, the resultFormat property value of the HTTPService component and of the Operation class is object,
and the data that is returned is represented as a simple tree of ActionScript objects. Flex interprets the XML data
that a web service or HTTP service returns to appropriately represent base types, such as String, Number, Boolean,
and Date. To work with strongly typed objects, populate those objects using the object tree that Flex creates.
WebService and HTTPService components both return anonymous Objects and Arrays that are complex types. If
makeObjectsBindable is true, which it is by default, Objects are wrapped in mx.utils.ObjectProxy instances and
Arrays are wrapped in mx.collections.ArrayCollection instances.
Note: ColdFusion is not case-sensitive, so it internally represents all of its data in uppercase. Keep in mind case
sensitivity when consuming a ColdFusion web service.
When consuming data from a web service invocation, you can create an instance of a specific class instead of an
Object or an Array. If you want Flex to create an instance of a specific class, use an mx.rpc.xml.SchemaTypeRegistry
object and register a QName object with a corresponding ActionScript class. For more information, see
“Customizing web service type mapping” on page 98.
There is strong data type support between ActionScript types and SOAP and Schema types; for information about
data serialization for web services, see “Serialization between ActionScript and web services” on page 91.
• RemoteObject
The RemoteObject component creates an Operation object for each operation supported by the associated Java
class. Access the data by using the Operation.lastResult property for the specific operation, or in a result
event by using the ResultEvent.result property.
By default, the resultFormat property value of the Operation class is object, and the data that is returned is
represented as a simple tree of ActionScript objects. Flex interprets XML data to appropriately represent base types,
such as String, Number, Boolean, and Date. To work with strongly typed objects, populate those objects using the
object tree that Flex creates.
The RemoteObject component returns anonymous Objects and Arrays that are complex types. If
makeObjectsBindable is true, which it is by default, Objects are wrapped in mx.utils.ObjectProxy instances and
Arrays are wrapped in mx.collections.ArrayCollection instances.
There is strong data type support between ActionScript and Java; for information about data serialization between
ActionScript and Java, see “Serialization between ActionScript and Java” on page 79.
Processing results in an event handler
Because calls to a remote service are asynchronous, you typically use events to signal that the service call has completed.
A result event indicates that the result is available. The event object passed to the event handler is of type ResultEvent.
Use the result property of the ResultEvent object to access the data returned by the service call, as the following
example shows:
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<?xml version="1.0"?>
<!-- ds\rpc\RPCResultEvent.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.rpc.events.ResultEvent;
import mx.rpc.events.FaultEvent;
import mx.controls.Alert;
// Handle result by populating the DataGrid control.
// The operation returns an Array containing product ID, name, and price.
public function handleResult(event:ResultEvent):void {
// Make sure that the result can be cast to the correct type.
if (event.result is ArrayCollection)
{
// Cast the result to the correct type.
myDG.dataProvider=event.result as ArrayCollection;
}
else
myDG.dataProvider = null;
}
public function handleFault(event:FaultEvent):void {
// Handle fault.
Alert.show(event.fault.faultString, "Fault");
}
]]>
</mx:Script>
<!-- Define a WebService component and connect to a service destination. -->
<mx:WebService
id="adbe_news"
useProxy="true"
destination="ws-catalog"
result="handleResult(event);"
fault="handleFault(event);"/>
<!-- Call the getProducts() operation of the web service.
The operation takes no parameters. -->
<mx:Button label="Get Data" click="adbe_news.getProducts();"/>
<!-- Define a DataGrid control to diplay the reults of the web service. -->
<mx:DataGrid id="myDG" width="100%" height="100%">
<mx:columns>
<mx:DataGridColumn dataField="productId" headerText="Product Id"/>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="price" headerText="Price"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
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The data type of the ResultEvent.result property is Object. Therefore, the event handler inspects the
ResultEvent.result property to make sure that it can be cast to the required type. In this example, you want to cast
it to ArrayCollection so that you can use it as the data provider for the DataGrid control. If the result cannot be cast to
the ArrayCollection, set the data provider to null.
Binding a result to other objects
Rather than using an event handler, bind the results of an RPC component to the properties of other objects, including
user interface components and models. The lastResult object contains data from the last successful invocation of
the component. Whenever a service request executes, the lastResult object is updated and any associated bindings
are also updated.
In the following example, two properties of the Operation.lastResult object for the GetWeather() operation of a
WebService component, CityShortName and CurrentTemp, are bound to the text properties of two TextArea
controls. The CityShortName and CurrentTemp properties are returned when a user makes a request to the
MyService.GetWeather() operation and provides a ZIP code as an operation request parameter.
<mx:TextArea text="{MyService.GetWeather.lastResult.CityShortName}"/>
<mx:TextArea text="{MyService.GetWeather.lastResult.CurrentTemp}"/>
Binding a result to an ArrayCollection object
You can bind the results to the source property of an ArrayCollection object, and use the ArrayCollection API to work
with the data. You can then bind the ArrayCollection object to a complex property of a user interface component, such
as a List, ComboBox, or DataGrid control.
In the following example, bind an Operation.lastResult object, employeeWS.getList.lastResult, to the
source property of an ArrayCollection object. The ArrayCollection object is bound to the dataProvider property of
a DataGrid control that displays the names, phone numbers, and e-mail addresses of employees.
<?xml version="1.0"?>
<!-- ds\rpc\BindingResultArrayCollection.mxml. Warnings on mx:Object -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" verticalGap="10">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.utils.ArrayUtil;
]]>
</mx:Script>
<mx:WebService id="employeeWS" destination="employeeWS"
showBusyCursor="true"
fault="Alert.show(event.fault.faultString, 'Error');">
<mx:operation name="getList">
<mx:request>
<deptId>{dept.selectedItem.data}</deptId>
</mx:request>
</mx:operation>
</mx:WebService>
<mx:ArrayCollection id="ac"
source="{ArrayUtil.toArray(employeeWS.getList.lastResult)}"/>
<mx:HBox>
<mx:Label text="Select a department:"/>
<mx:ComboBox id="dept" width="150">
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<mx:dataProvider>
<mx:ArrayCollection>
<mx:source>
<mx:Object label="Engineering" data="ENG"/>
<mx:Object label="Product Management" data="PM"/>
<mx:Object label="Marketing" data="MKT"/>
</mx:source>
</mx:ArrayCollection>
</mx:dataProvider>
</mx:ComboBox>
<mx:Button label="Get Employee List" click="employeeWS.getList.send();"/>
</mx:HBox>
<mx:DataGrid dataProvider="{ac}" width="100%">
<mx:columns>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="phone" headerText="Phone"/>
<mx:DataGridColumn dataField="email" headerText="Email"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
If you are unsure whether the result of a service call contains an Array or an individual object, you can use the
toArray() method of the mx.utils.ArrayUtil class to convert it to an Array. If you pass the toArray() method to an
individual object, it returns an Array with that object as the only Array element. If you pass an Array to the method, it
returns the same Array.
For information about working with ArrayCollection objects, see the Flex documentation.
Binding a result to an XMLListCollection object
You can bind the results to an XMLListCollection object when the resultFormat property is set to e4x. When using
an XMLListCollection object, you can use ECMAScript for XML (E4X) expressions to work with the data. You can
then bind the XMLListCollection object to a complex property of a user interface component, such as a List,
ComboBox, or DataGrid control.
In the following example, bind an Operation.lastResult object, employeeWS.getList.lastResult, to the
source property of an XMLListCollection object. The XMLListCollection object is bound to the dataProvider
property of a DataGrid control that displays the names, phone numbers, and e-mail addresses of employees.
Note: To bind service results to an XMLListCollection, set the resultFormat property of your HTTPService or
Operation object to e4x. The default value of this property is object.
For more information on handling XML data, see “Handling results as XML with the E4X result format” on page 181.
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<?xml version="1.0"?>
<!-- ds\rpc\BindResultXMLListCollection.mxml. -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
]]>
</mx:Script>
<mx:WebService id="employeeWS"
destination="employeeWS"
showBusyCursor="true"
fault="Alert.show(event.fault.faultString, 'Error');">
<mx:operation name="getList" resultFormat="e4x">
<mx:request>
<deptId>{dept.selectedItem.data}</deptId>
</mx:request>
</mx:operation>
</mx:WebService>
<mx:HBox>
<mx:Label text="Select a department:"/>
<mx:ComboBox id="dept" width="150">
<mx:dataProvider>
<mx:ArrayCollection>
<mx:source>
<mx:Object label="Engineering" data="ENG"/>
<mx:Object label="Product Management" data="PM"/>
<mx:Object label="Marketing" data="MKT"/>
</mx:source>
</mx:ArrayCollection>
</mx:dataProvider>
</mx:ComboBox>
<mx:Button label="Get Employee List"
click="employeeWS.getList.send();"/>
</mx:HBox>
<mx:XMLListCollection id="xc"
source="{employeeWS.getList.lastResult}"/>
<mx:DataGrid dataProvider="{xc}" width="100%">
<mx:columns>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="phone" headerText="Phone"/>
<mx:DataGridColumn dataField="email" headerText="Email"/>
</mx:columns>
</mx:DataGrid>
</mx:Application>
For information about working with XMLListCollection objects, see the Flex documentation.
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Handling results as XML with the E4X result format
You can set the resultFormat property value of HTTPService components and WebService components to e4x to
specify that the returned data is of type XML. Using a resultFormat of e4x is the preferred way to work with XML.
You can also set the resultFormat property to xml to specify that the returned data is of type flash.xml.XMLNode,
which is a legacy object for working with XML. Also, you can set the resultFormat property of HTTPService
components to flashvars or text to create results as ActionScript objects that contain name-value pairs or as raw
text, respectively. For more information, see Adobe LiveCycle ActionScript Reference.
When working with web service results that contain .NET DataSets or DataTables, it is best to set the resultFormat
property to object to take advantage of specialized result handling for these data types. For more information, see
“Handling web service results that contain .NET DataSets or DataTables” on page 184.
Note: If you want to use E4X syntax on service results, set the resultFormat property of your HTTPService or
WebService component to e4x. The default value is object.
When you set the resultFormat property of a WebService operation to e4x, you sometimes have to handle
namespace information contained in the body of the SOAP envelope that the web service returns. The following
example shows part of a SOAP body that contains namespace information. This data was returned by a web service
that retrieves stock quotes. The namespace information is in boldface text.
<soap:Body>
<GetQuoteResponse xmlns="http://ws.invesbot.com/">
<GetQuoteResult>
<StockQuote xmlns="">
<Symbol>ADBE</Symbol>
<Company>ADOBE SYSTEMS INC</Company>
<Price>&lt;big&gt;&lt;b&gt;35.90&lt;/b&gt;&lt;/big&gt;</Price>
</StockQuote>
</GetQuoteResult>
</GetQuoteResponse>
...
</soap:Body>
This soap:Body tag contains namespace information. Therefore, if you set the resultFormat property of the
WebService operation to e4x, create a namespace object for the http://ws.invesbot.com/namespace. The following
example shows an application that does that:
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<?xml version="1.0"?>
<!-- ds\rpc\WebServiceE4XResult1.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
xmlns="*">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
private namespace invesbot = "http://ws.invesbot.com/";
use namespace invesbot;
]]>
</mx:Script>
<mx:WebService
id="WS"
destination="stockservice" useProxy="true"
fault="Alert.show(event.fault.faultString, 'Error');">
<mx:operation name="GetQuote" resultFormat="e4x">
<mx:request>
<symbol>ADBE</symbol>
</mx:request>
</mx:operation>
</mx:WebService>
<mx:HBox>
<mx:Button label="Get Quote" click="WS.GetQuote.send();"/>
<mx:Text text="{WS.GetQuote.lastResult.GetQuoteResult.StockQuote.Price}"/>
</mx:HBox>
</mx:Application>
Optionally, you can create a variable for a namespace and access it in a binding to the service result, as the following
example shows:
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<?xml version="1.0"?>
<!-- ds\rpc\WebServiceE4XResult2.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
xmlns="*">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
public var invesbot:Namespace =
new Namespace("http://ws.invesbot.com/");
]]>
</mx:Script>
<mx:WebService
id="WS"
destination="stockservice" useProxy="true"
fault="Alert.show(event.fault.faultString, 'Error');">
<mx:operation name="GetQuote" resultFormat="e4x">
<mx:request>
<symbol>ADBE</symbol>
</mx:request>
</mx:operation>
</mx:WebService>
<mx:HBox>
<mx:Button label="Get Quote" click="WS.GetQuote.send()"/>
<mx:Text text="{WS.GetQuote.lastResult.invesbot::GetQuoteResult.StockQuote.Price}"/>
</mx:HBox>
</mx:Application>
You use E4X syntax to access elements and attributes of the XML that is returned in a lastResult object. You use
different syntax, depending on whether there is a namespace or namespaces declared in the XML.
No namespace specified
The following example shows how to get an element or attribute value when no namespace is specified on the element
or attribute:
var attributes:XMLList = XML(event.result).Description.value;
The previous code returns xxx for the following XML document:
<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<Description>
<value>xxx</value>
</Description>
</RDF>
Any namespace specified
The following example shows how to get an element or attribute value when any namespace is specified on the element
or attribute:
var attributes:XMLList = XML(event.result).*::Description.*::value;
The previous code returns xxx for either one of the following XML documents:
XML document one:
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<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description>
<rdf:value>xxx</rdf:value>
</rdf:Description>
</rdf:RDF>
XML document two:
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:cm="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<cm:Description>
<rdf:value>xxx</rdf:value>
</cm:Description>
</rdf:RDF>
Specific namespace specified
The following example shows how to get an element or attribute value when the declared rdf namespace is specified
on the element or attribute:
var rdf:Namespace = new Namespace("http://www.w3.org/1999/02/22-rdf-syntax-ns#");
var attributes:XMLList = XML(event.result).rdf::Description.rdf::value;
The previous code returns xxx for the following XML document:
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description>
<rdf:value>xxx</rdf:value>
<nsX:value>yyy</nsX:value>
</rdf:Description>
</rdf:RDF>
The following example shows an alternate way to get an element or attribute value when the declared rdf namespace
is specified on the element or attribute:
namespace rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
use namespace rdf;
var attributes:XMLList = XML(event.result).rdf::Description.rdf::value;
The previous code also returns xxx for the following XML document:
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description>
<rdf:value>xxx</rdf:value>
</rdf:Description>
</rdf:RDF>
Handling web service results that contain .NET DataSets or DataTables
Web services written with the Microsoft .NET Framework can return special .NET DataSet or DataTable objects to the
client. A .NET web service provides a basic WSDL document without information about the type of data that it
manipulates. When the web service returns a DataSet or a DataTable, data type information is embedded in an XML
Schema element in the SOAP message to specify how to process the rest of the message. To best handle results from
this type of web service, set the resultFormat property of a Flex WebService operation to object. You can optionally
set the resultFormat property of the operation to e4x. However, the XML and E4X formats are inconvenient because
you must navigate through the unusual structure of the response and implement workarounds if you want to bind the
data to another object.
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When you set the resultFormat property of a WebService operation to object, a DataTable or DataSet returned
from a .NET web service is automatically converted to an object with a Tables property, which contains a map of one
or more DataTable objects. Each DataTable object from the Tables map contains two properties: Columns and Rows.
The Rows property contains the data. The event.result object gets the following properties corresponding to DataSet
and DataTable properties in .NET. Arrays of DataSets or DataTables have the same structures described here, but are
nested in a top-level Array on the result object.
Property
Description
result.Tables
Map of table names to objects that contain table data.
result.Tables["someTable"].Columns
Array of column names in the order specified in the DataSet or DataTable schema for the
table.
result.Tables["someTable"].Rows
Array of objects that represent the data of each table row. For example,
{columnName1:value, columnName2:value, columnName3:value}.
The following MXML application populates a DataGrid control with DataTable data returned from a .NET web
service:
<?xml version="1.0" encoding="utf-8"?>
<!-- ds\rpc\DataSetDemo.mxml -->
<mx:Application xmlns="*" xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical">
<mx:Script>
<![CDATA[
import
import
import
import
mx.controls.Alert;
mx.controls.DataGrid;
mx.rpc.events.FaultEvent;
mx.rpc.events.ResultEvent;
private function onResult(event:ResultEvent):void {
// A DataTable or DataSet returned from a .NET webservice is
// automatically converted to an object with a "Tables" property,
// which contains a map of one or more dataTables.
if (event.result.Tables != null)
{
// clean up panel from previous calls.
dataPanel.removeAllChildren();
for each (var table:Object in event.result.Tables)
{
displayTable(table);
}
// Alternatively, if a table's name is known beforehand,
// it can be accessed using this syntax:
var namedTable:Object = event.result.Tables.Customers;
//displayTable(namedTable);
}
}
private function displayTable(tbl:Object):void {
var dg:DataGrid = new DataGrid();
dataPanel.addChild(dg);
// Each table object from the "Tables" map contains two properties:
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// "Columns" and "Rows". "Rows" is where the data is, so we can set
// that as the dataProvider for a DataGrid.
dg.dataProvider = tbl.Rows;
}
private function onFault(event:FaultEvent):void {
Alert.show(event.fault.toString());
}
]]>
</mx:Script>
<mx:WebService
id="nwCL"
wsdl="http://localhost/data/CustomerList.asmx?wsdl"
result="onResult(event)"
fault="onFault(event)" />
<mx:Button label="Get Single DataTable"
click="nwCL.getSingleDataTable()"/>
<mx:Button label="Get MultiTable DataSet"
click="nwCL.getMultiTableDataSet()"/>
<mx:Panel id="dataPanel"
width="100%" height="100%"
title="Data Tables"/>
</mx:Application>
The following example shows the .NET C# class that is the back-end web service implementation called by the Flex
application. This class uses the Microsoft SQL Server Northwind sample database:
<%@ WebService Language="C#" Class="CustomerList" %>
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Web.Services.Description;
using System.Data;
using System.Data.SqlClient;
using System;
public class CustomerList : WebService {
[WebMethod]
public DataTable getSingleDataTable() {
string cnStr = "[Your_Database_Connection_String]";
string query = "SELECT TOP 10 * FROM Customers";
SqlConnection cn = new SqlConnection(cnStr);
cn.Open();
SqlDataAdapter adpt = new SqlDataAdapter(new SqlCommand(query, cn));
DataTable dt = new DataTable("Customers");
adpt.Fill(dt);
return dt;
}
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[WebMethod]
public DataSet getMultiTableDataSet() {
string cnStr = "[Your_Database_Connection_String]";
string query1 = "SELECT TOP 10 CustomerID, CompanyName FROM Customers";
string query2 = "SELECT TOP 10 OrderID, CustomerID, ShipCity,
ShipCountry FROM Orders";
SqlConnection cn = new SqlConnection(cnStr);
cn.Open();
SqlDataAdapter adpt = new SqlDataAdapter(new SqlCommand(query1, cn));
DataSet ds = new DataSet("TwoTableDataSet");
adpt.Fill(ds, "Customers");
adpt.SelectCommand = new SqlCommand(query2, cn);
adpt.Fill(ds, "Orders");
return ds;
}
}
Handling asynchronous calls to services
Because ActionScript code executes asynchronously, if you allow concurrent calls to a service, ensure that your code
handles the results appropriately. By default, making a request to a web service operation that is already executing does
not cancel the existing request. In a Flex application in which a service can be called from multiple locations, the service
might respond differently in different contexts.
When you design a Flex application, consider whether the application requires disparate data sources, and the number
of types of services that the application requires. The answers to these questions help determine the level of abstraction
that you provide in the data layer of the application.
In a simple application, user interface components call services directly. In applications that are slightly larger,
business objects call services. In still larger applications, business objects interact with service broker objects that call
services.
To understand the results of asynchronous service calls to objects in an application, you need a good understanding
of scoping in ActionScript. For more information, see the Flex documentation.
Using the Asynchronous Completion Token design pattern
Flex is a service-oriented framework in which code executes asynchronously, therefore, it lends itself well to the
Asynchronous Completion Token (ACT) design pattern. This design pattern efficiently dispatches processing within
a client in response to the completion of asynchronous operations that the client invokes. For more information, see
www.cs.wustl.edu/~schmidt/PDF/ACT.pdf.
When you use the ACT design pattern, you associate application-specific actions and state with responses that indicate
the completion of asynchronous operations. For each asynchronous operation, you create an ACT that identifies the
actions and state that are required to process the results of the operation. When the result is returned, you can use its
ACT to distinguish it from the results of other asynchronous operations. The client uses the ACT to identify the state
required to handle the result.
An ACT for a particular asynchronous operation is created before the operation is called. While the operation is
executing, the client continues executing. When the service sends a response, the client uses the ACT that is associated
with the response to perform the appropriate actions.
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When you call a Flex remote object service, web service, or HTTP service, Flex returns an instance of the
mx.rpc.AsyncToken class. If you use the default concurrency value of multiple, you can use the token returned by
the data service's send() method to handle the specific results of each concurrent call to the same service.
You can add information to the token when it is returned, and then in a result event listener you can access the token
as event.token. This situation is an implementation of the ACT design pattern that uses the token of each data service
call as an ACT. How you use the ACT design pattern in your own code depends on your requirements. For example,
you could attach simple identifiers to individual calls, or more complex objects that perform their own set of
functionality, or functions that a central listener calls.
The following example shows a simple implementation of the ACT design pattern. This example uses an HTTP service
and attaches a simple variable to the token.
<mx:HTTPService id="MyService" destination="httpDest" result="resultHandler(event)"/>
<mx:Script>
<![CDATA[
...
public function storeCall():void {
// Create a variable called call to store the instance
// of the service call that is returned.
var call:Object = MyService.send();
// Add a variable to the token that is returned.
// You can name this variable whatever you want.
call.marker = "option1";
...
}
// In a result event listener, execute conditional
// logic based on the value of call.marker.
private function resultHandler(event:ResultEvent):void {
var call:Object = event.token
if (call.marker == "option1") {
//do option 1
}
else
...
}
]]>
</mx:Script>
Making a service call when another call is completed
Another common requirement when using data services is the dependency of one service call on the result of another.
Your code must not make the second call until the result of the first call is available. Make the second service call in the
result event listener of the first, as the following example shows:
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<?xml version="1.0"?>
<!-- ds\rpc\RPCSecondCall.mxml. -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
// Call the getForecastWithSalesInput operation with the result of the
// getCurrentSales operation.
public function resultHandler(currentsales:String):void {
ws.setForecastWithSalesInput(currentsales);
//Or some variation that uses data binding.
}
]]>
</mx:Script>
<mx:WebService id="ws" destination="wsDest">
<mx:operation name="getCurrentSales"
result="resultHandler(event.result.resultString)"/>
<mx:operation name="setForecastWithSalesInput"/>
</mx:WebService>
</mx:Application>
Using server-side logging with RPC services
The Proxy Service and Remoting Service log messages through the server-side logging system that is configured in the
services-config.xml file. To log messages, use the Service.HTTP or Service.Remoting filter pattern, respectively. For
information about server-side logging, see “Logging” on page 420.
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Chapter 5: Message Service
Using the Message Service
The Message Service expands the core messaging framework to add support for publish-subscribe messaging among
multiple Flex clients as well as message push from the server to clients. A Flex application uses the client-side
messaging API to send messages to, and receive messages from, a destination defined by the server. Messages are sent
over a channel and processed by a server endpoint, both of which are protocol-specific.
The Message Service also supports bridging to JMS topics and queues on an embedded or external JMS server by using
the JMSAdapter. For more information, see “Connecting to the Java Message Service (JMS)” on page 214.
Introducing the Message Service
You use the Flex client-side API and the corresponding server-side Message Service to create messaging applications.
Messaging lets a Flex application connect to a message destination on the server, send messages to the server, and
receive messages from other messaging clients. Messages sent to the server are routed to other Flex applications that
have subscribed to the same destination.
The server can also push messages to clients on its own. In the server push scenario, the server initiates the message
and broadcasts it to a destination. All Flex applications that have subscribed to the destination receive the message. For
an example, see the Trader Desktop sample application that ships with LiveCycle Data Services. For more information
on the running the sample applications, see “Running the LiveCycle Data Services sample applications” on page 12.
The Message Service lets separate applications communicate asynchronously as peers by passing messages back and
forth through the server. A message defines properties such as a unique identifier, LiveCycle Data Services headers,
any custom headers, and a message body. The names of LiveCycle Data Services headers are prefixed by the string
"DS".
The most well-known example of the type of application that can use the Message Service is an instant messaging
application. In that application, one client sends a message to the server, and the server then routes the message to any
subscribed clients. You can create other types of applications to implement broadcast messaging to simultaneously
send messages to multiple clients, set up a system to send alert messages, or implement other types of messaging
applications.
The following image shows the flow of messages from one Flex client to another. On the Flex client that sends the
message, the message is routed over a channel to a destination on the server. The server then routes the message to
other Flex clients, which perform any necessary processing of the received message.
LiveCycle Data Services server
Message consumer
Message
producer
Flex client
Flex client
MessagingService
Message consumer
Flex client
Client applications that send messages are called message producers. You define a producer in a Flex application by
using the Producer component. Client applications that receive messages are called message consumers. You define a
consumer in a Flex application by using the Consumer component.
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Producers send messages to specific destinations on the server. A Consumer component subscribes to a server-side
destination, and the server routes any messages sent to that destination to the consumer. In most messaging systems,
producers and consumers do not know anything about each other.
A Flex application using the Message Service often contains at least one pair of Producer and Consumer components.
This configuration enables each application to send messages to a destination and receive messages that other
applications send to that destination.
Types of messaging
The Message Service supports publish-subscribe messaging. In publish-subscribe messaging, each message can have
multiple consumers. You use this type of messaging when you want more than one consumer to receive the same
message. Examples of applications that can use publish-subscribe messaging are auction sites, stock quote services, and
other applications that require one message to be sent to many subscribers.
The Message Service lets you target messages to specific consumers that are subscribed to the same destination.
Consumers can apply a selector expression to the message headers, or Producers and Consumers can add subtopic
information to messages to target them. Therefore, even if multiple consumers are subscribed to the same destination,
you can target a message to a single consumer or to a subset of all consumers. For more information, see “Message
selectors and subtopics” on page 200.
Note: You can support point-to-point messaging, also known as queue-based messaging, between Flex clients by using the
JMSAdapter and bridging to a JMS queue. For more information, see “Connecting to the Java Message Service (JMS)” on
page 214.
The Message Service architecture
The components of the Message Service include channels, destinations, adapters, producers, and consumers. The
following image shows the messaging architecture:
LiveCycle Data Services Server Architecture
Endpoints
Message producer
Message consumer
Message
Broker
Service
Destination
Adapter
MessageDestination
Flex client
ActionScriptAdapter
Producer component
Consumer component
MessageDestination
Servlet-based
MessageService
Channel
NIO-based
JMSAdapter
MessageDestination
Custom adapter
Channels
Flex applications can access the Message Service over several different message channels. The Flex client tries the
channels in the order specified in the configuration files, until an available channel is found or all channels have been
tried.
Each channel corresponds to a specific network protocol and has a corresponding server-side endpoint. Use a realtime channel with messaging. Real-time channels include RTMPChannel, AMFChannel and HTTPChannel with
polling enabled, and StreamingAMFChannel and StreamingHTTPChannel. The RTMP channel maintains a direct
socket connection between the client and the server, so the server can push messages directly to the client with no
polling overhead. The AMF and HTTP channels with polling enabled poll the server for new messages when one or
more Consumer components on the client have an active subscription.
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The Message Service maintains a list of message destinations and the clients subscribed to each destination. You
configure the Message Service to transport messages over one or more channels, where each channel corresponds to a
specific transport protocol.
Destinations
A destination is the server-side code that you connect to using Producer and Consumer components. When you define
a destination, you reference one or more message channels that transport messages. You also reference a message
adapter or use an adapter that is configured as the default adapter.
Adapters
LiveCycle Data Services provides two adapters to use with the Message Service and lets you create your own custom
adapter:
• The ActionScriptAdapter is the server-side code that facilitates messaging when your application uses ActionScript
objects only or interacts with another system. The ActionScriptAdapter lets you use messaging with Flex clients as
the sole producers and consumers of the messages.
• The JMSAdapter lets you bridge destinations to JMS destinations, topics, or queues on a JMS server so that Flex
clients can send messages to and receive messages from the JMS server.
• A custom adapter lets you create an adapter to interact with other messaging implementations, or for situations
where you need functionality not provided by either of the standard adapters.
You reference adapters and specify adapter-specific settings in a destination definition of the configuration files.
Message Service configuration
You configure the Message Service by editing the messaging-config.xml file or the services-config.xml file. As a best
practice, use the messaging-config.xml file for your configuration to keep it separate from other types of
configurations.
Within the services-config.xml file, you specify the channels to use with a destination, set properties of the destination,
enable logging, configure security, and specify other properties. For more information, see “Configuring the Message
Service” on page 208.
Working with Producer components
You use the Producer component in a Flex application to enable the application to send messages. You can create
Producer components in MXML or ActionScript.
To send a message from a Producer component to a destination, you create an mx.messaging.messages.AsyncMessage
object, populate the body of the AsyncMessage object, and then call the Producer.send() method. You can create
text messages and messages that contain objects.
You can optionally specify acknowledge and fault event handlers for a Producer component. An acknowledge
event is dispatched when the Producer receives an acknowledge message to indicate that the destination successfully
received a message that the Producer sent. A fault event is dispatched when a destination cannot successfully process
a message due to a connection-, server-, or application-level failure.
For reference information about the Producer class, see Adobe LiveCycle ActionScript Reference.
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Creating a Producer component in MXML
You use the <mx:Producer> tag to create a Producer component in MXML. The tag must contain an id value. The
component typically specifies a destination that is defined in the messaging-config.xml file or the
services-config.xml file. The following code shows an <mx:Producer> tag that specifies a destination and
acknowledge and fault event handlers:
<?xml version="1.0"?>
<!-- ds\messaging\CreateProducerMXML.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import
import
import
import
mx.rpc.events.FaultEvent;
mx.messaging.*;
mx.messaging.messages.*;
mx.messaging.events.*;
private function acknowledgeHandler(event:MessageAckEvent):void {
// Handle acknowledge message event.
}
private function faultHandler(event:MessageFaultEvent):void {
// Handle message fault event.
}
// Compose the message as an instance of AsyncMessage,
// then use the Producer.send() method to send it.
private function sendMessage():void {
var message:AsyncMessage = new AsyncMessage();
message.body = userName.text + ": " + input.text;
producer.send(message);
}
]]>
</mx:Script>
<mx:Producer id="producer"
destination="chat"
acknowledge="acknowledgeHandler(event);"
fault="faultHandler(event);"/>
<mx:TextInput id="userName"/>
<mx:TextInput id="input"/>
<mx:Button label="Send"
click="sendMessage();"/>
</mx:Application>
In this example, the Producer component sets the destination property to chat, which is a destination defined in the
messaging-config.xml file. You can also specify the destination at run time by setting the destination property in
your ActionScript code.
To see the data sent by this application, run the application in the section “Creating a Consumer component in
MXML” on page 195 at the same time as you run this application. The application in that section uses a Consumer
component to show the data sent by the Producer component.
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Creating a Producer component in ActionScript
You can create a Producer component in ActionScript. The following code shows a Producer component that is
created in a method in an <mx:Script> tag:
<?xml version="1.0"?>
<!-- ds\messaging\CreateProducerAS.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="createProducer();">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
//Define a variable of type Producer.
private var producer:Producer;
// Create the Producer.
private function createProducer():void {
producer = new Producer();
producer.destination = "chat";
producer.addEventListener(MessageAckEvent.ACKNOWLEDGE, acknowledgeHandler);
producer.addEventListener(MessageFaultEvent.FAULT, faultHandler);
}
private function acknowledgeHandler(event:MessageAckEvent):void{
// Handle message acknowledge event.
}
private function faultHandler(event:MessageFaultEvent):void{
// Handle message fault event.
}
// Compose the message as an instance of AsyncMessage,
// then use the Producer.send() method to send it.
private function sendMessage():void {
var message:AsyncMessage = new AsyncMessage();
message.body = userName.text + ": " + input.text;
producer.send(message);
}
]]>
</mx:Script>
<mx:TextInput id="userName"/>
<mx:TextInput id="input"/>
<mx:Button label="Send"
click="sendMessage();"/>
</mx:Application>
Resending messages and timing-out requests
A Producer component sends a message once. If the delivery of a message is in doubt, the Producer component
dispatches a fault event to indicate that it never received an acknowledgment from the destination. When the event
is dispatched, the event handler can then make a decision to attempt to resend the message if it is safe to do so.
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Note: If a message has side effects, be careful about automatically trying to resend it. If it doesn’t have side effects, then
you can resend it safely. For example, an HTTP GET operation is read only so it can be safely resent. However, HTTP
POST, PUT, and DELETE operations have side effects on the server that make them hard to resend.
Two situations can trigger a fault that indicates delivery is in doubt. It can be triggered when the value of the
Producer.requestTimeout property is exceeded, or the underlying message channel becomes disconnected before
the acknowledgment message is received. The fault handler code can detect this scenario by inspecting the
ErrorMessage.faultCode property of the associated event object for the
ErrorMessage.MESSAGE_DELIVERY_IN_DOUBT value.
The Producer.connected property is set to true when the Flex client is connected to the server. The
Producer.send() method automatically checks this property before attempting to send a message. Two properties
control the action of the Producer component when it becomes disconnected from the server:
•
reconnectAttempts
Specifies the number of times the component attempts to reconnect to the server before dispatching a fault event.
The component makes the specified number of attempts over each available channel. A value of -1 specifies to
continue indefinitely and a value of zero disables attempts.
•
reconnectInterval
Specifies the interval, in milliseconds, between attempts to reconnect. Setting the value to 0 disables reconnection
attempts.
Working with Consumer components
You can create Consumer components in MXML or ActionScript. To subscribe to a destination, you call the
Consumer.subscribe() method.
You can also specify message and fault event handlers for a Consumer component. A Consumer component
broadcasts a message event when a message is sent to a destination and the message has been routed to a consumer
subscribed to that destination. A fault event is broadcast when the channel to which the Consumer component is
subscribed cannot establish a connection to the destination, or the subscription request is denied.
For reference information about the Consumer class, see the Adobe LiveCycle ActionScript Reference.
Creating a Consumer component in MXML
You use the <mx:Consumer> tag to create a Consumer component in MXML. The tag must contain an id value. It
typically specifies a destination that is defined in the server-side services-config.xml file.
The following code shows an <mx:Consumer> tag that specifies a destination and acknowledge and fault event
handlers:
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<?xml version="1.0"?>
<!-- ds\messaging\CreateConsumerMXML.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="logon();">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
// Subscribe to destination.
private function logon():void {
consumer.subscribe();
}
// Write received message to TextArea control.
private function messageHandler(event:MessageEvent):void {
// Handle message event.
ta.text += event.message.body + "\n";
}
private function faultHandler(event:MessageFaultEvent):void {
// Handle message fault event.
}
]]>
</mx:Script>
<mx:Consumer id="consumer"
destination="chat"
message="messageHandler(event);"
fault="faultHandler(event);"/>
<mx:TextArea id="ta" width="100%" height="100%"/>
</mx:Application>
You can unsubscribe a Consumer component from a destination by calling the component's unsubscribe() method.
To send data to this application, run the application in the section “Creating a Producer component in MXML” on
page 193 at the same time as you run this application. The application in that section uses a Producer component to
send data to the Consumer component.
Creating a Consumer component in ActionScript
You can create a Consumer component in ActionScript. The following code shows a Consumer component created
in a method in an <mx:Script> tag:
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<?xml version="1.0"?>
<!-- ds\messaging\CreateConsumerAS.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="logon();">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
// Create a variable of type Consumer.
private var consumer:Consumer;
// Create the Consumer.
private function logon():void {
consumer = new Consumer();
consumer.destination = "chat";
consumer.addEventListener
(MessageEvent.MESSAGE, messageHandler);
consumer.addEventListener
(MessageFaultEvent.FAULT, faultHandler);
consumer.subscribe();
}
// Write received message to TextArea control.
private function messageHandler(event:MessageEvent):void {
// Handle message event.
ta.text += event.message.body + "\n";
}
private function faultHandler(event:MessageFaultEvent):void{
// Handle message fault event.
}
]]>
</mx:Script>
<mx:TextArea id="ta" width="100%" height="100%"/>
</mx:Application>
Sending and receiving an object in a message
You can send and receive objects as part of a message. The following example sends and receives a message that
contains an object:
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<?xml version="1.0"?>
<!-- ds\messaging\SendObjectMessage.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="logon();">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
// Subscribe to destination.
private function logon():void {
consumer.subscribe();
}
// Create message from TextInput controls.
private function sendMessage():void {
var message:AsyncMessage = new AsyncMessage();
message.body = new Object();
message.body.uName = userName.text;
message.body.uInput = input.text;
message.body.theCollection = ['b','a',3,new Date()];
producer.send(message);
}
// Write received message to TextArea control.
private function messageHandler(event:MessageEvent):void {
// Handle message event.
ta.text = String(event.message.body.uName) + " ," +
String(event.message.body.uInput);
}
]]>
</mx:Script>
<mx:Producer id="producer"
destination="chat"/>
<mx:Consumer id="consumer"
destination="chat"
message="messageHandler(event);"/>
<!-- User input controls. -->
<mx:TextInput id="userName"/>
<mx:TextInput id="input"/>
<mx:Button label="Send"
click="sendMessage();"/>
<!-- Display received message. -->
<mx:TextArea id="ta"/>
</mx:Application>
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Handling a network disconnection
Use the Consumer.subscribed and Consumer.connected properties to monitor the status of the Consumer
component. The connected property is set to true when the Flex client is connected to the server. The subscribed
property is set to true when the Flex client is subscribed to a destination.
Two properties control the action of the Consumer component when the destination becomes unavailable, or the
subscription to the destination fails:
•
resubscribeAttempts
Specifies the number of times the component attempts to resubscribe to the server before dispatching a fault
event. The component makes the specified number of attempts over each available channel. You can set the
Channel.failoverURIs property to the URI of a computer to attempt to resubscribe to if the connection is lost.
You typically use this property when operating in a clustered environment. For more information, see “Clustering”
on page 442.
A value of -1 specifies to continue indefinitely, and a value of 0 disables attempts.
•
resubscribeInterval
Specifies the interval, in milliseconds, between attempts to resubscribe. Setting the value to 0 disables resubscription
attempts.
Calling the receive method
Typically, you use a real-time polling or streaming channel with the Consumer component. In both cases, the
Consumer receives messages from the server without having to initiate a request. For more information, see
“Channels” on page 191.
You can use a non-real-time channel, such as an AMFChannel with polling-enabled set to false, with a Consumer
component. In that case, call the Consumer.receive() method directly to initiate a request to the server to receive
any queued messages. Before you call the receive() method, call the subscribe() method to subscribe to the
destination. A fault event is broadcast if a failure occurs when the Consumer.receive() method is called.
Using a pair of Producer and Consumer components in an application
A Flex application often contains at least one pair of Producer and Consumer components. This configuration enables
each application to send messages to a destination and receive messages that other applications send to that
destination.
To act as a pair, Producer and Consumer components in an application must use the same message destination.
Producer component instances send messages to a destination and Consumer component instances receive messages
from that destination.
The following code shows a simple chat application that contains a pair of Producer and Consumer components. The
user types messages in a TextInput control; the Producer component sends the message when the user presses the
keyboard Enter key or clicks the Button control labeled Send. The user views messages from other users in the ta
TextArea control. If you open this application in two browser windows, any message sent by one instance of the
application appears in both.
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<?xml version="1.0"?>
<!-- ds\messaging\ProducerConsumer.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="logon();">
<mx:Script>
<![CDATA[
import mx.messaging.messages.*;
import mx.messaging.events.*;
// Subscribe to destination.
private function logon():void {
consumer.subscribe();
}
// Write received message to TextArea control.
private function messageHandler(event: MessageEvent):void {
ta.text += event.message.body + "\n";
}
// Compose the message as an instance of AsyncMessage,
// then use the Producer.send() method to send it.
private function sendMessage():void {
var message: AsyncMessage = new AsyncMessage();
message.body = userName.text + ": " + msg.text;
producer.send(message);
msg.text = "";
}
]]>
</mx:Script>
<mx:Producer id="producer" destination="chat"/>
<mx:Consumer id="consumer" destination="chat"
message="messageHandler(event)"/>
<mx:TextArea id="ta" width="100%" height="100%"/>
<mx:TextInput id="userName" width="100%"/>
<mx:TextInput id="msg" width="100%"/>
<mx:Button label="Send"
click="sendMessage();"/>
</mx:Application>
Message selectors and subtopics
The Message Service provides functionality for Producer components to add information to message headers and to
add subtopic information. Consumer components can then specify filtering criteria based on this information so that
only messages that meet the filtering criteria are received by the consumer.
The Consumer component sends the filtering criteria to the server when the Consumer calls the subscribe()
method. Therefore, while the Consumer component defines the filtering criteria, the actual filtering is done on the
server before a message is sent to the consumer.
Note: Filter messages based on message headers or subtopics. However, do not filter messages using both techniques at the
same time.
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Using selectors
A Producer component can include extra information in a message in the form of message headers. A Consumer
component then uses the selector property to filter messages based on message header values.
Use the AsyncMessage.headers property of the message to specify the message headers. The headers are contained
in an associative Array where the key is the header name and the value is either a String or a number.
Note: Do not start message header names with the text "JMS" or "DS". These prefixes are reserved.
The following code adds a message header called prop1 and sets its value:
<?xml version="1.0"?>
<!-- ds\messaging\SendMessageHeader.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
private function sendMessage():void {
var message:AsyncMessage = new AsyncMessage();
message.headers = new Array();
message.headers["prop1"] = 5;
message.body = input.text;
producer.send(message);
}
]]>
</mx:Script>
<mx:Producer id="producer"
destination="chat"/>
<mx:TextInput id="userName"/>
<mx:TextInput id="input"/>
<mx:Button label="Send"
click="sendMessage();"/>
</mx:Application>
To filter messages based on message headers, use the Consumer.selector property to specify a message selector. A
message selector is a String that contains a SQL conditional expression based on the SQL92 conditional expression
syntax. The Consumer component receives only messages with headers that match the selector criteria.
The following code sets the Consumer.selector property so that the Consumer only receives messages where the
value of prop1 in the message header is greater than 4:
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<?xml version="1.0"?>
<!-- ds\messaging\CreateConsumerMXML.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="logon();">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
// Subscribe to destination.
private function logon():void {
consumer.subscribe();
}
// Write received message to TextArea control.
private function messageHandler(event:MessageEvent):void {
// Handle message event.
ta.text += event.message.body + "\n";
}
]]>
</mx:Script>
<mx:Consumer id="consumer"
destination="chat"
selector="prop1 > 4"
message="messageHandler(event);"/>
<mx:TextArea id="ta" width="100%" height="100%"/>
</mx:Application>
Note: For advanced messaging scenarios, you can use the mx.messaging.MultiTopicConsumer and
mx.messaging.MultiTopicProducer classes.
If you run the previous two applications at the same time, the Consumer receives messages from the Producer because
the Producer sets the value of prop1 to 5.
Using subtopics
A Producer can send a message to a specific category or categories, called subtopics, within a destination. You then
configure a Consumer component to receive only messages assigned to a specific subtopic or subtopics.
Note: You cannot use subtopics with a JMS destination. However, you can use message headers and Consumer selector
expressions to achieve similar functionality when using JMS. For more information, see “Using selectors” on page 201.
In a Producer component, use the subtopic property to assign a subtopic to messages. Define a subtopic as a dot (.)
delimited String, in the form:
mainToken[.secondaryToken][.additionalToken][...]
For example, you can define a subtopic in the form "chat", "chat.fds", or "chat.fds.newton". The dot (.) delimiter is the
default; use the <subtopic-separator> property in the configuration file to set a different delimiter. For more
information, see “Setting server properties in the destination” on page 210.
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In the Consumer component, use the subtopic property to define the subtopic that a message must be sent to for it
to be received. You can specify a literal String value for the subtopic property. Use the wildcard character (*) in the
Consumer.subtopic property to receive messages from more than one subtopic.
The Message Service supports single-token wildcard characters (*) in the subtopic String. If the wildcard character is
the last character in the String, it matches any tokens in that position or in any subsequent position. For example, the
Consumer component specifies the subtopic as "foo.*". It matches the subtopics "foo.bar" and "foo.baz", and also
"foo.bar.aaa" and "foo.bar.bbb.ccc".
If the wildcard character is in any position other than the last position, it only matches a token at that position. For
example, a wildcard character in the second position matches any tokens in the second position of a subtopic value,
but it does not apply to multiple tokens. Therefore, if the Consumer component specifies the subtopic as "foo.*.baz",
it matches the subtopics "foo.bar.baz" and "foo.aaa.baz", but not "foo.bar.cookie".
You can use the optional disallow-wildcard-subtopics element in the server section of a messaging destination
to specify whether wildcard characters (*) to receive messages from more than one subtopic are disallowed. The default
value is false.
To send a message from a Producer component to a destination and a subtopic, set the destination and subtopic
properties, and then call the send() method, as the following example shows:
<?xml version="1.0"?>
<!-- ds\messaging\Subtopic1.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
private function useSubtopic():void {
var message:AsyncMessage = new AsyncMessage();
producer.subtopic = "chat.fds.newton";
message.body = "A subtopic message";
producer.send(message);
}
]]>
</mx:Script>
<mx:Producer id="producer"
destination="chat"/>
<mx:Button label="Send Data"
click="useSubtopic();"/>
</mx:Application>
To subscribe to a destination and a subtopic with a Consumer component, set the destination and subtopic
properties and then call the subscribe() method, as the following example shows. This example uses a wildcard
character (*) to receive all messages sent to all subtopics under the chat.fds subtopic.
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<?xml version="1.0"?>
<!-- ds\messaging\Subtopic2.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="logon();">
<mx:Script>
<![CDATA[
import mx.messaging.*;
import mx.messaging.messages.*;
import mx.messaging.events.*;
private function messageHandler(event:MessageEvent):void {
// Handle message event.
ta.text += event.message.body + "\n";
}
private function logon():void {
consumer.subtopic = "chat.fds.*";
consumer.subscribe();
}
]]>
</mx:Script>
<mx:Consumer id="consumer"
destination="chat"
message="messageHandler(event);"/>
<mx:TextArea id="ta" width="100%" height="100%"/>
</mx:Application>
To allow subtopics for a destination, set the allow-subtopics element to true in the destination definition in the
messaging-config.xml file. The subtopic-separator element is optional and lets you change the separator character;
the default value is "." (period).
<destination id="chat">
<properties>
<network>
<subscription-timeout-minutes>0</subscription-timeout-minutes>
</network>
<server>
<message-time-to-live>0</message-time-to-live>
<allow-subtopics>true</allow-subtopics>
<subtopic-separator>.</subtopic-separator>
</server>
</properties>
<channels>
<channel ref="my-rtmp"/>
</channels>
</destination>
If you run the previous two applications at the same time, the Consumer receives messages from the Producer.
For more information on configuration, see “Configuring the Message Service” on page 208.
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Multitopic producers and consumers
The MultiTopicProducer component sends messages to a destination with zero or more subtopics. It is like the
standard Producer component but can direct the message to any consumer that is subscribing to any one of a number
of subtopics. If the consumer is a MultiTopicConsumer component and that consumer has subscribed to more than
on subtopic in the list of subtopics used by the MultiTopicProducer, the consumer only receives the message once.
The following code creates a MultiTopicProducer component that sends messages to two subtopics:
...
<mx:Script
>
...
function sendMessage():void {
var producer:MultiTopicProducer = new MultiTopicProducer();
producer.destination = "NASDAQ";
var msg:AsyncMessage = new AsyncMessage();
msg.headers.operation = "UPDATE";
msg.body = {"SYMBOL":50.00};
// only send to subscribers to subtopic "myStock1" and "myStock2"
msg.addSubtopic("myStock1");
msg.addSubtopic("myStock2");
producer.send(msg);
}
...
</mx:Script>
...
Unlike the standard Consumer component, the MultiTopicConsumer component lets you register subscriptions for a
list of subtopics and selector expressions at the same time from a single message handler. Where the Consumer
component has subtopic and selector properties, this component has an addSubscription(subtopic,
selector) method you use to add a new subscription to the existing set of subscriptions. Alternatively, you can
populate the subscriptions property with a list of SubscriptionInfo instances that define the subscriptions for the
destination.
The following ActionScript code creates a MultiTopicConsumer component that subscribes to two subtopics:
...
<mx:Script>
...
private functio n initConsumer():void{
consumer.destination = "NASDAQ";
consumer.addEventListener(MessageEvent.MESSAGE, messageHandle
r) ;
consumer.addEventListener(MessageFaultE v e n t.FAULT, faultHandler);
consumer.addSubscription("myStock1", "operation IN ('BID', 'Ask')");
consumer.addSubscription("myStock2", "operation IN ('BID', 'Ask')");
consumer.subscribe();
...
</mx:Script>
...
Pushing messages from the server
You can use a Java object on the Livecycle Data Services server to push messages into a Message Service destination.
The messages are then distributed to instances of Flex client applications that subscribe to the destination.
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To illustrate server push with the Message Service, consider a sample application that includes the following
components:
• The feed Message Service destination configured in messaging-config.xml
• The Feed.java Java class that publishes (to the destination) messages that have unique message IDs and contain
random numbers.
• The Flex client application that subscribes to the destination and recieves messages published to the destination by
an instance of the Feed Java class.
• A simple JSP page that creates an instance of the Feed.java class and calls its start() method to start publishing
messages to the destination.
Message Service destination
The following example shows the feed Message Service destination:
<?xml version="1.0" encoding="UTF-8"?>
<service id="message-service"
class="flex.messaging.services.MessageService">
...
<destination id="feed">
<properties>
<network>
<session-timeout>0</session-timeout>
</network>
<server>
<mesage-time-to-live>0</message-time-to-live>
<durable>false</durable>
</server>
</properties>
</destination>
...
</service>
Java object that sends messages to destination
The following example shows the Feed.java class:
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package flex.samples.feed;
import java.util.*;
import flex.messaging.MessageBroker;
import flex.messaging.messages.AsyncMessage;
import flex.messaging.util.UUIDUtils;
public class Feed {
private static FeedThread thread;
public Feed() {
}
public void start() {
if (thread == null) {
thread = new FeedThread();
thread.start();
}
}
public void stop() {
thread.running = false;
thread = null;
}
public static class FeedThread extends Thread {
public boolean running = true;
public void run() {
MessageBroker msgBroker = MessageBroker.getMessageBroker(null);
String clientID = UUIDUtils.createUUID();
Random random = new Random();
double initialValue = 35;
double currentValue = 35;
double maxChange = initialValue * 0.005;
while (running) {
double change = maxChange - random.nextDouble() * maxChange * 2;
double newValue = currentValue + change;
if (currentValue < initialValue + initialValue * 0.15
&& currentValue > initialValue - initialValue * 0.15) {
currentValue = newValue;
} else {
currentValue -= change;
}
AsyncMessage msg = new AsyncMessage();
msg.setDestination("feed");
msg.setClientId(clientID);
msg.setMessageId(UUIDUtils.createUUID());
msg.setTimestamp(System.currentTimeMillis());
mg.setBody(new Double(currentValue));
msgBroker.routeMessageToService(msg, null);
System.out.println("" + currentValue);
try {
Thread.sleep(300);
} catch (InterruptedException e) {
}
}
}
}
}
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Flex client that subscribes to destination and displays messages
The following example shows the Flex client, which does the following:
• Subscribes to the destination with a button click.
• Handles incoming messages in the messageHandler() event handler.
• Displays each message as it arrives from the server in the "pushedValue" TextInput control.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
backgroundColor="#FFFFFF">
<mx:Script>
<![CDATA[
import mx.messaging.messages.IMessage;
private function messageHandler(message:IMessage):void
{
pushedValue.text = ""+ message.body;
}
]]>
</mx:Script>
<mx:Consumer id="consumer" destination="feed"
message="messageHandler(event.message)"/>
<mx:Button label="Subscribe to 'feed' destination"
click="consumer.subscribe()" enabled="{!consumer.subscribed}"/>
<mx:Button label="Unsubscribe from 'feed' destination"
click="consumer.unsubscribe()" enabled="{consumer.subscribed}"/>
<mx:TextInput id="pushedValue"/>
</mx:Application>
JSP that starts message feed
The following example shows the JSP code that starts the message feed:
<%@page import="flex.samples.feed.Feed"%>
<%
try {
Feed feed = new Feed();
feed.start();
out.println("Feed Started");
} catch (Exception e) {
out.println("A problem occured while starting the feed: "+e.getMessage());
}
%>
Configuring the Message Service
The most common tasks that you perform when configuring the Message Service are defining message destinations
and applying security to message destinations. Typically, you configure the Message Service in the messagingconfig.xml file. The services-config.xml file includes the messaging-config.xml file by reference.
The following example shows a basic Message Service configuration in the messaging-config.xml file. It contains the
following information:
• A service definition of the Message Service
• A reference to the MessageService class.
• A definition of the ActionScriptAdapter.
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• A destination definition that references two channels. You define channels outside the destination definition.
<service id="message-service"
class="flex.messaging.services.MessageService">
<adapters>
<adapter-definition
id="actionscript"
class="flex.messaging.services.messaging.adapters.ActionScriptAdapter"
default="true"/>
<adapter-definition id="jms"
class="flex.messaging.services.messaging.adapters.JMSAdapter"/>
</adapters>
<destination id="chat-topic">
<properties>
<server>
<message-time-to-live>0</message-time-to-live>
</server>
</properties>
<channels>
<channel ref="samples-rtmp"/>
<channel ref="samples-amf-polling"/>
</channels>
</destination>
</service>
Configuring the adapter
To use a Message Service adapter, such as the ActionScript, JMS, or ColdFusion Event Gateway Adapter, you reference
the adapter in a destination definition. If you do not explicitly specify an adapter, the destination uses the default
adapter as defined in the <adapters> tag. In addition to referencing an adapter, you also set its properties in a
destination definition.
The following example shows two adapter definitions: the ActionScriptAdapter and the JMSAdapter. In this example,
the ActionScriptAdapter is defined as the default adapter:
<service id="message-service"
class="flex.messaging.services.MessageService">
...
<adapters>
<adapter-definition
id="actionscript"
class="flex.messaging.services.messaging.
adapters.ActionScriptAdapter" default="true"/>
<adapter-definition
id="jms"
class="flex.messaging.services.messaging.adapters.JMSAdapter"/>
</adapters>
...
<destination id="chat-topic">
...
<adapter ref="actionscript"/>
...
</destination>
...
</service>
Since ActionScriptAdapter is defined as the default adapter, you can omit the <adapter> tag from the destination
definition,
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Defining the destination
You perform most of the configuration for the Message Service in the destination definition, including specifying the
adapter and channels used by the destination, and any network and server properties.
Setting network properties in the destination
A destination contains a set of properties for defining client-server messaging behavior. The following example shows
the network-related properties of a destination:
<destination id="chat-topic">
<properties>
<network>
<throttle-inbound policy="ERROR" max-frequency="50"/>
<throttle-outbound policy="ERROR" max-frequency="500"/>
</network>
</properties>
</destination>
Message Service destinations use the following network-related properties:
Property
Description
subscription-timeout-minutes Subscriptions that receive no pushed messages in this time interval, in
minutes, are automatically unsubscribed. When the value is set to 0 (zero),
subscribers are not forced to unsubscribe automatically. The default value
is 0.
throttle-inbound
The max-frequency attribute controls how many messages per second
the message destination accepts.
The policy attribute indicates what to do when the message limit is
reached:
throttle-outbound
•
A policy value of NONE specifies no throttling policy (same as frequency
of zero).
•
A policy value of ERROR specifies that when the frequency is exceeded,
throttle the message and send an error to the client.
•
A policy value of IGNORE specifies that when the frequency is
exceeded, throttle the message but don't send an error to the client.
The max-frequency attribute controls how many messages per second
the server can route to subscribed consumers.
The policy attribute indicates what to do when the message limit is
reached:
•
A policy value of NONE specifies no throttling policy (same as frequency
of zero).
•
A policy value of ERROR specifies that when the frequency is exceeded,
throttle the message and send an error to the client.
•
A policy value of IGNORE specifies that when the frequency is
exceeded, throttle the message but don't send an error to the client.
Setting server properties in the destination
A destination contains a set of properties for controlling server-related parameters. The following example shows
server-related properties of a destination:
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<destination id="chat-topic">
<properties>
...
<server>
<message-time-to-live>0</message-time-to-live>
</server>
</properties>
</destination>
Message Service destinations use the following server-related properties:
Property
Description
allow-subtopics
(Optional) The subtopic feature lets you divide the messages that a Producer
component sends to a destination into specific categories in the destination. You
can configure a Consumer component that subscribes to the destination to
receive only messages sent to a specific subtopic or set of subtopics. You use
wildcard characters (*) to subscribe for messages from more than one subtopic.
disallow-wildcard-subtopics
(Optional) Specifies whether wildcard characters (*) to receive messages from
more than one subtopic are disallowed. The default value is false.
cluster-message-routing
(Optional) Determines whether a destination in an environment that uses
software clustering uses server-to-server (default) or broadcast
messaging. With server-to-server mode, data messages are routed only to
servers with active subscriptions, but subscribe and unsubscribe messages are
broadcast across the cluster. With broadcast messaging, all messages are
broadcast across the cluster. For more information, see “Clustering” on page 442.
message-time-to-live
The number of milliseconds that a message is kept on the server pending
delivery before being discarded as undeliverable.
A value of 0 means the message is not expired.
send-security-constraint
(Optional) Security constraints apply to the operations performed by the
messaging adapter. The send-security-constraint property applies to
send operations.
subscribe-securityconstraint
(Optional) Security constraints apply to the operations performed by the
messaging adapter. The subscribe-security-constraint property
applies to subscribe, multi-subscribe, and unsubscribe operations.
subtopic-separator
(Optional) Token that separates a hierarchical subtopic value. For example, for
the subtopic 'foo.bar' the dot (.) is the subtopic separator. The default value is the
dot (.) character.
Referencing message channels in the destination
The following example shows a destination referencing a channel. Because the samples-rtmp channel is listed first, it
is used first and only if a connection cannot be established does the client attempt to connect over the rest of the
channels in order of definition.
<destination id="chat-topic">
...
<channels>
<channel ref="samples-rtmp"/>
<channel ref="samples-amf-polling"/>
</channels>
...
</destination>
For more information about message channels, see “Channels and endpoints” on page 38.
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Applying security to the destination
One way to secure a destination is by using a security constraint, which defines the access privileges for the destination.
You use a security constraint to authenticate and authorize users before allowing them to access a destination. You can
specify whether to use basic or custom authentication, and indicate the roles required for authorization.
Two security properties that you can set for a messaging destination include the following:
•
send-security-constraint
Specifies the security constraint for a Producer component sending a message to the server.
•
subscribe-security-constraint
Specifies the security constraint for a Consumer component subscribing to a destination on the server.
You use these properties in a destination definition, as the following example shows:
<destination id="chat">
...
<properties>
<server>
<send-security-constraint ref="sample-users"/>
<subscribe-security-constraint ref="sample-users"/>
</server>
</properties>
...
</destination>
In this example, the properties reference the sample-users security constraint defined in the services-config.xml file,
which specifies to use custom authentication:
<security>
<login-command class="flex.messaging.security.TomcatLoginCommand" server="Tomcat">
<per-client-authentication>false</per-client-authentication>
</login-command>
<security-constraint id="basic-read-access">
<auth-method>Basic</auth-method>
<roles>
<role>guests</role>
<role>accountants</role>
</roles>
</security-constraint>
<security-constraint id="sample-users">
<auth-method>Custom</auth-method>
<roles>
<role>sampleusers</role>
</roles>
</security-constraint>
</security>
For more information about security, see “Securing LiveCycle Data Services” on page 429.
Creating a custom Message Service adapter
You can create a custom Message Service adapter for situations where you need functionality not provided by the
standard adapters. A Message Service adapter class must extend the
flex.messaging.services.messaging.adapters.MessagingAdapter class. An adapter calls methods on an instance of a
flex.messaging.MessageService object. The MessagingAdapter and MessageService classes are in the flex-messagingcore.jar file. Documentation for these classes is included in the public LiveCycle Data Services Javadoc documentation.
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The primary method of any Message Service adapter class is the invoke() method, which is called when a client sends
a message to a destination. In the invoke() method, you can include code to send messages to all subscribing clients
or to specific clients by evaluating selector statements included with a message.
To send a message to clients, you call the MessageService.pushMessageToClients() method in your adapter's
invoke() method. This method takes a message object as its first parameter. Its second parameter is a Boolean value
that indicates whether to evaluate message selector statements. You can call the
MessageService.sendPushMessageFromPeer() method in your adapter's invoke() method to broadcast messages
to peer server nodes in a clustered environment.
package customclasspackage;
{
import
import
import
import
flex.messaging.services.messaging.adapters.MessagingAdapter;
flex.messaging.services.MessageService;
flex.messaging.messages.Message;
flex.messaging.Destination;
public class SimpleCustomAdapter extends MessagingAdapter {
public Object invoke(Message message) {
MessageService msgService = (MessageService)service;
msgService.pushMessageToClients(message, true);
msgService.sendPushMessageFromPeer(message, true);
return null;
}
}
}
Optionally, a Message Service adapter can manage its own subscriptions by overriding the
ServiceAdapter.handlesSubscriptions() method and return true. You also must override the
ServiceAdapter.manage() method, which is passed CommandMessages for subscribe and unsubscribe operations.
The ServiceAdapter.getAdapterState() and ServiceAdapter.setAdapterState() methods are for adapters
that maintain an in-memory state that must be replicated across a cluster. When an adapter starts up, it gets a copy of
that state from another cluster node when another node is running.
To use an adapter class, specify it in an adapter-definition element in the messaging-config.xml file, as the
following example shows:
<adapters>
...
adapter-definition id="cfgateway" class="foo.bar.SampleMessageAdapter"/>
...
</adapters>
Optionally, you can implement MBean component management in an adapter. This implementation lets you expose
properties to a JMX server that can be used as an administration console. For more information, see “Monitoring and
managing services” on page 427.
Using server-side logging with the Message Service
The Message Service logs messages through the server-side logging system that is configured in the services-config.xml
file. To log messages, use the Service.Message, Service.Message.*, or Service.Message.JMS filter pattern, depending on
which service messages you want to log. For information about server-side logging, see “Logging” on page 420.
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Connecting to the Java Message Service (JMS)
The LiveCycle Data Services Message Service supports bridging LiveCycle Data Services to Java Message Service (JMS)
messaging destinations by using the JMS Adapter. The JMS Adapter lets Flex clients publish messages to and consume
messages from a JMS server. For more information on the Message Service, see “Using the Message Service” on
page 190.
About JMS
Java Message Service (JMS) is a Java API that lets applications create, send, receive, and read messages. Flex
applications can then exchange messages with Java client applications.
In a standard configuration of the Message Service, a destination references the ActionScriptAdapter. The
ActionScriptAdapter lets you use messaging with Flex clients as the sole producers and consumers of the messages.
You use the JMS Adapter to connect LiveCycle Data Services to JMS topics or queues. The JMS Adapter supports
topic-based and queue-based messaging. The JMS Adapter class lets Flex applications participate in existing
messaging-oriented middleware (MOM) systems. Therefore, a Java application can publish messages to and respond
to messages from Flex applications.
To connect LiveCycle Data Services to a JMS server, you create a destination that references the JMS Adapter. The
following image shows LiveCycle Data Services using the JMS Adapter:
LiveCycle Data Services server
Endpoints
Message
Broker
Service
Destination
Adapter
Message Service
Message destination
Servlet-based
Flex client
NIO-based
JMS adapter
JMS server
Java client
JMS Message Queue or Topic
The Flex client sends and receives messages through a destination that references the JMS Adapter. The JMS Adapter
then connects to the destination on the JMS server. Since the destination is accessible by a Java client, the Java client
can exchange messages with the Flex client.
Writing client-side code to use JMS
The Flex client uses the Consumer and Producer components to send and receive messages through the JMS Adapter,
just as it would for an application using the ActionScriptAdapter. For example, if the name of a destination that
references the JMS Adapter is messaging_JMS_Topic, you reference it from a Producer component as the following
example shows:
<mx:Producer id="producer"
destination="messaging_JMS_Topic"
acknowledge="acknowledgeHandler(event);"
fault="faultHandler(event);"/>
JMS topics and queues
The JMS Adapter supports both JMS topics and JMS queues. The JMS Adapter supports the use of message headers
and selectors for JMS topics, but hierarchical topics and subtopics are not supported.
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Topics support dynamic client subscribe and unsubscribe, and therefore do not require the same level of
administration as JMS queues. When using JMS queues, define a unique queue for each client.
If two Flex clients listen to the same JMS queue, and the JMS server sends a message to the queue, only one of the clients
receives the message at a given time. This operation is expected because JMS queues are meant to be consumed by one
consumer.
JMS queues are point-to-point, unlike topics which are one-to-many. However, due to the administrative overhead of
JMS queues, the JMS Adapter is not the best choice for point-to-point messages between clients. A better choice for
point-to-point messaging is to use the ActionScript Adapter in conjunction with message filtering on the client side.
For more information, see “Message selectors and subtopics” on page 200.
Setting up your system to use the JMS Adapter
You can use any JMS server with LiveCycle Data Services that implements the JMS specification. To use the JMS
Adapter to connect to a JMS server, you perform several types of configurations, including the following:
1 Configure your web application so that it has access to the JMS server. For example, if you are using Tomcat, you
might have to add the following Resource definitions to the application to add support for Apache ActiveMQ,
which supports JMS version 1.1:
<Context docBase="${catalina.home}/../../apps/team" privileged="true"
antiResourceLocking="false" antiJARLocking="false" reloadable="true">
<!-- Resourced needed for JMS -->
<Resource name="jms/flex/TopicConnectionFactory"
type="org.apache.activemq.ActiveMQConnectionFactory"
description="JMS Connection Factory"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
brokerURL="vm://localhost"
brokerName="LocalActiveMQBroker"/>
<Resource name="jms/topic/flex/simpletopic"
type="org.apache.activemq.command.ActiveMQTopic"
description="my Topic"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
physicalName="FlexTopic"/>
<Resource name="jms/flex/QueueConnectionFactory"
type="org.apache.activemq.ActiveMQConnectionFactory"
description="JMS Connection Factory"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
brokerURL="vm://localhost"
brokerName="LocalActiveMQBroker"/>
<Resource name="jms/queue/flex/simplequeue"
type="org.apache.activemq.command.ActiveMQQueue"
description="my Queue"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
physicalName="FlexQueue"/>
<Valve className="flex.messaging.security.TomcatValve"/>
</Context>
The JMS server is often embedded in your J2EE server, but you can interact with a JMS server on a remote computer
accessed by using JNDI. For more information, see “Using a remote JMS provider” on page 219.
2 Create a JMS Adapter definition in the messaging-config.xml file:
<adapters>
<adapter-definition id="jms"
class="flex.messaging.services.messaging.adapters.JMSAdapter"/>
</adapters>
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For more information on configuring the JMS Adapter, see “Configure the JMS Adapter” on page 216.
3 Create a destination that references the adapter in the messaging-config.xml file:
<destination id="messaging_AMF_Poll_JMS_Topic" channels="my-amf-poll">
<adapter ref="jms"/>
<properties>
<jms>
<connection-factory>
java:comp/env/jms/flex/TopicConnectionFactory
</connection-factory>
<destination-type>Topic</destination-type>
<destination-jndi-name>
java:comp/env/jms/topic/flex/simpletopic
</destination-jndi-name>
<message-type>javax.jms.TextMessage</message-type>
</jms>
</properties>
<channels>
<channel ref="samples-rtmp"/>
<channel ref="samples-amf-polling"/>
</channels>
</destination>
This destination references the first Apache ActiveMQ Resource, which supports topic-based messaging.
Note: Since the channel only defines how the Flex client communicates with the server, you do not have to perform
any special channel configuration to use the JMS Adapter.
For more information, see “Configuring a destination to use the JMS Adapter” on page 216.
4 Compile your Flex application against the services-config.xml file, which includes the messaging-config.xml file by
reference.
Configuring the Message Service to connect to a JMS Adapter
Typically, you configure the Message Service, including the JMS Adapter, in the messaging-config.xml file.
Configure the JMS Adapter
You configure the JMS Adapter individually for the destinations that use it, as the following example shows:
<adapters>
<adapter-definition id="jms"
class="flex.messaging.services.messaging.adapters.JMSAdapter"/>
</adapters>
Configuring a destination to use the JMS Adapter
You perform most of the configuration of the JMS Adapter in the destination definition. Configure the adapter with
the proper JNDI information and JMS ConnectionFactory information to look up the connection factory in JNDI.
The following example shows a destination that uses the JMS Adapter:
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<destination id="chat-topic-jms">
<properties>
...
<jms>
<destination-type>Topic</destination-type>
<message-type>javax.jms.TextMessage</message-type>
<connection-factory>jms/flex/TopicConnectionFactory</connection-factory>
<destination-jndi-name>jms/topic/flex/simpletopic</destination-jndi-name>
<delivery-mode>NON_PERSISTENT</delivery-mode>
<message-priority>DEFAULT_PRIORITY</message-priority>
<preserve-jms-headers>"true"</preserve-jms-headers>
<acknowledge-mode>AUTO_ACKNOWLEDGE</acknowledge-mode>
<connection-credentials username="sampleuser" password="samplepassword"/>
<max-producers>1</max-producers>
</jms>
</properties>
...
<adapter ref="jms"/>
</destination>
The JMS Adapter accepts the following configuration properties. For more specific information about JMS, see the
Java Message Service specification or your application server documentation.
Property
Description
acknowledge-mode
Not used with JMS Adapter.
connection-credentials
(Optional) The username and password used while creating the JMS connection
for example:
<connection-credentials username="sampleuser"
password="samplepassword"/>
Use only if JMS connection level authentication is being used.
connection-factory
Name of the JMS connection factory in JNDI.
delivery-mode
JMS DeliveryMode for producers.
The valid values are PERSISTENT and NON_PERSISTENT. The PERSISTENT mode
specifies that all sent messages be stored by the JMS server, and then forwarded
to consumers. This configuration adds processing overhead but is necessary for
guaranteed delivery. The NON_PERSISTENT mode does not require that
messages be stored by the JMS server before forwarding to consumers, so they can
be lost if the JMS server fails while processing the message. This setting is suitable
for notification messages that do not require guaranteed delivery.
delivery-settings/mode
(Optional) Specifies the message delivery mode used to deliver messages from the
JMS server. If you specify async mode, but the application server cannot listen for
messages asynchronously (that is
javax.jms.MessageConsumer.setMessageListener is restricted), or the application
server cannot listen for connection problems asynchronously (for example,
javax.jms.Connection.setExceptionListener is restricted), you get a configuration
error asking the user to switch to sync mode.
The default value is sync.
delivery-settings/sync-receiveinterval-millis
(Optional) Default value is 100. The interval of the receive message calls. Only
available when the mode value is sync.
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Property
Description
delivery-settings/sync-receivewait-millis
(Optional) Default value is 0 (no wait). Determines how long a JMS proxy waits for
a message before returning. Using a high sync-receive-wait-millis value
along with a small thread pool can cause messages to back up if many proxied
consumers are not receiving a steady flow of messages. Only available when the
mode value is sync.
destination-jndi-name
Name of the destination in the JNDI registry.
destination-type
(Optional) Type of messaging that the adapter is performing. Valid values are
topic for publish-subscribe messaging and queue for point-to-point messaging.
The default value is topic.
initial-context-environment
A set of JNDI properties for configuring the InitialContext used for JNDI lookups of
your ConnectionFactory and Destination. Lets you use a remote JNDI server for
JMS. For more information, see “Using a remote JMS provider” on page 219.
max-producers
The maximum number of producer proxies that a destination uses when
communicating with the JMS server. The default value is 1, which indicates that all
clients using the destination share the same connection to the JMS server.
message-priority
JMS priority for messages that producers send.
The valid values are DEFAULT_PRIORITY or an integer value indicating the
priority. The JMS API defines ten levels of priority value, with 0 as the lowest priority
and 9 as the highest. Additionally, clients should consider priorities 0-4 as
gradations of normal priority, and priorities 5-9 as gradations of expedited priority.
message-type
Type of message to use when transforming Flex messages into JMS messages.
Supported types are javax.jms.TextMessage and javax.jms.ObjectMessage.
If the client-side Publisher component sends messages as objects, set the
message-type to javax.jms.ObjectMessage.
message-type
The javax.jms.Message type which the adapter uses for this destination. Supported
types are javax.jms.TextMessage and javax.jms.ObjectMessage.
preserve-jms-headers
(Optional) Defaults to true. Determines whether the adapter preserves all
standard JMS headers from JMS messages to LiveCycle Data Services messages.
Every JMS message has a set of standard headers: JMSDestination,
JMSDeliveryMode, JMSMessageID, JMSTimestamp, JMSExpiration,
JMSRedelivered, JMSPriority, JMSReplyTo, JMSCorrelationID, and JMSType. The
JMS server sets these headers when the message is created and they are passed to
LiveCycle Data Services. LiveCycle Data Services converts the JMS message into a
LiveCycle Data Services message and sets JMSMessageID and JMSTimestamp on
the LiveCycle Data Services message as messageId and timestamp, but the rest of
the JMS headers are ignored. Setting the preserve-jms-headers property to
true preserves all of the headers.
Configuring a server for the JMS Adapter
When a destination specifies a <destination-type> of topic for the JMS Adapter, you can set the durable property
in the server definition. When true, the durable property specifies that messages are saved in a durable message store
to ensure that they survive connection outages and reach destination subscribers. The default value is false.
Note: This property does not guarantee durability between Flex clients and the JMS Adapter, but between the JMS
Adapter and the JMS server.
The following example sets the durable property to true:
<server>
<durable>true</durable>
</server>
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Using a remote JMS provider
In many cases, the JMS server is embedded in your J2EE server. However, you can also interact with a JMS server on
a remote computer accessed by using JNDI.
You can use JMS on a remote JNDI server by configuring the optional initial-context-environment element in
the jms section of a message destination that uses the JMS Adapter. The initial-context-environment element
takes property subelements, which in turn take name and value subelements. To establish the desired JNDI
environment, specify the javax.naming.Context constant names and corresponding values in the name and value
elements, or specify String literal names and corresponding values.
The bold-faced code in the following example is an initial-context-environment configuration:
<destination id="chat-topic-jms">
<properties>
...
<jms>
<destination-type>Topic</destination-type>
<message-type>javax.jms.TextMessage</message-type>
<connection-factory>jms/flex/TopicConnectionFactory</connection-factory>
<destination-jndi-name>jms/topic/flex/simpletopic</destination-jndi-name>
<delivery-mode>NON_PERSISTENT</delivery-mode>
<message-priority>DEFAULT_PRIORITY</message-priority>
<acknowledge-mode>AUTO_ACKNOWLEDGE</acknowledge-mode>
<!-- (Optional) JNDI environment. Use when using JMS on a remote JNDI server. -->
<initial-context-environment>
<property>
<name>Context.SECURITY_PRINCIPAL</name>
<value>anonymous</value>
</property>
<property>
<name>Context.SECURITY_CREDENTIALS</name>
<value>anonymous</value>
</property>
<property>
<name>Context.PROVIDER_URL</name>
<value>http://{server.name}:1856</value>
</property>
<property>
<name>Context.INITIAL_CONTEXT_FACTORY</name>
<value>fiorano.jms.runtime.naming.FioranoInitialContextFactory</value>
</property>
</initial-context-environment>
</jms>
</properties>
...
<adapter ref="jms"/>
</destination>
Flex treats name element values that begin with the text "Context." as constants defined by javax.naming.Context and
verifies that the Context class defines the constants that you specify. Some JMS providers also allow custom properties
to be set in the initial context. You can specify these properties by using the string literal name and corresponding value
that the provider requires. For example, the FioranoMQ JMS provider configures failover to back up servers with the
following property:
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<property>
<name>BackupConnectURLs</name>
<value>http://backup-server:1856;http://backup-server-2:1856</value>
</property>
If you do not specify the initial-context-environment properties in the jms section of a destination definition,
the default JNDI environment is used. The default JNDI environment is configured in a jndiprovider.properties
application resource file and or a jndi.properties file.
Naming conventions across JNDI providers for topic connection factories and destinations can vary. Depending on
your JNDI environment, the connection-factory and destination-jndi-name elements must correctly reference
the target named instances in the directory. Include the client library JAR files for your JMS provider in the WEBINF/lib directory of your web application, or in another location from which the class loader loads them. Even when
using an external JMS provider, LiveCycle Data Services uses the connection-factory and destination-jndiname configuration properties to look up the necessary connection factory and destination instances.
J2EE restrictions on JMS
Section 6.6 of the J2EE 1.4 specification limits some of the JMS APIs that can be used in a J2EE environment. The
following table lists the restricted APIs that are relevant to the JMS Adapter and the implications of the restrictions.
API
Implication of restriction
Alternative
javax.jms.MessageConsumer.get/setMessag
eListener
No asynchronous message
delivery
Set the mode attribute of the
delivery-settings
configuration property to sync.
javax.jms.Connection.setExceptionListener
No notification of connection
problems
Set the mode attribute of the
delivery-settings
configuration property to sync.
javax.jms.Connection.setClientID
No durable subscribers
Set the durable configuration
property to false.
javax.jms.Connection.stop
Not an important implication
None
The JMS Adapter handles these restrictions by doing the following:
• Providing an explicit choice between synchronous and asynchronous message delivery.
• When asynchronous message delivery is specified and setMessageListener is restricted, a clear error message is sent
to ask the user to switch to synchronous message delivery.
• When asynchronous message delivery is specified and setExceptionListener is restricted, a clear error message is
sent to ask the user to switch to synchronous message delivery.
• Providing fine-grained tuning for synchronous message delivery so asynchronous message delivery is not needed.
• Providing clear error messages when durable subscribers cannot be used due to setClientID being restricted and
asking the user to switch durable setting to false.
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Chapter 6: Data Management Service
Introducing the Data Management Service
The Adobe LiveCycle Data Services Data Management Service automates data synchronization between Adobe Flex
client application and the middle tier. You can build applications that provide data synchronization, on-demand data
paging, and occasionally connected application services. Additionally, you can manage large collections of data and
nested data relationships, such as one-to-one and many-to-one associations.
With the data modeling features introduced in LiveCycle Data Services 3, you can use model-driven development to
take advantage of advanced Data Management Service features without writing Java code or configuring services on
the server. For more information, see “Model-driven applications” on page 326 and “The Model Assembler” on
page 293.
Note: The Data Management Service is not available in BlazeDS.
About the Data Management Service
Why the Data Management Service is useful
The Data Management Service lets you reduce the amount of code required to write a rich Internet application. You
can write most of the code in a declarative style in XML. Using the Data Management Service, you can quickly and
easily build and maintain applications, and enhance collaboration between programmers and designers. This method
of programming also provides features such as on-demand paging, synchronization of data between client, server, and
other clients for improved access to information and collaboration. You can also make data available offline. The Data
Management Service is built on the LiveCycle Data Services message-based framework, a flexible, efficient and scalable
framework that integrates seamlessly with existing J2EE and ColdFusion server environments.
When you use the Data Management Service, changes to data at the Flex client side are automatically batched and sent
to the Data Management Service running in your application server. The Data Management Service then passes the
changes to your business layer or directly to your persistence layer; you can use data access objects (DAOs) with
straight JDBC calls, Hibernate, Java Persistence API (JPA), or any other solution. By using the Data Management
Service, you can avoid writing data synchronization code in your Flex client application.
Depending on the type of application you are building, the Data Management Service can save you from writing a great
deal of client-side code in the following scenarios:
• Keeping track of all the items created, updated, and deleted by the user at the client side.
• Keeping track of the original value of the data as initially retrieved by the client. The persistence layer often needs
the original value to implement optimistic locking.
• Making a series of RPC calls to send changes (creates, updates, deletes) to the middle tier.
• Handling the conflicts that arise during the data synchronization process.
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Comparing the Data Management Service and RPC approaches
The Data Management Service uses an approach to data that is fundamentally different from the remote procedure
call (RPC) approach. Unlike the RPC approach, the Data Management Service supports automatic and manual
synchronization of a common set of data on multiple clients and server-side data resources. The client automatically
tracks changes made to these objects and can apply those changes on the server objects. The server can then update
any clients viewing these same objects. It also supports offline client-side data persistence.
Note: Flex 4 supports a limited subset of data management features for RPC services on the client. You use these features
in conjunction with the data-centric development features in Flash Builder 4. For more information, see Creating datadriven applications with Flex.
Flow of data between clients and the server
The Data Management Service uses the LiveCycle Data Services message-based framework, which passes data
messages between Flex client applications and the Data Management Service. Data Management Service client
applications act as both message producers and consumers that send data to a Data Management Service destination
and subscribe to the destination to receive data updates.
The primary client-side object you use with the Data Management Service is the DataService component. You can
create a DataService component in MXML or ActionScript, and call methods on a Data Management Service
destination. The DataService component performs activities such as filling client-side objects with data from remote
data resources, committing data changes to the server, and detecting data synchronization conflicts. For more
information, see “Data Management Service clients” on page 226.
Note: If you build model-driven applications that use the Data Management Service, you do not invoke the DataService
component directly. Instead, you work with a service wrapper class that uses the DataService component internally. For
more information, see “Model-driven applications” on page 326.
Changes to data on the client are tracked and sent to the Data Management Service destination when you choose to
commit them. If successfully applied, they are propagated to other clients.
The following image shows the flow of data between a back-end data resource and an ArrayCollection object that a
DataService component manages in a Flex application:
Flex client application
DataService
component
Network tier
Server tier
fill() gets
data from
server
Data Management
Service
Network
endpoint
Adapter
Data messages
Managed
ArrayCollection
commit()
sends
updates
to server
Remote data
resource
Key concepts of data management
Managed objects
A managed object, also referred to as a persistent entity, is an object for which the Data Management Service manages
client-server communication. A managed object is represented as a Java object on the server and an ActionScript
object in a Flex client.
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The Data Management Service can manage both strongly typed objects, which have an explicit class, and weak typed
or anonymous objects. In ActionScript, a weak typed object is represented as an instance of the Object class. In Java,
it is represented by an object that implements the java.util.Map interface. The Data Management Service uses the
standard LiveCycle Data Services serialization mechanism to convert from ActionScript to Java and that mechanism
supports mixing strong and weak data types, and performing customized conversions between these classes in a
flexible manner.
The Data Management Service must intercept the get and set property operations for its managed instances. This
allows it to track changes made to managed objects from your application and to implement on-demand loading
features. If you use a weakly typed object, the object is proxied by an instance of mx.data.ManagedObjectProxy, a
dynamic object wrapper that performs this logic. The existence of this proxy is usually transparent to your application.
However, you cannot use properties with the same names as properties already in the ManagedObjectProxy instance.
Avoid using the following property names in your objects:
• dispatcher
• notifiers
• object
• propertyList
• proxyClass
• uid
When you use a strongly typed class in ActionScript, the easiest way to add managed behavior to your object is to use
the [Managed] metadata tag at the class level in your ActionScript class.
When using model-driven development and the Model Assembler, managed ActionScript objects are generated
automatically; for more information, see “Model-driven applications” on page 326.
Entities and value objects
Data management distinguishes between two types of objects: entities and value objects. Entities are objects that have
one or more identity properties that, when combined, determine a unique fixed identity for the object. For example, a
customer record in a database maps to an entity in data management. The entity could have a customerid property
that maps to a CUSTOMERID primary key column of the database table and that property would be an identity
property. For more information, see “Identity properties” on page 223.
A value object is an object for which the identity is determined by the values of its properties. Examples of value objects
include primitive object types such as int and String, and complex objects such as objects that store the parameters to
a query.
The Data Management Service only directly manages entities, but it uses value objects. A managed entity is also called
a persistent entity. Identity properties of entities must be value objects. A property of a managed object is treated as a
value object unless the property has a managed association. In that case, the property defines a reference to one or more
other managed objects.
Identity properties
When you use data management, all persistent entities must have one or more identity properties that uniquely
identify each managed instance. Generally, each identity property maps to a primary key column in a relational
database table that the managed object represents.
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Identity values can be initially undefined when you create a new entity instance. However, after the server has persisted
the entity, the identity values must be fixed for the lifetime of the object. Data management ensures that each client
only works with a single version of each entity instance. When the client receives an updated version of an entity
instance from the server, it merges those changes into that instance.
For model-driven development, you specify identity properties in id child elements of an entity element. For nonmodel development, you specify identity properties in destination definitions in a configuration file; for more
information, see “Uniquely identifying data items” on page 249.
Queries
The primary way to fetch data from the server is with a DataService.fill() method on the Flex client. The fill()
method populates an ArrayCollection object with the retrieved data. Any parameters in the fill() method define a
query for the data to retrieve, and the method returns a collection of objects from the server based on that query. A
fill() method with no parameters retrieves all items.
Parameters of fill() method are value objects that form a unique identity for a particular query. A set of fill
parameters returns a consistent set of managed entities to the client. The entities act as a key to identify the list of
objects. Other clients using the same key get the same set of objects when you use the synchronization features of data
management.
There are two ways to implement queries on the server. Using the default approach, you provide a method that takes
the set of query parameters from the fill() method on the client and returns the entire collection to the client. You
can also use the paged-fill approach where your method takes additional start and count parameters. Paging works
with either approach. In the first case, paging only pages from the client to the server. In the second case, you page
directly from the client to the database.
Modeling relationships between objects
The Data Management Service supports two basic approaches to modeling relationships in your object model. You
can manipulate identity properties directly in your object model, or you can model those relationships using
associations, which are strongly typed references to objects of the associated type. For destinations configured in the
services-config.xml file, you declare associations in XML elements in a destination definition. You can declare manyto-one, one-to-one, one-to-many, and many-to-many associations between objects.
When using model-driven development and the Model Assembler, you establish associations in entity elements in a
data model; for more information, see “Model-driven applications” on page 326.
Using identity properties directly in your object model is a fairly simple approach but involves more code for fetching
and managing the relationships between objects. Instead of referring to related objects using the dot notation (a.b[i].c),
you execute queries from a method you call explicitly.
There is no correct approach to how you model objects in every situation, and your choice is largely a matter of style.
Queries are more flexible in terms of how you can fetch the data; it is easy to add new parameters to the query for
sorting or filtering the query.
Associations manage membership of the query automatically. Using queries sometimes requires more work to make
sure that membership changes in the query results are properly and efficiently updated on the clients. With queries,
you must execute the query explicitly in ActionScript code, but with association properties you can leverage lazy and
load-on-demand behavior so that queries are executed automatically as the application tries to fetch the data.
For more information, see “Hierarchical data” on page 293.
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Destinations and classes
Each DataService component on the client manages the data for a particular destination on the server. A destination
is typically created for each type of data that you want to manage. For the most programming flexibility when you have
inheritance in your data model, define a destination for each class and set the item-class attribute for the destination.
One destination can extend another destination to mirror your class hierarchy, making it easier to manage complex
object models. If you do not set the item-class attribute for a particular destination, that destination can manage
arbitrary types of objects that share the same identity property and associations.
Adapters and assemblers
An adapter is responsible for updating the persistent data store in a manner appropriate to the data store type. The
Java adapter delegates this responsibility to a class called an assembler class. For more information, see
“Understanding data management adapters” on page 245.
Note: When you build model-driven applications with the Model Assembler, you do not manually code or configure
assemblers. A Model Assembler is automatically instantiated for each entity element in a model file when you deploy the
model file to the server. For more information, see “Model-driven applications” on page 326.
Strategies for fetching objects
When you define an explicit association between entities, you have several options for specifying how the client fetches
the associated entity object. When the lazy property is set to false and the load-on-demand property is set to false,
the associated object or objects are fetched when the referencing object is fetched.
If you set the lazy property of an association to true, the identities of the associated object are fetched when the parent
object is fetched. If you set the load-on-demand property to true, no information for the associated object is fetched
when the parent object is fetched. Instead, the property value is fetched the first time the client asks for that value. For
a one-to-many, many-to-one, or many-to-many association, you can additionally use the page-size property so that
when you do fetch the value of the collection, it is retrieved one page at a time.
Note: When you use load-on-demand or paging for a property, the Data Management Service cannot detect conflicts
made to that property.
For more information, see “Data paging” on page 303.
Paging and lazy loading
The Data Management Service provides several ways to improve performance with large sets of data by incrementally
paging data from the server to the client and from server to the database. For more information, see “Data paging” on
page 303.
Transactions
By default, LiveCycle Data Services encapsulates client-committed operations in a single J2EE distributed transaction.
All client data changes are handled as a unit. If one value cannot be changed, changes to all other values are rolled back.
For more information, see “Using transactions” on page 248.
Conflict resolution
The Data Management Service provides exceptions that let you handle conflicts between versions of data items on the
client and server. For more information, see “Handling data synchronization conflicts” on page 242.
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Data Management Service clients
LiveCycle Data Services includes a client-side DataService component that you use in conjunction with the server-side
Data Management Service to distribute and synchronize data among multiple client applications. You create clientside Flex applications that can share and synchronize distributed data.
Note: With the data modeling features introduced in LiveCycle Data Services 3, you automatically generate client-side
service wrapper classes and supporting classes in Flash Builder instead of using the DataService component directly. For
more information, see “Model-driven applications” on page 326.
For information about configuring the server-side Data Management Service, see “Data Management Service
configuration” on page 244 and “Standard assemblers” on page 268 and “Custom assemblers” on page 254.
Creating a Data Management Service client
A Flex client application uses a client-side DataService component to receive data from, and send data to, the serverside Data Management Service. A DataService component can fill a client-side ArrayCollection object with data and
manage synchronization of the ArrayCollection object data with the versions of data in other clients and on the server.
You can create DataService components in MXML or ActionScript.
A DataService component requires a valid Data Management Service destination. You define destinations in the datamanagement-config.xml configuration file. For information about Data Management Service destinations, see “Data
Management Service configuration” on page 244.
Creating a DataService component
A DataService component manages the interaction with a server-side Data Management Service destination. You can
create a DataService component in MXML or ActionScript.
The following example shows MXML code for creating a DataService component. The DataService component
destination property must reference a valid server-side Data Management Service destination.
<?xml version="1.0"?>
<!-- ds\datamanagement\DataServiceMXML.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:DataService id="ds" destination="contact"/>
</mx:Application>
The following example shows ActionScript code for creating the same DataService component:
<?xml version="1.0"?>
<!-- ds\datamanagement\DataServiceAS.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="initApp();">
<mx:Script>
<![CDATA[
import mx.data.DataService;
public var ds:DataService;
public function initApp():void {
ds = new DataService("contact");
}
]]>
</mx:Script>
</mx:Application>
When you create a DataService component in ActionScript, you must import the mx.data.DataService class and
declare a variable of type DataService, for which you set the value to a new DataService object.
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Getting a set of data from a destination
When you call a DataService component fill() method, you fill an ArrayCollection object with the data from a Data
Management Service destination. You can create an ArrayCollection object in MXML or ActionScript. The
ArrayCollection API provides a set of methods and properties for manipulating a set of data; for information, see the
Flex documentation set.
To release an ArrayCollection object that you filled, you call the DataService component releaseCollection()
method. If you call the fill() method again on the same ArrayCollection object with the same parameters, it fetches
a fresh copy of the data. If you call the fill() method again with different parameters, it releases the first fill and then
fetches the new one.
The first parameter of a fill() method is the ArrayCollection to fill. The values of any additional parameters depend
on the type of server-side destination that you call.
For example, when you call a destination that uses the Java adapter with a custom assembler, the arguments following
the ArrayCollection to fill could be the arguments of a corresponding server-side method that is declared in the
destination.
The Data Management destination is responsible for interpreting the query parameters. The HibernateAssembler and
SQLAssembler use a common pattern: the first parameter is the name of the query; the second parameter specifies an
object that contains the values for the arguments to that query (if any) by using a name-value format, as the following
example shows:
...
var myFirstName:String = "...";
myService.fill(myCollection, "getByFirstName", {firstName:myFirstName});
...
The value of the myFirstName variable is substituted into the query expecting a parameter named firstName.
For more information, see “Data Management Service configuration” on page 244.
Note: To improve the speed of your application, you can set the DataService.indexReferences property to false if
you have a small number of fills or references to items managed by a DataService component from association properties
of other items.
Populating an ArrayCollection and data provider control with data
To populate a data provider control, such as a DataGrid control, with data, you can use data binding to bind a managed
ArrayCollection object to the data provider control dataProvider property. When you set the associated DataService
component autoCommit property to true, changes to data in the DataGrid are automatically sent to the Data
Management Service destination.
The following example shows an ArrayCollection object that is bound to a DataGrid control dataProvider property:
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<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" xmlns="*"
backgroundColor="#FFFFFF">
<mx:ArrayCollection id="products"/>
<mx:DataService id="ds" destination="inventory"/>
<Product/>
<mx:DataGrid dataProvider="{products}" editable="true" width="100%" height="100%">
<mx:columns>
<mx:DataGridColumn dataField="name" headerText="Name"/>
<mx:DataGridColumn dataField="category" headerText="Category"/>
<mx:DataGridColumn dataField="price" headerText="Price"/>
<mx:DataGridColumn dataField="image" headerText="Image"/>
<mx:DataGridColumn dataField="description" headerText="Description"/>
</mx:columns>
</mx:DataGrid>
<mx:Button label="Get Data" click="ds.fill(products)"/>
</mx:Application>
Sending changes from a managed ArrayCollection object
By default, the commit() method of a DataService component is automatically called when data changes in the
ArrayCollection object that it manages. You can also call the commit() method manually and set a DataService
component autoCommit property to false to allow only manual calls to the commit() method. It is important to set
autoCommit to false when you are going to make more than one change in the same frame so that the DataService
component can batch those changes and send them in one batch to the destination.
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The following example shows a manual update operation on an item in an ArrayCollection object that a DataService
component manages:
<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="initApp();">
<mx:Script>
<![CDATA[
import mx.data.DataService;
import mx.collections.ArrayCollection;
import samples.customer.Customer;
...
public function initApp():void {
var customers:ArrayCollection = new ArrayCollection();
var customerService:DataService = new DataService("customers");
customerService.autoCommit = false;
var customer:Customer = customers.getItemAt(4);
customer.city = "Oakland";
customer.name = "CyberTech Enterprises";
customerService.commit();
}
...
]]>
</mx:Script>
</mx:Application>
The DataService component creates a single update message that includes the change to the customer.name and
customer.city properties. This message is sent to the destination when the DataService component's commit()
method is called.
The following example shows two manual update operations on an item in an ArrayCollection object that a
DataService component manages:
...
var customer:Customer = customers.getItemAt(4);
var oldName:String = customer.name;
customer.name = "CyberTech Enterprises";
customer.name = oldName;
customerService.commit();
...
If the update value is the same as the original value, there is no update operation issued. When there are multiple
updates to the same item, only the latest one is issued. If it is same as original value, there is no update issued.
When the value of the customer.name property is changed to "CyberTech Enterprises", the DataService
component creates a single update message. On the subsequent change back to the old name by using customer.name
= oldName, the original update message for the customer name is removed. The result is that nothing is sent when the
commit() method is called.
The following example shows the addition and removal of a customer to an ArrayCollection object that the
DataService component manages:
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<?xml version="1.0"?>
<!-- fds\datamanagement\AddRemoveItem.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
creationComplete="initApp();">
<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.data.DataService;
import samples.customer.Customer;
public function initApp():void {
var customers:ArrayCollection = new ArrayCollection();
var customerService:DataService = new DataService("customers");
customerService.autoCommit = false;
customers.addItemAt(new Customer(), 4);
// Remove the previously added customer.
customers.removeItemAt(4);
customerService.commit();
}
]]>
</mx:Script>
</mx:Application>
The DataService component attempts to log two updates that cancel out each other. When the addItemAt() method
is called, the DataService component creates a create message for the customers destination. On the subsequent call
to removeItemAt(4), the previous create message is removed. Nothing is sent when the commit() method is called.
Working with single data items
The mx.data.DataService class has several methods for working with individual data items. The following table
describes these methods:
Method
Description
createItem()
Lets you create a new data item without working with an ArrayCollection. An example of
when this method is useful is a call center application where a customer fills in a form to
create a single ticket item. In contrast, call center employees must see all the ticket items,
so their application would fill an ArrayCollection with data items.
Items are created automatically when you add them to an existing managed collection.
When you call the createItem() method, you create a managed reference to that item
that must be released explicitly. When you add an item to a managed collection, the
reference to that item is released when you release the collection.
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Method
Description
getItem()
Lets you get a single data item from the item identity. This method is useful when the
application needs to get just a particular record and doesn’t need require a fill()
request to retrieve the entire collection. For example to renew a driver’s license, you
could call getItem(ssn:xxx) and getItem(licenseNumber:xxx) rather than
fill().
deleteItem()
Deletes an item which is managed using a createItem(), getItem(), or fill()
method call. The delete is sent to the server as soon as the transaction is committed.
releaseItem()
Releases the specified item from management. If you hold onto ItemReference instances,
you should call the releaseItem() method on the ItemReference instance to ensure
that you release the proper reference when you might have made more than one call to
the getItem() method to retrieve the same item from different parts of your client
application.
Calling the releaseItem() method releases any associated resources, including
nested properties. The specified item no longer receives updates from the remote
destination. In addition, if there are any uncommitted changes to this item and it does
not appear in any other collection, the changes are also released. If the specified item
exists in more than one collection, the value returned is a copy of the original unless the
allowCopy parameter is set to false.
The following example shows a method that gets a specific data item when a DataGrid control changes. You get the
item from the ResultEvent.result event. The identity value sent to the destination is companyId, which is set to the
companyId of the currently selected item in the DataGrid control. The destination retrieves items based on their
identity, which is specified in the destination definition in the data-management-config.xml configuration file.
<mx:Script>
<![CDATA[
...
private function companyChange() {
dsCompany.getItem({companyId: dg.selectedItem.companyId});
}
]]>
</mx:Script>
...
Connecting to and disconnecting from a destination
A DataService component starts out disconnected from its server-side destination. The first time you perform an
operation, the DataService component tries to connect to the destination. If the operation succeeds, a result event is
sent to the DataService component. If the operation fails, a fault event is sent. You can call the
DataService.disconnect() method to force a connected client to disconnect; in this case, the DataService
component keeps a copy of its managed data and automatically resubscribes to pick up changes when you reconnect.
You can also bind to the DataService.connected property, which indicates the current connected state of the
DataService component.
You can also call DataService.release() method to release all managed objects fetched by a DataService
component.
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Working with managed objects on the client
There are two types of managed collections of objects: fills and managed associations. A fill is usually a query defined
by a set of parameters called fill parameters, which should always identify a globally consistent set of values. Although
one of the fill parameters can be a query string such as an HQL query for Hibernate, security can be compromised if
you expose the ability for ad hoc queries to be formed from untrusted client code. A managed association is a
relationship between two destination that you declare in a destination definition in the data-management-config.xml
file; for more information, see “Hierarchical data” on page 293.
When you set the autoSyncEnabled property of the client-side DataService component to true before executing the
fill, the results are synchronized with changes detected by other clients. In this case, the parameters of the fill method
should identify a globally consistent set of values. In other words, if from some other session another client sends the
same fill parameters, they get the same results.
Important: With the autoSyncEnabled property set to true, do not use session state to modify the results of the query
without obscuring the fill parameters from other clients. You can use session state for security to allow the query or not.
However, if you include data such as the user ID in the where clause of a query, you can expose that user data to another
user that executes the same query. When the fill is refreshed, the same query is executed with the user session, which
creates or updates an item or invokes the refreshFill() method of the server-side assembler. One way to avoid this problem
entirely is by ensuring that two clients cannot use the same set of fill parameters. You include the user session ID or some
other ID unknown to other clients as an additional fill parameter. Your assembler can ignore this fill parameter; it is used
by the Data Management Service to keep the queries separate.
Typically, fill parameters are primitive values such as ints or strings that are used in queries. You can use complex
objects, but in that case, the properties must serialize to the server and back again, and the values of the properties must
be identical after they return. They should follow the value object pattern and override the equals() method. A copy
of the fill parameters is sent to the server as part of the query and returned along with any message returned from the
server that updates that collection, so avoid large object graphs as part of your fill parameters and ensure that they
serialize to the server and back again.
Maintaining object identities
Each object managed by the Data Management Service must have one or more properties that uniquely identify the
object value. These property values can be assigned on the server or on the client.
When the server assigns identities, the identity properties usually include the values of the primary key of the object.
If you use identity properties that are not primitive types such as ints or Strings, make sure that your client-side and
server-side identity properties serialize to each other as with other managed properties. In other words, they should
follow the value object pattern. Identity properties that are not primitive types also must override the
java.lang.Object.equals() and java.lang.Object.hashcode() methods. A FaultEvent is thrown when you
specify a name that does not exist on the object in the property attribute of the identity element in a destination
definition on the server.
When identities are assigned on the client, if you are using any syncing features, the identities must be unique across
all clients. To avoid one client seeing the data of another client, you can include a value that is not known to other
clients using the mx.utils.UIDUtils.createUID() method, or your session ID, or some other unique identifier you
get from the server.
For more information, see “Uniquely identifying data items” on page 249.
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About the DataStore object
The Data Management Service keeps outgoing and incoming data changes in a client-side object called DataStore.
There are two modes for choosing the default DataStore instance: shared or not shared. If you use a shared DataStore
instance, all DataService components that use the same channel set also use the same DataStore instance. A shared
DataStore instance is used in the following situations:
1 The DataService component uses runtime configuration; it does not compile in the destination information using
the –services compiler option.
2 The DataService component has one or more association element (for example, a one-to-many element).
3 The destination that a DataService component uses is referred to by an association element in another destination.
You can have independent DataStore instances if the data is totally independent. If you have an independent
DataService component, the default depends on whether you specify your configuration in configuration files and
compile the configuration in the SWF file. If you do compile in the configuration, you get an independent data store.
If you do not, it isn't possible to discover whether you are using associations early enough in the initialization process,
so a shared DataStore object is created.
If you want to change the default, you can create your own DataStore object and manually assign it to the dataStore
property of one or more DataService instances. Do this when you first initialize your DataService component before
you have called any other DataService methods, such as fill() or getItem().
Note: All DataService components that share the same DataStore must be using the same set of channels and the same
setting for the useTransactions flag. Settings that are not consistent throw an error.
When you call a DataService component commit() method, it commits all of the changes for the DataStore object,
which include the changes for all DataService components that share that DataStore object. Similarly, when you
change one DataService component autoCommit property, the value changes for all DataServices components that
share the same DataStore object.
The DataStore.CommitQueueMode property controls how commits are queued to the server. By default, the client
sends commit requests one at a time. In other words, the client waits for the result or failure of the first commit before
sending the next one. If a batch fails, all messages are put back into the uncommitted queue so there is no possibility
of receiving a batch with potentially stale changes. This is a conservative policy from a performance perspective. Many
servers have conflict detection that would detect errors on those subsequent batches anyway, and can introduce
unnecessary performance delays in certain data streaming applications.
You can also choose the auto mode. This mode checks for simple dependencies between any outstanding batches and
the next batch to commit. If there are none, it sends the new batch. If there has been an update or delete request that
depends on an outstanding create request, it holds the update or delete request until the create is completed. This
imposes some overhead on each commit to check for dependencies. You can also set the value to NOWAIT. In this
mode, the Data Management Service just commits the batches without checking dependencies. This is the fastest
mode. However, there can be issues if the server does not properly handle update requests that depend on create
requests without identity properties defined.
Handling errors
The DataService component dispatches fault events for errors that occur when processing an operation. This includes
errors that occur when connecting to the server, and errors that an assembler class sends in response to processing an
operation. For operations that you invoke in ActionScript, such as fill() and commit(), you can also listen for errors
on that specific operation by adding a responder to the returned AsyncToken. For more information, see the
documentation for the mx.data.errors package in the Adobe LiveCycle ActionScript Reference.
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A DataService component automatically connects to a ChannelSet when it performs its first operation. When errors
occur in your clients when processing a commit() request, the changes in the commit are put back into the
uncommitted changes. You can choose to revert those changes by calling the DataService component
revertChanges() method with an item argument, or you can call the revertChanges() method with no argument
to revert all changes.
Routing data messages
Depending on your application requirements, you can use the auto synchronization feature to automatically route data
messages between the server and client, or you can manually route data messages.
Automatically routing data messages
When you use the auto synchronization feature by setting a DataService component autoSyncEnabled property to
true (default value), the server keeps track of every item and collection managed on each client. If you set the cacheitems property to true (default value), it additionally caches a copy of all states managed by all active clients. If you
set the cache-items property to false, it only stores the identity properties of all items managed by all active clients.
The server also stores the list of client IDs subscribed to each item or collection. When a change is made to an item,
the Data Management Service can quickly determine which clients have to be notified of that change even if the clients
are managing randomly overlapping sets of data. The overhead for making this quick determination is potentially a
large set of cached data on the server, and some overhead for maintaining the indexes and data structures required to
do this notification as that data changes.
Manually routing data messages
Manually routing data messages is a more scalable way for Data Management Service clients to receive pushed updates.
You can route data messages by manual routing specification rather than by using auto synchronization to
automatically determine which clients get which objects.
Note: When you manually route messages, you cannot use the autoRefresh fill capability. Instead, if you want to update
fills you must put in calls to manually manage fill membership.
For manual routing, you use the properties and methods of the DataService.manualSync property. The
manualSync property is of type mx.data.ManualSyncConfiguration. This class lets you subscribe to changes made by
other clients or on the server and it lets you control how your changes are published to other clients that subscribe to
manually route data messages.
Using manual routing, you can route data updates to interested clients without requiring that the server maintain all
the in-memory sequence and client data structures necessary to support the auto-sync-enabled case. Clients that
participate in manual routing must explicitly subscribe to topics or use selector expressions that describe the changes
they want to receive. Similarly, they also specify topics or metadata that are attached to changes they make. The server
then routes the changes of a particular client to any clients subscribed to matching criteria. This system is implemented
using the MultiTopicConsumer and MultiTopicProducer classes, but the client interacts with them through the
manualSync property of the DataService component.
The manualSync property of the DataService component contains several types of properties: those that affect message
producer behavior and those that affect the message consumer behavior. The producer properties let you attach
metadata to the changes produced by a client (subtopics and default headers). The consumer properties and methods
control whether a client is subscribed to changes from the server and, if subscribed, whether it provides a list of the
subscriptions the client has. If the metadata that a producer attaches to a change matches any one subscription of the
consumer, that consumer receives the message.
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For changes made by using the server push API (DataServiceTransaction), you can specify the producer properties on
DataServiceTransaction. Clients can subscribe to receive changes that match a given pattern. Changes that match that
pattern can be produced on another client or on the server push API.
By using subtopics, you can easily and efficiently form separate isolated groups (for example, meetings or other
collaborative groups). These groups can overlap through the use of multiple subtopics in either the producer or
consumers. Also, a producing client does not have to consume the messages it produces, which provides additional
flexibility.
For each subscription, you can also specify a selector expression in the Consumer component selector property to
select messages the client wants to receive. The subtopics can be used to do OR functionality. Selector expressions
provide a more flexible way to do intersected groups (AND and value-based conditionals). On a Producer, you can set
the defaultHeaders property to evaluate the selector expression for a given Consumer component. Selector
expressions are less efficient to implement on the server. Each unique selector expression must be evaluated for each
message sent to that destination.
To use manual routing, you must set the allow-subtopics element in the destination definition in the datamanagement-config.xml file to true, as the following example shows:
<destination id="inventory">
<adapter ref="java-dao" />
<properties>
<source>flex.samples.product.ProductAssembler</source>
<scope>application</scope>
<metadata>
<identity property="productId"/>
</metadata>
<server>
<allow-subtopics>true</allow-subtopics>
</server>
</properties>
</destination>
Using the manualSync property
You use the DataService.manualSync property to perform manual routing on a client. Each client independently
defines its manualSync configuration. The manualSync property is of type ManualSyncConfiguration, and you can
use the following properties and methods directly on the manualSync property:
Properties and methods
Description
producerSubtopics
The list of subtopics each change is published to.
producerDefaultHeaders
An Object containing name-value pairs that is passed along with
outbound data messages from the client. The server evaluates these
values against the selector expressions defined by other clients to
determine which clients to push the results to.
consumerSubscriptions
This is a list of SubscriptionInfo instances. Each SubscriptionInfo has a
subtopic and a selector expression.
consumerSubscribe(clientId),
consumerUnsubscribe()
Subscribing for changes on the server is a two-step process. First you
add subscriptions, and then you call consumerSubscribe().
consumerAddSubscription(subtopic, Convenience methods to update the consumerSubscriptions
selector),
property of the ManualSyncConfiguration.
consumerRemoveSubscription(subtop
ic, selector)
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The following example shows ActionScript code for establishing manual routing on a client:
...
<mx:Script>
<![CDATA[
...
var ds:DataService = new DataService("Meeting");
ds.autoSyncEnabled = false;
ds.manualSync.producerSubtopics.addItem("flex-room");
ds.manualSync.consumerAddSubscription("flex-room");
ds.manualSync.consumerSubscribe();
ds.fill(…);
...
]]>
</mx:Script>
Using manual routing in a clustered environment
If a client uses autoSyncEnabled, the Data Management Service broadcasts changes to all cluster members. The Data
Management Service is not globally aware of whether any clients are using autoSyncEnabled. To improve scalability
when manually routing messages, you can set the use-cluster-broadcast element in the server element of the
Data Management Service to false. By default, you configure the Data Management Service in the data-managementconfig.xml file.
The following example shows a use-cluster-broadcast element set to false:
<?xml version="1.0" encoding="UTF-8"?>
<service id="data-service" class="flex.data.DataService">
...
<properties>
<use-cluster-broadcast>false</use-cluster-broadcast>
</properties>
</service>
Controlling whether clients receive pushed changes
By default, the Data Management Service detects data changes made from Flex clients and the server push API and
propagates those changes to other clients. You can change this default behavior for a specific destination by setting
auto-sync-enabled to false in the destination configuration.
To turn on the auto-sync behavior for a specific ArrayCollection on the client side, set the DataService component
autoSyncEnabled property to true before you call its fill() method. Similarly, to retrieve a managed item from an
individual reference, you set the DataService component autoSyncEnabled property to true before you call its
getItem() or createItem() method.
Changing the value of the autoSyncEnabled property does not affect existing managed objects on that client. It only
affects fill(), getItem() and createItem() method calls that you make after changing the value. This lets you have
managed instances with the autoSyncEnabled property set to true and others with the autoSyncEnabled property
set to false from the same destination in the same client.
Controlling pushed changes
By default, when a client detects changes made on the server or by other clients, the changes are immediately applied
to the client. You can turn this functionality off for a given destination by setting a DataService component autoMerge
property to false. When pending changes come in, the mergeRequired property is set to true on the DataStore
object. To merge the pending changes, you call the DataService.merge() method. To avoid conflicts, merge changes
before you modify any data locally on the client.
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Note: A client does not make page requests while unmerged updates exist if a DataService component autoMerge
property is set to false, paging is enabled, and the page size is a nonzero value. You can test for this case by checking the
value of the mergeRequired property of the DataService component or its associated DataStore object.
Releasing paged items from a collection
When paging is enabled, you can remove pages of data sent from the server to the client to optimize performance when
dealing with large data sets. To remove pages of data from an ArrayCollection object, you use the DataService
releaseItemsFromCollection(), isRangeResident(), and isCollectionPaged() methods.
The releaseItemsFromCollection() method releases a range of items in the ArrayCollection. When paging
through a large collection, you might want to free resources occupied by items in the collection and stop subscribing
for updates for those items. You specify the startIndex of the first item that you want to release and the number of
items to release. If an item at that position is not yet paged, that index is skipped.
The isRangeResident() method returns true if the supplied range of items is all paged in. The
isCollectionPaged() method returns true if the passed collection is using paging features. If the collection is
paged, it is safe to pass the collection to the releaseItemsFromCollection() method to release individual items in
the collection from management.
The following example shows a method in an MXML application that uses the isCollectionPaged() and
releaseItemsFromCollection() methods to determine if data in a DataGrid control is paged and then release items
that are not in the displayed range as you scroll through the grid:
...
private function doUpdateManagedScrollGrid(scroll:Object, dataService:DataService,
collection:ListCollectionView, visibleRowCount:int):void {
trace("scroll position: " + scroll.event.position + " row count: " + visibleRowCount +
" length: " + collection.length);
//scrollCurrentPosition = scroll.event.position;
//scrollVisibleMax = visibleRowCount + scrollCurrentPosition;
// Nothing to optimize here if paging is not enabled.
if (!dataService.isCollectionPaged(collection))
return;
// The first index we want to fetch
var top:int = Math.min(Math.max(scroll.event.position - PAD - 1, 0),
collection.length);
// round up to the start of the last page
top = top - (top % PAGE_SIZE);
// The last index we want to fetch
var bot:int = Math.min(scroll.event.position + visibleRowCount + PAD,
collection.length);
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// round down to the end of the next page size
bot = bot + (PAGE_SIZE - (bot % PAGE_SIZE));
var ct:int;
ct = dataService.releaseItemsFromCollection(collection, 0, top);
trace("released: " + ct + " from: 0-" + top);
if (bot < collection.length)
ct = dataService.releaseItemsFromCollection(collection, bot,
Math.max(collection.length- bot, 0));
trace("released: " + ct + " from: " + bot + "-" + (collection.length - bot));
try {
trace("fetching: " + top + ": " + (bot-top));
collection.getItemAt(top, bot-top);
trace("all resident");
}
catch (ipe:ItemPendingError) {
trace("pending...");
}
}
...
Mapping client-side objects to Java objects
To represent a server-side Java object in a client application, you use the [RemoteClass(alias=" ")] metadata tag
to create a strongly typed ActionScript object that maps directly to the Java object. You specify the fully qualified class
name of the Java class as the value of alias. This is the same technique that you use to map to Java objects when using
RemoteObject components.
You can use the [RemoteClass] metadata tag without an alias if you do not map to a Java object on the server but you
do send back your object type from the server. The ActionScript object is serialized to a Map object when it is sent to
the server, but the object returned from the server to the clients is your original ActionScript type. Both the client-side
and server-side classes must contain an empty constructor. Also, the compiled SWF file must contain a reference to
your ActionScript class. It the SWF file does not contain a reference to that class, a generic ASObject instance is created
instead of the desired object type.
To create a managed association between client-side and server-side objects, you also use the [Managed] metadata tag
or explicitly implement the mx.data.IManaged interface.
The CRM application that is included in the Adobe LiveCycle Data Services sample applications provides a good
example of a managed association. The following example shows the source code for the client-side ActionScript
Company class, which has a managed association with the server-side Java Company class:
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package samples.crm
{
[Managed]
[RemoteClass(alias="samples.crm.Company")]
public class Company
{
public var companyId:int;
public var name:String = "";
public var address:String = "";
public var city:String = "";
public var state:String = "";
public var zip:String = "";
public var industry:String = "";
public function Company()
{
}
}
}
The following example shows the source code for the corresponding server-side Java Company class. This example
shows properties defined using the JavaBean style getX/setX syntax. You also can define public fields just as you do in
ActionScript.
package samples.crm;
import java.util.Set;
public class Company
{
private int companyId;
private String name;
private String address;
private String city;
private String zip;
private String state;
private String industry;
public String getAddress()
{
return address;
}
public void setAddress(String address)
{
this.address = address;
}
public String getCity()
{
return city;
}
public void setCity(String city)
{
this.city = city;
}
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public int getCompanyId()
{
return companyId;
}
public void setCompanyId(int companyId)
{
this.companyId = companyId;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public String getState()
{
return state;
}
public void setState(String state)
{
this.state = state;
}
public String getZip()
{
return zip;
}
public void setZip(String zip)
{
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this.zip = zip;
}
public String getIndustry()
{
return this.industry;
}
public void setIndustry(String industry)
{
this.industry = industry;
}
public String toString()
{
return "Company(companyId=" + companyId + ", name=" + name + ",
address=" + address +
", state" + state + ", zip=" + zip + " industry=" + industry + ")";
}
}
Define a computed property in ActionScript
There can be times when you want your client-side managed classes to expose properties that are computed from the
value of other properties. These types of properties tend to be read-only, but you want them to update properly when
either of the source properties changes. It is fairly easy to add these constructs to your client-side managed classes. If
you make these properties part of your data model, it is easier to show them as a column in a DataGrid component or
use them to display a row in a list from an ItemRenderer object. Make sure you define these properties as transient
with the [transient] metadata tag, since you do not want data management to track changes made to them or to
serialize them to the server. You also must send PropertyChange events whenever either of the source properties has
changed. The following code snippet implements a read-only displayName property by concatenating the firstName
and lastName properties:
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private var firstName:String;
private var lastName:String;
[Transient]
public function get displayName():String {
return _firstName + " " + _lastName;
}
public function get firstName():String {
return _firstName;
}
public function set firstName(fn:String):void {
var oldDN:String = displayName;
firstName = fn;
var newDN:String = displayName;
dispatchEvent(PropertyChangeEvent.createUpdateEvent
(this, "displayName", oldDN, newDN));
}
public function get lastName():String {
return _lastName;
}
public function set lastName(ln:String):void {
var oldDN:String = displayName;
lastName = ln;
var newDN:String = displayName;
dispatchEvent(PropertyChangeEvent.createUpdateEvent
(this, "displayName", oldDN, newDN));
}
Handling data synchronization conflicts
When working with distributed data applications, there are often times when clients try to make data changes that
conflict with changes that were already made. The following scenarios are core cases where data synchronization
conflicts occur:
Conflict type
Description
Update with stale data
The server detects a conflict when a client commits changes because the data has
changed since the client received the data.
Client is pushed changes when A client is in the midst of changing the data that conflicts with changes pushed to
it has uncommitted, conflicting it from the server.
changes
Delete with stale data
The server detects a conflict when the client tries to delete an item with a stale
version of that object.
Client is pushed changes to an
item it has deleted locally
A client has an uncommitted request to delete data when an update has just
occurred to the same data, and a data message has been pushed to the client from
the server.
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Conflict type
Description
Update to deleted data
without client push
A client tries to update data that has already been deleted from the server.
Update to deleted date with
client push
A client tries to update data that has already been deleted, and a data message has
been pushed to the client from the server. The client tries to send the update, but
there is a conflict on the client.
Client sends update and
receives
REMOVE_ITEM_FROM_FILL
message for same item.
A client updates an item and then receives a REMOVE_ITEM_FROM_FILL message
from the server for that item.
You can determine whether the update/item-gone-from-the-server conflict is a
delete versus a remove-from-fill conflict by testing the serverObjectDeleted
flag on the Conflict object. The flag is true when the conflict is not caused by an
item being removed on the server (serverObject is not null). It is false when
the conflict is caused by a remove-item-from-fill on the server (serverObject is
null).
The following example shows a simple event handler that displays an Alert box on the client where a conflict occurs,
and accepts the server version of the data:
...
public function useDS:void {
...
ds.addEventListener(DataConflictEvent.CONFLICT, conflictHandler);
...
}
public function conflictHandler(event:DataConflictEvent):void {
var conflicts:Conflicts = ds.conflicts;
var c:Conflict;
for (var i:int=0; i<conflicts.length; i++) {
c = Conflict(conflicts.getItemAt(i));
Alert.show("Reverting to server value", "Conflict");
c.acceptServer();
}
}
You can call Conflicts.getConflict(Item) to test if there is a conflict for a specific item.
For more information about the mx.data.Conflicts and mx.data.Conflict, and mx.data.events.DataConflictEvent
classes, see the Adobe LiveCycle ActionScript Reference.
When you use the Java adapter with a custom assembler, you can write logic in your assembler class that handles data
synchronization and throws a DataSyncException if the previous version of the data does not match what is currently
in the data resource. A DataSyncException results in a DataConflictEvent on the client. For more information, see
“Custom assemblers” on page 254.
You can also let the user decide which version of data gets used when a conflict occurs, as the following code snippets
show. PersonForm represents a custom component that displays all of the properties of the Person object assigned to
its dataSource property.
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// Conflict event handler:
function resolveConflictsHandler():void {
displayConflictsScreen();
}
...
<!-- Conflicts screen MXML code: -->
<PersonForm id="serverValue" editable="false" dataSource="{ds.conflicts.current.serverObject}"/>
<PersonForm id="clientValue" dataSource="{ds.conflicts.current.clientObject}"/>
<PersonForm id="originalValue" dataSource="{ds.conflicts.current.originalObject}"
editable="false"/>
<mx:Button label="Accept Server" click="ds.conflicts.current.acceptServer()"/>
<mx:Button label="Accept Client" click="ds.conflicts.current.acceptClient()"/>
...
Data Management Service configuration
To enable distributed data in Flex client applications, you connect to a server-side Data Management Service
destination. You configure destinations as part of the Data Management Service definition in a configuration file.
For information about using the client-side DataService component and connecting to a Data Management Service
destination in MXML or ActionScript, see “Data Management Service clients” on page 226.
Note: With the modeling features introduced in LiveCycle Data Services 3, you can use model-driven development to take
advantage of advanced Data Management Service features without writing Java code or configuring destinations on the
server. This content contains information about configuration for non-model development and model-driven
development. Model annotations for model-driven development are described in Application Modeling with Adobe
LiveCycle® Data Services. For additional information, see “Model-driven applications” on page 326.
About Data Management Service configuration
The most common configuration tasks for the Data Management Service are defining destinations, applying security
to destinations, and modifying logging settings. For information about security and logging, see “Security” on page 429
and “Logging” on page 420.
You configure Data Management Service destinations in the data-management-config.xml file. You can also
dynamically configure services by using the run-time configuration feature; for more information, see “Run-time
configuration” on page 411.
A Data Management Service destination uses an adapter that provides the infrastructure for interacting with data
resources. The two adapters included in LiveCycle Data Services are the ActionScript Object Adapter and the Java
Adapter.
The properties available for a destination depend on the type of adapter you use. For example, when you use the Java
Adapter, you can configure source, scope, and other properties.
You specify data adapters in a destination. You can also specify adapter-specific settings. For general information
about adapters, see “Key concepts of data management” on page 222.
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Understanding data management adapters
An adapter is responsible for updating the persistent data store, or in-memory data in the case of the ActionScript
Object Adapter, in a manner appropriate to the specific data store type. The Java Adapter delegates this responsibility
to the assembler class.
The Java Adapter and the ActionScript Object Adapter are included with Adobe LiveCycle Data Services. The Java
Adapter passes data changes to methods available on a Java class, called a Java assembler, which handles interaction
with the underlying data resource.
You use the ActionScript Object Adapter when a Flex client application is the only creator and consumer of transient
data objects and there is no back-end data resource. The Data Management Service uses the ActionScript Object
Adapter to manage objects in the server's memory.
The Java Adapter lets you synchronize Java objects on the server with ActionScript objects on the client. This adapter
passes data changes to methods available in a Java class called an assembler. The following table describes the types of
Java assemblers:
Assembler
Description
Custom assembler
Use a custom assembler if you have sophisticated data models and understand Java
server-side code. This type of assembler offers the most flexibility, but is also the most
complex to use. For more information, see “Custom assemblers” on page 254.
SQL Assembler
The SQL Assembler is a specialized assembler that provides a bridge from the Data
Management Service to a SQL database management system. Use this type of assembler
if your database data model does not have complex object relationships and you want
to expose that data model to MXML without writing Java server-side code.
For more information, see “Standard assemblers” on page 268.
Hibernate Assembler
The Hibernate Assembler is a specialized assembler that provides a bridge from the Data
Management Service to the Hibernate object-relational mapping system. Use this
assembler if you do not want to write a custom assembler, you require access to database
objects, you are using or have used the Hibernate object-relational mapping system, and
you are comfortable with Java.
For more information, see “Standard assemblers” on page 268.
Model Assembler
You use the Model Assembler for model-driven development. LiveCycle Data Services
generates Model Assembler instances based on entities defined in a model. For more
information, see “Model-driven applications” on page 326.
When using the ActionScript Object Adapter, you can use any field in an ActionScript object to provide a unique
identity property in the identity element of the destination's metadata section. You can establish a composite
identity by specifying more than one identity property. If unspecified, by default the uid property of the ActionScript
object is the identity property.
The following destination definition, which you create in the data-management-config.xml file, specifies a single
identity property. For more information about destinations, see “About Data Management Service destinations” on
page 246.
<destination id="notes">
<adapter ref="actionscript"/>
<properties>
<metadata>
<identity property="noteId"/>
</metadata>
</properties>
</destination>
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Each item must have a unique identity property and there is no back-end data resource that automatically creates
identity properties. Therefore, for an application in which you require an ArrayCollection of data items, you must
generate item identity properties on the client when you create managed objects. The code in the following example
uses the mx.utils.UIDutil.createUID() method to generate a universally unique customer.custId property to
serve as the identity property. You could also specify custId as the identity property in a destination definition in the
data-management-config.xml file.
private function newCustomer():void {
dg.selectedIndex = -1;
customer = new Customer();
customer.custId = mx.utils.UIDutil.createUID();
}
The following example shows a client application that uses the ActionScript Object Adapter to persist a single data item
if it doesn't already exist in a TextArea control across all clients. When the server is stopped, the data is lost because
there is no back-end data resource.
<?xml version="1.0"?>
<!-- ds\datamanagement\ASAdapter.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
height="100%" width="100%"
creationComplete="initApp();">
<mx:Script>
<![CDATA[
import mx.data.DataService;
import mx.rpc.AsyncToken;
public var noteObj:Object = new Object();
[Bindable]
public var getToken:AsyncToken;
private var ds:DataService;
private function initApp():void {
ds = new DataService("notes");
ds.autoCommit = false;
noteObj.noteId = 1;
noteObj.noteText =
"Type your notes here and share them with other clients!";
// The first getItem method parameter is the identity property of noteObj.
getToken = ds.getItem({noteId:noteObj.noteId}, noteObj);
}
]]>
</mx:Script>
<mx:Binding source="log.text" destination="getToken.result.noteText"/>
<mx:TextArea id="log" width="100%" height="100%" text="{getToken.result.noteText}"/>
<mx:Button label="Send" click="ds.commit();"/>
</mx:Application>
About Data Management Service destinations
A Data Management Service destination is the endpoint that you send data to and receive data from when you use the
Data Management Service to provide data distribution and synchronization in your applications.
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Note: For model-driven development with the Model Assembler, you do not configure destinations in configuration files.
LiveCycle Data Services configures Model Assembler destinations automatically when a model is deployed to the server.
You configure Data Management Service destinations in the data-management-config.xml file. By default, the datamanagement-config.xml file is located in the WEB_INF/flex directory of the web application that contains Adobe
LiveCycle Data Services. The data-management-config.xml file is referenced in the top-level services-config.xml file.
You can also dynamically configure services by using the run-time configuration feature; for more information, see
“Run-time configuration” on page 411.
The following example shows a basic Data Management Service configuration. It contains one destination that uses
the Java Adapter to interact with a data resource.
<destination id="inventory">
<adapter ref="java-dao" />
<properties>
<source>flex.samples.product.ProductAssembler</source>
<scope>application</scope>
<metadata>
<identity property="productId"/>
</metadata>
<network>
<paging enabled="false" pageSize="10" />
</network>
</properties>
</destination>
A Data Management Service destination references one or more channels that transport messages, and contains
network- and server-related properties. It can also reference a data adapter, which is server-side code that lets the
destination work with data through a particular type of interface, such as a Java object. You can also configure a specific
data adapter as the default data adapter, in which case you do not have to reference it inside the destination. A
destination can also reference or define security constraints for a destination.
To use the Java Adapter, you write an assembler class or use the HibernateAssembler or SQLAssembler class. An
assembler class is a Java class that interacts indirectly or directly with a data resource. When you use either the
HibernateAssembler class or the SQLAssembler class, you typically start with the existing Assembler class, and only
have to write Java code if you extend the functionality they provide. A common design pattern is for the assembler to
call a data access object (DAO) that calls a data resource.
General Data Management Service configuration
Some aspects of configuring Data Management Service destinations apply to most destinations, and others are
determined by the particular data adapter that a destination uses. This section describes general configuration for Data
Management Service destinations.
Setting the scope of an assembler
Use the scope element of a Data Management Service destination to specify whether the assembler is available in the
request scope (stateless), the application scope, or the session scope.
Note: When you use model-driven development with the Model Assembler, assembler instances are always in the
application scope.
When a client invokes a fill(), update(), delete(), or create() method, a request (DataMessage) is sent to the
server destination for processing. The destination delegates to its configured assembler to perform the processing.
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When you set scope to request, a new assembler instance is created to process each and every inbound request.
When you set scope to session, assembler instances are created and then cached individually for each client
session.You would use a session-scoped assembler when you want to code your assembler to maintain some internal
state for the client across calls, or you want to access the assembler instance for a given client from somewhere else (for
example, while handling a remoting request), by looking up the assembler instance in the session. When using a
session-scoped assembler, it is essential to properly synchronize changes to any internal state (variables/properties)
that the assembler defines.When you set scope to application, a single assembler instance is created and cached at an
application-wide level. That single assembler instance handles all requests from all clients that target the destination.
In this scenario, you generally want to avoid any mutable state in the assembler; many clients can concurrently use a
stateless assembler without issue. For most applications, your state is stored and managed in a shared transactional
backend, such as a database, so a stateless assembler works well. If you do want to track any state in an applicationscoped assembler, you must protect reads and writes of that state with Java synchronization (synchronized keyword
or explicit lock objects).In almost all cases, a Data Service destination is best served by an application-scoped assembler
that exposes a portion of a transactional shared backend, which is generally a database. Scenarios for a request-scoped
assembler are few and far between. A session-scoped assembler is generally only useful if you want to access the
assembler instance from other code executing on the server by looking up the assembler instance in the session.
Configuring paging
LiveCycle Data Services gives several options for paging data from the server to the client. For more information, see
“Data paging” on page 303.
Using transactions
By default, LiveCycle Data Services encapsulates client-committed operations in a single J2EE distributed transaction.
All client data changes are handled as a unit. If one value cannot be changed, changes to all other values are rolled back.
Distributed transactions are supported as long as your Java 2 Enterprise Edition (J2EE) server provides support for
J2EE transactions (JTA).
When you are not using model-driven development, you enable or disable transactions in the data-managementconfig.xml file. The boldface text in the following example shows the use-transactions property set to true (the
default value) at the service level so that it applies to all Data Management Service destinations:
...
<service id="data-service" class="flex.data.DataService">
...
<properties>
<use-transactions>true</use-transactions>
</properties>
</service>
...
If you set the use-transactions property to false, each assembler method can create and commit its own
transaction. The batch of changes processes until the first error occurs. It is assumed that all changes that precede the
error are applied to the data store. When these changes make it back to the client, their result handler is triggered. The
change that caused the error is reported as a fault on the client. All changes that occur in the batch after the error are
not sent to the assembler and are also reported as faults on the client.
For model-driven development, you enable or disable transactions in the use-transactions annotation in an entity,
as the following example shows:
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<entity name="Book" persistent="true">
<annotation name="DMS">
<item name="use-transactions">
true
</item>
</annotation>
...
</entity>
Uniquely identifying data items
A Data Management Service destination contains one or more identity properties that you can use to designate data
properties to be used to guarantee unique identity among items in a collection of objects. In the case of the SQL
assembler, an identity property maps to a database field.
The boldface text in the following example shows an identity property in a destination:
...
<destination id="contact">
<properties>
...
<metadata>
<identity property="name"/>
</metadata>
</properties>
</destination>
...
For model-driven development, you configure identity properties in id child elements of a persistent entity, as the
boldface text in the following example shows. The type attribute specifies the data type of the identity property.
Model-driven service providers and code generators are only required to support integer.
<entity name="QuoteRequest" persistent="true">
<id name="id" type="integer"/>
<property name="state" type="State"/>
<property name="carModel" type="CarModel" />
<property name="suspensionDetails" type="SuspensionDetail[]" />
</entity>
When you are not using model-driven development, the identity element takes an optional type attribute, which is
the Java class of the specified identity property. You must use this when your identity type may not have a one-to-one
correspondence with ActionScript types. The most common problem is that an ActionScript Number is converted to
either a long or an integer, depending on its value. The code in the following example shows an identity element
with a type attribute:
<identity property="id" type="java.lang.Long">
A common mistake is to try to use one identity element for all properties, as the following example shows:
<metadata>
<!— Don't do this. -->
<identity property="firstName,lastname"/>
</metadata>
Instead, you can specify multiple identity elements for a multiple field identity, as the following example shows:
<metadata>
<identity property="firstName"/>
<identity property="lastName"/>
</metadata>
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The identity element can optionally take an undefined-value attribute, which you use to treat the identity of a
property (usually of type int) as undefined. When an object is initially created on the client, often its identity is not
known until the item is created on the server. In other situations, the client code defines the identity property value
before the item is created by the Data Management Service. If null is not valid for a your data type, for example, if you
have an int or Number as your identity property, you set the undefined-value attribute on the identity element to
specify the undefined value. Often the number 0 (zero) is not a valid identity, so this would be the undefined value, as
the following example shows:
<metadata>
<identity property="id" undefined-value="0"/>
</metadata>
If you do not specify an undefined value, the Data Management Service does not let you create two objects at the same
time because both have the same identity value.
Using identity to manage relationships between objects
The Java Adapter supports flat objects that only contain primitive fields and properties, as well as objects that have
complex objects as properties. If you have complex objects as properties and those objects have their own identity
property or properties, you can choose to define a separate destination to manage the synchronization of those
instances based on the identity property or properties specified in an identity element in the destination definition.
The following example shows a destination named contact that has a many-to-one relationship with a destination
named account. The account destination has a complex property named contact and the contact destination manages
each contact instance.
<!-- Child destination -->
<destination id="contact">
<properties>
<metadata>
<identity property="contactId" undefined-value="0"/>
<!-- Reference to acount destination that has a "contact" property -->
<many-to-one property="account" destination="account" lazy="true"/>
</metadata>...
</destination>
If there is no identity property for complex object properties and each instance is owned by its parent object, you
can use the parent destination to manage the state of the object properties. For more information, see “Hierarchical
data” on page 293.
Caching data items
By default, the Data Management Service caches items returned from fill() and getItem() calls and uses cached
items to implement paging and to build object graphs on the server when implementing lazy associations. This causes
a complete copy of the managed state of all active clients to be kept in each server's memory.
When you are not using model-driven development, you can turn off item caching by setting cache-items to false,
as the following example shows:
...
<destination id="contact">
<properties>
...
<cache-items>false</cache-items>
...
</properties>
</destination>
...
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If you set cache-items to false, you must specify a method to support paging or lazy associations in a get-method
element when using this destination. When the cache-items property is false, the Data Management Service only
caches the identity properties of the items on the server. This greatly reduces the footprint of data kept on the server,
but there is still some memory used on the server for each managed object on each client. To eliminate this overhead
entirely, you set DataService.autoSyncEnabled to false on the client, and either manually refresh clients or use
the manual synchronization feature to route changes to clients. For information about manual synchronization, see
“Manually routing data messages” on page 234.
For model-driven development, you disable item caching by setting the cache-items annotation of an entity to
false, as the following example shows:
<entity name="Book" persistent="true">
<annotation name="DMS">
<item name="cache-items">false</item>
</annotation>
...
</entity>
Synchronizing data automatically
When you are not using model-driven development, the auto-sync-enabled element controls the default value of
the client-side DataService.autoSyncEnabled property for clients that are using a destination. The default value of
this element is true.
The following example shows an auto-sync-enabled element:
...
<destination id="contact">
<properties>
...
<auto-sync-enabled>false</auto-sync-enabled>
...
</properties>
</destination>
...
For model-driven development, you set auto synchronization in the auto-sync annotation of an entity, as the
following example shows. The default value is true.
<entity name="Book" persistent="true">
<annotation name="DMS">
<item name="auto-sync-enabled">
false
</item>
</annotation>
...
</entity>
Using strong and anonymous types
Note: This topic does not apply to model-driven development with the Model Assembler.
The properties of a strongly typed object are defined at compile time by using declared fields or get and set methods.
An anonymous type is usually represented in Java by a java.util.Map, and in ActionScript by an instance of type Object.
For anonymous objects, type checking is performed at run time, not compile time.
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You can use either strongly typed objects or anonymous objects with the Data Management Service on either the client
or the server. For example, to use anonymous objects on both the client and server, your assembler returns
java.util.Map instances that are converted to Object instances on the client. When the client modifies those Object
instances, they are sent back to the assembler as java.util.Map instances.
To use strongly typed objects on the client and server, you define an ActionScript class that has explicit public
properties for the data you want to manage with the [Managed] metadata tag. You map this class to a Java class on the
server by using the [RemoteClass(alias="java-class-name")] metadata tag. Your Data Management Service
destination in this case does not have to be configured with either class explicitly, which allows a single destination to
support whatever instances your client sends to it. The client just has to expect the instances returned by the Java
assembler, and the Java assembler has to recognize instances returned by the client. This allows one destination to
support an entire class hierarchy of instances and you do not have to configure the Data Management Service
destination explicitly for each class as long as they all have the same identity and association properties.
Using item-class to convert to anonymous ActionScript objects
The Data Management Service supports a technique that allows your Java assembler to return strongly typed Java
instances that are converted to anonymous types on the client. In this case, you do not have to maintain ActionScript
classes for each of your Java classes. When those anonymous instances are modified, the server receives them as
java.util.Map instances. Data Management Service supports the item-class element in the properties section of a
destination definition to automatically convert these instances back into a single strongly typed Java class that the Java
assembler expects. Set the item-class element to refer to the Java class that your assembler expects. This pattern
supports only the common case where each destination returns only instances of a single Java class. If your assembler
must operate on a class hierarchy and you do not want to use strongly typed instances on the client, you must convert
from the java.util.Map to your strongly typed instances in your assembler yourself.
You can also write a custom assembler that uses anonymous objects on the server that are serialized to strongly typed
ActionScript classes on the client. To do this, you create an instance of the class flex.messaging.io.amf.ASObject that
implements the java.util.Map interface. Set the type property of that instance to be the fully qualified class name of the
ActionScript class that you want that instance to serialize to on the client, and store the property values that the
ActionScript instance expects as key-value pairs in the java.util.Map. When that object is received by the client, the
serialization code creates an instance of the proper type. Ensure that you declare an instance of the ActionScript class
in your client-side code even if you are not going to use it. You must have a reference to the class to create a dependency
on it so that it stays in the SWF file, as the following example shows:
public var myclass:MyClass;
Using operation-specific security constraints
For destinations that use the ActionScript Object Adapter or the Java Adapter, you can reference security constraints
in the following elements, which are child element of the server element in a destination. These elements apply
security constraints to the corresponding create, read, update, delete, and count operations.
Element
Description
<create-security-constraint
ref="sample-users"/>
Applies the security constraint referenced in the ref attribute to the create
requests.
<read-security-constraint
ref=”sample-users”/>
Applies the security constraint referenced in the ref attribute to fill requests.
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Element
Description
<update-security-constraint
ref="sample-users"/>
Applies the security constraint referenced in the ref attribute to update
requests.
<delete-security-constraint
ref="sample-users"/>
Applies the security constraint referenced in the ref attribute to delete
requests.
<count-security-constraint
ref="sample-users"/>
Applies the security constraint referenced in the ref attribute to count
requests.
For model-driven development, you apply operation-level security constraints in operationname-securityconstraint-ref annotations in an entity, as the following example shows:
<entity name="Book" persistent="true">
<annotation name="DMS">
<item name=
"update-security-constraint-ref">
sample-users
</item>
</annotation>
...
</entity>
Setting a reconnection policy
Use the optional reconnectfetch property to determine what the client-side DataService component fetches in the
event of a reconnection to the remote destination. There are two options: IDENTITY (just retrieve the sequence id) and
INSTANCE (retrieve the complete contents of the fill). The default value is IDENTITY.
The following example shows a reconnect fetch property set in a destination:
...
<destination id="contact">
<properties>
...
<network>
...
<reconnect fetch=" INSTANCE" />
</network>
...
</properties>
</destination>
For model-driven development, you set a reconnection policy in a reconnect-fetch anotation in an entity, as the
following example shows:
<entity name="Book" persistent="true">
<annotation name="DMS">
<item name="reconnect-fetch">
INSTANCE
</item>
</annotation>
...
</entity>
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Custom assemblers
If you are using complex data models and understand Java server-side code, you can create custom assemblers to use
with the Java Adapter. This type of assembler offers the most flexibility for handling specific application requirements,
but requires you to write more code than the standard assemblers.
Using custom assemblers
Depending on the application objects you want the Data Management Service to manage, you define one or more
destinations in the data-management-config.xml file. Each destination maps directly to an application object that you
want to manage. You define an assembler class for each destination.
Your assembler class only has to support the methods that correspond to the operations that the clients use. Your
assembler usually implements at least one fill method. Fill methods implement queries, each of which returns a
collection of objects to the client code. If your client must update objects, your assembler must include a sync method
or individual create, update, and delete methods.
Depending on your server architecture, you directly transfer your domain model objects to the client or implement a
distinct layer of data transfer objects (DAOs) that replicate only the model state you want to expose to your client tier.
The Data Management Service supports two approaches to writing custom assembler classes: the Assembler interface
approach and the fill-method approach. The Assembler interface approach is a more traditional way to build Java
components. You extend the flex.data.assemblers.AbstractAssembler class, which implements the
flex.data.assemblers.Assembler interface. You override methods such as the getItem(), fill(), createItem(), and
updateItem() methods. The AbstractAssembler class provides default implementations of all of the Assembler
interface methods. The AbstractAssembler class and Assembler interface are documented in the LiveCycle Data
Services Javadoc API documentation. For more information, see “The Assembler interface approach” on page 256.
The fill-method approach is designed for simple applications. You declare individual methods by using XML elements
named fill-method, sync-method, and get-method in a destination definition in a configuration file. You map
these XML elements to methods of any name on your assembler class. For more information, see “The fill-method
approach” on page 264.
Add the methods required for the feature set required for your clients. For example, if your client application is readonly, you only have to provide a get method or a fill method as needed by your clients. A get method is required on an
assembler if a client uses the DataService.getItem() method. A get method is also required if you set the value of
the cache-items property to false and have lazy associations that point to an item or you are using paging. A fill
method is required if a client uses the DataService.fill() method.
Later, if you want the assembler to support updates, you add a sync-method definition. In this approach, the assembler
class does not have to implement any special Flex interfaces.
You can also combine the Assembler interface approach and the fill-method approach in the same assembler class. If
you use an XML declaration for a method, the Data Management Service calls that method instead of the equivalent
implementation of an Assembler interface method. Combining the Assembler interface approach with fill-method and
count-method XML declarations in a destination definition can be a useful way to expose queries to your clients; it
prevents the assembler's actual fill() method from acting on different types of fill requests. If a matching fillmethod element is found in the destination, the Data Management Service calls that method. Otherwise, the Data
Management Service calls the assembler's implementation of the fill() method defined in the Assembler interface.
Note: When creating assemblers for use in LiveCycle Foundation rather than a stand-alone LiveCycle Data Services web
application, you must use the Assembler interface approach exclusively.
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Configuring a destination that uses a custom assembler
The following table describes the destination properties for using the Java Adapter with a custom assembler. Unless
otherwise indicated, these elements are subelements of the properties element.
Element
Description
source
Required. Assembler class name.
scope
Optional. Scope of the assembler. Valid values are application, session, and request.
itemclass
Optional. For more information, see “Using strong and anonymous types” on page 251.
cacheitems
Optional. Default value is true. Determines whether client-side DataService caches the
last version of each item.
metadata
identit
y
Required. Property to guarantee unique identity among items in a collection of objects.
For more information, see “Uniquely identifying data items” on page 249.
paging
Optional. Contains attributes for configuring data paging. For more information, see
“Data paging” on page 303.
network
fillmethod
(fill-method approach only) Method to invoke when a fill request is made. The required
name child element designates the name of the method to call.
The optional params element designates input parameter types for the fill operation,
and accommodates method overloading.
The optional fill-contains-method element points to a method in the Assembler
class that takes a changed or created item and the List of fill parameters and returns true
or false, depending on whether the item is in that fill. If the fill is not ordered and the
method returns true, the item is added to the end of the list of managed items for that
fill. If the fill is ordered and you return true, the fill method is re-executed to get the
proper ordering of the list. If the method returns false, the fill-method is left as is for that
update.
The optional ordered element determines whether order is important for this filled
collection. Default value is true. Allows for performance optimization when order is not
important.
The optional security-constraint and security-run-as elements reference a
security setting in the services-config.xml file.
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Element
Description
syncmethod
(fill-method approach only) Method to invoke for update, delete, and insert operations.
The required name child element specifies the name of the method to invoke. There is no
params element because the parameter is predefined as a List of ChangeObjects.
The optional security-constraint and security-run-as child elements
reference a security setting in the services-config.xml file.
getmethod
(fill-method approach only) Method to retrieve a single item instance instead of a List of
item instances. If present, this element always takes a single parameter, which is the Map
of values used to denote object identity.
The required name child element specifies the name of the method to invoke.
countmethod
(fill-method approach only) Method to retrieve an integer from the assembler that you
can use to return a count of items without first loading all of a data set into memory. Like
the fill-method element, the count-method element can accept parameters.
This method does not retrieve the size of a filled sequence, in that any given sequence
can represent a subset of data, and sequences are always fully loaded into the server.
Count method implementations can execute a COUNT statement against a database.
The required name child element specifies the name of the method to invoke.
The following example shows a simple destination definition; it uses an assembler that implements the Assembler
interface:
<destination id="inventory">
<properties>
<source>flex.samples.product.ProductAssembler</source>
<scope>application</scope>
<metadata>
<identity property="productId"/>
</metadata>
<network>
<paging enabled="false" pageSize="10" />
</network>
</properties>
</destination>
The Assembler interface approach
To use the Assembler interface approach in an assembler, you must implement the flex.data.assemblers.Assembler
interface. The flex.data.assemblers.AbstractAssembler class extends this interface, so extending this class is the easiest
way to write your own assembler.
Note: When you create assemblers for use in LiveCycle Foundation rather than a stand-alone LiveCycle Data Services
web application, you use the Assembler interface approach exclusively.
Depending on the fill request that a client sends, the fill() method performs a specific query to create the Collection
object that is returned to the client side. An assembler that implements the Assembler interface has an
autoRefreshFill() method, which returns a Boolean value that determines whether to refresh fills when data items
change. The autoRefreshFill() method of the AbstractAssembler class returns true.
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Whenever an item is created or updated, the autoRefreshFill() method is called for every fill managed by the server
at the time of the create or update. Fills are identified by a set of fill parameters, so the autoRefreshFill() method
is called once with every set of outstanding fill parameters. If the autoRefreshFill() method returns true for a given
set of fill parameters, the refreshFill() method is invoked with those fill parameters, the created or updated item,
and a flag denoting whether the change is an update or a create. The purpose of the refreshFill() method is to
determine if and how the modification of the item affects its membership in that fill.
The refreshFill() method can return the following values:
Value
Usage
EXECUTE_FILL
Re-executes a fill for this newly updated or created item. once the fill is re-executed,
the new result is used to determine whether the create or update has caused the
membership and position of the modified item to change for the particular fill.
This is the default behavior. If you do not override the refreshFill() method in
your custom assembler code, this is the behavior it uses.
DO_NOT_EXECUTE_FILL
Do not execute a fill for this newly updated or created item.
APPEND_TO_FILL
Adds the changed item to the end of the list returned by the last fill invocation.
REMOVE_FROM_FILL
Removes this item from the set of items in this filled collection if it is in the collection.
The default behavior of the refreshFill() method is to always return EXECUTE_FILL. To improve performance, you
can override the refreshFill() method to base its behavior on the value of the isCreate flag. On a create (the
isCreate flag is true), you could return APPEND_TO_FILL or DO_NOT_EXECUTE_FILL for each set of fill parameters,
depending on whether the new item belongs to that fill or not. On an update (the isCreate flag is false), you could
return APPEND_TO_FILL if the item was not part of the fill but after the change is part of the fill, REMOVE_FROM_FILL
if the item was part of the fill but after the change is no longer part of the fill, or DO_NOT_EXECUTE_FILL if the update
has no impact on fill membership.
In addition to fill() methods, the Assembler interface provides getItem()and getItems() methods for getting
specific data items. It also provides the createItem() method for creating new items, the updateItem() method for
updating an existing item, and the deleteItem() method for deleting items. You can override the createItem(),
updateItem(), and deleteItem() methods to add your own synchronization logic.
The following example shows the source code for the ProductAssembler class that is part of the Data Management
Service application in the LiveCycle Data Services Test Drive:
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package flex.samples.product;
import java.util.List;
import java.util.Collection;
import java.util.Map;
import flex.data.DataSyncException;
import flex.data.assemblers.AbstractAssembler;
public class ProductAssembler extends AbstractAssembler {
public Collection fill(List fillParameters, PropertySpecifier ps) {
ProductService service = new ProductService();
return service.getProducts();
}
public Object getItem(Map identity) {
ProductService service = new ProductService();
return service.getProduct(((Integer) identity.get("productId")).intValue());
}
public void createItem(Object item) {
ProductService service = new ProductService();
service.create((Product) item);
}
public void updateItem(Object newVersion, Object prevVersion, List changes) {
ProductService service = new ProductService();
boolean success = service.update((Product) newVersion);
if (!success) {
int productId = ((Product) newVersion).getProductId();
throw new DataSyncException(service.getProduct(productId), changes);
}
}
public void deleteItem(Object item) {
ProductService service = new ProductService();
boolean success = service.delete((Product) item);
if (!success) {
int productId = ((Product) item).getProductId();
throw new DataSyncException(service.getProduct(productId), null);
}
}
}
The Java source code for the ProductAssembler class and other classes it uses are in the
WEB_INF/src/flex/samples/product directory of the lcds-samples web application. The ProductAssembler class uses
the Assembler interface approach. It extends the flex.data.assemblers.AbstractAssembler class and does not override
the autoRefreshFill() method, which returns true.
ProductAssembler delegates SQL database interaction to a data access object (DAO) called ProductService. The
following example shows the source code for the ProductService class:
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package flex.samples.product;
import java.util.ArrayList;
import java.util.List;
import java.sql.*;
import flex.samples.ConnectionHelper;
import flex.samples.DAOException;
public class ProductService {
public List getProducts() throws DAOException {
List list = new ArrayList();
Connection c = null;
try {
c = ConnectionHelper.getConnection();
Statement s = c.createStatement();
ResultSet rs = s.executeQuery("SELECT * FROM product ORDER BY name");
while (rs.next()) {
list.add(new Product(rs.getInt("product_id"),
rs.getString("name"),
rs.getString("description"),
rs.getString("image"),
rs.getString("category"),
rs.getDouble("price"),
rs.getInt("qty_in_stock")));
}
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException(e);
} finally {
ConnectionHelper.close(c);
}
return list;
}
public List getProductsByName(String name) throws DAOException {
List list = new ArrayList();
Connection c = null;
try {
c = ConnectionHelper.getConnection();
PreparedStatement ps = c.prepareStatement("SELECT * FROM product WHERE UPPER(name)
LIKE ? ORDER BY name");
ps.setString(1, "%" + name.toUpperCase() + "%");
ResultSet rs = ps.executeQuery();
while (rs.next()) {
list.add(new Product(rs.getInt("product_id"),
rs.getString("name"),
rs.getString("description"),
rs.getString("image"),
rs.getString("category"),
rs.getDouble("price"),
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rs.getInt("qty_in_stock")));
}
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException(e);
} finally {
ConnectionHelper.close(c);
}
return list;
}
public Product getProduct(int productId) throws DAOException {
Product product = new Product();
Connection c = null;
try {
c = ConnectionHelper.getConnection();
PreparedStatement ps = c.prepareStatement("SELECT * FROM product WHERE
product_id=?");
ps.setInt(1, productId);
ResultSet rs = ps.executeQuery();
if (rs.next()) {
product = new Product();
product.setProductId(rs.getInt("product_id"));
product.setName(rs.getString("name"));
product.setDescription(rs.getString("description"));
product.setImage(rs.getString("image"));
product.setCategory(rs.getString("category"));
product.setPrice(rs.getDouble("price"));
product.setQtyInStock(rs.getInt("qty_in_stock"));
}
} catch (Exception e) {
e.printStackTrace();
throw new DAOException(e);
} finally {
ConnectionHelper.close(c);
}
return product;
}
public Product create(Product product) throws DAOException {
Connection c = null;
PreparedStatement ps = null;
try {
c = ConnectionHelper.getConnection();
ps = c.prepareStatement("INSERT INTO product (name, description, image, category,
price, qty_in_stock) VALUES (?, ?, ?, ?, ?, ?)");
ps.setString(1, product.getName());
ps.setString(2, product.getDescription());
ps.setString(3, product.getImage());
ps.setString(4, product.getCategory());
ps.setDouble(5, product.getPrice());
ps.setInt(6, product.getQtyInStock());
ps.executeUpdate();
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Statement s = c.createStatement();
// HSQLDB Syntax to get the identity (company_id) of inserted row
ResultSet rs = s.executeQuery("CALL IDENTITY()");
// MySQL Syntax to get the identity (product_id) of inserted row
// ResultSet rs = s.executeQuery("SELECT LAST_INSERT_ID()");
rs.next();
// Update the id in the returned object. This is important as this value must get returned to
the client.
product.setProductId(rs.getInt(1));
} catch (Exception e) {
e.printStackTrace();
throw new DAOException(e);
} finally {
ConnectionHelper.close(c);
}
return product;
}
public boolean update(Product product) throws DAOException {
Connection c = null;
try {
c = ConnectionHelper.getConnection();
PreparedStatement ps = c.prepareStatement("UPDATE product SET name=?,
description=?, image=?, category=?, price=?, qty_in_stock=? WHERE
product_id=?");
ps.setString(1, product.getName());
ps.setString(2, product.getDescription());
ps.setString(3, product.getImage());
ps.setString(4, product.getCategory());
ps.setDouble(5, product.getPrice());
ps.setInt(6, product.getQtyInStock());
ps.setInt(7, product.getProductId());
return (ps.executeUpdate() == 1);
} catch (SQLException e) {
e.printStackTrace();
throw new DAOException(e);
} finally {
ConnectionHelper.close(c);
}
}
public boolean remove(Product product) throws DAOException {
Connection c = null;
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try {
c = ConnectionHelper.getConnection();
PreparedStatement ps = c.prepareStatement("DELETE FROM product WHERE product_id=?");
ps.setInt(1, product.getProductId());
int count = ps.executeUpdate();
return (count == 1);
} catch (Exception e) {
e.printStackTrace();
throw new DAOException(e);
} finally {
ConnectionHelper.close(c);
}
}
public boolean delete(Product product) throws DAOException {
return remove(product);
}
}
ProductAssembler stores the state of individual products in a JavaBean named Product. The following example shows
the source code for the Product class:
package flex.samples.product;
import java.io.Serializable;
public class Product implements Serializable {
static final long serialVersionUID = 103844514947365244L;
private
private
private
private
private
private
private
int productId;
String name;
String description;
String image;
String category;
double price;
int qtyInStock;
public Product() {
}
public Product(int productId, String name, String description, String image, String
category, double price, int qtyInStock) {
this.productId = productId;
this.name = name;
this.description = description;
this.image = image;
this.category = category;
this.price = price;
this.qtyInStock = qtyInStock;
}
public String getCategory() {
return category;
}
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public void setCategory(String category) {
this.category = category;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getImage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public int getProductId() {
return productId;
}
public void setProductId(int productId) {
this.productId = productId;
}
public int getQtyInStock() {
return qtyInStock;
}
public void setQtyInStock(int qtyInStock) {
this.qtyInStock = qtyInStock;
}
}
Note: Include the messaging.jar and flex-messaging-common.jar files in your classpath when you compile code that uses
LiveCycle Data Services Java APIs.
The following example shows a destination that uses ProductAssembler:
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<destination id="inventory">
<properties>
<source>flex.samples.product.ProductAssembler</source>
<scope>application</scope>
<metadata>
<identity property="productId"/>
</metadata>
<network>
<paging enabled="false" pageSize="10" />
</network>
</properties>
</destination>
The fill-method approach
The fill-method approach is designed for simple applications. You declare individual methods by using XML elements
named fill-method, sync-method, and get-method in a destination definition in a configuration file. You use these
elements to map arbitrary methods of an assembler as fill and sync methods. The method names that you specify in
these elements correspond to methods in the assembler class. These methods are called when data operations occur
on a Flex client application. Never declare a sync-method element if the items are read-only.
If the signature of the fill request sent for a client does not match a fill-method element, the Data Management
Service calls the fill() method defined in the assembler if it implements the flex.data.assemblers.Assembler
interface.
When you use fill-method elements, each fill method is identified by the types of parameters declared in a
corresponding fill-method element. Do not declare two fill methods that take the same types of arguments or an
error occurs when you try to invoke the fill method. Another important consideration is that a null value passed to a
fill method acts like a wildcard that matches any data type. If you expect to use many fill methods, assign them a name
or identity as the first parameter to uniquely identify the query you want to perform. You can then initiate queries with
different names within your fill method.
You can implement any number of fill methods to fill a client-side ArrayCollection object with data items. You specify
fill methods in the fill-method section of the destination; each of these methods is assigned as a fill method that can
accept an arbitrary number of parameters of varying types and returns a List object. The data types must be available
at run time. Any call to a client-side DataService component's fill() method results in a server-side call to the
appropriate Java fill method with the parameters that the client provides.
In a sync-method element, you specify a method that accepts a change list as its only input parameter. You can choose
to implement the sync method as a single method that takes a list of ChangeObject objects, or you can extend the
AbstractAssembler class and override the updateItem(), createItem(), and deleteItem() methods.
The change list is a java.util.List implementation that contains objects of type flex.data.ChangeObject. Each
ChangeObject in the list contains methods to access an application-specific changed Object instance. Each
ChangeObject also contains convenience methods for getting more information about the type of change that
occurred and for accessing the changed data members. Only use the iterator in this list to iterate through the
ChangeObjects. Use of the get method in the list is not allowed. The flex.data.ChangeObject class is included in the
LiveCycle Data Services Javadoc API documentation.
Note: The compiled assembler class and any other required classes, such as a DAO class, must be available in the web
application classpath. When you compile code that uses LiveCycle Data Services Java APIs, you include the messaging.jar
and flex-messaging-common.jar files in your classpath.
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Detecting changes to fill results
You use fill methods to implement queries that return a collection of items for a particular destination. When a client
executes a fill method with its DataService.autoSyncEnabled property set to true, it listens for changes to the
results of this query so that it can update the list displayed on the client. By default, the Data Management Service
implements this functionality by using an technique called auto-refresh, which usually ensures that the client results
are in sync with the database. With auto-refresh, whenever either the client or the server push API creates or updates
an item, the Data Management Service re-executes any fill() methods currently managed on active clients. The Data
Management Service compares the identity properties of the returned items to its cached results. If any have been
added or removed, the Data Management Service builds an update collection message that it sends to the clients that
have that fill method cached. For simple applications, auto-refresh could be all you require; however, when the number
of fill methods with unique parameters managed by clients grows large, the auto-refresh technique can result in the
execution of many unnecessary queries.
You can keep fill methods from being executed unnecessarily in several ways. You can disable auto-refresh, and use
the refreshFill() method of the flex.data.DataServiceTransaction class (the server push API) to explicitly invalidate
a fill or set of fill methods. You explicitly invalidate a fill or set of fill methods by specifying a pattern that matches the
parameters of the fill methods you want to refresh. Alternatively, you can leave auto-refresh enabled, and set it so that
it only re-executes a fill method when a specified item changes the fill results. Another option is to disable auto-refresh
and call the addItemToFill() or removeItemFromFill() methods to make explicit changes to an individual filled
collection.
When you leave auto-refresh enabled, you supply a method that is called for each item that is created or updated for
each unique set of fill parameters currently managed on active clients. This method returns a value that indicates how
the fill should be treated for that change. How this method works depends on whether your assembler implements the
Assembler interface or uses XML-based fill-method and sync-method elements in a destination.
Detecting changes with the Assembler interface approach
When you implement the Assembler interface, a refreshFill() method is called for each active fill managed on the
client. The refreshFill() method is given the list of fill parameters and the changed items and returns a code that
indicate whether the fill should be re-executed, the item should be appended to the fill, the fill should be left unchanged
for this operation, or the item should be removed from the fill; for more information, see “The Assembler interface
approach” on page 256.
Detecting changes with the fill-method approach
When you use the fill-method approach, you define a fill-contains-method element that points to a method in
your Assembler class. That method takes the changed or created item and the List of fill parameters and returns true
or false depending on whether the item is in that fill result. If the fill is not ordered and the method returns true, the
item is added to the end of the list of managed items for that fill. If the fill is ordered and you return true, the fill
method is re-executed to get the proper ordering of the list. If the method returns false, the fill method is left as is for
that update.
The following example shows fill-method elements with fill-contains-method elements for unordered and
ordered fills:
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<fill-method>
<name>loadUnorderedPatternGroups</name>
<params>java.lang.String,java.lang.Boolean</params>
<ordered>false</ordered>
<fill-contains-method>
<name>unorderedPatternContains</name>
</fill-contains-method>
</fill-method>
<fill-method>
<name>loadOrderedPatternGroups</name>
<params>java.lang.Boolean,java.lang.String</params>
<ordered>true</ordered>
<fill-contains-method>
<name>orderedPatternContains</name>
</fill-contains-method>
</fill-method>
The following example shows the unorderedPatternContains() and orderedPatternContains() methods in the
corresponding assembler:
...
public boolean unorderedPatternContains(Object[] params, Object group) {
AssocGroup g = (AssocGroup)group;
if (g.getName().indexOf((String)params[0]) != -1)
return true;
return false;
}
public boolean orderedPatternContains(Object[] params, Object group) {
AssocGroup g = (AssocGroup)group;
if (g.getName().indexOf((String)params[1]) != -1)
return true;
return false;
}
Using property specifiers
There are two basic use cases for the PropertySpecifier class. In one case, you receive a PropertySpecifier in assembler
methods such as getItem(). In this case, the PropertySpecifier provides a hint so that your code can optimize the
fetching of the properties. For the Assembler.getItem() method you only need to return the properties specified in
the PropertySpecifier.
There are a couple of ways to determine which properties are specified in the PropertySpecifier. You can use the
PropertySpecifier.includeProperty(String name) method to test if a specific property is included by a given
PropertySpecifier. You also can look at how the PropertySpecifier is defined.
A PropertySpecifier can have a default mode, which means that all properties should be returned unless they are listed
as exceptions in the configuration. For example, if you define an association with load-on-demand or page-size, it
is not included in the default PropertySpecifier. You can also define a PropertySpecifier for the all mode, in which case,
it returns all properties. PropertySpecifiers can also be defined to contain an explicit list of property names, or you can
define one that includes the default properties plus an explicit list of property names.
default All properties other than load on demand or paged association properties.
all All properties.
default plus list Default properties plus an extra set of properties retrievable by the getExtraProperties() method.
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just list A set of properties retrievable by the getExtraProperties() method.
A typical reason you might use the PropertySpecifier is if you define master and detail views of the properties in your
value objects. All properties in the detail view would be marked as load-on-demand or with page-size so that they are
not put into the default set of properties. The only properties you can mark load-on-demand are associations. When
the initial fill() or getItem() call is made for that item, it does not need to return any of these load-on-demand or
paged properties. The default fill() method must only return properties defined in as default properties for that
item. When the client tries to access these properties, a separate request is made to the server to fetch them. In that
case, if you set load-on-demand to true, your getItem() method is called with a PropertySpecifier that only includes
the property accessed on the client. If you set the page-size attribute on your association property, the
getPagedCollectionProperty() method is used instead to fetch a range of items from that association property.
The second use case for a PropertySpecifier is when you must specify one for a Data Management Service API such as
the DataServiceTransaction class. The PropertySpecifier provides a way to specify a list of properties for a given
operation. For example, the refreshFill() method takes a PropertySpecifier that specifies which properties from the
adapter layer should be refreshed. The DataServiceTransaction.getItem() method can also take a
PropertySpecifier to indicate which properties should be fetched from the assembler. Whenever you call a Data
Management Service API function that takes a PropertySpecifier argument, null can be used instead of providing a
PropertySpecifier instance. For the refreshFill() method, supplying null means to not refresh any properties of
items. In that case, items are only added to or removed from the collection as necessary; no properties of updated items
are refreshed. For the getItem() method, passing null means to use the default property descriptor.
To create a new PropertySpecifier on the server, you first need to get the DataDestination for the type of object you are
dealing with. You do this with the static method DataDestination.getDataDestination(String destName). Once you
have the DataDestination, you can use the getDefaultPropertySpecifier() and getAllPropertySpecifier()
methods to retrieve predefined PropertySpecifiers that refer to the default set or all properties, respectively.
You also can use the PropertySpecifier.getPropertySpecifier(DataDestination dest, List props, boolean includeDefault)
to create a PropertySpecifier that refers to a specific set of properties you specify in the props parameter. You use this
method in general when you want to create a PropertySpecifier from an explicit list of properties. In that case, you have
two choices: you can include just the list of properties you specify, or you can include use the includeDefault parameter
to include all default properties in addition to the list of properties specified in the props parameter.
Suppose you have a Person type with a load-on-demand addresses property and you want to call to the getItem()
method to retrieve a given user’s addresses property. You could write the following code to get a PropertySpecifier that
retrieves just the addresses property:
ArrayList props = new ArrayList();
props.add("addresses");
PropertySpecifier.getPropertySpecifier(DataDestination.getDataDestination
("Person"), props, false);
You could write the following code to get a PropertySpecifier that includes all of the non-load-on-demand properties
(firstName, lastName, and so forth) in addition to the addresses property:
ArrayList props = new ArrayList();
props.add("addresses");
PropertySpecifier.getPropertySpecifier(DataDestination.getDataDestination
("Person"),props, true);
Using server-side logging with custom assemblers
Custom assemblers log messages through the server-side logging system that is configured in the services-config.xml
file. To log messages, use the Service.Data.* filter pattern or another wildcard pattern. For information about serverside logging, see “Logging” on page 420.
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Standard assemblers
LiveCycle Data Services includes standard assemblers that use the Java adapter.
The SQL Assembler is a specialized assembler that provides a bridge from the Data Management Service to a SQL
database management system. Use this type of assembler if your database data model is not complex and you want to
expose that data model to MXML without writing Java server-side code.
The two Hibernate assemblers are specialized assemblers that provide a bridge from the Data Management Service to
the Hibernate object/relational persistence and query service. Use the Hibernate Assembler or the Hibernate
Annotations Assembler if you do not want to write a custom assembler, you require access to database objects, you are
using or have used the Hibernate object-relational mapping system, and you are comfortable with writing Java code.
You configure the Hibernate Assembler in configuration files; you configure the Hibernate Annotations Assembler in
Hibernate annotations in Java classes.
The Model Assembler extends the Hibernate Assembler and is used with Adobe application modeling technology;
Model Assembler instances are dynamically generated based on a model.
The SQL Assembler
The SQL Assembler is a specialized Java assembler class that you use with the Java adapter to provide a bridge to a SQL
database management system. Using the SQL Assembler, you can build simple create, read, update, and delete
(CRUD) applications based on the Data Management Service without writing server-side code. You can directly
specify the SQL statements that you want to execute when the user creates, updates, or deletes items. You can also
specify a number of SELECT statements to retrieve data in different ways. This assembler is useful when your database
data model is not very complex and you want to expose it to MXML without writing Java code. You configure the
connection to the database and write SQL code in a Data Management Service destination definition. You are only
required to include SQL code for operations that a Flex application calls. The SQL Assembler does not support
hierarchical (nested) destinations.
The SQL Assembler class, flex.data.assemblers.SQLAssembler, extends the flex.data.assemblers.AbstractAssembler
class and is included in the public LiveCycle Data Services Javadoc API documentation. When necessary, you can
extend SQLAssembler to override methods. The resources directory the LiveCycle Data Services installation includes
the source code for the SQLAssembler and HibernateAssembler classes.
Configuring a destination that uses the SQL Assembler
Before using the SQL Assembler from a Flex client, you configure a destination that specifies database connection
information and SQL statements. The following example shows a complete destination definition that uses the SQL
Assembler; the lcds-samples web application included with LiveCycle Data Services uses this destination:
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<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
<use-transactions>true</use-transactions>
<source>flex.data.assemblers.SQLAssembler</source>
<scope>application</scope>
<metadata>
<identity property="PRODUCT_ID"/>
</metadata>
<server>
<database>
<driver-class>org.hsqldb.jdbcDriver</driver-class>
<!-- Modify the URL below with the actual location of the
flexdemodb database on your system -->
<url>jdbc:hsqldb:hsql://myserver:9002/flexdemodb</url>
<username>sa</username>
<password></password>
<login-timeout>15</login-timeout>
</database>
<!-- Use this syntax when using a JNDI data source-->
<!-<database>
<datasource>java:comp/env/jdbc/flexdemodb</datasource>
</database>
-->
<actionscript-class>Product</actionscript-class>
<fill>
<name>all</name>
<sql>SELECT * FROM PRODUCT ORDER BY NAME</sql>
</fill>
<fill>
<name>by-name</name>
<sql>SELECT * FROM PRODUCT WHERE NAME LIKE CONCAT('%',
CONCAT(#searchStr#,'%'))</sql>
</fill>
<fill>
<name>by-category</name>
<sql>SELECT * FROM PRODUCT WHERE CATEGORY LIKE CONCAT('%',
CONCAT(#searchStr#,'%'))</sql>
</fill>
<get-item>
<sql>SELECT * FROM PRODUCT WHERE PRODUCT_ID = #PRODUCT_ID#</sql>
</get-item>
<create-item>
<sql>INSERT INTO PRODUCT
(NAME, CATEGORY, IMAGE, PRICE, DESCRIPTION, QTY_IN_STOCK)
VALUES (#NAME#, #CATEGORY#, #IMAGE#, #PRICE#, #DESCRIPTION#,
#QTY_IN_STOCK#)</sql>
<id-query>CALL IDENTITY()</id-query> <!-- HSQLDB syntax to
retrieve value of autoincremented column -->
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</create-item>
<update-item>
<sql>UPDATE PRODUCT SET NAME=#NAME#, CATEGORY=#CATEGORY#,
IMAGE=#IMAGE#, PRICE=#PRICE#, DESCRIPTION=#DESCRIPTION#,
QTY_IN_STOCK=#QTY_IN_STOCK#
WHERE PRODUCT_ID=#_PREV.PRODUCT_ID#</sql>
</update-item>
<delete-item>
<sql>DELETE FROM PRODUCT WHERE PRODUCT_ID=#PRODUCT_ID#</sql>
</delete-item>
<count>
<name>all</name>
<sql>SELECT count(*) FROM PRODUCT</sql>
</count>
</server>
</properties>
</destination>
For examples of MXML applications that perform CRUD and query operations on this destination, see the samples
web application included with LiveCycle Data Services.
Specifying the Java adapter
Specify an instance of the Java adapter if it is not already set as the default adapter. In the following example, java-dao
is the id value of a Java adapter instance defined in the configuration file:
<destination id="SqlPerson">
<adapter ref="java-dao"/>
...
</destination>
Setting the destination source
Specify the flex.data.assemblers.SQLAssembler class name in the source element of the destination definition, as the
following examples shows. Generally, you also set the scope value to application.
<destination id="SqlPerson">
<adapter ref="java-dao"/>
<properties>
<use-transactions>true</use-transactions>
<source>flex.data.assemblers.SQLAssembler</source>
<scope>application</scope>
...
</properties>
</destination>
Setting the identity property
Specify the identity property, which maps to the database field. Additionally, this name corresponds to the name of
a property of an ActionScript object in the Flex client application. The ActionScript object can be anonymous or
strongly typed. The following example shows the configuration for an identity element:
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<destination id="SqlPerson">
<adapter ref="java-dao"/>
<properties>
...
<metadata>
<identity property="PRODUCT_ID"/>
</metadata>
...
</properties>
</destination>
Configuring the database connection
You can connect to a SQL database by specifying a data source or a driver in the destination definition. Using a data
source is recommended because it provides application server enhancements, such as connection pooling.
The following example shows a datasource element in a destination definition:
<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
<database>
<driver-class>org.hsqldb.jdbcDriver</driver-class>
<!-- Modify the URL below with the actual location of the
flexdemodb database on your system -->
<url>jdbc:hsqldb:hsql://yourserver:9002/flexdemodb</url>
<username>sa</username>
<password></password>
<login-timeout>15</login-timeout>
</database>
...
</properties>
</destination>
You use the optional login-timeout property for a data source or a driver. You specify this value in seconds. When
you use a data source, this value is used as a parameter to the DataSource.setLoginTimeout(seconds) method. If
no timeout is specified, a timeout is not set and you rely on the data source/application server settings. The timeout
settings are almost always included with the data source definition. When you use a driver, set this value as a parameter
to the DriverManager.setLoginTimeout(seconds) method. If no timeout is specified, the default value is 20
seconds.
The following example shows a database element that provides database driver settings in a destination definition.
<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
<database>
<datasource>java:comp/env/jdbc/flexdemodb</datasource>
</database>
...
</properties>
</destination>
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Configuring return types
For operations that return objects to the Flex client, you can specify the return type in javaclass- or actionscriptclass elements, as the following example shows:
<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
...
<actionscript-class>Product</actionscript-class>
<!--<java-class>samples.Product</java-class> -->
...
</server>
...
</properties>
</destination>
The actionscript-class element specifies the ActionScript type that you want returned from the server when no
alias mapping to a specific Java class exists. The ActionScript class that you specify must have the RemoteClass
metadata syntax, but without an alias that specifies a Java class.
The java-class element specifies a server-side Java class that maps to an ActionScript class that uses the
RemoteClass(alias=javaclassname) metadata syntax. You use this element when you map a specific ActionScript
type to a specific Java type that uses this syntax. The Java and ActionScript property names match the database field
names. The ActionScript class designating the Java class specified in the java-class element must be available on the
client.
Configuring fill operations
You configure fill operations in fill elements in the server section of a destination definition. The fill elements
contain name and sql or statement elements, depending on whether you are using a single SQL statement or a stored
procedure. The SQL code indicates properties from the object to use with #propName#. The following example shows
several fill elements:
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<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
...
<fill>
<name>all</name>
<sql>SELECT * FROM PRODUCT ORDER BY NAME</sql>
</fill>
<fill>
<name>by-name</name>
<sql>SELECT * FROM PRODUCT WHERE NAME LIKE CONCAT('%',
CONCAT(#searchStr#,'%'))</sql>
</fill>
<fill>
<name>by-category</name>
<sql>SELECT * FROM PRODUCT WHERE CATEGORY LIKE CONCAT('%',
CONCAT(#searchStr#,'%'))</sql>
</fill>
...
</server>
...
</properties>
</destination>
In a Flex client application, the DataService.fill() method uses the named fill query that is defined in the
destination. The arguments can be an anonymous ActionScript object with named parameters or a strongly typed
ActionScript object. These arguments are used to define the SQL parameter values. A list is returned. The return type
can be anonymous, based on a javaclass- value, or based on an actionscript-class value.
The following example is a simple client-side DataService.fill() method without named parameters:
ds.fill(dataCollection, named-sql-query, parameters);
The following example is a client-side DataService.fill() method with named parameters:
<mx:Button label="Search" click="ds.fill(products, combo.selectedIndex == 0 ? 'by-name' : 'bycategory', {searchStr: searchStr.text})"/>
Configuring a getItem operation
You configure a getItem operation in a get-item element in the server section of a destination definition. The
getitem- element contains a sql element or a statement element, depending on whether you are using a single SQL
statement or a stored procedure. The SQL code indicates properties from the object to use with #propName# text,
where propName is the property name. The following example shows a get-item element:
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<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
...
<get-item>
<sql>SELECT * FROM PRODUCT WHERE PRODUCT_ID = #PRODUCT_ID#</sql>
</get-item>
...
</server>
</properties>
</destination>
In a Flex client application, the DataService.getItem() method takes a single argument that is the identity of the
item. The identity maps to the identity property specified in the Data Management Service destination. This field
also links with the database field and the property name on the ActionScript object. The PreparedStatement uses the
id argument value for its single ordered parameter.
Note: Do not use a SQL variable name in the get-item SQL statement that is different from the identity property name.
If you do that, when a conflict occurs, the identity property is used to call DataService.getItem(), resulting in an error
because of a parameter mismatch between the identity and the SQL variable.
The item returned is an anonymous object with property names consistent with database field names, a strongly typed
ActionScript object where the type was specified using the actionscript-class element in the destination, or a
strongly typed ActionScript object where the RemoteClass(alias="java-class") is equivalent to the class specified
using the java-class element in the destination. In all cases, the property names are consistent with the database field
names.
The following example shows the code for a DataService.getItem() method:
ds.getItem({employee_id:cursor.current.employeeid});
The property name employee_id is the id property on the ActionScript object as well as the database field name.
Configuring a createItem operation
You configure a createItem operation in a create-item element in the server section of a destination definition. The
create-item element contains one or more sql or statement elements, depending on whether you are using a single
SQL statement or a stored procedure. The SQL code indicates properties from the object to use with #propName#.
The createItem operation requires that you define two SQL queries. The create-item element creates the object and
the id-query element obtains the identity property of the newly created object from the database. The idqueryelement can precede the create-item SQL statement. The Data Management Service executes the sql-update and
the id-query within the same DataServiceTransaction object and uses the same connection to the database. The
parameters for the SQL statement are retrieved from the properties of the createItem instance. As an alternative, you
can set up a procedure call in the database that does the insert and id selection. For the create-item element only,
you can designate the procedure-param element as an OUT parameter, which means that the value is returned to the
client in the property-value field of the ActionScript instance.
You can use the identity results of the id-query in any SQL statement that comes after it. If the id-query comes first,
it is executed before all of the SQL statements. If the id-query comes after any SQL statement, it is always executed
after the first SQL statement. If you require additional flexibility in ordering, use run-time configuration of
destinations as described in “Run-time configuration” on page 411.
The following example shows two create-item elements. The second element uses procedure-param elements.
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<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
...
<create-item>
<sql>INSERT INTO employee (first_name, last_name, title, email, phone,
company_id) VALUES (#firstName#, #lastName#, #title#, #email#,
#phone#, #companyId#)</sql>
<id-query>SELECT LAST_INSERT_ID()</id-query>
</create-item>
<create-item>
<procedure name="MY_INSERT_PROC">
<procedure-param property-value="#id#" type="OUT"/>
<procedure-param property-value="#firstName#"/>
<procedure-param property-value="#lastName#"/>
<procedure-param property-value="#title#"/>
<procedure-param property-value="#email#"/>
<procedure-param property-value="#phone#"/>
<procedure-param property-value="#companyId#"/>
</procedure>
</create-item>
...
</server>
</properties>
</destination>
The following example shows Flex client code for an Employee object and a DataService.create() method that
creates the employee in the database:
...
var employee:Employee = new Employee();
employee.first_name = "Joe";
employee.last_name = "Dev";
employee.title = "engineer";
employee.email = "[email protected]";
employee.phone = "617-229-2065";
employee.company_id = 2;
ds.createItem(employee);
ds.commit();
...
Configuring a deleteItem operation
You configure a deleteItem operation in a delete-item element in the server section of a destination definition. The
delete-item element contains a sql element or a statement element, depending on whether you are using a single
SQL statement or a stored procedure. The SQL code indicates which properties from the object to use with
#propName#.
The following example shows a delete-item element:
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<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
...
<delete-item>
<sql>DELETE FROM PRODUCT WHERE PRODUCT_ID=#PRODUCT_ID#</sql>
</delete-item>
...
</server>
</properties>
</destination>
The following example shows Flex client code for deleting an item from the database. The properties for the instance
to delete are mapped to the fields in the delete-item query in the configuration file. If all properties are not set, the
delete operation fails.
...
var removedItem:Object = cursor.remove();
ds.commit();
...
If the server value is changed, the delete SQL operation fails to execute. In this situation, a DataSyncException is
thrown. The exception contains the results of the get-item query.
Configuring an updateItem operation
You configure an updateItem operation in an update-item element in the server section of a destination definition.
The update-item element contains a sql element or a statement element, depending on whether you are using a
single SQL statement or a stored procedure. The SQL code indicates properties from the object to use with
#propName#.
The following example shows an update-item element:
<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
...
<update-item>
<sql>UPDATE PRODUCT SET NAME=#NAME#, CATEGORY=#CATEGORY#,
IMAGE=#IMAGE#, PRICE=#PRICE#, DESCRIPTION=#DESCRIPTION#,
QTY_IN_STOCK=#QTY_IN_STOCK#
WHERE PRODUCT_ID=#_PREV.PRODUCT_ID#</sql>
</update-item>
...
</server>
</properties>
</destination>
The server passes in the current value and the previous value from the client. If these are different, the parameters of
the SQL statement are replaced and the update against the database is executed. If these are different, then the server
value could have changed. The item is retrieved from the database using the get-item query defined in the
destination. You can use _PREV to reference the previous version of the object.
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The following example shows the Flex client-side ActionScript code for an updateItem operation:
...
cursor.current.last_name = lastName.text;
cursor.current.first_name = firstName.text;
ds.commit();
...
Configuring a count operation
You configure a count operation in a count element in the server section of a destination definition. The count
element contains a name element and a sql element or a statement element, depending on whether you are using a
single SQL statement or a stored procedure. The SQL code indicates properties from the object to use with
#propName#.
The following example shows a count element:
<destination id="sql-product">
<adapter ref="java-dao"/>
<properties>
...
<server>
...
<count>
<name>all</name>
<sql>SELECT count(*) FROM PRODUCT</sql>
</count>
</server>
</properties>
</destination>
In a Flex client application, the DataService.count() method execution and definition are similar to those of the
DataService.fill() method. You can define multiple SQL statements in the definition. The statement that you use,
and its parameters, are passed during the count method execution.
The following example shows a simple use of the DataService.count() method:
ds.count(named-sql-query, parameters);
The following example shows a more complex use of the DataService.count() method:
var countToken:AsyncToken = ds.count("firstNamedCount", parameters);
public function firstNamedCountResultHandler(event):void
{
var count:int = event.result;
}
Using server-side logging with the SQL Assembler
The SQL Assembler logs messages through the server-side logging system that is configured in the services-config.xml
file. To log SQL Assembler messages, use the Service.Data.SQL filter pattern or a wildcard pattern. For information
about server-side logging, see “Logging” on page 420.
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The Hibernate assemblers
The Hibernate assemblers are Java assembler classes that you use with the Java adapter to provide a bridge to a
Hibernate object/relational persistence and query service. Hibernate provides a persistence mechanism to facilitate
data access with a server-side database. There aretwo Hibernate assemblers, the Hibernate Assembler and the
Hibernate Annotations Assembler. You configure the Hibernate Assembler in configuration files. You configure the
Hibernate Annotations Assembler in Hibernate annotations.
You create Hibernate mappings to describe how the data represented by a Java object maps to the columns of a
database table. LiveCycle Data Services lets you define mappings in two ways: by using Hibernate mapping files or by
using Hibernate annotations.
A mapping file is an XML file that you deploy on your server with a Java class file. Annotations are metadata that you
insert in a Java source code file so that they are compiled into the Java class file. For either of these mapping types, you
use the Hibernate global configuration file to specify connection information to the database associated with the Java
object.
After you define your mappings and create the Hibernate configuration file, you create a LiveCycle Data Services
destination that references a Hibernate Assembler. The assembler class that you use depends on how you define your
mappings. Use the HibernateAssembler class with a mapping file and the HibernateAnnotationsAssembler class with
annotations.
The Data Management Service count(), get(), create(), update(), and delete() methods correspond to
Hibernate operations of similar names and behavior, and they require no configuration other than the configuring the
Hibernate mappings. Any named queries you define in your Hibernate configuration file are directly exposed as
queries to Flex clients with no additional configuration as long as the user is authorized to execute queries for this
destination based on any read-security-constraint you have set.
For more information on Hibernate, see the Hibernate website at http://www.hibernate.org.
Configuring your system for Hibernate
By default, a LiveCycle Data Services web application is not configured to support Hibernate. Before you can run an
application that uses Hibernate, copy all JAR files from install_root]/resources/hibernate to the WEB-INF/lib directory
of your web application.
The Hibernate Assembler supports Hibernate 3.0 and later. Using this assembler, you do not need to write DataManagement-specific Java code to integrate with Hibernate.
Hibernate configuration files
Hibernate uses two types of configuration files: the global configuration file and mapping files. The global
configuration file, hibernate.cfg.xml, contains declarations for database settings and behaviors. The mapping file
contains declarations for how Java classes and fields map to database tables and columns.
Note: You do not use mapping files if you use Hibernate annotations.
Hibernate requires that the files be accessible in the web application classpath. Place the hibernate.cfg.xml file in the
WEB-INF/classes directory and any mapping files in the same directory as the corresponding Java class file.
The following example hibernate.cfg.xml file defines the access to a database and references a single annotated Java file
named Contact:
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<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings. -->
<property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
<property name="connection.url">
jdbc:hsqldb:hsql://localhost:9002/flexdemodb
</property>
<property name="connection.username">sa</property>
<property name="connection.password"></property>
<!-- JDBC connection pool (use the built-in). -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect. -->
<property name="dialect">org.hibernate.dialect.HSQLDialect</property>
<!-- Enable the Hibernate automatic session context management. -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache. -->
<property name="cache.provider_class">
org.hibernate.cache.NoCacheProvider
</property>
<!-- Echo all executed SQL to stdout. -->
<property name="show_sql">true</property>
<!-- Drop and recreate schema -->
<property name="hbm2ddl.auto">create</property>
<!-- Load the annotated Java class. -->
<mapping class="flex.samples.contactannotate.Contact"/>
</session-factory>
</hibernate-configuration>
Supported Hibernate data retrieval methods
The Hibernate assemblers currently support the following ways to retrieve data from Hibernate:
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Hibernate feature
Description
load and get
Retrieves a single object by identity.
The Data Management Service getItem() functionality corresponds to the
Hibernate get functionality. The Hibernate Assembler does not use the load
method.
Hibernate Query Language (HQL)
Retrieves a list of items based on an HQL query.
You can configure the Data Management Service fill functionality to recognize
fill arguments as HQL query strings along with a map of parameters.
To use HQL queries from your client code, set
<allowhqlqueries>true</allowhqlqueries>---- in the fillconfiguration section.
Note: By allowing clients to specify arbitrary HQL queries, you are exposing a
potentially dangerous operation to untrusted client code. Clients may be able
to retrieve data you did not intend for them to retrieve or execute queries that
cause performance problems in your database. Adobe recommends that you
use the HQL queries for prototyping, but replace them with named queries
before your deploy your application, and use the default setting
<allowhqlqueries>false</allow-hql-queries>-- in your production
environment.
When allow-hql-queries is set to true, the first parameter to the fill()
method is the string token "flex:hql", the second parameter is the HQL
string and the third parameter specifies the parameter set for the queries as
either an array or a java.util.Map. The client-side DataService.fill()
method looks similar to the following example:
myService.fill(myCollection, "flex:hql", "from Person p
where p.firstName = :firstName", {firstName:"Paul"});
The last parameter contains the parameter name and value bindings for the
query. The preceding example uses named parameters.
Positional parameters are also supported; that is, you could write the HQL string
as follows:
myService.fill(myCollection, "flex:hql", "from Person p where p.firstName = ? ",
["Paul"]);
In that case, the last parameter is an array of values instead of a map of values.
The use of positional parameters instead of named parameters is considered a
less reliable approach, but both approaches are supported.
Named Hibernate queries
In Hibernate, you configure a named query by using the Hibernate
configuration element named query. You can then call this query from a Flex
client by passing the name of the Hibernate query as the second argument to a
DataService.fill() method. As with HQL queries, if the Hibernate query is
using named parameters, you specify the parameters on the client with an
anonymous object that contains those parameters. If your Hibernate query is
using positional parameters, you provide an array of parameters. The following
example shows a fill() method that uses a named query:
myDS.fill(myCollection,
"eg.MyHibernateEntity.myQueryName",
myQueryParameterObjectOrArray);
About the Hibernate assemblers
The Hibernate assemblers are specialized Java assembler classes that you use with the Java adapter to provide a bridge
to the Hibernate object/relational persistence and query service. The Hibernate Assemblers use the Hibernate
configuration files at run time to help define the data model and use Hibernate APIs to persist data changes into a
relational database. Hibernate operations are encapsulated within the assembler.
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The Hibernate assemblers uses the Hibernate mappings to expose named queries to client-side code. Your client code
can provide parameters to these queries by using fill parameter arguments. You can also optionally allow clients to use
HQL queries by setting the allow-hql-queries- element to true in the destination configuration.
Note: If you use the allow-hql-queries option, you expose arbitrary queries that can be executed by untrusted code.
Use this option only for prototyping and switch to named queries before deploying your production application.
Flex supports Hibernate version or timestamp elements for automatic concurrent conflict detection in Hibernate
entity mappings. If these settings are used in a Hibernate configuration file, they take precedence over any
update/delete conflict modes defined. A warning is logged that the automatic Hibernate conflict detection is used if
conflict modes are defined.
The Hibernate assemblers does not support criteria-based queries but you can extend the
flex.data.assemblers.HibernateAssembler class and expose whatever queries you like by writing some additional Java
code. This class is documented in the LiveCycle Data Services Javadoc API documentation and the source code for the
HibernateAssembler is included with the product.
To expose custom handling of type mappings on query parameter bindings, Flex honors the Hibernate type mappings
provided in the Hibernate configuration file for a persistent Java object. The values for the type attribute are treated
as Hibernate types that map Java types to SQL types for all supported databases.
The basic steps that you use to integrate Hibernate into your application are as follows:
1 Create mappings, either using mapping files or annotations. For more information, see “Using Hibernate mapping
files” on page 281 and “Using Hibernate annotations” on page 284.
2 Edit the global Hibernate configuration file, hibernate.cfg.xml, to define the database connection and to specify the
Java classes that support Hibernate. For more information, see “Hibernate configuration files” on page 278.
3 Define an adapter that uses the JavaAdapter. To use the Hibernate Assembler, specify an instance of the Java
adapter. For more information, see “Using Hibernate mapping files” on page 281.
4 Define a LiveCycle Data Services destination that references the Hibernate Assembler in the data-management-
config.xml file. For more information, see “Configuring destinations to use Hibernate” on page 290.
Using Hibernate mapping files
A Hibernate mapping file contains declarations for how Java classes and fields map to database tables and columns.
The Data Management Service must have access to this file at run time. Hibernate requires that the file be accessible
in the web application classpath.
Example using Hibernate mapping files
The Test Drive example in the lcds-samples\hibernate directory uses a Hibernate mapping file with a Java class. In that
example, the Java class is named Contact.java, and the associated mapping file is named Contact.hbm.xml. When you
deploy the compiled Contact.class file, you deploy the mapping file to the same directory. In this example, the
deployment directory is lcds-samples\WEB-INF\classes\flex\samples\contact.
You can view the application by requesting the following URL:
http://localhost:8400/lcds-samples/hibernate/index.html
Note: Before you run this application, make sure that you configure your system as described in the section “Configuring
your system for Hibernate” on page 278, and remove the comments from the hibernate-contact destination in the
lcds-samples\WEB-INF\flex\data-management-config.xml file.
The following example shows the mapping file, Contact.hbm.xml:
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<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="flex.samples.contact.Contact" table="contact">
<id name="contactId" column="contact_id">
<generator class="native"/>
</id>
<property name="firstName" column="first_name"/>
<property name="lastName" column="last_name"/>
<property name="address"/>
<property name="city"/>
<property name="state"/>
<property name="zip"/>
<property name="country"/>
<property name="phone"/>
<property name="email"/>
<property name="notes"/>
</class>
<query name="all">From Contact</query>
</hibernate-mapping>
The Contact.hbm.xml file contains the following information:
• The class element specifies the name of the associated Java class and database table.
• The id element specifies the property that corresponds to the primary key of the database table.
• The property elements associate a property of the Java class with a column in the database table. Use the column
attribute with the firstName and lastName properties to specify the column in the database table corresponding to
those properties. This configuration is necessary because the column name does not match the property name.
None of the remaining properties requires the column attribute because the column name in the database table
matches the property name.
• The query element specifies the named query used to populate the Java object from the database.
To connect to the Java class and use the associated Hibernate mappings, edit the data-management-config.xml file
to define an adapter that uses the JavaAdapter and a destination that uses the HibernateAssembler. The following
example shows an excerpt from the data-management-config.xml file:
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<adapters>
<adapter-definition id="actionscript"
class="flex.data.adapters.ASObjectAdapter"
default="true"/>
<!-- Define an adapter that uses the JavaAdapter. -->
<adapter-definition id="java-dao"
class="flex.data.adapters.JavaAdapter"/>
</adapters>
<destination id="hibernate-contact">
<!-- Reference the JavaAdapter. -->
<adapter ref="java-dao"/>
<properties>
<use-transactions>true</use-transactions>
<!-- Specify the HibernateAssembler. -->
<source>flex.data.assemblers.HibernateAssembler</source>
<scope>application</scope>
<network>
<paging enabled="false" pageSize="10" />
</network>
<server>
<!-- Specify the Java class. If this is not specified,
it defaults to the destinationId-->
<item-class>flex.samples.contact.Contact</item-class>
<fill-configuration>
<use-query-cache>false</use-query-cache>
<allow-hql-queries>true</allow-hql-queries>
</fill-configuration>
</server>
</properties>
</destination>
Use the metadata element to specify managed association elements, such as the page-size, load-on-demand,
one-to-many, many-to-one, or other options that differ from the default determined from the hibernate
configuration. For more information on the metadata element, see “Hierarchical data” on page 293.
The <identity> child element of the metadata element specifies the primary key of the object. When working
with Hibernate Assemblers, the identity element is optional. If you omit the identity element, the metadata
section is automatically generated from the Hibernate configuration.
If you include the <identity> element, the property attribute must specify the name of a property in the Java class.
In this case, no default information is generated. Include the identity element when you want to take complete
control over the metadata section for your data type. You can then handle Hibernate associations without creating
associations in Data Management so that they are treated as value objects. This technique is an advanced use and
is not typically recommended.
Finally, create an instance of the DataService component in your client-side Flex application that references the
Hibernate destination:
<mx:DataService id="ds"
destination="hibernate-contact"
conflict="conflictHandler(event)"
autoCommit="false"/>
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Using Hibernate annotations
Hibernate annotations replace the Hibernate mapping file with metadata that you add to the Java source code file.
Annotations simplify your implementation because you do not have to maintain the mapping file separately from the
source code file. Instead, you include mapping information and source code in a single Java file.
Add annotations to your Java class
The general steps for using Hibernate annotations in a Java file are as follows:
1 Ensure that your system is configured to use Hibernate annotations as described in “Configuring your system for
Hibernate” on page 278.
2 Edit your Java class to import javax.persistence.*.
package flex.samples.contactannotate;
// Import JPA annotations.
import javax.persistence.*;
...
3 Add annotations to the Java class.
4 Compile the class, making sure to include ejb3-persistence.jar in the classpath. The ejb3-persistence.jar contains
the javax.persistence package. You copied ejb3-persistence.jar file to the WEB-INF/lib directory when you copied
all JAR files from install_root]/resources/hibernate to the WEB-INF/lib.
5 Edit hibernate.cfg.xml to add a mapping to the class file, as the following example shows:
<!-- Load the annotated Java class. -->
<mapping class="flex.samples.contactannotate.Contact"/>
Notice that you use the class attribute of the mapping element to specify the annotated class, rather than the
resource attribute to specify a mapping file.
6 Edit the data-management-config.xml file to define a destination that uses the HibernateAnnotationsAssembler
and specifies the Java class as the value of the item-class element.
Note: If you change anything in data-management-config.xml, you typically have to recompile your client-side
applications and restart your server-side application for the changes to take effect.
Example using Hibernate annotations
The following example modifies the Test Drive example in the lcds-samples/hibernate directory to replace the
Hibernate mapping file with annotations in the Java class.This example also shows how to modify the
hibernate.cfg.xml and data-management-config.xml files, and the Contact.as file of the client-side Flex code.
Create Contact.java
1 Create a directory for the annotated Java class named lcds-samples\WEB-INF\src\flex\samples\contactannotate.
2 Copy Contact.java from lcds-samples\WEB-INF\src\flex\samples\contact to contactannotate.
3 Edit contactannotate\Contact.java to perform the following:
• Rename the package to flex.samples.contactannotate to correspond to the new directory name.
• Add the import statement for the javax.persistence package.
• Add the @Entity and @Table annotations to specify the name of the database table.
• Add the @NamedQuery annotation to specify the query mapping for the database.
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• Add the @ID and @Column annotations to specify the property that corresponds to the primary key of the
database table.
• Add the
@Column annotations to the firstName and lastName properties to specify the column in the database
table corresponding to those properties. This configuration is necessary because the column name does not
match the property name. None of the remaining properties requires the @Column annotation because the
column name in the database table matches the property name.
The following code shows the modified Contact.java file:
package flex.samples.contactannotate;
// Import JPA annotations.
import javax.persistence.*;
// Map the @Entity class to the contact database table.
@Entity
@Table(name="contact")
// Create a query mapping.
@NamedQuery(name="all",query="From Contact")
public class Contact {
// Map the identifier property to the contactId column.
@Id @GeneratedValue
@Column(name="contact_id")
private int contactId;
@Column(name="first_name")
private String firstName;
@Column(name="last_name")
private String lastName;
private String address;
private String city;
private String state;
private String zip;
private String country;
private String email;
private String phone;
private String notes;
public String getAddress() {
return address;
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}
public void setAddress(String address) {
this.address = address;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public int getContactId() {
return contactId;
}
public void setContactId(int contactId) {
this.contactId = contactId;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getEmail() {
return email;
}
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public void setEmail(String email) {
this.email = email;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getNotes() {
return notes;
}
public void setNotes(String notes) {
this.notes = notes;
}
public String getPhone() {
return phone;
}
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public void setPhone(String phone) {
this.phone = phone;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
}
4 Change directory to lcds-samples.
5 Compile the class by using the following javac command:
javac -d WEB-INF/classes/ -cp WEB-INF/lib/ejb3-persistence.jar
WEB-INF/src/flex/samples/contactannotate/Contact.java
Edit hibernate.cfg.xml
The global Hibernate configuration file, hibernate.cfg.xml, specifies many Hibernate configuration options, including
the mapping property. Edit the lcds-samples\WEB-INF\classes\hibernate.cfg.xml file to perform the following:
• Use the mapping property and class attribute to specify the annotated Java class.
• Comment out the reference to the Contact mapping file.
The following code shows the hibernate.cfg.xml for this example, with the new mapping property:
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<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
<property name="connection.url">
jdbc:hsqldb:hsql://localhost:9002/flexdemodb
</property>
<property name="connection.username">sa</property>
<property name="connection.password"></property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.HSQLDialect</property>
<!-- Enable the Hibernate automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">
org.hibernate.cache.NoCacheProvider
</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and recreate schema -->
<property name="hbm2ddl.auto">create</property>
<!-- Add these lines to reference the annotated java file. -->
<!-- Load the annotated Java class. -->
<mapping class="flex.samples.contactannotate.Contact"/>
<!-- Add comments around these lines to remove the reference to the mapping file. -->
<!-- Load the database table mapping file -->
<!-- <mapping resource="flex/samples/contact/Contact.hbm.xml"/> -->
</session-factory>
</hibernate-configuration>
Create a destination that uses the annotated Java class
To use the annotated Java class, create a destination in the data-management-config.xml file named hibernate-contact
that uses the HibernateAnnotationsAssembler.
Note: If the data-management-config.xml file already contains a destination named hibernate-contact, comment it out.
Do not delete it because it is the destination used by the Hibernate example that uses a mapping file. For more
information on that example, see “Using Hibernate mapping files” on page 281.
The following example shows an excerpt from the data-management-config.xml file that defines the hibernate-contact
destination:
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<destination id="hibernate-contact">
<adapter ref="java-dao"/>
<properties>
<use-transactions>true</use-transactions>
<source>flex.data.assemblers.HibernateAnnotationsAssembler</source>
<scope>application</scope>
<network>
<paging enabled="false" pageSize="10" />
</network>
<item-class>flex.samples.contactannotate.Contact</item-class>
<server>
<fill-configuration>
<use-query-cache>false</use-query-cache>
<allow-hql-queries>true</allow-hql-queries>
</fill-configuration>
</server>
</properties>
</destination>
Edit Contact.as
Edit the lcds-samples\hibernate\src\Contact.as client-side source code file to use the annotated Contact class.
Contact.as contains the following line:
[RemoteClass(alias="flex.samples.contact.Contact")]
Change the name of the class to reflect the new directory location, as the following example shows:
[RemoteClass(alias="flex.samples.contactannotate.Contact")]
After you edit Contact.as, recompile the main application file, contactmgr.mxml. For more information on setting up
your development environment to compile the Test Drive examples, see “Building and deploying LiveCycle Data
Services applications” on page 9.
You can now view the application by requesting the following URL:
http://localhost:8400/lcds-samples/hibernate/index.html
Configuring destinations to use Hibernate
Create a destination in the data-management-config.xml or services-config.xml file to reference a Java class that uses
Hibernate. Typically, you use the data-management-config.xml file for all configuration related to Data Services.
The following example shows a destination that uses the HibernateAssembler. This HibernatePerson destination has
a many-to-one relationship with a HibernateGroup destination.
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<destination id="HibernatePerson" channels="rtmp-ac">
<adapter ref="java-adapter" />
<properties>
<source>flex.data.assemblers.HibernateAssembler</source>
<scope>application</scope>
<!-- Specify any managed association elements. -->
<metadata>
<many-to-one property="group"
destination="HibernateGroup" lazy="true"/>
<one-to-many property="friends" read-only="true" paged-collection="true"
destination="HibernatePerson" lazy="true"/>
</metadata>
<network>
<paging enabled="true" pageSize="10" />
</network>
<server>
<!-- If this element is not present, the adapter assumes that
the Hibernate entity has the same name as the destination id.
-->
<item-class>contacts.hibernate.Person</item-class>
<!-- Conflict modes determine whether to check for conflicts at all
and if so whether to check on changed properties only or whether
to verify that the client had correct data for the entire object.
Valid values for update-conflict-mode are none, property, and object.
Valid values for delete-conflict-mode are none and object.
-->
<update-conflict-mode>property</update-conflict-mode>
<delete-conflict-mode>object</delete-conflict-mode>
<fill-configuration>
<use-query-cache>false</use-query-cache>
<allow-hql-queries>true</allow-hql-queries>
</fill-configuration>
</server>
</properties>
</destination>
The following table describes each of the destination elements that are specific to the Hibernate Assembler. These
elements are children of the server element.
Element
Description
create-security-constraint
(Optional) Applies the security constraint referenced in the ref attribute to create
requests.
delete-conflict-mode
Verifies that delete data from a Flex client application is not stale. If omitted, no data
verification occurs.
Valid values are none and object. A data conflict results in a DataConflictEvent on
the client.
delete-security-constraint
(Optional) Applies the security constraint referenced in the ref attribute to delete
requests.
fill-configuration
(Optional) The allow-hql-queries child element determines whether HQL
queries can be used. The default value is false.
The use-query-cache element is an option to the Hibernate query method
which lets Hibernate cache queries. The default value is false.
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Element
Description
hibernate-config-file
(Optional) Location of Hibernate configuration file; default is to look for this file in
classpath.
item-class
(Optional) Exposes custom handling of type mappings on query parameter
bindings; LiveCycle Data Services honors the Hibernate type mappings provided in
the Hibernate configuration for a persistent Java object.
To gain access to the class metadata for such programmatic query creation and
parameter type mapping, you configure a destination with the name of the
Hibernate entity that represents the persistent Java object.
If omitted from the configuration, the Hibernate entity type is assumed to be the
same as the destination id.
metadata
(Optional) Specify managed association elements such as one-to-one, many-toone, many-to-many, and one-to-many. For more information, see “Hierarchical
data” on page 293.
You can also specify an identity element. If you include the identity element,
the property attribute must specify the name of a property in the Java class. Include
the identity element when you want to take complete control over the metadata
section for your data type. You can then handle Hibernate associations without
creating associations in Data Management configuration so that they are treated as
value objects. If you omit the identity element, the metadata section is
automatically generated from the Hibernate configuration.
page-queries-from-database
(Optional) If you set this element to true, the Hibernate Assembler only fetches the
pages of filled collections that clients have requested from the database. By default,
the assembler fetches all items in the queries from the database and pages them
out to the clients one page at a time. You might have to implement a COUNT
database query when you use this approach if your clients must know the size of
the query before they have paged in the last items.
source
Specifies the assembler class, either HibernateAssembler or
HibernateAnnotationsAssembler, which is the class that handles data changes.
These elements are subelements of the properties element.
scope
(Optional) Specifies the scope of the assembler; the valid values are application,
session, and request. The default value is application.
update-conflict-mode
Verifies that update data from a Flex client application is not stale. If omitted, no
data verification occurs. Valid values are none, property, and object. A data
conflict results in a DataConflictEvent on the client.
update-security-constraint
(Optional) Applies the security constraint referenced in the ref attribute to update
requests.
Note: if you declare a Hibernate destination in your data-management-config.xml file that has a reference to entities with
no destination, a destination is created automatically. Its name is the entity-name in the Hibernate configuration, which
is often the class name. This destination is not accessible directly to the client through fill calls unless it is explicitly
declared in the data-management-config.xml file. This prevents execution of queries against domain objects without the
an explicit decision to expose those queries.
Using server-side logging with the Hibernate assemblers
The Hibernate assemblers logs messages by using the server-side logging system that is configured through the
services-config.xml file. For information about server-side logging, see “Logging” on page 420. To log Hibernate
assembler messages, use the following log filter:
<filters>
<pattern>Service.Data.Hibernate</pattern>
</filters>
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The Model Assembler
The Model Assembler feature lets you generate Data Management Service destinations based on an application model
without writing any Java code. The generated server code uses the Hibernate object/relational persistence and query
service. It extends the Hibernate Assembler.
The Model Assembler logs messages through the server-side logging system that is configured in the
services-config.xml file. For information about server-side logging, see “Logging” on page 420. To log Model
Assembler messages, use the Services.Data.Fiber log filter pattern or a wildcard pattern.
More Help topics
“Model-driven applications” on page 326
Hierarchical data
The Data Management Service provides several ways to manage the hierarchical relationships among managed
objects. You can also mix different approaches in the same application, depending on your application requirements.
About hierarchical data
A hierarchical collection is hierarchical data that includes at least one complex object whose properties are not simple
primitive values. For example, consider a collection that contains a Person object that has an Address property, which
itself has street, city, and state properties.
There are three techniques for managing hierarchical data with the Data Management Service:
Hierarchical values approach A single Data Management Service destination manages an entire tree of data. In this
approach, you treat the complex property as a value object.
Managed associations approach You define a parent destination that has declared associations to child destinations,
which manage the values of the properties of the child objects. In this approach, the complex property references other
entities.
Note: You use the managed associations approach in model-driven development with the Model Assembler, but you do
not manually write Java code or configure destinations. Instead, you create associations in a data model and deploy the
model to the server. For more information, see “Model-driven applications” on page 326.
Query approach You implement a relationship between two objects using queries where one of the parameters of a fill
method defined in an assembler is the property defined as the identity property of the related object.
You can use one of these approaches, or you can combine approaches on a property-by-property basis.
In the hierarchical values approach and the managed associations approach, the parent destination returns the same
graph of objects from its fill invocation. However, in the hierarchical values approach, the adapter of the parent object
is responsible for saving the state of the entire complex property. The parent is also responsible for updating the entire
graph in response to a sync invocation; on any change, it receives the complete new graph for the object and updates
that graph with any changes.
For the managed associations approach, the parent destination manages the identity properties of the referenced child
objects and the relationship between the parent and child objects. The child assembler owns the state of the child
objects. A side benefit of using the managed association approach is that you can use destinations independently of
each other in one application, while using them together in another application.
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In the managed associations approach, the configuration for the parent destination contains an additional element that
defines an association for the child object that has its own destination. This association tag refers to the separate
destination that is responsible for managing the state of the child object.
When you use the hierarchical values approach or the managed association approach, you either mark each class in
the top-level object graph of managed classes with the [Managed] metadata tag or explicitly implement the
mx.data.IManaged interface. This ensures that the managed objects support the proper change events and that getter
methods for one-to-one association properties that are lazily loaded can throw ItemPendingErrors. For more
information about lazy loading and ItemPendingErrors, see “The managed association approach” on page 295.
The following example shows the code for an ActionScript class that uses the [Managed] metadata tag. This Employee
class is used in an ArrayCollection of Employees, which is used as a property of a Company class.
Note: You do not manually code managed ActionScript classes, such as the following class, when you use model-driven
development. Instead, ActionScript classes are generated automatically from a model file. For more information, see
“Model-driven applications” on page 326 and the Application Modeling Technology Reference.
package samples.crm
{
[Managed]
[RemoteClass(alias="samples.crm.Employee")]
public class Employee {
public var employeeId:int;
public var firstName:String = "";
public var lastName:String = "";
public var title:String = "";
public var phone:String = "";
public var email:String = "";
}
}
The following example shows a class that implements the mx.data.IManaged interface instead of using the [Managed]
metadata tag. When you implement mx.data.IManaged, you must support the mx.core.IUID interface, which requires
a uid property. You also must include the referenceIds and destination variables declared under the last
comment block in this class.
import
import
import
import
mx.core.mx_internal;
mx.data.Managed;
mx.data.IManaged;
mx.utils.UIDUtil;
[RemoteClass(alias="foo.bar.Customer")]
public class Customer implements IManaged {
public function Customer() {
super();
}
[Bindable(event="propertyChange")]
public function get firstName():String {
_firstName = Managed.getProperty(this, "firstName", _firstName);
return _firstName;
}
public function set firstName(value:String):void {
var oldValue:String = this._firstName;
_firstName = value;
Managed.setProperty(this, "firstName", oldValue, _firstName);
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}
// all implementors of IManaged must support IUID which requires a uid
// property
[Bindable(event="propertyChange")]
public function get uid():String {
// If the uid hasn't been assigned a value, just create a new one.
if (_uid == null) {
_uid = UIDUtil.createUID();
}
return _uid;
}
//
//
//
//
//
//
public function set uid(value:String):void {
_uid = value;
}
These are special requirements of any object that wants to be
"managed" by a DataService.
The referencedIds is a list of object IDs that belong to properties that
are lazily loaded.
The destination is used to look up metadata information about the
associations this object has been configured with on the server.
mx_internal var referencedIds:Object = {};
mx_internal var destination:String;
private var _firstName:String;
private var _uid:String;
}
Note: The referencedIds and destination variables in this example are in the mx_internal namespace, which Adobe uses
to mark things that may change in future versions of the Flex framework. Your inherited class or component may not
work with future releases of Flex.
The managed association approach
In the managed association approach, the parent destination is not responsible for processing updates for changes
made to properties of the child objects. It is only responsible for processing the changes to the identity property values
of children referenced by the parent. Suppose a Person object has an Address property. Using the hierarchical values
approach, the Person destination would handle a change to the city of a person address. However, in the managed
association approach, the Address destination would process a change to the city.
In the managed association approach, the Person destination would process a change if someone assigned an Address
with a different identity property to the Address property of the Person object. You can also configure whether the
relationship supports lazy loading of object graphs from the server to the client.
Note: You use the managed association approach with model-driven development. The Java code and configuration file
examples included here do not apply to model-driven development. For more information about using associations with
model-driven development, see “Model-driven applications” on page 326 and the Application Modeling Technology
Reference.
The destination relationships you configure can be unidirectional or bidirectional. When you configure destinations
in a configuration file, unidirectional relationships use the many-to-one, one-to-one, and one-to-many elements,
and bidirectional relationships use the many-to-many element. These managed association elements are subelements
of the metadata element, which is a supplement of the properties element.
Note: Managing a one-to-many relationship can require much more computation than managing a many-to-one
relationship.
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Some managed associations rely on database tables. To establish a many-to-many relationship between these tables,
create a join table rather than using a foreign key.
You set the read-only attribute of an association property to true for the inverse side of a two-way relationship. This
setting indicates that the assembler does not depend on the state of this property being populated, which ensures that
dependent items are created before independent items. Setting the read-only attribute to true does not mean that
you cannot edit the association value. Rather, it means that the association is read only with respect to the assembler,
which does not use that value to update the database. Instead, the assembler uses the other side of the relationship.
Managed association example
The Sales Builder sample application provides an example of a many-to-one relationship. On the Flex client side of the
application, a DataService component named account manages a collection of Account objects that works with a
destination named account on the server. The Account objects have a set of properties, including a salesRep
property of type SalesRep, which works with a destination named sales-rep on the server. The account destination
defines a many-to-one relationship to the sales-rep destination, so SalesRep changes, additions, or deletions are
propagated up to the corresponding Account object or objects to which the particular SalesRep objects belong.
The following example shows the source code for the Account class:
package com.salesbuilder.model
{
[Managed]
[RemoteClass(alias="com.salesbuilder.model.Account")]
public class Account
{
public var accountId:int;
public var name:String;
public var phone:String;
public var fax:String;
public var ticker:String;
public var ownership:String;
public var numberEmployees:int;
public var annualRevenue:Number = 0;
public var priority:int;
public var address1:String;
public var address2:String;
public var city:String;
public var zip:String;
public var notes:String;
public var url:String;
public var rating:int;
public var currentYearResults:Number = 0;
public var lastYearResults:Number = 0;
public var industry:Industry;
public var salesRep:SalesRep;
public var category:AccountCategory;
public var state:State;
}
}
The following example shows the source code for the SalesRep class:
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package com.salesbuilder.model
{
[Managed]
[RemoteClass(alias="com.salesbuilder.model.SalesRep")]
public class SalesRep
{
public var salesRepId:int;
public var firstName:String;
public var lastName:String;
public function get fullName():String
{
return firstName + " " + lastName;
}
}
}
On the server side, Java-based Account and SalesRep objects represent accounts and sales representatives. These
classes are mapped to the corresponding client-side Account and SalesRep objects.
Destination configuration
The following example shows relevant sections of the account and sales-rep destinations, including the
manytoone-- element in the account destination that defines the relationship between the destinations. The boldface
text highlights the configuration for the many-to-one relationship.
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...
<!-- account destination has a many-to-one relationship to the sales-rep destination -->
<destination id="account">
<properties>
<source>com.salesbuilder.assembler.AccountAssembler</source>
<scope>application</scope>
<metadata>
<identity property="accountId" undefined-value="0"/>
<many-to-one property="salesRep" destination="sales-rep" lazy="true"/>
<many-to-one property="industry" destination="industry" lazy="true"/>
<many-to-one property="category" destination="account-category" lazy="true"/>
<many-to-one property="state" destination="state" lazy="true"/>
</metadata>
<network>
<paging enabled="false" pageSize="10" />
</network>
</properties>
</destination>
<!-- sales-rep destination -->
<destination id="sales-rep">
<properties>
<source>com.salesbuilder.assembler.SalesRepAssembler</source>
<scope>application</scope>
<metadata>
<identity property="salesRepId" undefined-value="0"/>
</metadata>
<network>
<paging enabled="false" pageSize="10" />
</network>
</properties>
</destination>
The query approach
You can implement a relationship between two objects by using queries where one of the parameters of a fill()
method in the assembler is the identity property (defined in a destination definition in the
data-management-config.xml file) of the related object. The query approach is more efficient for large collections of
objects than the managed association approach. For example, it would make sense to use it if you have a Company
object that has a large number of Employee instances.
The following code from the CRM sample application shows the crm-company destination definition, which declares
the companyId property as the identity property:
<destination id="crm-company">
<adapter ref="java-dao" />
<properties>
<source>flex.samples.crm.company.CompanyAssembler</source>
<scope>application</scope>
<metadata>
<identity property="companyId"/>
</metadata>
...
</properties>
</destination>
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The following example shows the fill() method of the EmployeeAssembler class in the CRM application. The
boldface text highlights the part of the method that finds employees by company, based on the numeric
company.companyId property value provided in a client's fill request.
...
public Collection fill(List fillParameters){
if (fillParameters.size() == 0){
return dao.getEmployees();
}
String queryName = (String) fillParameters.get(0);
if (queryName.equals("by-name"))
return dao.findEmployeesByName((String) fillParameters.get(1));
if (queryName.equals("by-company"))
return dao.findEmployeesByCompany((Integer) fillParameters.get(1));
return super.fill(fillParameters); // throws a nice error
}
The boldface code in the following example is the corresponding client-side fill request that gets employees by
company:
private function companyChange():void {
if (dg.selectedIndex > -1)
{
if (company != companies.getItemAt(dg.selectedIndex))
{
company = Company(companies.getItemAt(dg.selectedIndex));
dsEmployee.fill(employees, "byCompany",
company.companyId);
}
}
}
The query approach to implementing a relationship has some characteristics that make it not appropriate for all
situations. When you change an employee companyId, the Data Management Service must update the results of the
fill methods affected by that change for clients that display the list of employees to be updated automatically. By default,
it uses the auto-refresh feature to re-execute every outstanding fill method that returns employees. You can adjust this
behavior to avoid re-executing these queries so aggressively, but that requires some additional coding in your
assembler.
The query approach also does not detect conflicts when you update that association. You would not want to detect a
conflict if two clients added an employee to the same company at roughly the same time, but you could want to detect
a conflict if two clients simultaneously update addresses for the same customer. With managed association properties,
you can use the Data Management Service conflict detection mechanism to detect data conflicts on the complete
contents of the collections; however, with a fill method, conflicts are only detected on the properties of the item, not
the filled collection the item was returned in.
The CRM application implements a relationship between companies and employees in the fill() method of the
EmployeeAssembler class. The source code for the Java assembler and DAO classes are in the
WEB_INF/src/flex/samples/crm directory of the lcds-samples web application.
Managing class hierarchies
If you have strongly typed Java classes that extend each other and you want to manage both the supertype and the
subtype, there are two strategies you can use. You can use the single destination approach in which one destination
manages the entire type hierarchy, or you can use the multiple destinations approach in which you define a separate
destination for each managed class in the hierarchy. You cannot mix these two approaches for the same class hierarchy.
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You can only use the single destination approach if all of the classes in the class hierarchy have the same association
properties. If a subclass introduces a new association, you define a separate destination for each concrete class in the
class hierarchy. In both strategies, the identity properties must be the same for all managed classes in the type
hierarchy. Additionally, in both approaches there must be ActionScript classes defined for each concrete Java class.
For the multiple destinations approach, you also specify the item-class element for each destination to refer to the
entity class name of the object associated with the destination. You should also specify the extends attribute of the
metadata element to refer to the super type destination. When using the multiple destinations approach, the following
rules apply:
• The fill or getItem method can return instances of the class defined for this association (if any) or any subclasses of
that destination.
• The updateItem, createItem, or deleteItem methods are called on the assembler defined for the most specific
destination defined for the given class.
• Subclasses automatically inherit identity properties and associations and do not have to be redeclared.
• If you do not define a separate assembler instance (using a source, or factory element), the assembler instance for
the extends destination is used for the child destination.
When you use the extends attribute of the metadata element in a destination, you use the item-class element to
bind each destination to a specific Java class; for information about the item-class element, see “Data Management
Service clients” on page 226. You also must have an ActionScript class mapped to each Java class so the type is
preserved as objects are sent to the client.
The instances returned by your assembler from a given destination should be instances managed by this destination
or the destination of a subtype. An extended destination inherits the identity properties and associations of its base
type. It can extend more than one destination, but those destinations must have the same identity properties.
If you want to use one assembler instance for an entire class hierarchy, make sure that you use the attribute-id
element so that each destination uses the same attribute name to store the class and also ensure the source and scope
properties are copied among the destinations.
Single destination approach for managing class hierarchies
The following examples show the source code of Java and ActionScript classes and destination configuration for the
single destination approach.
Foo.java
package samples.oneDestExtends;
public class Foo
{
public Foo() {}
public int id;
public int property1;
public int property2;
public Foo selfReference; // my store ref to instance of Foo or Bar
}
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Bar.java
public class Bar extends Foo
{
public int property3;
public int property4;
// NOTE: cannot add additional managed associations in the subclass using this approach
}
Foo.as
[Managed]
[RemoteClass(alias="samples.oneDestExtends.Foo")]
public class Foo implements java.io.Serializable
{
public function Foo() {}
public var id:int
public var property1:int
public var property2:int
public var selfReference:Foo;
}
Bar.as
[Managed]
[RemoteClass(alias="samples.oneDestExtends.Bar")]
public class Bar extends Foo
{
public function Bar()
{
super();
}
public var property3:int;
public var property4:int;
}
data-management-config.xml
...
<destination id="oneDestExtends.foo">
<properties>
<metadata>
<identity property="id"/>
<many-to-one property="selfReference" destination="oneDestExtends.foo"/>
</metadata>
<source>oneDestExtends.FooAssembler</source>
</properties>
</destination>
...
<!-- No destination required for Bar in this approach -->
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Multiple destination approach for managing class hierarchies
The following example code shows the Java class source code and destination configuration for an application that uses
the multiple destinations approach. In this case, a Node class has a ParentNode subclass. The Node class has an association
called parent of type ParentNode and the ParentNode class adds an association called children of type Node.
Node.java:
package samples.multiDestExtends;
public class Node implements java.io.Serializable
{
public Node() {}
public int id;
public ParentNode parent;
}
ParentNode.java:
public class ParentNode extends Node
{
// Contains either Node or ParentNode instances
public List children = new LinkedHashSet();
}
data-management-config.xml
...
<destination id="multiDestExtends.Node">
<properties>
<metadata>
<identity property="id" undefined-value="-1"/>
<many-to-one property="parent"
destination="multiDestExtends.ParentNode" lazy="true"/>
</metadata>
<item-class>samples.multiDestExtends.Node</item-class>
<source>samples.multiDestExtends.NodeAssembler</source>
<scope>application</scope>
</properties>
</destination>
<destination id="multiDestExtends.ParentNode">
<properties>
<metadata extends="multiDestExtends.Node">
<one-to-many property="children"
destination="multiDestExtends.Node" read-only="true"
lazy="true" page-size="2"/>
</metadata>
<item-class>samples.multiDestExtends.ParentNode</item-class>
<!-- inherits same assembler instance by default -->
</properties>
</destination>
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Node.as:
[RemoteClass(alias="samples.treepagingjdbc.Node")]
[Managed]
public class Node
{
public var id : int;
public var name:String;
public var parent:ParentNode;
public function Node()
{
super();
}
}
ParentNode.as
import mx.collections.ArrayCollection;
[RemoteClass(alias="samples.treepagingjdbc.ParentNode")]
[Managed]
public class ParentNode extends Node
{
public var children:ArrayCollection;
public function ParentNode()
{
super();
}
}
Data paging
Paging can drastically improve performance of applications by decreasing query times and reducing the amount of
consumer memory. LiveCycle Data Services supports three types of paging: client-to-server paging, server-to-datasource paging, and association paging.
With client-to-server paging enabled, the server reads a collection of objects in its entirety into server memory; the data
is then paged on demand to client applications. Server-to-data-source paging extends the benefits of paging to the
application data source so that pages are only read into server memory as they are needed. Association paging allows
you to bring associated objects to the client on demand.
Client-to-server paging
When client-to-server paging is enabled, the initial fill request from a client causes the assembler associated with a Data
Management Service destination to retrieve the entire collection of objects. The server then sends the first page of items
to the Flex client. As the client code tries to access ArrayCollection elements that are not resident, additional pages are
retrieved from the server.
To enable client-to-server paging when you are not using model-driven development, add a paging element to the
network properties section of your destination definition in the data-management-config.xml file. You can set the
default page size in the page-size attribute of the paging element.
The following example shows a destination definition with client-to-server paging enabled:
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<destination id="inventory">
<properties>
<source>flex.samples.product.ProductAssembler</source>
<scope>application</scope>
<metadata>
<identity property="productId"/>
</metadata>
<network>
<paging enabled="true" pageSize="10" />
</network>
</properties>
</destination>
To enable client-to-server paging and set the page size for model-driven development, set the paging-enabled and
the page-size annotations on an entity , as the following example shows:
<entity name="Book" persistent="true">
<annotation name="DMS">
<item name="paging-enabled">
true
</item>
<item name="page-size">
10
</item>
</annotation>
...
</entity>
Server-to-data-source paging
When the original fill query is resource-intensive or returns more results than are desirable to cache on the server, you
can extend paging from the Flex client all the way to the data source. In this case, the assembler retrieves items from
the data source one page at a time, and only when the client requests a page. This type of paging is called server-todata-source paging. This type of paging is only enabled if client-to-server paging is enabled.
When you use server-to-data-source paging, each time the client requests a page, the assembler is asked for that page
of items and the items are sent directly to the client. This type of paging is supported whether or not you set the
autoSyncEnabled property of the DataService component on the client to true. This configuration is partially
supported for the SQLAssembler. It is supported for the HibernateAssembler, and you can implement it with your own
Java Assembler implementation.
To enable server-to-data-source paging for the Hibernate Assembler, set the page-queries-from-database
attribute to true in the server properties of the destination. To enable server-to data source paging with the SQL
Assembler, set the page-query element to true. The page-query element is a child of the fill element.
The steps required to enable server-to-data-source paging for a custom assembler depend on whether the assembler
implements the flex.data.assemblers.Assembler interface. If your Assembler does implement this interface, you should
define the useFillPage(List fillParameters) method to return true for the fill parameters where you want to
extend paging to the data source. You then implement the fill(List fillParameters, int startIndex, int
numberOfRows) method to fetch subsets of your collection from your data source based on the startIndex and
numberOfRows parameters. The Data Management Service invokes this method with parameters to the pages that
clients request.
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If your assembler does not implement the flex.data.assemblers.Assembler interface, set the custom attribute of the
paging element to true in the network properties section of the destination definition in the datamanagement-config.xml file. Next, specify a fill method that matches the fill parameters used by your client with two
additional parameters: the start index and the number of items requested.
When you use server-to-data-source paging, your assembler must implement the count() method. For more
information, see “Data paging” on page 303.
When you enable paging for model-driven development, server-to-data-source paging is enabled by default. To
disable server-to-data-source paging for model-driven development, set the page-queries-from-database
annotation on an entity filter to false, as the following example shows:
<entity name="Book" persistent="true">
...
<filter>
<annotation name="DMS">
<item name="page-queries-from-database">
false
</item>
</annotation>
...
</filter>
...
</entity>
Dynamic sizing
When server-to-data-source paging is enabled, the server does not immediately know the total size of the collection
that is being paged because it is retrieving the collection one page at a time. To return the size of a data-source-paged
collection to the client, the Data Management Service invokes the count() method of the assembler after the client
makes its initial fill request. However, the count query is often almost as expensive as its corresponding select query.
The dynamic sizing option lets you avoid potentially expensive count queries.
To enable dynamic sizing when you are not using model-driven development, implement your count() method to
return -1 for appropriate fill parameters. With dynamic sizing, the paged fill method of the assembler is called with a
startIndex value of 0 and the number of items is set to the pageSize + 1. If the assembler method returns less than
the number requested, the size of the fill is known. If it returns the pageSize+1 items requested, pageSize items are
returned to the client but the client sets the collection size to pageSize + 1 with one empty slot at the end. When the
client requests that empty item, the next pageSize+1 items are requested and the process repeats until the assembler
returns less than pageSize+1 items.
If you are using the Hibernate assembler and the HQL query sent from the client is a simple query, the Hibernate
assembler attempts to implement a count query by modifying the query sent from the client. If you are using a named
query, the Hibernate assembler looks for a query named original-query-name.count. If that query exists, it uses it to
compute the size of the paged collection. Otherwise, it uses the dynamic sizing approach.
To enable dynamic sizing for model-driven development, set the dynamic-sizing annotation on an entity to true,
as the following example shows:
<entity name="Book" persistent="true">
<item name="dynamic-sizing">
true
</item>
...
</entity>
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Association property loading
The following options are available to control how the client loads association properties:
• Loading only the identity properties
• Not loading associated items until they are used
• Paging associated items
• Using paged updates
By default, the entire associated collection is sent to the client when the parent item is fetched. For general information
about association properties, see “Hierarchical data” on page 293.
Loading only the identity properties
To avoid loading entire associated items when the parent object is loaded, the Data Management Service provides the
lazy load option. With lazy loading, only the identity properties of the associated items are loaded with the parent
object. The associated items are passed to the client by reference (identity property) instead of by value (entire object).
When the client attempts to access an associated item for which it only has an identity property, an ItemPendingError
is thrown. For information about ItemPendingErrors, see “Item pending errors” on page 308.
When using lazy loading, the assembler only returns the identity properties of the referenced objects. It does not have
to fully populate these referenced objects.
If you are not using model-driven development, enable lazy loading by setting the lazy attribute of an association
element, such as a many-to-one, one-to-one, one-to-many, or many-to-many element, to true.
For model-driven development, enable lazy loading by setting the lazy annotation on an entity property to true, as
the following example shows:
<entity name="Book" persistent="true">
<property name="name" type="string">
<annotation name="DMS">
<item name="lazy">true</item>
</annotation>
...
</property>
</entity>
Not loading associated items until they are needed
When lazy loading is enabled, the assembler only has to fetch associated identity properties to satisfy a fill request.
Although using lazy loading lets you avoid retrieving entire associated objects, it can still be inefficient for large
association collections. To avoid loading an associated collection until it is needed on the client, the Data Management
Service provides the load-on-demand option.
When you set the load-on-demand to true on an association, the association property value is ignored from the initial
getItem() and fill() method calls. When the client first accesses the property, the getItem() method is called
again for the parent item, and this time the property value is fetched. If load-on-demand is enabled and lazy is set to
true for the association, when the associated property is first accessed only the identity properties of the items are
fetched and the getItem() method is called on each identity property as that item is needed. If load-on-demand is
enabled and lazy is set to false, the entire items are fetched when the association property is accessed.
For model-driven development, enable load-on-dmand by setting the load-on-demand annotation on an entity to
true, as the following example shows:
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<entity name="Book" persistent="true">
<annotation name="DMS">
<item name="load-on-demand">
true
</item>
</annotation>
...
</entity>
Paging associated items
For multi-valued association properties (for example, one-to-many and many-to-many properties), consider bringing
in associated items or their identity properties one page at a time, instead of the entire associated collection when it is
needed as load-on-demand lets you do. As with load-on-demand, the initial getItem() and fill() method calls do
not return any of the association property values to the client. When the property is accessed on the client, the
getItem() method is called again for the parent item. This time it must return a page of the associated collection. The
length is returned to the client and the page containing the requested item is also returned.
Like load-on-demand, association paging is set independently of the lazy property. If the lazy property is set to true
and either load-on-demand or paging is used, when the client attempts to access an item for which only the identity
property is available, another ItemPendingError is thrown and the item is retrieved in its entirety by invoking the
getItem() method.
To enable association paging between the client and the server when not using model-driven development, set the
page-size attribute of an association element in a destination to the desired value, as the following example shows:
<one-to-many property="members" destination="Person" page-size="3"/>
To enable server-to-data-source association paging when not using model-driven development, in addition to the
page-size attribute, set the paged-collection attribute of an association element in a destination to the desired
value as the following example shows. This setting lets you retrieve a subset of the collection from the assembler.
<one-to-many property="members" destination="Person" page-size="3" paged-collection="true"/>
For model-driven development, enable association paging by setting the page-size annotation of an association
property of an entity to true, as the following example shows:
<entity name="Company" persistent="true">
<property name="employee" type="Employee">
<annotation name="DMS">
<item name="page-size">5</item>
</annotation>
...
</property>
</entity>
For model-driven development, server-to-data-source association paging is enabled by default when you set the pagesize annotation. This is because, unlike custom assemblers, the Model Assembler is guaranteed to implement the
useFillPage(List fillParameters) method to return true for its fill parameters.
Using paged updates
The paged-updates Boolean attribute of an association property controls how changes are propagated between
clients and the server. When the paged-updates attribute is set to false (default value), the entire collection is sent
when the association value changes. When the paged-updates attribute is set to true, only the identity properties of
the newly added or removed items are sent.
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If the client uses paged updates to update a collection property, when those changes are committed to the server, the
updateCollectionProperty() method on the Assembler interface is invoked to update the collection property.
When association values are paged (page-size value is set to a value greater than zero), paged updates are
automatically enabled. However, enabling load-on-demand for associations does not automatically enable paged
updates.
For model-driven development, enable paged updates by setting the paged-updates annotation of an entity property
to true, as the following example shows:
<entity name="Company" persistent="true">
<property name="name" type="string">
<annotation name="DMS">
<item name="paged-updates">
false
</item>
</annotation>
...
</property>
</entity>
Paging and property specifiers
The PropertySpecifier object tells assembler operations, such as getItem(), fill(), and refreshItem() methods,
which properties of a data item to populate. When a client discovers that it has the identity property of an item locally
but not the entire item, it invokes a getItem() method on the server using the default property specifier. The default
property specifier denotes that load-on-demand and paged association properties are not required to be populated on
the item returned by the assembler for the getItem() call. As a result, you can code your custom assembler to skip
such properties in its implementation of the getItem(Map identity, PropertySpecifier ps) method when ps
is the default property specifier. Alternatively, your implementation of this method can invoke the Boolean
PropertySpecifier.includeProperty() method with a specific property name to determine whether the property
must be populated on this invocation of the getItem() method. You can use this method so that your assembler
behavior is not hard-coded to know the settings of the load-on-demand and page-size properties that you use for a
specific destination. For example, the implementation of the Hibernate assembler uses this variant to determine which
properties must be fetched, and it reacts to the configuration changes that you make without requiring code changes
to the assembler.
Item pending errors
When the Flex client accesses a lazily loaded value for the first time, an ItemPendingError is thrown either from the
ArrayCollection.getItem() method for multiple-valued associations or from the Managed.getProperty()
method for single-valued associations. This causes a request to fetch the referenced object, and an event handler in the
ItemPendingError is invoked to notify the client when the item is available. When you use Flex data binding, this
behavior happens automatically when you set the lazy attribute to true; the data appears when it is needed. If you do
not use data binding in conjunction with lazy loading, you can catch the ItemPendingError in your code and handle
it accordingly.
An ItemPendingError is thrown when retrieving an item from an ArrayCollection requires an asynchronous call.
When you bind a managed ArrayCollection to a List-based control other than a Tree control, itemPendingErrors are
handled automatically when you have the paging element set to true on the destination. If the receiver of this error
needs notification when the asynchronous call completes, it must use the addResponder() method and specify an
object that supports the mx.rpc.IResponder interface to respond when the item is available. The
mx.collections.ItemResponder class implements the IResponder interface and supports a data property.
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In the following example, an ItemPendingError is thrown and caught when a group object is not yet available to a
groupCollection object on the client. The groupCollection object is filled from the AssocGroup destination on the
server. The destination has an admin property that is a lazily loaded reference to an AssocPerson instance. The
printAdminName() method is called for the first group in the groupCollection object. If a group is not available, it
throws an ItemPendingError. An ItemResponder is registered to handle the ItemPendingError; the ItemResponder
calls the printAdminName() method when the group is available. If there is a fault, the ItemResponder calls the
fetchAdminError() method.
...
import mx.collections.ItemResponder;
import mx.messaging.messages.ErrorMessage;
import mx.collections.errors.ItemPendingError;
...
public function printAdminName (data:Object, group:Object):void {
trace(group.admin.firstName);
}
public function fetchAdminError(message:ErrorMessage):void {
trace("error occurred fetching admin: " + message.faultString);
}
// This method is called to retrieve a "group" object
// that has a lazily loaded reference to a Person in its admin property.
// The printAdminName function may throw the ItemPendingError
// when it retrieves the group.admin property if that object has
// not yet been loaded by the client.
// The function registers a listener that calls printAdminName
// again when the value is available.
public function dumpAdminName():void {
try {
printAdminName(null, groupCollection.getItemAt(0));
}
catch (ipe:ItemPendingError) {
trace("item pending error fetching admin.");
ipe.addResponder(new ItemResponder(printAdminName, fetchAdminError,
groupCollection.getItemAt(0)));
}
}
...
Hibernate association paging configuration
The following configuration example shows a Hibernate destination with a one-to-many element that has the
pagesize- attribute set to a nonzero value:
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<destination id="account.hibernate">
<adapter ref="java-dao" />
<properties>
<use-transactions>true</use-transactions>
<source>flex.data.assemblers.HibernateAssembler</source>
<scope>application</scope>
<metadata>
<identity property="id"/>
<one-to-many property="accountContacts" destination="accountContact.hibernate"
read-only="true" pageSize="2" />
<many-to-one property="consultant" destination="consultant.hibernate"
lazy="true" />
</metadata>
<server>
<hibernate-config-file>support-hibernate.cfg.xml</hibernate-config-file>
<hibernate-entity>support.Account</hibernate-entity>
<fill-configuration>
<use-query-cache>false</use-query-cache>
<allow-hql-queries>true</allow-hql-queries>
</fill-configuration>
</server>
</properties>
</destination>
Occasionally connected clients
Occasionally connected data management clients work with managed data in both online and offline states. You can
write an AIR-based (desktop) or browser-based clients that work online and offline. The offline cache stores the
managed items, destination metadata, executed fill membership, and the uncommitted messages along with conflicts.
When the application goes offline, the application maintains access to the data.
The client stores the contents of executed data management operations to disk for later retrieval when an application
resumes in online mode. The offline mode lets you create an application that can work when the host is shut down, a
network connection is unavailable, or the host is restarted with the application loaded.
There are three basic types of occasionally connected clients. From the most powerful to the least, the types of clients
are as follows:
• AIR-based client that uses a custom offline adapter
• AIR-based client with no custom offline adapter
• Browser-based (Flash Player) client that stores data in local shared objects (LSOs)
AIR-based clients
An AIR-based client with a custom offline adapter provides the best offline experience. This type of client works with
the AIR SQLite database to cache data and perform offline fill, commit, and delete operations when the client is
disconnected from the LiveCycle Data Services server.
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In the custom offline adapter, you write logic for SQL queries that retrieve locally cached items just as the Data
Management Service assembler retrieves items from the data source on the server. Unlike the other types of
occasionally connected clients, this type gives you full query capabilities; you can perform offline fill operations on
locally cached data whether or not the same fill operations have already been performed while online and cached
locally. The local data store is not just a cache of data that the client has already requested, but is a true local data store
that is actively populated with data from the server.
Clients that do not use custom offline adapters only cache data that the user has already accessed while connected to
the server. That works well for providing the same data back to the user for the same queries when the application goes
offline, but not for performing offline queries that have not yet been cached.
When you do not use an offline adapter for an AIR-based client, data is stored in the AIR SQLite database in binary
large object (BLOB) format. This type of client can only perform operations that have already been performed online
and cached locally.
Note: When using a SQLite offline adapter, you can use an encrypted SQLite database to ensure that data is unavailable
to all other users and applications running on the same machine. To encrypt the generated SQLite database, set the
DataService.encryptLocalCache property to true. The database is encrypted with a random encryption key and
password using the SQLite encryption feature. The password is stored locally using AIR EncryptedLocalStore support,
associated with the database name.
Browser-based clients
In the case of browser-based clients, local data is stored in local shared objects (LSOs) in BLOB format. Similar to an
AIR-based client without a custom offline adapter, this type of client can only perform operations that have already
been performed online and cached locally.
Another limitation of this type of client is that the LSO database does not support concurrent writes. This results in an
error when you try to save data to the LSO database when a save is already in progress.
Working with data offline
For all occasionally connected clients, you use a common set of APIs to create a local data store, cache data locally,
connect to the server destination, and inspect the data cache.
For an AIR-based client that uses a custom offline adapter, you also create an offline adapter and set the
DataService.offlineAdapter property in your client application code. For more information, see “Using an offline
adapter with an AIR-based client” on page 317.
Creating a local data store
Set the DataService.cacheID property to store data locally. The cacheID property is a string that provides an
identifier for locally stored data.
If two clients use different cacheID values, they use independent cached stores of data. If they use the same value for
the cacheID property, they share the same store of data. In general, it is not a good practice to run two clients at the
same time using the same cacheID value. A cacheID value of null or an empty string is considered unset. If you do
not set the cacheID property, all cache methods and properties are considered inconsistent and throw errors.
You can change the value of the cacheID property during an application's operation. When changed, the current state
of the data is flushed to local storage. All currently loaded data remains in memory, letting you selectively add or
remove cached data stored on disk using the new identifier. This results in copy-on-write behavior if you set the
DataService.autoSaveCache property to true.
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Call the DataService.getCacheIDs() method to retrieve all cacheID values used for a single application. When two
or more AIR applications run under the same domain and use the same cacheID value, changes are reflected in all
instances as if they are the same application. This mechanism bypasses conflict detection between the running
instances; there can be no conflicts between applications for any changes made locally.
The following creationComplete() event handler for a DataGrid control sets the cacheID property.
Note: For an AIR-based client that uses a custom offline adapter, you would set the DataService.offlineAdapter property
in addition to the properties shown here. For more information, see “Using an offline adapter with an AIR-based client”
on page 317.
< mx:Script>
<![CDATA [
...
protected function
dataGrid creationCompleteHandler(event:FlexEvent):void
{
// Create a DataService instance.
var myDataService:DataService = new DataService("destination1");
// Set the unique ID for the local data store.
myDataService.cacheID = "cache1";
// Save the cache automatically when online.
myDataService.autoSaveCache = true;
// If working offline don't attempt to connect to the server.
myDataService.autoConnect = false;
// Query against the local store when not connected.
myDataService.fallBackToLocalFill=true;
// Perform a fill operation.
myDataService.fill(users, "notorious");
}
]]>
</mx:Script>
Caching data locally
Set the DataService.autoSaveCache property to true to automatically cache data locally. The default value is
false. Set autoSaveCache to true to save data locally after any change, including creates, reads, updates, deletes,
page requests, and lazy loading. For information about lazy loading, see “The managed association approach” on
page 295.
The following creationComplete() event handler for a DataGrid control sets the cacheID property.
Note: For an AIR-based client that uses a custom offline adapter, you would set the DataService.offlineAdapter property
in addition to the properties shown here. For more information, see “Using an offline adapter with an AIR-based client”
on page 317.
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< mx:Script>
<![CDATA [
...
protected function
dataGrid creationCompleteHandler(event:FlexEvent):void
{
// Create a DataService instance.
var myDataService:DataService = new DataService("destination1");
// Set the unique ID for the local data store.
myDataService.cacheID = "cache1";
// Save the cache automatically when online.
myDataService.autoSaveCache = true;
// If working offline don't attempt to connect to the server.
myDataService.autoConnect = false;
// Query against the local store when not connected.
myDataService.fallBackToLocalFill=true;
// Perform a fill operation.
myDataService.fill(users, "notorious");
}
]]>
</mx:Script>
Fill parameters identify the items in a fill request. In the preceding example, the key for the list of items returned in the
fill request is notorious. When the application is reloaded in a disconnected state, it requests the items with the key
value of "notorious" from the local store.
If you set the autoSaveCache property to false, you can call the DataService.saveCache() method to manually
save data to the local file system. The saveCache()method lets you control the timing of save operations. Use it to
force a save of the current state of the cache to local storage. You can specify an optional parameter to provide further
granularity over what is stored locally; the parameter must be a managed ArrayCollection or a managed item.
Call the DataService.clearCache()method to remove all locally stored data associated with the DataService
instance. The clearCache() method takes an optional parameter to remove a specific piece of data from the local
cache.
The following example shows the DataService saveCache() and clearCache() methods with an ArrayCollection as
a parameter:
<mx:Application creationComplete="loadData()">
<mx:DataService id="usersOfD" destination="D" />
<mx:DataGrid id="usersGrid" dataProvider="{users}">
</mx:DataGrid>
<mx:Button label="Save"
click="usersOfD.saveCache(ArrayCollection(usersGrid.dataProvider))"/>
<mx:Button label="Clear"
click="usersOfD.clearCache(ArrayCollection(usersGrid.dataProvider))" />
<mx:Script>
<![CDATA[
[Bindable]
private var users:ArrayCollection;
...
private function loadData(){
usersOfD.fill(users);
}
...
]]>
/mx:Script>
</mx:Application>
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In the preceding example, the users are loaded when the application is initialized by calling the fill() method of the
usersOfD service. Clicking the Save button calls the saveCache() method to pass in the users ArrayCollection. The
items of the collection are stored to the local store.
Clicking the Clear button calls the clearCache() method to pass in the same users ArrayCollection. The items of
the collection are removed from the local store. Since this collection was the only data stored locally, no data remains
in the local store.
Disabling connection attempts and performing local fills
You can use the combination of the DataService.autoConnect property and the
DataService.fallBackToLocalFill property to disable connection attempts and perform local fill requests.
Set the autoConnect property to false so that operations that require a connection do not fault when the DataService
instance is disconnected unless there is problem loading data from the local cache. When you also set the
fallBackToLocalFill property to true, the DataService instance makes local fill requests when not connected to the
server.
The following creationComplete() event handler for a DataGrid control sets the autoConnect property to false and
the fallBackToLocalFill property to true.
Note: For an AIR-based client that uses a custom offline adapter, you would set the DataService.offlineAdapter property
in addition to the properties shown here. For more information, see “Using an offline adapter with an AIR-based client”
on page 317.
< mx:Script>
<![CDATA [
...
protected function
dataGrid creationCompleteHandler(event:FlexEvent):void
{
// Create a DataService instance.
var myDataService:DataService = new DataService("destination1");
// Set the unique ID for the local data store.
myDataService.cacheID = "cache1";
// Save the cache automatically when online.
myDataService.autoSaveCache = true;
// If working offline don't attempt to connect to the server.
myDataService.autoConnect = false;
// Query against the local store when not connected.
myDataService.fallBackToLocalFill=true;
// Perform a fill operation.
myDataService.fill(users, "notorious");
}
]]>
</mx:Script>
Request parameters identify the items in a request. In the preceding example, the key for the list of items returned in
the fill request is notorious. When the application is reloaded in a disconnected state, it requests the items with the
key value of "notorious" from the local store.
The DataService.connect() method corresponds to the autoConnect property. The connect() method lets you
control the timing of a reconnect attempt when the autoConnect property is set to false. The DataService instance
always attempts to load any local data before attempting to establish a connection and satisfy a fill() or getItem()
request. Setting the autoConnect property to false prevents any attempts to connect with the remote destination.
Changing the value to true is equivalent to calling the connect() method. This behavior lets you use data binding to
establish the connectivity of an application using a user interface component such as a CheckBox.
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If there is a connection available after the local cache is loaded, the current value of the reconnectPolicy property
determines how a request for the current data is made. If the reconnectPolicy property is set to IDENTITY, no
request for remote data is made because it is assumed that the data is up-to-date. If the reconnectPolicy property is
set to INSTANCE, a request for the remote data is made and the result of that fill is used to overwrite the current inmemory version. In this situation, if the autoSaveCache property is set to true when the new data is returned, it is
saved to local storage overwriting the previous version.
For paged and lazily loaded data, each time a request is satisfied, the results are stored locally when the autoSaveCache
property is set to true. To make all of the data available offline for a paged result set, call the createCursor() method
of the ArrayCollection you using and then call the cursor’s seek() method, specifying a prefetch value of the entire
length.
When a client tries to commit stale data from changes made offline, the assembler on the server can use the old and
new versions of the object to report a conflict.
Note: Run-time configuration information is saved to the local cache when present during a save, and is restored during
initialization if a connection cannot be established. For more information about run-time configuration, see “Run-time
configuration” on page 411.
Inspecting the data cache
You use the mx.data.CacheDataDescriptor class to inspect the various attributes of offline cached data. This class
contains the following properties: lastAccessed:Time, lastWrite:Time, creation:Time, metadata:Object, and
id:Object.
The DataService class contains the following related methods: getCacheDescriptors(), getCacheData(), and
clearCacheData().
The getCacheDescriptors() method returns an ICollectionView of CacheDataDescriptor instances describing
the attributes for all of the cached data. If a managed ArrayCollection or a managed item is specified, the collection
returned contains only a single CacheDataDescriptor specific to the specified argument. The getCacheData()
method returns the collection or item data based on the specified cache descriptor. The returned value is pulled directly
from the local cache and is not managed. Additionally, a new instance of the collection or object is returned on each
call. Calling the clearCacheData() method removes the associated data from the local store for the descriptor
specified.
The following example shows an application that inspects the data cache. In this example, all of the cached collection
and item information is returned for the usersOfD service. The metadata property is set as a string that contains a
descriptive name for the cached data. The grid displays the descriptive name along with the last accessed, creation, and
last updated times.
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<mx:Application creationComplete="displayCacheInfo()">
<mx:DataService id="usersOfD" destination="D" />
<mx:DataGrid id="cachedDataInfo" dataProvider="{cacheInfo}"
change="updateDisplay()">
<mx:columns>
<mx:DataGridColumn headerText="Name" dataField="metadata" />
<mx:DataGridColumn headerText="Last Accessed"
dataField="lastAccessed"/>
<mx:DataGridColumn headerText="Created" dataField="created" />
<mx:DataGridColumn headerText="Last Updated" dataField="lastWrite"/>
</mx:columns>
</mx:DataGrid>
<mx:DataGrid id="dataDisplay" dataProvider="{cacheData}"/>
<mx:ArrayCollection id="cacheData"/>
<mx:Script>
<![CDATA[
[Bindable]
private var cacheInfo:ArrayCollection;
private function displayCacheInfo(){
usersOfD.getCacheDescriptors(cacheInfo, CacheDataDescriptor.FILL);
}
private function updateDisplay():void{
var token:AsyncToken =
usersOfD.getCacheData(cachedData.selectedItem);
token.addResponder(new AsyncResponder(
function (event:ResultEvent, o:Object):void{
cacheData = ArrayCollection(event.token.result);
},
function (event:FaultEvent, o:Object):void{
Alert.show("Could not load cache data");
}));
}
]]>
</mx:Script>
</mx:Application>
The following example shows an application in which all of the cached collection and item information is returned for
the usersOfD service. The metadata property is set to a string that contains a descriptive name for the cached data.
The DataGrid displays the descriptive name along with the last accessed, creation, and last updated times. When the
user selects an item and clicks the Remove button, the selected item (CacheDataDescriptor) is used first to access the
existing data from the cache if it is not already loaded, and then to pass that item to the clearCacheData() method,
which removes it from the local cache.
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<mx:Application creationComplete="displayCacheInfo()">
<mx:DataService id="usersOfD" destination="D" />
<mx:DataGrid id="cachedData" dataProvider="{cacheInfo}">
<mx:columns>
<mx:DataGridColumn headerText="Name" dataField="metadata" />
<mx:DataGridColumn headerText="Last Accessed"
dataField="lastAccessed"/>
<mx:DataGridColumn headerText="Created" dataField="created"/>
<mx:DataGridColumn headerText="Last Updated" dataField="lastWrite"/>
</mx:columns>
</mx:DataGrid>
<mx:Button label="Remove"
click="removeFromCache(cachedData.selectedItem)"/>
<mx:Script>
<![CDATA[
[Bindable]
private var cacheInfo:ArrayCollection;
private function displayCacheInfo(){
usersOfD.getCacheDescriptors(cacheInfo);
}
private function
removeFromCache(descriptor:CacheDataDescriptor):void{
var token:AsyncToken = usersOfD.getCacheData(descriptor);
token.responder = new AsyncResponer(
function (result:ResultEvent, o:Object):void{
usersOfD.clearCacheData(descriptor);
},
function (fault:FaultEvent, o:Object):void{
Alert.show("Failed to get specified cache data");
}));
}
]]>
</mx:Script>
</mx:Application>
Using an offline adapter with an AIR-based client
To get the best occasionally connected client experience, use an AIR-based client with a custom SQLite offline adapter.
In the custom offline adapter, you write logic for SQL queries that retrieve locally cached items in a way similar to how
a Data Management Service assembler retrieves items from the data source on the server.
When using a SQLite offline adapter, high-level offline persistence behavior, such as how fills are replayed, is the same
as in LiveCycle Data Services 3. However, the persistence format differs for AIR clients. Instead of persisting each item
as a BLOB on each row in the item's SQLite table, each has a column for each of its properties. This makes it easier to
view and manipulate client-side data.
To migrate to the SQLite adapter functionality, existing clients must recreate their caches. For migrated clients, it is
possible that differences in persistence can lead to subtle differences in behavior. If this happens, you can revert to the
Livecycle Data Services 3 persistence format by making a declaration on the DataService instance to explicitly set the
offline adapter to a DataServiceOfflineAdapter instance instead of a SQLiteOfflineAdapter instance, as the following
code shows:
DataService.offlineAdapter = new DataServiceOfflineAdapter();
Note: You can use model-driven development to build this type of client; for more information, see “Building an offlineenabled application” on page 333.
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The custom offline adapter must extend the mx.data.SQLiteOfflineAdapter class, which provides SQLite offline query
capabilities for AIR clients that use data management. The custom class must override the getQueryCriteria()
method and can also override the getQueryCriteriaParameters() and getQueryOrder() methods of the
SQLiteOfflineAdapter class.
The following table describes the SQLiteOfflineAdapter methods.
Method
Description
getQueryCriteria()
Defines the SQL WHERE clause.
getQueryCriteriaParameters()
Defines the parameters of SQL WHERE clause.
getQueryOrder()
Defines the SQL ORDERBY clause.
The SQLite table for a particular destination is named Entity_destination. The table column names match the entity
property names, unless they conflict with a SQLite keyword, in which case a _ is prepended to the name.
The following example shows a custom offline adapter named ProductOfflineAdapter that overrides all three
SQLiteOfflineAdapter methods:
package com.adobe.offline
{
import mx.data.SQLiteOfflineAdapter;
import mx.utils.StringUtil;
import mx.core.mx_internal;
public class ProductOfflineAdapter extends SQLiteOfflineAdapter
{
override protected function getQueryCriteria(originalArgs:Array):String
{
var queryCriteria:String;
var args:Array = originalArgs.concat();
var filterName:String = args.shift();
var accessedFieldNames:Array;
switch (filterName)
{
case "getAll":
break;
case "getByProductid":
return "productid = :productid";
break;
case "getByDescription":
return "description = :description";
break;
case "getByPrice":
return "price = :price";
break;
case "getByProductname":
return "price = :productname";
break;
}
if (!queryCriteria)
{
queryCriteria = super.getQueryCriteria(originalArgs);
}
return queryCriteria;
}
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override protected function getQueryCriteriaParameters(originalArgs:Array):Object
{
var queryCriteriaParameters:Object;
var args:Array = originalArgs.concat();
var filterName:String = args.shift();
switch (filterName)
{
case "getAll":
break;
case "getByProductid":
queryCriteriaParameters = {":productid"};
break;
case "getByDescription":
queryCriteriaParameters = {":description"};
break;
case "getByPrice":
queryCriteriaParameters = {":price"};
break;
case "getByProductname":
queryCriteriaParameters = {":productname"};
break;
}
if (!queryCriteriaParameters)
{
queryCriteriaParameters = super.getQueryCriteriaParameters(originalArgs);
}
return queryCriteriaParameters;
}
override protected function getQueryOrder(originalArgs:Array):String
{
var queryOrder:String;
var args:Array = originalArgs.concat();
var filterName:String = args.shift();
var accessedFieldNames:Array;
switch (filterName)
{
case "getAll":
break;
case "getByProductid":
break;
case "getByDescription":
break;
case "getByPrice":
break;
case "getByProductname":
break;
}
if (!queryOrder)
{
queryOrder = super.getQueryOrder(originalArgs);
}
return queryOrder;
}
}
}
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The following example shows an AIR-based client that uses a custom offline adapter. For information on building a
complete model-driven application that uses this client MXML file, see “Building an offline-enabled application” on
page 333.
In the MXML file, the lines in bold highlight code that is specific to this type of application.
• Import the offline adapter. In this case, the adapter is in the com.adobe.offline package.
• Create a variable for the offline adapter. In this case, the variable is myOfflineAdapter.
• Assign the myOfflineAdapter variable to the offlineAdapter property of the DataService instance, which in this
case is productService.serviceControl.
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" xmlns:OfflineAIRAPP="OfflineAIRAPP.*"
preinitialize="app_preinitializeHandler(event)"
creationComplete="windowedapplication1_creationCompleteHandler(event)">
<fx:Script>
<![CDATA[
import com.adobe.offline.ProductOfflineAdapter;
import
import
import
import
import
import
import
import
import
mx.controls.Alert;
mx.events.FlexEvent;
mx.messaging.Channel;
mx.messaging.ChannelSet;
mx.messaging.channels.RTMPChannel;
mx.messaging.events.ChannelEvent;
mx.rpc.AsyncToken;
mx.rpc.events.FaultEvent;
mx.rpc.events.ResultEvent;
public var myOfflineAdapter:ProductOfflineAdapter;
public function channelConnectHandler(event:ChannelEvent):void
{
productService.serviceControl.autoConnect=false;
}
protected function
app_preinitializeHandler(event:FlexEvent):void
{
var cs:ChannelSet = new ChannelSet();
var customChannel:Channel = new RTMPChannel("my-rtmp",
"rtmp://localhost:2037");
cs.addChannel(customChannel);
productService.serviceControl.channelSet=cs;
customChannel.addEventListener(ChannelEvent.CONNECT,
channelConnectHandler);
}
protected function dataGrid_creationCompleteHandler(event:FlexEvent):void
{
getAllResult.token = productService.getAll();
}
protected function
windowedapplication1_creationCompleteHandler(event:FlexEvent):void
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{
productService.serviceControl.autoCommit = false;
productService.serviceControl.autoConnect = false;
productService.serviceControl.autoSaveCache = false;
productService.serviceControl.offlineAdapter = new
ProductOfflineAdapter();
productService.serviceControl.fallBackToLocalFill = true;
productService.serviceControl.encryptLocalCache = true;
productService.serviceControl.cacheID = "myOfflineCache";
}
protected function connectBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.connect();
}
protected function DisconnectBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.disconnect();
}
protected function commitBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.commit();
}
protected function saveCacheBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.saveCache();
}
]]>
</fx:Script>
<fx:Declarations>
<s:CallResponder id="getAllResult" />
<OfflineAIRAPP:ProductService id="productService"
fault="Alert.show(event.fault.faultString + '\n' +
event.fault.faultDetail)"/>
</fx:Declarations>
<mx:DataGrid editable="true" x="9" y="10" id="dataGrid"
creationComplete="dataGrid_creationCompleteHandler(event)"
dataProvider="{getAllResult.lastResult}">
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<mx:columns>
<mx:DataGridColumn headerText="productid" dataField="productid"/>
<mx:DataGridColumn headerText="description" dataField="description"/>
<mx:DataGridColumn headerText="price" dataField="price"/>
<mx:DataGridColumn headerText="productname" dataField="productname"/>
</mx:columns>
</mx:DataGrid>
<s:Button x="10" y="246" label="Connect" click="connectBtn_clickHandler(event)"
id="connectBtn" width="84" height="30"/>
<s:Button x="112" y="204" label="Save to Local Cache" id="saveCacheBtn"
click="saveCacheBtn_clickHandler(event)" height="30"/>
<s:Button x="110" y="246" label="Commit to Server" id="commitBtn"
click="commitBtn_clickHandler(event)" width="135" height="30"/>
<s:Button x="10" y="204" label="Disconnect" id="DisconnectBtn"
click="DisconnectBtn_clickHandler(event)" height="30"/>
<s:Label x="270" y="204" text="{'Commit Required: ' +
productService.serviceControl.commitRequired}"/>
<s:Label x="270" y="246" text="{'Connected: ' +
productService.serviceControl.connected}"/>
</s:WindowedApplication>
The windowedapplication1_creationCompleteHandler() method sets the following properties that affect offline
behavior:
Property
Description
autoCommit
Determines if the application automatically commits
data changes.
autoConnect
Determines if the application automatically connects
to the server when a connection is available.
autoSaveCache
Determines if data is automatically saved to the offline
cache.
offlineAdapter
Assigns a custom offline adapter.
fallBackToLocalFill
Determines if the application falls back to using local
fills from the AIR SQLite database when not connected
to the server.
encryptLocalCache
Set this property to true to to encrypt the SQLite
database and ensure that data is unavailable to all
other users and applications running on the same
machine. The database is encrypted with a random
encryption key and password using the SQLite
encryption feature. The password is stored locally
using AIR EncryptedLocalStore support, associated
with the database name.
cacheID
Assigns a cache ID for storing the local copy of data in
the AIR SQLite database.
About caching with Flash Player and AIR
Flash Player and AIR each cache data to the local disk. Flash Player uses local shared objects (LSOs), while AIR uses a
SQLite database.
Flash Player creates a .sol file to store the LSO. Flash Player creates a new directory for the application and domain
based on your platform and operating system. For example, for a Flash Player application on Microsoft Windows, the
.sol files are created in the under the following directory:
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c:/Documents and Settings/userName/Application Data/Macromedia/Flash Player/#SharedObjects
Note: There are performance and scalability limitations when using LSOs to cache data offline. There is a configurable
user limit, with a default size of 100 kilobytes. Writes are monolithic, so each save writes all managed data for that data
store.
When using AIR, SQL database files are created in the _ds_localcache subdirectory of the application storage
directory. The location of the application storage directory is defined by the setting of the
air.File.applicationStorage property. For example, for an AIR application named TestApp running on
Windows, SQL database files are created in the following directory:
C:/Documents and Settings/userName/Application Data/TestApp/Local Store/_ds_localstore
When using AIR, each DataService.cacheID value corresponds to a single database file.
When you compile your application, you must link in the appropriate SWC file to control caching, depending on
whether you are deploying your application on Flash Player or AIR, as follows:
•
playerfds.swc
•
airfds.swc
Link this SWC file for applications running in Flash Player.
Link this SWC file for applications running in AIR.
Server push
Use the server-side DataServiceTransaction class to push changes to managed data stored on clients.
Using server push APIs
Use the flex.data.DataServiceTransaction class to push server-side data changes made outside the Data Management
Service to Data Management Service clients when your code is running within the same web application as LiveCycle
Data Services. The changes are injected into the Data Management Service as if they were initiated in the system. The
DataServiceTransaction class is documented in the LiveCycle Data Services Javadoc API documentation.
Use a DataServiceTransaction instance from server-side code outside the Data Management Service to push changes
to managed data stored on clients that have their client-side DataService object’s autoSyncEnabled property set to
true or have subscribed with matching criteria using the manualSync property.
There are two distinct use cases for the DataServiceTransaction class:
• Use the instance of DataServiceTransaction that is created for each assembler operation that modifies the state of
objects that the Data Management Service manages.
• Create an instance of DataServiceTransaction in your own code.
For the first use case, (use the DataServiceTransaction that is created when an Assembler operation is called), call its
static getCurrentDataServiceTransaction() method. Next call its updateItem(), deleteItem(), or
createItem() method to trigger additional changes. Call these methods to apply changes you have persisted or will
be persisting in this transaction. If the current transaction is rolled back, these changes are not pushed to clients.
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As an example of how you can push data when you already have an instance of DataServiceTransaction, consider a JSP
page that updates a database and a Data Management Service destination that uses the same database. Flex clients
connected to the Data Management Service destination normally are not notified of changes that the JSP page makes
to the database. However, you can modify the JSP page to call a data access object (DAO) in the data-managed
application when it makes database changes. The DAO in turn calls the createItem() method on the assembler,
which automatically creates a DataServiceTransaction instance. Immediately following the createItem() method
success, you could include code to call the getCurrentDataServiceTransaction() of the DataServiceTransaction
instance and then call its createItem() method.
For the second use case (you do not already have a DataServiceTransaction instance), you can call the static
DataServiceTransaction.begin() method to initiate a transaction, as the following example shows:
...
public void createBook(){
DataServiceTransaction dtx = DataServiceTransaction.begin(false);
// Create a product:
Product prod = new Product();
prod.setProductName("Product1");
prod.setDescription("A great product");
prod.setPrice(10);
ProductDAO dao = new ProductDAO();
dao.create(product);
//Inform the Data Management Service:
dtx.createItem("product", prod);
dtx.commit();
}
To roll back a transaction when working with a DataServiceTransaction instance, you mark the
javax.transaction.UserTransaction instance as rolled back as you would in a normal J2EE application, or you can call
the setRollbackOnly() method on the DataServiceTransaction.
The DataServiceTransaction class provides access to the current transaction in a thread local state, and holds messages
to be pushed to clients when the transaction completes. You also use this class to register for synchronization events
before and after completion of the transaction.
Each DataServiceTransaction instance is stored in thread-local state and it is assumed that it is only operated on one
thread at a time. It is not thread safe.
If you use the DataServiceTransaction class from within a sync, update, create, or delete method of your assembler, do
not use this class to indicate changes made to items that are already in the midst of being changed in this transaction.
Doing so queues an additional change to that object instead of modifying the currently active one, which can create a
conflict. Instead, you update the NewVersion instance with your changed property values and add any newly changed
property values to the list of changed properties sent to you. For example, if after every update made to an instance,
you want to change the versionId of that instance, you add the versionId to the list of changes and also update the
versionId value in your newVersion instance.
If you are using the ChangeObject interface, you call the addChangedPropertyName() method to add the versionId
property. If you are using the updateItem() method, you just add that property to the list provided to your
updateItem() method.
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Refreshing fills from server code
The DataServiceTransaction.refreshFill() method lets you manually refresh a fill or matching set of fills from
server code either as part of your assembler's sync method or from other server-side code. You specify a list of fill
parameters that are used to create a matching list of fills that are currently being cached by active clients. This list can
be null, which means that all fills on that destination match. If the list is non-null, the refreshFill() matches fills
made by clients with the same number of parameters if all of the slots match based on the rules in the following table:
Value
Rule
Null value
Matches that slot unconditionally.
Class value
Matches a parameter in the slot of that type.
Any other value
Matches fill parameters by using the equals method.
There are two variants of the refreshFill() method. The simpler variant takes a destination and fill parameters as
its two parameters. The other variant takes an additional parameter that specifies a PropertySpecifier instance. This
variant compares the properties of all of the items in the collection. It could use the item cache to avoid updating all
items if the item cache is enabled. It compares the properties of all items in the new version of the fill and sends update
messages for any properties that have changed. If the item cache is disabled, this refreshFill() method sends update
item events for all items in the collection just in case they have changed.
The DataServiceTransaction class also has addItemToFill() and removeItemFromFill() methods that you can use
to make an explicit change to a filled collection actively managed by other clients. Use of these methods generates an
update collection message in the DataServiceTransaction that is sent to the committing client, any clients that have
called fill on that collection, and any clients that have subscribed to this change using the manual sync mode properties
set in the DataServiceTransaction. This is an efficient way to modify a managed collection on clients without reexecuting the entire query.
Note: When you compile code that uses LiveCycle Data Services Java APIs, you must include the flex-messaging-data.jar
and flex-messaging-common.jar files in your classpath.
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Chapter 7: Model-driven applications
Adobe application modeling technology is a set of technologies that facilitates the development of data-centric
applications. Use application modeling technology with Flash Builder to generate code based on a data model for
communicating with Data Management Service and RPC service destinations. Generated client code for Data
Management Service destinations is built on the DataService object. Generated client code for RPC services is built on
ActionScript objects such as RemoteObject and WebService objects.
Two types of model-driven development
There are two types of model-driven development with LiveCycle Data Services:
• The first type is end-to-end model-driven development for both client and server code. You control the application
code on the client and server by customizing the model from which code is generated.
• The second type is model-driven development of client code you can use with existing server destinations on the
LiveCycle Data Services server. In this case, you generate a model and the corresponding client-side ActionScript
code by introspecting a destination on the LiveCycle Data Services server. This type of development is useful when
you have existing destinations. However, it gives you no control over the server implementation and very little
control over the client implementation. You can make only limited changes to the model, and those changes affect
only client code generation.
When you perform end-to-end model-driven development, you can generate Data Management Service destinations
based on a model without writing any Java code. The generated server code is based on the Assembler interface of the
Data Management Service and uses the Hibernate object/relational persistence and query service. The generated server
code works in combination with the generated client code in Flash Builder.
Use the following software to build an end-to-end model-driven applications with LiveCycle Data Services:
• LiveCycle Data Service server
• Flash Builder
• Application modeling plug-in for Eclipse (the Modeler)
• SQL database configured as a JDBC data source (Model Assembler feature only)
For general information about application modeling technology, see the Application Modeling Technology Reference.
The role of Flash Builder in model-driven development
Flash Builder uses application modeling technology in features that simplify the development of data-centric Flex
client applications. Flash Builder generates client code for calling remote services.
The data-centric development features in Flash Builder depend on an application modeling technology model from
which Flash Builder generates the ActionScript code for calling a remote service.
Building your first model-driven application
This set of tasks builds an end-to-end model-driven application that uses the lcds-samples web application and the
ordersdb SQL database on the LiveCycle Data Services server. These tasks are specific to the LiveCycle Data Services
installation with an integrated Apache Tomcat application server. Application-server-specific configuration is noted
where applicable.
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End-to-end model-driven development lets you control the client and server code for your application by customizing
the model from which code is generated. With just Flash Builder, the Modeler, and the LiveCycle Data Services server,
you can quickly build an end-to-end data-centric application.
Summary of steps
Perform the following tasks to build a basic end-to-end model-driven application:
1 Install LiveCycle Data Services, Flash Builder, and the application modeling plug-in.
2 Configure a JDBC data source.
3 Configure Remote Data Services (RDS) on the server.
4 Configure Flash Builder to use RDS.
5 Configure server-side debug logging.
6 Create a J2EE server project in Flash Builder.
7 Build a model and generate code.
8 Create and run a Flex client.
Configure a JDBC data source
An end-to-end model-driven application depends on a JDBC data source configured on the application server. In the
data source configuration, you reference the relational database for which you want to build a model-driven
application.
On the Tomcat server, you configure JDBC data sources in context files. On the LiveCycle Data Services installation
with an integrated Tomcat server, the data source for this application is preconfigured in the lcds-samples.xml context
file located in the following directory:
install_root/tomcat/conf/Catalina/localhost
where install_root is the directory where you installed LiveCycle Data Services. Within the lcds-samples.xml file, the
following data source is preconfigured for the lcds-samples web application. How you configure a JDBC data source
depends on the application server you use. For more information, see your application server documentation.
<Context privileged="true" antiResourceLocking="false"
antiJARLocking="false" reloadable="true">
<Resource name="jdbc/ordersDB" type="javax.sql.DataSource"
driverClassName="org.hsqldb.jdbcDriver"
maxIdle="2" maxWait="5000"
url="jdbc:hsqldb:hsql://localhost:9002/ordersdb"
username="sa" password="" maxActive="4"/>
</Context>
Note: The database driver classes required to connect to the sample database are pre-installed in the
install_root/tomcat/lib/hsqldb.jar file for the LiveCycle Data Services installation with integrated Tomcat server. If you
are using a different configuration, ensure that you have the database driver classes in your classpath.
More Help topics
“Configuring a data source” on page 371
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Configure RDS on the server
To successfully retrieve data from the data source, enable the RDS server (the RDSDispatchServlet servlet) in the lcdssamples web application. To perform this task, edit the web.xml file in an XML editor or text editor. The web.xml file
for the lcds-samples web application is located in the following directory:
install_root/tomcat/webapps/lcds-samples/WEB-INF/web.xml
where install_root is the directory where you installed LiveCycle Data Services.
In the web.xml file, remove the comments from the RDSDispatchServlet definition. Set the useAppserverSecurity
parameter value to false.
<servlet>
<servlet-name>RDSDispatchServlet</servlet-name>
<display-name>RDSDispatchServlet</display-name>
<servlet-class>flex.rds.server.servlet.FrontEndServlet</servlet-class>
<init-param>
<param-name>useAppserverSecurity</param-name>
<param-value>false</param-value>
</init-param>
<load-on-startup>10</load-on-startup>
</servlet>
<servlet-mapping id="RDS_DISPATCH_MAPPING">
<servlet-name>RDSDispatchServlet</servlet-name>
<url-pattern>/CFIDE/main/ide.cfm</url-pattern>
</servlet-mapping>
Note: For local development, you can use the RDSDispatchServlet servlet without configuring application server security,
as shown above. Configure application server security for all other deployments.
More Help topics
“Configuring RDS on the server” on page 371
Configure server-side debug logging
During development, it is useful to set server-side logging to the debug level and capture messages related to modeldriven applications. While you are running model-driven Flex clients, you can view the related server traffic in the
application server console window.
To see log messages related to model-driven applications, replace the logging section of the lcds-samples/WEBINF/flex/services-config.xml file with the following section:
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<logging>
<!-- You may also use flex.messaging.log.ServletLogTarget -->
<target class="flex.messaging.log.ConsoleTarget" level="Debug">
<properties>
<prefix>[LCDS]</prefix>
<includeDate>false</includeDate>
<includeTime>false</includeTime>
<includeLevel>true</includeLevel>
<includeCategory>false</includeCategory>
</properties>
<filters>
<!--<pattern>Endpoint.*</pattern>-->
<!--<pattern>Service.*</pattern>-->
<pattern>Service.Data.Fiber</pattern>
<pattern>Message.*</pattern>
<pattern>DataService.*</pattern>
<pattern>Configuration</pattern>
</filters>
</target>
</logging>
Configure Flash Builder to use RDS
After you configure RDS on the server, configure Flash Builder to connect to the RDS server.
Complete the following steps to configure Flash Builder for RDS:
1 Start your application server if it isn’t already running.
2 In Flash Builder, select Window > Preferences.
3 Expand the Adobe tree node and select RDS Configuration.
4 Under Currently Configured RDS Servers, select LCDS (localhost).
5 Enter a description and the hostname and port number of your RDS server. For this application, use the default
hostname value (127.0.0.1) and the default port value (8400).
6 Enter the context root of the web application that hosts your RDS server. For this application, use the default value
(lcds-samples).
7 Leave the password field blank and select Prompt for Password.
Note: You are not using web application security for this application. If you were using web application security, you
would enter a valid username and password combination.
8 Click Test Connection.
9 If the connection is successful, click OK.
Create a Flex project in Flash Builder
To use Flash Builder with LiveCycle Data Services, create a Flex project that corresponds to the server and web
application you are using. This project references the J2EE application server hosting LiveCycle Data Services. That is,
when you create the project, select J2EE as the Application Server type. Ensure that the project references the context
root where you created the data source. After you create the project, all of the client libraries required to interact with
the J2EE application server are automatically added to your project’s class path.
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Complete the following steps to create a Flex project:
1 Start your application server if it isn’t already running.
2 Start Flash Builder if it isn’t already running.
3 In Flash Builder, select File > New > Flex Project.
4 Enter a project name.
5 Use the default project location.
6 Set the application type as Web.
7 Select the Flex SDK version you want to use. You can use the default Flex SDK or Flex SDK 3.5.
8 In the Application Server list, select J2EE.
9 Make sure Use Remote Object Access Service is checked.
10 Make sure the LiveCycle Data Services checkbox is checked.
11 Click Next.
12 Enter the server location information for your server.
13 Click Validate Configuration.
14 If the configuration is valid, click Finish to create the project.
Build a model and generate code
1 Start the samples database by running the startdb.bat or startdb.sh file, depending on your operating system. These
files are located in the following directory:
install_root/sample_db
where install_root is the directory where you installed LiveCycle Data Services.
2 Start your application server if it isn’t already running.
3 Start Flash Builder if it isn’t already running.
4 In Flash Builder, make sure that you have created a Flex J2EE server project and it is the active project.
Note: To make a project active, open an application file in the project and make it the active file in the editor.
5 In the Package Explorer, click the Filters button. In the Filters dialog, deselect ".model". This configuration lets you
view model files in the Flash Builder Package Explorer.
6 In the Package Explorer, click the Open Model for Active Project button located at right end of the toolbar. Clicking
this button for the first time creates a directory named .model and a model file with the same name as the Flex
project. The model file opens automatically.
After the model is created, clicking the Open Model for Active Project button opens the model file for editing. The
same button also appears in the toolbar for the Data/Services view when in the Flash perspective.
7 Switch to the Data Model perspective (the Modeler): click the Open Perspective button in the right corner of the
Flash Builder window and then select Data Model.
8 Select the Design tab to enter the Design view.
9 By default, the RDS Data view is in the lower right side of the Data Model perspective. In the RDS Data view, expand
the RDS server tree nodes to view the tables in the java:/comp/env/jdbc/ordersDB data source.
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10 Select all of the tables in the ordersDB data source and drag them to the Design view canvas. An entity is added to
the model for each database table. The entities are represented in a diagram that is similar to a UML (Unified
Modeling Language) diagram.
11 Save the model and click the Deploy Model to LCDS server button. Accept the default settings and click OK.
Clicking OK generates a Model Assembler destination on the server for each entity. You can call these destinations
from a Flex client to work with data stored in the database. By default, the model file is saved in the WEBINF/datamodel directory of the web application to which you deploy.
In the application server console, you can see a ProductAssembler class is instantiated after you deploy the model.
12 Switch back to the Flash perspective. You should see a new service in the Data/Services view. Based on the model
you created, Flash Builder generates ActionScript classes that provide access to service operations from a client
application. The operations for the service are available in the Data/Services view.
Updating database tables when you deploy models
When you redeploy a model to the server with the Update radio button selected, verify that your database tables are
updated correctly. There are situations where the Hibernate does not drop table columns even though you have
removed the corresponding properties from entities in the model. This happens when a database owner (DBO) name
is a prefix in the table name; for example, PUBLIC.EMPLOYEE, where PUBLIC is the DBO name. There is no
indication from Hibernate or the Modeler that the update failed. You can work around this issue by removing the DBO
name from the table name. When looking for a table, Hibernate prepends the DBO (PUBLIC, in this case) to the table
name. If the table name in the model is already PUBLIC.EMPLOYEE, Hibernate looks for
PUBLIC.PUBLIC.EMPLOYEE and fails to find it.
Another fact to be aware of is that the Modeler cannot perform tasks that your database management system cannot
perform. Issues can arise when you redeploy a model to the server with the Update radio button selected when you
changed the data type of an entity property. The changes may not be reflected properly in the database tables on the
server if the entity you changed is used as a property in another entity.
For example, suppose you have an entity called State with stateId integer and stateName string properties. You also
have a Customer entity with a state property with a data type of State. You first deploy the model to create the State
database table and update the Customer table to reference the State table as a foreign key. You then change the stateId
property of the State entity from integer to string. When you redeploy the model with the Update radio button selected,
the State table still uses integer for stateId even though you changed the model to make stateId a string.
Create and run a Flex client
To use the client and server code generated from the model, create a Flex web client that has a simple master-detail
user interface.
Complete the following steps to create a Flex client:
1 Start the samples database if it isn’t already running.
2 Start your application server if it isn’t already running.
3 Start Flash Builder if it isn’t already running.
4 In Flash Builder, switch to Design view in the Flash perspective.
5 In the Package Explorer, expand the nodes of your Flex project to src > (default package) and open the displayed
MXML file.
6 Select the Components tab in the lower left side of the Flash Builder window.
7 Expand the Controls folder in the Components tree.
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8 Drag the DataGrid control to the Design view canvas.
9 Select the Data/Services tab under the Design view canvas.
10 In the Data/Services view, expand the ProductService node.
11 Drag the getAll():Product[] function to the DataGrid control. Accept the default Bind To Data settings. The
DataGrid columns changes to match the property names of the Product entity.
12 Right-click the DataGrid control and select Generate Details Form.
13 Select Model Driven Form and click OK to generate a Form.
14 Reposition the form so that it is not covering the DataGrid control.
15 Run the application. The DataGrid control should fill with data; the productService.getAll() function is called
in the DataGrid control’s creationComplete event handler.
Note: Calling the getAll() function results in a call to the fill() method of the underlying DataService instance.
16 Select a row in the DataGrid control to display details in the form.
17 Click Delete to delete an item from the database.
Note: Deleting an item with the form results in a call to the deleteItem() method of the underlying DataService
instance.
18 Click Add, enter data for a new item in the form, and then click Save to add an item to the database.
Note: Adding an item with the form results in a call to the createItem() method of the underlying DataService
instance.
Working with dynamic destinations in model-driven applications
Model-driven applications use dynamic destinations; for more information, see “Accessing dynamic components with
a Flex client application” on page 417. As demonstrated in this application, you do not always have to explicitly assign
a channel in the Flex client or in the model. If you do not specify a channel set and channel when you use a dynamic
destination, LiveCycle Data Services attempts to use the default application-level channel assigned in the defaultchannels element in the services-config.xml file.
If you rely on application-level default channels, you must make sure that those channels are the ones expected by the
destination you are using. For example, if the dynamic destination is created without specifying any channels on the
server, it implicitly expects connections only over the service-level default channels. This is fine if service-level and
application-level channels match, but if service-level default channels are different than application-level default
channels, the client cannot contact the destination using the application-level default channels. In that case, a channel
set with the proper channel is required on the client and you cannot rely on the application-level default channels.
Accessing DataService properties and methods in model-driven applications
In model-driven Flex clients that use the Data Management Service, the client-side mx.data.DataService component
is inside a generated service wrapper instance. The service wrapper is an instance of the
com.adobe.fiber.services.wrapper.DataServiceWrapper class. This is different than a typical Flex client that calls a Data
Management Service, for which you usually instantiate a DataService directly in an MXML element or in the script
block of an MXML file.
In model-driven development, the DataService instance is accessed as the serviceControl property of the service
wrapper. You have the same access to the DataService members that you have for non-model-driven clients. You set
DataService properties and methods by using the following dot notation in your ActionScript code:
•
xxxService.serviceControl.propertyName
•
xxxService.serviceControl.methodName()
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So, for example, to save data to a local cache (offline), set the DataService.cacheID property as follows:
protected function dataGrid_creationCompleteHandler(event:FlexEvent):void
{
...
productService.serviceControl.cacheID="cache2";
...
}
More Help topics
“Building the client application” on page 372
Building an offline-enabled application
You can use an offline adapter with an AIR SQLite database to perform offline fills when a desktop client is
disconnected from the LiveCycle Data Services server. An offline adapter contains the SQL queries for AIR SQLite for
retrieving cached items like an assembler on the server retrieves items from the data source. An offline adapter can
contain logic to perform fills based on criteria defined in a model just as the Model Assembler on the server contains
logic to retrieve items from the data source based on criteria defined in a model.
This set of tasks builds an end-to-end model-driven application that works both online and offline. This application
has an offline-enabled AIR desktop client that stores and manipulates data in an AIR SQLite database as well as the
data source on the LiveCycle Data Services server.
When entities in a model contain annotations for offline code generation, offline adapter classes are automatically
generated when you click the Generate Code button on the Modeler toolbar. The generated classes extend the
mx.data.SQLiteOfflineAdapter class, which provides SQLite offline query capabilities for AIR clients that use data
management. The generated classes override the getQueryCriteria(), getQueryCriteriaParameters(), and
getQueryOrder() methods of the SQLiteOfflineAdapter class.
The overridden methods contain query code for each implicit filter and filter element in the model. Criteria-based
filters, pass-through filters that contain simple JPQL queries and JPQL queries with cascading properties are
supported. Pass-through filters that contain complex user-defined JPQL queries are not supported.
The following table describes the offline adapter methods.
Method
Description
getQueryCriteria()
Defines the SQL WHERE clause.
getQueryCriteriaParameters()
Defines the parameters of SQL WHERE clause.
getQueryOrder()
Defines the SQL ORDERBY clause.
This application uses the lcds-samples web application and the ordersDB data source on the LiveCycle Data Services
server. These tasks are specific to a LiveCycle Data Services installation with an integrated Apache Tomcat application
server. Application-server-specific configuration is noted where applicable.
Summary of steps
Perform the following tasks to build a model-driven offline application:
1 Install LiveCycle Data Services, Flash Builder, and the application modeling plug-in. (Common with the Build your
first model-driven application section.)
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2 “Configure a JDBC data source” on page 327. (Common with the Build your first model-driven application section.)
3 “Configure RDS on the server” on page 328. (Common with the Build your first model-driven application section.)
4 “Configure server-side debug logging” on page 328. (Common with the Build your first model-driven application
section.)
5 “Configure Flash Builder to use RDS” on page 329. (Common with the Build your first model-driven application
section.)
6 “Create a Flex project in Flash Builder” on page 329.
Important: Set the application type of the Flex project to Desktop instead of Web. This type of offline-enabled
application requires an AIR-based desktop client.
7 “Build a model and generate code” on page 334. (Specific to this workflow.)
8 “Create and run an offline-enabled desktop client” on page 335. (Specific to this workflow.)
Build a model and generate code
1 Start the samples database by running the startdb.bat or startdb.sh file, depending on your operating system. These
files are located in the following directory:
install_root/sampledb
where install_root is the directory where you installed LiveCycle Data Services.
2 Start your application server if it isn’t already running.
3 Start Flash Builder if it isn’t already running.
4 In Flash Builder, make sure that you have created a Flex J2EE server project with Application Type set to Desktop,
and it is the active project. This type of offline-enabled application requires an AIR-based desktop client.
Note: To make a project active, open an application file in the project and make it the active file in the editor.
5 In the Package Explorer, click the Filters button. In the Filters dialog, deselect ".model". This configuration lets you
view model files in the Flash Builder Package Explorer.
6 In the Package Explorer, click the Open Model for Active Project button located at right end of the toolbar. Clicking
this button for the first time creates a directory named .model and a model file with the same name as the Flex
project. The model file opens automatically.
After the model is created, clicking the Open Model for Active Project button opens the model file for editing. The
same button also appears in the toolbar for the Data/Services view when in the Flash perspective.
7 Switch to the Data Model perspective (the Modeler): click the Open Perspective button in the right corner of the
Flash Builder window and then select Data Model.
8 Select the Design tab to enter the Design view.
9 By default, the RDS Data view is in the lower right side of the Data Model perspective. In the RDS Data view, expand
the RDS server tree nodes to view the tables in the java:/comp/env/jdbc/ordersDB data source.
10 Select the PRODUCT table in the ordersDB data source and drag it to the Design view canvas. A Product entity is
added to the model.
11 Select the Product entity in Design view and select the Code Gen tab in the Properties view below the Design view
canvas.
12 In the Code Gen panel, click the Generate Offline Adapter checkbox and set the name of the Offline Adapter
Package to com.adobe.offline.
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13 Save the model and click the Deploy Model to LCDS server button. Accept the default settings and click OK.
Clicking OK generates a Model Assembler destination on the server for each entity. You can call these destinations
from a Flex client to work with data stored in the database. By default, the model file is persisted in the WEBINF/datamodel directory of the web application to which you deploy; the model is redeployed from this location
on server startup.
14 Click the Generate Code button on the Modeler toolbar to generate the offline adapter code.
15 In the Package Explorer, expand the src folder, which now contains a com.adobe.offline package.
16 Expand the com.adobe.offline package, and double-click the ProductOfflineAdapter.as ActionScript class file to
view it.
Note that the ProductOfflineAdapter class extends the mx.data.SQLiteOfflineAdapter class and overrides its
getQueryCriteria(), getQueryCriteriaParameters(), and getQueryOrder() methods to provide query
cases specific to the implicit filters in the Product entity: getAll, getByProductId, getByDescription, getByPrice, and
getByProductname.
Create and run an offline-enabled desktop client
To use the client and server code generated from the model, create a Flex desktop (AIR) client that has a simple masterdetail user interface.
Note: In Flash Builder, you must use a Flex project with Appliction Type set to Desktop rather than Web.
Complete the following steps to create a Flex desktop client:
1 Start the samples database if it isn’t already running.
2 Start your application server if it isn’t already running.
3 Start Flash Builder if it isn’t already running.
4 In Flash Builder, switch to Design view in the Flash perspective.
5 In the Package Explorer, expand the nodes of your Flex project to src > (default package) and open the MXML file
you want to use.
6 Set up a DataGrid control:
a Select the Components tab in the lower left side of the Flash Builder window.
b Expand the Controls folder in the Components tree.
c Drag the DataGrid control to the Design view canvas.
d Select the DataGrid control in the Design view canvas and set its editable property to true in the Properties view.
e Select the Data/Services tab under the Design view canvas.
f
In the Data/Services view, expand the ProductService node.
g Drag the getAll():Product[] function to the DataGrid control. Accept the default Bind To Data settings. The
DataGrid columns changes to match the property names of the Product entity. T
7 Set up a Disconnect Button control:
a
In Design view, from the Controls folder in the Components tree, drag a Button control to the canvas below the
DataGrid control.
b Change the label property of the Button control to Disconnect and set its id property to disconnectBtn.
c Right-click the Button control and select Generate Click Handler.
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d Modify the generated click handler code to match the following code. This click handler disconnects the
serviceControl DataService instance from the server.
protected function disconnectBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.disconnect();
}
8 Set up a Connect Button control:
a In Design view, from the Controls folder in the Components tree, drag a Button control to the canvas below the
Disconnect Button control.
b Change the label property of the Button control to Connect and set its id property to connectBtn.
c Right-click the button control and select Generate Click Handler.
d Modify the generated click handler code to match the following code. This click handler connects the
serviceControl DataService to the server.
protected function connectBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.connect();
}
9 Set up a Save To Local Cache Button control:
a In Design view, from the Controls folder in the Components tree, drag a Button control to the canvas to the right
of the Disconnect Button control.
b Change the label property of the Button control to Save To Local Cache and set its id property to saveCacheBtn.
c Right-click the Button control and select Generate Click Handler.
d Modify the generated click handler code to match the following code. This click handler saves data to the local
SQLite database.
protected function saveCacheBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.saveCache();
}
10 Set up a Commit To Server Button control:
a In Design view, from the Controls folder in the Components tree, drag a Button control to the canvas below the
Save To Local Cache Button control.
b Change the label property of the Button control to Commit To Server and set its id property to commitBtn.
c Right-click the Button control and select Generate Click Handler.
d Modify the generated click handler code to match the following code. This click handler commits data to the
remote server-side database.
protected function commitBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.commit();
}
11 Set up Commit Required and Connected Label controls:
a In Design view, from the Controls folder in the Components tree, drag a Label control to the canvas the right of
the Save To Local Cache Button control.
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b Set the text property of the Label control to following binding code. This label displays the current value of the
serviceControl.commitRequired property at run time.
{'Commit Required: ' + productService.serviceControl.commitRequired}
c From the Controls folder in the Components tree, drag a Label control below the Commit Required Label
control in the Design view canvas.
d Set the text property of the Label control to the following binding code. This label displays the current value of
the serviceControl.connected property at run time.
{'Connected: ' + productService.serviceControl.connected}
12 In Source view, add the following code to the script block of the MXML file. Replace all existing code that is above
the event handlers for the DataGrid and Button controls.
import
import
import
import
import
import
import
import
import
import
com.adobe.offline.ProductOfflineAdapter;
mx.controls.Alert;
mx.events.FlexEvent;
mx.messaging.Channel;
mx.messaging.ChannelSet;
mx.messaging.channels.RTMPChannel;
mx.messaging.events.ChannelEvent;
mx.rpc.AsyncToken;
mx.rpc.events.FaultEvent;
mx.rpc.events.ResultEvent;
public var myOfflineAdapter:ProductOfflineAdapter;
public function channelConnectHandler(event:ChannelEvent):void
{
productService.serviceControl.autoConnect=false;
}
protected function
app_preinitializeHandler(event:FlexEvent):void
{
var cs:ChannelSet = new ChannelSet();
var customChannel:Channel = new RTMPChannel("my-rtmp",
"rtmp://localhost:2037");
cs.addChannel(customChannel);
productService.serviceControl.channelSet=cs;
customChannel.addEventListener(ChannelEvent.CONNECT,
channelConnectHandler);
}
protected function
windowedapplication1_creationCompleteHandler(event:FlexEvent):void
{
productService.serviceControl.autoCommit = false;
productService.serviceControl.autoConnect = false;
productService.serviceControl.autoSaveCache = false;
productService.serviceControl.offlineAdapter =
new ProductOfflineAdapter();
productService.serviceControl.fallBackToLocalFill=true;
productService.serviceControl.encryptLocalCache = true;
productService.serviceControl.cacheID = "myOfflineCache";
}
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Especially for AIR applications, it is a best practice to create and assign channel sets at runtime. The code in the
app_preinitializeHandler() method creates a channel set, adds a channel to it, and assigns the channel set to
the productService.
The windowedapplication1_creationCompleteHandler() method sets the following properties that affect
offline behavior:
Property
Description
autoCommit
Determines if the application automatically
commits data changes.
autoConnect
Determines if the application automatically
connects to the server when a connection is
available.
autoSaveCache
Determines if data is automatically saved to the
offline cache.
offlineAdapter
Assigns a custom offline adapter.
fallBackToLocalFill
Determines if the application falls back to using
local fills from the AIR SQLite database when not
connected to the server.
encryptLocalCache
Set this property to true to to encrypt the SQLite
database and ensure that data is unavailable to all
other users and applications running on the same
machine. The database is encrypted with a
random encryption key and password using the
SQLite encryption feature. The password is stored
locally using AIR EncryptedLocalStore support,
associated with the database name.
cacheID
Assigns a cache ID for storing the local copy of data
in the AIR SQLite database.
13 Add the following event handler references to the WindowedApplication element:
preinitialize="app_preinitializeHandler(event)"
creationComplete="windowedapplication1_creationCompleteHandler(event)"
14 Return to Design view.
15 Make sure you have server-side logging configured as described in “Configure server-side debug logging” on
page 328.
Position the AIR window and the application server console side by side.
16 Run the application.
The DataGrid control fills with data; the productService.getAll() function is called in the DataGrid control’s
creationComplete event handler.
Note: Calling the getAll() function results in a call to the fill() method of the underlying DataService instance.
17 Change the data in one or more DataGrid cell.
18 Click Commit. The client calls the serviceControl.commit() method to submit the changed data to the server
database.
19 Make additional data changes and click Save To Local Cache. The client calls the serviceControl.saveCache()
method to submit data changes to the local SQLite database.
20 Stop the application server.
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21 Close the client and then run it again.
The DataGrid control fills with data from the local SQLite database.
Calling the getAll() function still resulted in a call to the fill() method of the underlying DataService instance.
However, that fill() call performed the local getAll query specified in the ProductOfflineAdapter class because
the DataService.fallBackToLocalFill property is set to true.
22 Restart the application server. Click Commit To Server and watch the local changes get persisted to the server
database.
Similarly, you can make data changes, and then click Disconnect, Save To Local Cache, Reconnect, and Commit
To Server.
Note: This application does not use a model-driven form because of explicit calls to the DataService.commit() method
in the generated model-driven form MXML component. Those call result in connection errors when you click the modeldriven form buttons while offline.
Completed MXML file
The following example shows the completed MXML file for the offline-enabled client:
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" xmlns:OfflineAIRAPP="OfflineAIRAPP.*"
preinitialize="app_preinitializeHandler(event)"
creationComplete="windowedapplication1_creationCompleteHandler(event)">
<fx:Script>
<![CDATA[
import com.adobe.offline.ProductOfflineAdapter;
import
import
import
import
import
import
import
import
import
mx.controls.Alert;
mx.events.FlexEvent;
mx.messaging.Channel;
mx.messaging.ChannelSet;
mx.messaging.channels.RTMPChannel;
mx.messaging.events.ChannelEvent;
mx.rpc.AsyncToken;
mx.rpc.events.FaultEvent;
mx.rpc.events.ResultEvent;
public var myOfflineAdapter:ProductOfflineAdapter;
public function channelConnectHandler(event:ChannelEvent):void
{
productService.serviceControl.autoConnect=false;
}
protected function
app_preinitializeHandler(event:FlexEvent):void
{
var cs:ChannelSet = new ChannelSet();
var customChannel:Channel = new RTMPChannel("my-rtmp",
"rtmp://localhost:2037");
cs.addChannel(customChannel);
productService.serviceControl.channelSet=cs;
customChannel.addEventListener(ChannelEvent.CONNECT,
channelConnectHandler);
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}
protected function dataGrid_creationCompleteHandler(event:FlexEvent):void
{
getAllResult.token = productService.getAll();
}
protected function
windowedapplication1_creationCompleteHandler(event:FlexEvent):void
{
productService.serviceControl.autoCommit = false;
productService.serviceControl.autoConnect = false;
productService.serviceControl.autoSaveCache = false;
productService.serviceControl.offlineAdapter = new
ProductOfflineAdapter();
productService.serviceControl.fallBackToLocalFill=true;
productService.serviceControl.encryptLocalCache = true;
productService.serviceControl.cacheID = "myOfflineCache";
}
protected function connectBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.connect();
}
protected function DisconnectBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.disconnect();
}
protected function commitBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.commit();
}
protected function saveCacheBtn_clickHandler(event:MouseEvent):void
{
productService.serviceControl.saveCache();
}
]]>
</fx:Script>
<fx:Declarations>
<s:CallResponder id="getAllResult" />
<OfflineAIRAPP:ProductService id="productService"
fault="Alert.show(event.fault.faultString + '\n' +
event.fault.faultDetail)"/>
</fx:Declarations>
<mx:DataGrid editable="true" x="9" y="10" id="dataGrid"
creationComplete="dataGrid_creationCompleteHandler(event)"
dataProvider="{getAllResult.lastResult}">
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<mx:columns>
<mx:DataGridColumn headerText="productid" dataField="productid"/>
<mx:DataGridColumn headerText="description" dataField="description"/>
<mx:DataGridColumn headerText="price" dataField="price"/>
<mx:DataGridColumn headerText="productname" dataField="productname"/>
</mx:columns>
</mx:DataGrid>
<s:Button x="10" y="246" label="Connect" click="connectBtn_clickHandler(event)"
id="connectBtn" width="84" height="30"/>
<s:Button x="112" y="204" label="Save to Local Cache" id="saveCacheBtn"
click="saveCacheBtn_clickHandler(event)" height="30"/>
<s:Button x="110" y="246" label="Commit to Server" id="commitBtn"
click="commitBtn_clickHandler(event)" width="135" height="30"/>
<s:Button x="10" y="204" label="Disconnect" id="DisconnectBtn"
click="DisconnectBtn_clickHandler(event)" height="30"/>
<s:Label x="270" y="204" text="{'Commit Required: ' +
productService.serviceControl.commitRequired}"/>
<s:Label x="270" y="246" text="{'Connected: ' +
productService.serviceControl.connected}"/>
</s:WindowedApplication>
More Help topics
“Building the client application” on page 372
Customizing client-side functionality
You can customize client-side functionality in the following ways when using Adobe modeling technology with Flash
Builder:
• Modify generated ActionScript service wrapper and value object source files
• Modify the template files from which the ActionScript source files and the model-driven form are generated
Note: The ability to modify the templates for ActionScript service wrapper and value object source files was introduced
in LiveCycle Data Services 3.1.
Generated ActionScript source files
The ActionScript source files are based on a model. Service wrappers and value objects are generated for every entity
in the model; there is an implicit service for every entity in a model. Service wrappers are also generated for every
explicit service element in the model. Each generated wrapper and value object has a superclass that you do not change
and a subclass you can change. The subclasses do not get regenerated when you regenerate ActionScript code for the
application, so your changes are preserved.
The following table describes generated service wrapper and value object source files:
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Class file
Description
_Super_ServiceName.as
The parent class of the service class that is overwritten for each generation. This class
contains the service functions.
ServiceName.as
The service class in which you can implement custom functionality by overriding the
superclass behavior.
_Super_EntityName.as
The parent class of the value object that is overwritten for each generation. This class
contains the properties and methods that an entity defines.
EntityName.as
The value object class in which you can implement custom functionality by overriding
the superclass behavior.
EntityNameEntityMetadata.
as
Contains information about an entity and its relationship with other entities in the
model.
To build an application the uses a custom method, see “Implement and use a client-side entity method” on page 342.
Code generation templates
The service wrapper and value object files are generated based on a code generation template. For more information,
see “Customizing client-side code generation” on page 345.
Implement and use a client-side entity method
This set of tasks walks through the process of building an end-to-end model-driven application that uses an entity
method implemented in an ActionScript value object class.
Assume that you create a model that is based on a relational database. Next, assume that you want to calculate a
discount price based a product price from the database. To meet your business needs, you can implement a custom
method in a value object that calculates the discount price. After you modify the generated Product value object, your
new application logic becomes part of the client-side functionality.
You perform similar steps to implement a custom service function in a generated service wrapper.
To implement the entity method, you perform these steps:
1 Add a discount method to the Product entity in the model to calculate a discount price based on the price value
from the database.
2 Add a discountPrice derived property to the Product entity in the model and set its expr (expression) value to call
the discount method.
3 Regenerate the ActionScript source files.
4 Implement a discountPrice() method in the Product value object that is generated from the Product entity in
the model. The superclass of the Product class contains a stub for the discountPrice()method with the correct
signature. The implementation in the Product value object overrides that stub method.
Summary of steps
Perform the following tasks to build a model-driven application that uses a client-side value object method:
1 Install LiveCycle Data Services, Flash Builder, and the application modeling plug-in. (Common with the Build your
first model-driven application section.)
2 “Configure a JDBC data source” on page 327. (Common with the Build your first model-driven application section.)
3 “Configure RDS on the server” on page 328. (Common with the Build your first model-driven application section.)
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4 “Configure server-side debug logging” on page 328. (Common with the Build your first model-driven application
section.)
5 “Configure Flash Builder to use RDS” on page 329. (Common with the Build your first model-driven application
section.)
6 “Create a Flex project in Flash Builder” on page 329. (Common with the Build your first model-driven application
section.)
7 “Build a model and generate code” on page 343. (Specific to this workflow.)
8 “Create and run a Flex client that uses a custom method” on page 344. (Specific to this workflow.)
Build a model and generate code
1 Start the samples database by running the startdb.bat or startdb.sh file, depending on your operating system. These
files are located in the following directory:
install_root/sampledb
where install_root is the directory where you installed LiveCycle Data Services.
2 Start your application server if it isn’t already running.
3 Start Flash Builder if it isn’t already running.
4 In Flash Builder, make sure that you have created a Flex J2EE server project and it is the active project.
Note: To make a project active, open an application file in the project and make it the active file in the editor.
5 In the Package Explorer, click the Filters button. In the Filters dialog, deselect ".model". This configuration lets you
view model files in the Flash Builder Package Explorer.
6 In the Package Explorer, click the Open Model for Active Project button located at right end of the toolbar. Clicking
this button for the first time creates a directory named .model and a model file with the same name as the Flex
project. The model file opens automatically.
After the model is created, clicking the Open Model for Active Project button opens the model file for editing. The
same button also appears in the toolbar for the Data/Services view when in the Flash perspective.
7 Switch to the Data Model perspective (the Modeler): click the Open Perspective button in the right corner of the
Flash Builder window and then select Data Model.
8 Select the Design tab to enter the Design view.
9 By default, the RDS Data view is in the lower right side of the Data Model perspective. In the RDS Data view, expand
the RDS server tree nodes to view the tables in the java:/comp/env/jdbc/ordersDB data source.
10 Select the PRODUCT table in the ordersDB data source and drag it to the Design view canvas. A Product entity is
added to the model based on the database table. The database table consists of the following fields:
•
ProductId: Stores the identifier value of the item.
•
Description: Stores a description of the item.
•
Price: Stores the price of the item.
•
ProductName: Store the name of the item.
11 Switch to Source view, and add the code shown in bold to the Product entity:
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<entity name="Product" persistent="true">
...
<property name="discountPrice" type="float" expr="discount(price)"/><method
name="discount" arguments="p:float" return-type="float"/>
</entity>
The discountPrice property is a derived property that calls the discount method in its expression.
12 Save the model file to regenerate the ActionScript code.
13 Click the Deploy Model to LCDS server button. Accept the default settings and click OK.
Clicking OK generates a Model Assembler destination on the server for each entity in the model. You can call these
destinations from a Flex client to work with data stored in the database. By default, the model file is saved in the
WEB-INF/datamodel directory of the web application to which you deploy.
14 In the Package Explorer, expand the src folder.
15 Expand the ProjectName package, where ProjectName is the name of your Flash Builder project.
16 Double-click the _SuperProduct.as ActionScript class file to view it.
Note that the _SuperProduct class contains a discount() method stub generated from the discount method
element in the model.
17 Double-click the Product.as ActionScript class file to view it.
18 In the Product.as file, add the following method code below the END OF DO NOT MODIFY SECTION comment:
override public function discount (p:Number):Number
{
var discountPrice:Number = p - (p * .05);
return discountPrice;
}
19 Save the Product.as file. This customized file is not overwritten when you regenerate code for the project. Only the
superclass is overwritten; your customization is preserved.
Create and run a Flex client that uses a custom method
To use the client and server code generated from the model, create a Flex web client that has a simple master-detail
user interface. For detailed information, see “Building the client application” on page 372.
Complete the following steps to create a Flex web client:
1 Start the samples database if it isn’t already running.
2 Start your application server if it isn’t already running.
3 Start Flash Builder if it isn’t already running.
4 In Flash Builder, switch to Design view in the Flash perspective.
5 In the Package Explorer, expand the nodes of your Flex project to src > (default package) and open the displayed
MXML file.
6 Select the Components tab in the lower left side of the Flash Builder window.
7 Expand the Controls folder in the Components tree.
8 Drag the DataGrid control to the Design view canvas.
9 Select the Data/Services tab under the Design view canvas.
10 In the Data/Services view, expand the ProductService node.
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11 Drag the getAll():Product[] function to the DataGrid control. The DataGrid columns changes to match the
property names of the Product entity.
12 Right click the DataGrid control and select Generate Details Form.
13 Select Model Driven Form and click OK to generate a Form.
14 Reposition the form so that it is not covering the DataGrid control.
15 Run the application. The DataGrid control fills with data; the productService.getAll() function is called in the
DataGrid control’s creationComplete event handler.
The values of the discountPrice property in the DataGrid control and the form automatically display the value that
the Product.discount() method returns.
Note: Calling the getAll() function results in a call to the fill() method of the underlying DataService instance.
Customizing client-side code generation
Service wrappers, value objects, offline adapters, and model-driven forms are generated from FreeMarker templates.
FreeMarker is a Java-based template engine; for more information see freemarker.org.
You can generate and customize these templates to change the structure of the generated files. When you generate
templates, Flash Builder uses the generated templates instead of the default templates.
To extract templates for a Flash Builder project:
1 In the Flash Builder Package Explorer, right click your model file.
2 From the pop-up menu, select Data Model > Extract Templates For Active Generators to generate template files.
Note: You are prompted to replace an existing template file before it is overwritten.
You can change the location in which the templates are extracted in the Code Generation Preferences dialog. To
change the template locations:
1 Select Window > Preferences > Adobe > Data Model > Code Generation.
2 In the Code Generation dialog, select the Generator Configuration button for ActionScript Generation or Model
Driven Form and change the Template Lookup Path field.
3 Click OK.
The template files are searched for in the location specified in the Template Lookup Path. If they are not found in this
location, then default values are used. The lookup directory is where the extract operation places the files. The
following illustration shows the Template Lookup Path field.
Note: There is no guarantee that your customized template and generated code will work in future releases of LiveCycle
Data Services. Also, to apply a LiveCycle Data Services patch or update, you must extract the templates again.
Service wrapper templates
You can generate and customize the following template files for service wrapper classes:
Template file
Description
ASCustomServiceChild.ftl
Generates ServiceName.as for custom service
ASCustomServiceSuper.ftl
Generates _Super_ServiceName.as for custom service
ASDataManagementServiceChild.ftl
Generates ServiceName.as for Data Management Service
wrapper
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Template file
Description
ASDataManagementServiceSuper.ftl
Generates _Super_ServiceName.as for Data Management
Service wrapper
ASRPCServiceChild.ftl
Generates ServiceName.as for RPC service wrapper
ASRPCServiceSuper.ftl
Generates _Super_ServiceName.as for RPC service wrapper
By default, the templates are generated in the templates/as directory of the Flash Builder project.
The templates use the following tokens that correspond to Java classes to perform code generation. See the LiveCycle
Data Services Javadoc documentation for more information about the corresponding Java APIs.
Template token
Description
model
Corresponds to fiber.core.api.Model
service
Corresponds to fiber.core.api.Service
util
Corresponds to fiber.gen.as.utils.ASGenerationUtil
packageMap
Corresponds to Map of String to String: entity names to
package names
typeHelper
Corresponds to
fiber.gen.as.wrapper.ASServiceGenTypeHelper
termFormatter
Corresponds to fiber.gen.as.ASTermFormatter
To better understand the templates, see the related Javadoc, examine the source code of the generated classes, and see
Client code generation in the Application Modeling Technology Reference.
For information about the related ActionScript APIs, see:
• com.adobe.fiber.valueobjects
• com.adobe.fiber.services.wrapper.DataServiceWrapper
Value object templates
You can generate and customize the following templates for value object classes:
Template file
Description
ASValueObjectChild.ftl
Generates EntityName.as
ASValueObjectMetaData.ftl
Generates _EntityNameEntityMetadata.as
ASValueObjectSuper.ftl
Generates _Super_EntityName.as
By default, the templates are generated in the templates/as directory of the Flash Builder project.
The templates use the following tokens that correspond to Java classes to perform code generation. See the LiveCycle
Data Services Javadoc documentation for more information about the corresponding Java APIs.
Template token
Description
model
Corresponds to fiber.core.api.Model
entity
Corresponds to fiber.core.api.Entity
util
Corresponds to fiber.gen.as.utils.ASGenerationUtil
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Template token
Description
packageMap
Corresponds to Map of String to String: entity names to
package names
typeHelper
Corresponds to
fiber.gen.as.wrapper.ASServiceGenTypeHelper
termFormatter
Corresponds to fiber.gen.as.ASTermFormatter
To better understand the templates, see the related Javadoc, examine the source code of the generated classes, and see
Client code generation in the Application Modeling Technology Reference.
For information about the related ActionScript APIs, see:
• com.adobe.fiber.valueobjects
• com.adobe.fiber.services.wrapper.DataServiceWrapper
Offline adapter template
You can generate and customize the following template for offline adapter classes:
Template file
Description
ASOfflineAdapter.ftl
Generates EntityNameOfflineAdapter.as
By default, the template is generated in the templates/as directory of the Flash Builder project.
The template uses the following tokens that correspond to Java classes to perform code generation. See the LiveCycle
Data Services Javadoc documentation for more information about the corresponding Java APIs.
Template token
Description
offlineHelper
Corresponds to fiber.gen.as.offline.OfflineHelper
entity
Corresponds to fiber.core.api.Entity
util
Corresponds to fiber.gen.as.utils.ASGenerationUtil
packageMap
Corresponds to Map of String to String: entity names to
package names
typeHelper
Corresponds to
fiber.gen.as.wrapper.ASServiceGenTypeHelper
termFormatter
Corresponds to fiber.gen.as.ASTermFormatter
To better understand the templates, see the related Javadoc, examine the source code of the generated classes.
Model-driven form template
You can change the appearance of the model-driven form by customizing the following template:
Template file
Description
ASModelDrivenForm.ftl
Generates EntityNameForm.mxml and associated images
By default, the template is generated in the templates/as/form directory of the Flash Builder project. After modifying
the template, regenerate the form in Flash Builder to apply your changes.
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Model-driven applications
Typically, you modify the appearance of Flex components or change the location of components in the model-driven
form. For example, you can use standard Button images or a List control in place of a ComboBox control. The two
inputs to the model-driven form are the service wrapper and value object (data type) that are generated from an entity
in the model.
You can change the FreeMarker expressions that determine what code is generated around the service wrapper and
value object. However, this is an advanced task that requires knowledge of the Java and ActionScript modeling APIs.
The template uses the following tokens that correspond to Java classes to perform code generation. See the LiveCycle
Data Services Javadoc documentation for more information about the corresponding Java APIs.
Template token
Description
model
Corresponds to fiber.core.api.Model
entity
Corresponds to fiber.core.api.Entity
util
Corresponds to fiber.gen.as.utils.ASGenerationUtil
packageMap
Corresponds to Map of String to String: entity names to
package names
typeHelper
Corresponds to
fiber.gen.as.wrapper.ASServiceGenTypeHelper
termFormatter
Corresponds to fiber.gen.as.ASTermFormatter
To better understand the templates, see the related Javadoc, examine the source code of the generated MXML
component and the service wrapper and value object classes, and see Client code generation in the Application
Modeling Technology Reference.
For information about the related ActionScript APIs, see:
• com.adobe.fiber.valueobjects
• com.adobe.fiber.services.wrapper.DataServiceWrapper
Customizing server-side functionality
You can customize server-side functionality by modifying Java source files that are created when using Adobe
modeling technology. You can configure Flash Builder to create Java source files.
The Java source files are based on a model. Assume, for example, that you create a model that is based on a relational
database. Next assume that you want to implement application logic to track the date and time that a record was
deleted. You can modify Java source files to meet your business requirements. After you deploy the Java source files to
the J2EE application server, your application logic becomes part of the server-side functionality.
Note: The ability to generate Java source files that are based on a model was introduced in LiveCycle Data Services 3.1.
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The following illustration provides a visual representation of Java source files being created by using Adobe modeling
technology.
Data
Model
Java Source
Files
LiveCycle
Data Services
Relational
Database
Action Script
Classes
1
2
Flash Client Application
3
The Customizing server-side functionality section discusses how to modify Java source files are generated. For
information about modifying the ActionScript classes that are generated from a data model, see “Customizing clientside functionality” on page 341.
The following table describes the steps in this illustration.
Step
Description
1
A data model is created based an existing relational database.
2
Java source files and ActionScript classes are created based on the data model.
3
The Java source files are modified and deployed to the J2EE application server hosting LiveCycle Data
Services. Adobe modeling technology also creates ActionScript source files that you can use to develop
a client application.
Note: You can use any valid data model to generate Java source files, not just a data model based on a relational database.
The data model used in Customizing server-side functionality is based on a relational database.
Generated Java source files
The following Java source files are created for each entity in the data model:
• _Super_<entity>.java: The parent class that is overwritten for each generation. This class contains each identifier
value and data property in the entity as a member along with getter and setter functions. This class also contains
methods that an entity defines. The method contains implementation logic. In addition, both equals and hashcode
methods are created by using the identifier properties as the definition of equals. For example, objects with the same
id fields are equal. This class and its data properties are JPA annotated for use in the persistence layer. Do not
modify a _Super_<entity>.java file.
• <entity>.java: This class extends the super class, and is generated only once. It is an empty class that can be
customized with business logic. This class does contain at least one JPA annotation, @Entity, and possibly the
@IdClass and @Table annotations. This class is only generated if it does not exist.
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• <entity>PK.java: This class is generated when an entity has more than one id property. This class is also generated
when the id property is a persistent entity with more than one id property. The persistence layer for the entity uses
the Primary Key (PK) class. This class is JPA annotated for use in the persistence layer.
• <entity>BeanInfo.java: In the event of one or more properties in an entity with a name that does not conform to
the JavaBean standard, a BeanInfo class is generated for the entity class. This class provides the correct getter and
setter function names for the JavaBean API used by various parts of the service side logic.
• <entity>Assembler.java: This class extends the FiberAssembler class and is generated once. This class contains a
subset of the methods defined by the AbstractAssembler class which all delegate to the super class. This class is
provided as a base class for customization. It is not generated by default.
Note: The example in Customizing server-side functionality modifies the Assembler.java class. The application logic is
added to the deteteItem() method and tracks the date and time that a record was deleted.
Implementing an assembler method on the server
You can customize the Assembler.java class that is generated based on a data model. The data model created in
Implementing an assembler method on the server is based on the Product table. This table is located in the sample
database that is available with LiveCycle Data Services. The Product table consists of the following fields:
•
Products: Stores the identifier value of the item.
•
Description: Stores a description of the item.
•
Price: Stores the price of the item.
•
ProductName: Store the name of the item.
If you generate Java source files that are based on a data model that references the Product table, the following methods
are located in the ProductAssembler.java file. This assembler extends fiber.data.assemblers.FiberAssembler, which
extends flex.data.assemblers.AbstractAssembler.
Methods inherited AbstractAssembler:
•
count(): Retrieve the number of items for a given query.
•
createItem(): Creates an item (a new record).
•
deleteItem(): Deletes an item (an existing record).
•
fill(): Performs a fill operation.
•
getItem(): Retrieves an item with the specified map of identifier values.
•
updateItem(): Updates a specific item (a record).
Methods specific to FiberAssembler:
•
validateCreateItem(): Called by the createItem() method just before delegating to the persistence layer.
•
validateDeleteItem(): Called by the deleteItem() method just before delegating to the persistence layer.
•
validateUpdateItem(): Called by the updateItem() method just before delegating to the persistence layer.
You can customize an assembler method on the server to meet your business requirements. For example, you can
create application logic in the deleteItem() method that tracks the date and time when an item is deleted. In
addition, you can create application logic that prevents certain records from being deleted.
To customize the Assembler class as part of creating a client application, perform the following tasks:
1 Install LiveCycle Data Services, Flash Builder, and the application modeling plugin. (Common with the Build your
first model-driven application section.)
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2 “Configure a JDBC data source” on page 327. (Common with the Build your first model-driven application section.)
3 “Configure RDS on the server” on page 328. (Common with the Build your first model-driven application section.)
4 “Configure server-side debug logging” on page 328. (Common with the Build your first model-driven application
section.)
5 “Configure Flash Builder to use RDS” on page 329. (Common with the Build your first model-driven application
section.)
6 “Create a Flex project in Flash Builder” on page 329. (Common with the Build your first model-driven application
section.)
7 “Create a data model based on the Product table” on page 351. (Specific to this workflow.)
8 “Generate Java source files based on the data model” on page 353. (Specific to this workflow.)
9 “Generate Java source files based on the data model” on page 353. (Specific to this workflow.)
10 “Modify the Java source files” on page 353. (Specific to this workflow.)
11 “Deploy the Java source files to the J2EE application server” on page 356. (Specific to this workflow.)
12 “Modify the data model” on page 356. (Specific to this workflow.)
13 “Create and run a Flex client” on page 357. (Specific to this workflow.)
Note: The remaining sections discuss each of the steps marked as specific to this workflow in detail.
Create a data model based on the Product table
You can create a data model that is based on a relational database after the RDS server is configured. A data model is
created in Flash Builder. The example data model is based on a single table named Product. The data model is an FML
file that contains XML elements. After you create a data model, the FML file becomes part of your project. The
following illustration shows a visual representation of the Product data model in the Data Model perspective.
The following code example represents the corresponding Product.fml file.
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<model xmlns="http://ns.adobe.com/Fiber/1.0">
<annotation name="DMS">
<item name="datasource">java:/comp/env/jdbc/ordersDB</item>
<item name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</item>
</annotation>
<entity name="Product" persistent="true">
<annotation name="ServerProperties">
<item name="ServerType">LCDS</item>
</annotation>
<annotation name="DMS">
<item name="Table">PRODUCT</item>
</annotation>
<id name="productid" type="integer">
<annotation name="DMS">
<item name="ColumnName">PRODUCTID</item>
</annotation>
</id>
<property name="description" type="string" length="255">
<annotation name="DMS">
<item name="ColumnName">DESCRIPTION</item>
</annotation>
</property>
<property name="price" type="float">
<annotation name="DMS">
<item name="ColumnName">PRICE</item>
</annotation>
</property>
<property name="productname" type="string" length="255">
<annotation name="DMS">
<item name="ColumnName">PRODUCTNAME</item>
</annotation>
</property>
</entity>
</model>
1 From within the Package Explorer, right click your project and select New > Other.
2 In the New dialog, open the Data Model option.
3 Select Data Model and click Next.
4 In the New Data Model dialog, select your project.
5 In the Filename field, specify the filename for your model. Name your data model Product. Click Next.
6 Select the From A Database option. Click Next.
7 From the RDS Server drop-down list, select the RDS server that you configured.
8 From the Data Source drop-down, select the data source that you configured. Select
java:/comp/env/jdbc/ordersDB.
9 In the Table field, select the tables. Select Product.
10 Click Finish.
11 In the Package Explorer, select the FML file that represents your data model.
12 Right click and from the pop-up menu, select Data Model > Deploy Data Model To The LCDS Server.
13 In the Deploy Data Model dialog, select the server from the Server list.
14 In the Deploy Data Model dialog, keep the default data model name. Leave the overwrite option deselected.
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15 Select the Unchanged option for the Database Table options.
16 Click Finish. A confirmation message appears if the data model is successfully deployed to the J2EE application
server.
Note: When you redeploy a model to the server with the Update radio button selected, verify that your database tables are
updated correctly. There are situations where Hibernate does not drop table columns even though you have removed the
corresponding properties from entities in the model. This happens when a database owner (DBO) name is a prefix in the
table name; for example, PUBLIC.EMPLOYEE, where PUBLIC is the DBO name. There is no indication from Hibernate
or the Modeler that the update failed. You can work around this issue by removing the DBO name from the table name.
When looking for a table, Hibernate prepends the DBO (PUBLIC, in this case) to the table name. If the table name in the
model is already PUBLIC.EMPLOYEE, Hibernate looks for PUBLIC.PUBLIC.EMPLOYEE and fails to find it.
Generate Java source files based on the data model
After you create the data model, you can generate Java source files that are based on the data model. To generate Java
source files, you configure the Java Generator Configuration option within Flash Builder, as shown in the following
illustration.
In the Base Output Path field, specify the location where the Java source files are created. In this example, the Java
source files are written to the C:\JavaFiles directory. The Java source files are placed within a package name that
matches the data model name. For example, if the data model is named Product, then the package name is Product.
Click the Generate customizable skeleton assembler for each entity option to create an Assembler.java file. This file
contains methods that perform operations on the data. For example, this class contains a deleteItem() method that
can be customized.
1 From the Flash Builder menu, select Window > Preferences.
2 In the Preferences dialog, select Adobe > Data Model > Code Generation.
3 Select Default from the Java drop-down list to enable Java generation. (Java generation is disabled by default.)
4 Click Configure Generator.
5 Specify the directory location in which to write the generated Java source files.
6 Click the Generate Customizable Skeleton Assembler For Each Entity option to create an Assembler.java file.
7 Click OK.
8 Change the perspective in Flash Builder to Data Model.
9 From the toolbar above the Source view, click the Generate Code button.
Modify the Java source files
After you create the Java source files, you can modify them to meet your business requirements. For example, assume
that you want to track the date and time when a record was deleted. In this situation, add Java application logic to the
deleteItem() method that is located in the ProductAssembler.java file.
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To retrieve an item’s data values, create a Product instance that represents the deleted recorded by casting item to
Product. Then you can invoke a method to retrieve a data value. For example, you can invoke the getProductname()
method to get the item name, as the following example shows.
//Get the name and price of the item being deleted
Product myProduct = (Product)item;
Float myPrice = myProduct.getPrice();
String strPrice = myPrice.toString();
String strName = myProduct.getProductname();
The item object is a parameter of the deleteItem() method. You can only cast item to a strongly typed data type if
the cast value is based on a generated class that is deployed to LiveCycle Data Services. In this example, Product
represents the Product.java file that is generated and deployed to LiveCycle Data Services.
Likewise, you can retrieve the value of an item by using a PropertyProxy instance. Use the BeanProxy constructor and
pass item. Then retrieve the value by invoking the PropertyProxy instance’s getValue() method and pass a string
value that specifies the value to retrieve.
PropertyProxy p = new BeanProxy(item);
Float f = (Float) p.getValue("price");
You can also control whether to delete an item based on conditions such as a data value. For example, assume that you
do not want to delete a record where the item is a memory stick. You can add application logic to prevent a record
being deleted. The following example shows the modified deleteItem() method that tracks the date and time when
an item is deleted. If the user attempts to delete a record where an item is a memory stick, an exception is thrown.
public void deleteItem(Object item)
{
try
{
//Get the description and price of the item being deleted
Product myProduct = (Product)item;
Float myPrice = myProduct.getPrice();
String strPrice = myPrice.toString();
String strName = myProduct.getProductname();
File myFile = new File("C:\\log.txt");
BufferedWriter out = new BufferedWriter(new FileWriter(myFile));
//Do not allow flash memory to be deleted
if (strName.equals("memory stick"))
{
//Write a message to the log file that flash memory cannot be deleted
out.write("A record where item is memory stick cannot be deleted");
out.close();
//Throw an Exception
Exception myException = new Exception("A record where item
is memory stick cannot be deleted.");
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throw myException;
}
//Get the time when the item is deleted
String DATE_FORMAT_NOW = "yyyy-MM-dd HH:mm:ss";
Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
String myTime = sdf.format(cal.getTime());
//Write out the values to the log file
out.write("The "+strName+ " item priced at "+ strPrice +"
was deleted at: "+myTime);
out.close();
super.deleteItem(item);
}
catch (Exception e)
{
e.printStackTrace();
}
}
To modify Java source files, copy the Java files from the location specified by using the Generator Configuration option
to a Java IDE. When you copy the Java source files to your Java project, place the Java files within the correct package.
By default, the name of the package matches the name of the data model. The following illustration shows a Java
project with the Java source files. Notice that the package is named Product.
Add the LiveCycle Data Service JAR files to your project’s class path. The LiveCycle Data Service JAR files are located
in the following path:
[Install Directory]/lcds/tomcat/webapps/lcds-samples/WEB-INF/lib
where [Install Directory] is the LiveCycle Data Services installation location. Ensure that you add the following
JAR files to the class path:
• flex-messaging- core.jar
• flex-messaging-common.jar
•
flex-messaging-data.jar
•
hibernate-annotation.jar
•
ejb3-persistence.jar
•
fiber-lcds.jar
Within the Java IDE, you can modify the Java files to meet your business requirements. After you are done modifying
the Java source files, you can compile them.
Note: Instead of modifying the generated Assembler class, you can create your own Assembler class that extends
FiberAssembler . (See “Creating a Java class that extends a LiveCycle Data Services class” on page 21.)
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Deploy the Java source files to the J2EE application server
After you modify and compile the Java source files, package them into a JAR file. For example, if you are using Eclipse,
export your Java project as a JAR file. Place the JAR file in the application’s lib directory. Assuming that the application
is named lcds-samples, place the JAR file into the following directory:
[Install Directory]/lcds/tomcat/webapps/lcds-samples/WEB-INF/lib
where [Install Directory] is the LiveCycle Data Services installation location.
Modify the data model
After the JAR file is deployed to the J2EE application server hosting LiveCycle Data Services, modify the data model
to reference the modified Java classes. Ensure that your ProductAssembler Java class is used. To modify the data model,
use the Modeler in Flash Builder. Under Data Mgmt, add the value Product.ProductAssembler to the Assembler Class
option.
After you modify the data model to reference the ProductAssembler class, redeploy the data model to the server. For
more information about using the Modeler in Flash Builder, see the see the Application Modeling Technology
Reference.
1 Change the perspective to Data Model in Flash Builder. Make sure the view is in Design view.
2 Select the Product data model.
3 In the Properties view, select the Data Mgmt tab.
4 Change the Assembler Class option to Product.ProductAssembler.
5 Save the data model.
6 In Project Explorer, right click your data model file. From the pop-up menu, select Data Model > Deploy Data
Model To The LCDS Server.
7 In the Deploy Data Model dialog, select the server from the Server list.
8 In the Deploy Data Model dialog, keep the default data model name.
9 Select the overwrite option.
10 Click Finish. A confirmation message appears if the data model is successfully deployed to the J2EE application
server.
Note: If you do not deploy the JAR file that contains the Java classes, you are not able to redeploy the data model. This is
because the data model references the Java classes and cannot be deployed if the Java classes are not deployed.
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Create and run a Flex client
Create a client application in Flash Builder that is based on the data model. When you delete an item, the Java code
located in the assembler’s deleteItem() method tracks the date and time that the item was deleted.
The client application uses the deployed data model to bind data to its controls. In the previous illustration, notice that
data retrieved from the Product table is displayed in a DataGrid control:
Complete the following steps to create a Flex client:
1 Start the samples database if it isn’t already running.
2 Start your application server if it isn’t already running.
3 Start Flash Builder if it isn’t already running.
4 In Flash Builder, switch to Design view in the Flash perspective.
5 In the Package Explorer, expand the nodes of your Flex project to src > (default package) and open the displayed
MXML file.
6 Select the Components tab in the lower left side of the Flash Builder window.
7 Expand the Controls folder in the Components tree.
8 Drag the DataGrid control to the Design view canvas.
9 Set the editable property of the DataGrid to true.
10 Set the width of the DataGrid to 100%.
11 Select the Data/Services tab under the Design view canvas.
12 In the Data/Services view, expand the ProductService node.
13 Drag the getAll():Product[] function to the DataGrid control. Accept the default Bind To Data settings. The
DataGrid columns changes to match the property names of the Product entity.
14 Right click the DataGrid control and select Generate Details Form.
15 Select Model Driven Form and click OK to generate a Form.
16 Reposition the form so that it is not covering the DataGrid control.
17 Run the application. The DataGrid control should fill with data; the productService.getAll() function is called
in the DataGrid control’s creationComplete event handler.
Note: Calling the getAll() function results in a call to the fill() method of the underlying DataService instance.
18 Select a row in the DataGrid control to display details in the form.
19 Click Delete to delete an item from the database.
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Note: Deleting an item with the form results in a call to the deleteItem() method of the underlying DataService
instance.
When you delete an item, the Java code located in the assembler’s deleteItem() method tracks the date and time that
the item was deleted. If you delete row 4, a log file is created that contains the following information:
The case of cds items priced at 22.0 was deleted at: 2010-02-17 17:40:08.
Implementing an entity method on the server
You can add custom functionality to the server by adding new methods to the generated entity Java file. For example,
assume that you create business logic that discounts the price of items located in the Product table. You can add a new
property to the data model that stores the discounted price. To perform this task, modify the Product data model file
by adding a property element and method element to it, as shown in the following example:
<property name="discountPrice" type="float" expr="discount(price)">
</property>
<method return-type="float" arguments="p:float" name="discount"></method>
Note: You can add these element right before the closing </entity> tag. This adds a property named discountPrice to the
Product entity. Before reading this section, it is recommended that you first perform the steps specified in “Implementing
an assembler method on the server” on page 350. To reference this property on in the client application, you need to
implement the discount function in the ActionScript generated class. For information about modifying client application
logic, see “Customizing client-side functionality” on page 341.
Notice that the property element specifies a derived property named discountPrice. The derived property is
populated by using the expr attribute. In this example, the value of the expr attribute is discount(price). This value
references a method defined in the method element. When you generate Java source files by using the data model that
contains these elements, the super class contains a method named discount().
protected Float discount(Float p)
{
throw new UnsupportedOperationException("Function discount must be overridden");
}
You write the implementation of this method in the entity class, which extends the super class. That is, when the
_Super_Product class is generated, it contains the discount() method. You override the discount() method in the
Product class (the entity class) by defining the application logic.
The following example shows the implementation of the discount() method located in the Product class.
import javax.persistence.*;
@Entity
@Table(name="PRODUCT")
public class Product extends _Super_Product
{
public Float discount(Float p)
{
//discount the price by 5
Float myPrice = p - 5;
return myPrice ;
}
}
The return value of the discount() method represents the discount price.
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Note: To keep this example straightforward, the discount() method returns a static value by reducing the price by the
value five. However, you can add application logic to dynamically generate a value. For example, you can add application
logic that retrieves a value from a relational database.
You can retrieve the discount price value by creating an instance of Product. From within the Assembler class, you can
cast item to Product. Then you can invoke the Product instance’s discountPrice() method to get the discount price
value. The following code example shows the modified deleteItem() method in the ProductAssembler class. The
lines of code in bold represent the application logic that retrieves the discount price value.
public void deleteItem(Object item)
{
try
{
//Get the description and price of the item being deleted
Product myProduct = (Product)item;
Float myPrice = myProduct.getPrice();
String strPrice = myPrice.toString();
String strName = myProduct.getProductname();
File myFile = new File("C:\\log.txt");
BufferedWriter out = new BufferedWriter(new FileWriter(myFile));
System.out.println(strName);
//Do not allow flash memory to be deleted
if (strName.equals("memory stick"))
{
//Write a message to the log file that flash memory cannot be deleted
out.write("A record where item is memory stick cannot be deleted");
out.close();
//Throw an Exception
Exception myException = new Exception("A record where item is memory
stick cannot be deleted.");
throw myException;
}
//Get the time when the item is deleted
String DATE_FORMAT_NOW = "yyyy-MM-dd HH:mm:ss";
Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
String myTime = sdf.format(cal.getTime());
//Get the value of the discount priceFloat discountVal = myProduct.discount(myPrice);
//Write out the values to the log file
out.write("The "+strName+ " item priced at "+ strPrice +" was deleted at:
"+myTime);
out.close();
super.deleteItem(item);
}
catch (Exception e)
{
e.printStackTrace();
}
}
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In the previous code example, the value of discount price was retrieved by invoking the Product object’s
discountPrice() method. Instead of calling the method directly, you can use an EntityUtility object as shown in the
following code example. The EntityUtility is available from the superclass, FiberAssembler.
EntityUtility eu = entityUtilityFactory.getEntityUtility(entity);
Float discountPrice = (Float) eu.getPropertyValue("discountPrice", item);
Both ways return the same value. To implement an entity method on the server, follow the same steps that are specified
in “Implementing an assembler method on the server” on page 350. However, there are a few differences. First after
your create data model, ensure that you add the property element and method element to it as discussed earlier.
Next, when you modify the Java source files, modify both the Product class and the ProductAssembler class. In the
Product class, create the application logic for the discountPrice() method. In the ProductAssembler class, create an
instance of Product and invoke the discountPrice() method.
After you modify the Java source files, modify the data model and redeploy it to the server. (See “Modify the data
model” on page 356.)
Add the following DMS annotation to your data model to ensure that the modified Product class is used:
<item name="ServerGeneratedEntites">false</item>
Also ensure that the following annotation is present on the Product entity so that your ProductAssembler class is used:
<annotation name="DMS">
<item name="AssemblerClass">Product.ProductAssembler</item>
</annotation>
The following code example shows the FML file that contains the new annotations. The new lines are in bold.
<model xmlns="http://ns.adobe.com/Fiber/1.0">
<annotation name="DMS">
<item name="datasource">java:/comp/env/jdbc/ordersDB</item>
<item name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</item>
<item name="ServerGeneratedEntities">false</item>
</annotation>
<annotation name="group"/>
<entity name="Product" persistent="true">
<annotation name="ServerProperties">
<item name="ServerType">LCDS</item>
</annotation>
<annotation name="DMS">
<item name="AssemblerClass">Product.ProductAssembler</item>
<item name="Table">PRODUCT</item>
</annotation>
<annotation name="VisualModeler">
<item name="width">115</item>
<item name="height">110</item>
<item name="x">10</item>
<item name="y">10</item>
</annotation>
<id name="productid" type="integer">
<annotation name="DMS">
<item name="ColumnName">PRODUCTID</item>
</annotation>
</id>
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<property name="description" type="string" length="255">
<annotation name="DMS">
<item name="ColumnName">DESCRIPTION</item>
</annotation>
</property>
<property name="price" type="float">
<annotation name="DMS">
<item name="ColumnName">PRICE</item>
</annotation>
</property>
<property name="productname" type="string" length="255">
<annotation name="DMS">
<item name="ColumnName">PRODUCTNAME</item>
</annotation>
</property>
<property name="discountPrice" type="float" expr="discount(price)">
</property>
<method return-type="float" arguments="p:float" name="discount"></method>
</entity>
</model>
You can use the Modeler in Flash Builder to add these annotations to the data model. For more information about
using the Modeler in Flash Builder, see the see the Application Modeling Technology Reference.
Create the client application using Flash Builder, When you delete an item, the value of the discount price property is
written to the TXT file. (See “Create and run a Flex client” on page 357.)
Modifying Java template files
You can modify template files that are used to generate the Java source files. After you modify the template files and
generate the Java source files, the modifications appear in the generated Java source files. The template files are
FreeMarker files; for more information, see freemarker.org.
Each Java source file has a corresponding template file. You can extract and customize the following template files:
Template file
Description
JavaAssemblerSkeleton.ftl
Generates EntityNameAssembler.java
JavaBeanInfo.ftl
Generates EntityNameBeanInfo.java
JavaEntityBeanChild.ftl
Generates EntityName.java
JavaEntityBeanSuper.ftl
Generates _Super_EntityName.java
JavaIdBean.ftl
Generates EntityNamePK.java
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The template files are searched for in the location specified in the Template Lookup Path field (see the following
illustration). If they are not found in this location, then default values are used. The lookup directory is where the
extract operation places the files. The following illustration shows the Template Lookup Path field.
In this example, the template files are written to the C:\JavaFiles\templates directory.
Note: You are prompted to replace an existing template file before it is overwritten.
(Optional) To change the template lookup path:
1 From the Flash Builder menu, select Window > Preferences.
2 In the Preferences dialog, select Adobe > Data Model > Code Generation.
3 Click Configure Generator for Server-side Java Generation.
4 Enter a valid path in the Template Lookup Path field.
5 Click OK.
The templates use the following tokens that correspond to Java classes to perform code generation. See the LiveCycle
Data Services Javadoc documentation for more information about the corresponding Java APIs.
Template token
Description
model
Corresponds to fiber.core.api.Model
entity
Corresponds to fiber.core.api.Entity
util
Corresponds to fiber.gen.java.utils.JavaGenerationUtil
packageMap
Corresponds to Map of String to String: entity names to
package names
typeHelper
Corresponds to fiber.gen.java.wrapper.JavaTypeHelper
termFormatter
Corresponds to fiber.gen.java.JavaTermFormatter
To better understand the templates, see the related Javadoc and examine the source code of the generated classes.
Modify Java template files:
1 From the Flash Builder menu, select Window > Preferences.
2 In the Preferences dialog, select Adobe > Data Model > Code Generation.
3 Select Default from the Java drop-down list. (By default, this value is None.)
4 Click Configure Generator.
5 Specify the directory location in which template files are written in the Template Lookup Path field.
6 Click OK.
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7 In Project Explorer, right click your data model file. From the pop-up menu, select Data Model > Extract Templates
For Active Generators.
8 Open a template file from the location specified in the Template Lookup Path field.
9 Modify the FreeMarker template file to meet your business requirements.
10 Generate Java source files. (See “Generate Java source files based on the data model” on page 353.)
Note: There is no guarantee that your customized template and generated code will work in future releases of LiveCycle
Data Services. Also, to apply a LiveCycle Data Services patch or update, you must extract the templates again.
An example of modifying the template files
Assume, for example, that you want to modify the JavaAssemblerSkeleton.ftl so that only the deleteItem() method
appears. In this situation, you can open the JavaAssemblerSkeleton.ftl file in a text editor and remove all methods
except for the deleteItem() method, as shown in the following example.
<#--*************************************************************************
*
* ADOBE CONFIDENTIAL
* __________________
*
* Copyright 2010 Adobe Systems Incorporated
* All Rights Reserved.
*
* NOTICE: All information contained herein is, and remains
* the property of Adobe Systems Incorporated and its suppliers,
* if any. The intellectual and technical concepts contained
* herein are proprietary to Adobe Systems Incorporated and its
* suppliers and may be covered by U.S. and Foreign Patents,
* patents in process, and are protected by trade secret or copyright law.
* Dissemination of this information or reproduction of this material
* is strictly forbidden unless prior written permission is obtained
* from Adobe Systems Incorporated.
**************************************************************************-->
<#if packageMap.get(entity.getName() + "__Assembler")??>
<#assign packageName = packageMap.get(entity.getName() + "__Assembler") />
<#elseif packageMap.get(entity.getName())??>
<#assign packageName = packageMap.get(entity.getName()) />
<#else>
<#assign packageName = model.name />
</#if>
<#assign type=entity.getName() />
<#assign classname=util.formatAssemblerName(type) />
<#-- Body of generated value object -->
<#assign classbody>
public class ${classname} extends
${typeHelper.addImport("fiber.data.assemblers.FiberAssembler", false)}
{
/**
* Deletes an item.
*
* @param item the item to delete.
*/
@Override
public void deleteItem(Object item)
{
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super.deleteItem(item);
}
}
</#assign>
<#-- ====================================================================================== ->
<#-- Package declaration and imports -->
/**
* Skeleton Model Driven Assembler which you can use to customize behavior.
* This assembler manages the ${entity.getName()} entity.
*
* You do not need to use this class unless you need to customize the server
* side logic of an assembler operation (e.g. any of the CRUD operations).
*
* This class is only generated when there is no file already present
* at its target location. Thus custom behavior that you add here will
* survive regeneration if the model is modified.
*
* The following annotation must be present on the entity in the model
* in order for this class to be used by the server:
*
*
<entity name="${entity.getName()}">
*
<annotation name="DMS">
*
<item name="AssemblerClass">${packageName}.${classname}</item>
*
</annotation>
*
* If this annotation is not present, the server will use the default
* model driven assembler, even if this class is available on the server.
*
* Before deploying a model with the AssemblerClass value set,
* you will need to compile this class (and any associated classes) and place
* them in the classpath of the LCDS web application.
*
*/
package ${packageName};
<#list typeHelper.getImports() as imp>
<#if imp??>
import ${imp};
</#if>
</#list>
import fiber.data.services.ModelValidationException;
import java.util.List;
import java.util.Map;
import java.util.Collection;
import flex.data.PropertySpecifier;
${classbody}
After you modify the template files and generate the Java source files, the modifications appear in the generated Java
source files. For example, the ProductAssembler class contains only the deleteItem() method.
Generating database tables from a model
You can create a model from which you can generate tables in a SQL database and Model Assembler code for working
with the database from a Flex client.
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Complete these steps to generate database tables from a model:
1 Create a database in your database server or choose an existing database to work with.
2 Copy the driver JAR file for your database server to the WEB-INF/lib directory of your web application (for
example, the lcds-samples web application).
3
In the Modeler, create a model in your Flex project by clicking the Open Model for Active Project icon at the right
end of the Package Explorer icon bar. The new model is displayed.
4 Add the following annotation below the <model ...> element. The datasource value must match the name of the
JDBC data source you defined on your application server.
<annotation name="DMS">
<item name="datasource">java:/comp/env/jdbc/your_database_name</item>
</annotation>
5 Below the annotation, add entity elements with the ServerProperties annotation shown in the following example.
Application modeling technology generates a corresponding database table and Model Assembler destination for
each entity. The Table annotation is optional; if not specified, the generated table name matches the entity name.
<entity name="Thing1" persistent="true">
<annotation name="ServerProperties">
<item name="ServerType">LCDS</item>
</annotation>
<annotation name="DMS">
<item name="Table">THING1</item>
</annotation>
</entity>
6 Add at least one id element to each entity and add zero or more property elements to the entities. Application
modeling technology generates database columns for each id and property in an entity. The id and property
annotations are optional; if not specified, the generated table column names match the id and property names.
<entity name="Thing1" persistent="true">
<annotation name="ServerProperties">
<item name="ServerType">LCDS</item>
</annotation>
<annotation name="DMS">
<item name="Table">THING1</item>
</annotation>
<id name="orderlineid" type="integer">
<annotation name="DMS">
<item name="ColumnName">THING1ID</item>
</annotation>
</id>
<property name="quantity" type="integer">
<annotation name="DMS">
<item name="ColumnName">QUANTITY</item>
</annotation>
</property>
</entity>
Within persistent entities, an id property is a data property, the value of which represents part or all the identity of
the entity instance. Persistent entities must specify at least one id property. A property element can contain a data
property of any valid type, or a derived property for which the value is computed based on the values of data
properties.
7 Save the model to generate ActionScript service wrappers and value objects that represent each entity. You can see
these objects in the Flash Builder Data/Services panel.
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Note: There are several ways to create channels for client applications to contact the server. As a best practice,
manually create a channel set in your client MXML application, as described in “Configuring channels and endpoints”
on page 39. Alternatively, you can add channel set annotations in the model; for more information, see “Annotations
for client-side generation” in Application Modeling Technology Reference. A default channel is used if one is
configured on the server and you do not create a channel set in MXML or the model.
8 Click the Deploy Model to LCDS Server icon on the Modeler icon bar to deploy the model to the LiveCycle Data
Services server.
9 To the right of Database Tables, select Recreate. Click Finish. The model is deployed to the server and database
tables and Model Assembler destinations are generated on the server.
You can now populate the generated database tables using one of these methods:
• From a Flex client application that you create in Flash Builder
• Manually
• With a database script
Complete the following steps to quickly build a simple Flex user interface to populate your database and then display
data in the database.
Important: The model-driven form, which is used in this procedure, is a developer productivity aid only. It is not a general
solution for RIA form generation and development. Regenerating a model-driven form overwrites the existing form.
1 Open the default MXML file of your Flex project into the Flash Builder Design view.
2 From the Components panel, drag a DataGrid control onto the Design view stage.
3 In the Data/Services panel, drag the getAll() operation onto the DataGrid control. Dragging the operation to the
DataGrid control automatically binds the operation result to the DataGrid control.
4 In the Data/Services panel, right-click one of the listed data types and select Generate form > Model Driven Form.
5 Go to the Source view and find the code that references the generated form at the bottom of the MXML file. The
form is an MXML component saved in the src/ProjectName/forms directory of the Flex project.
6 Change the value of the form's valueObject attribute to: valueObject="{dataGrid.selectedItem as
YourDataType}" where YourDataType is the name of the data type you are working with.
7 Save the MXML application and run it.
8 You can use the Add button to add a new item of your specified data type. When you click the Save button, a new
instance of the data type is created on the client. On the server, a new instance of the data type is created and the
database is updated accordingly.
9 After adding and saving some items, refresh the browser to see that the items now exist in the database and are sent
back to the client.
10 Click an item in the DataGrid control and the form displays the details for that item.
Creating a client for an existing service destination
You can create a model-driven client that uses existing service destinations on the LiveCycle Data Services server. For
this type of application you use a Flash Builder service wizard to generate a model and corresponding ActionScript
code. This type of development is useful when you have existing destinations.
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Unlike entities that you use with model-driven destinations, you cannot deploy entities for existing destinations to the
server, so you cannot apply server-side (DMS) annotations. You can apply ActionScript-generation annotations that
apply only to the client. Note however that a model that contains entities generated from an existing destination is
overwritten if you re-import the destination; all manual changes are lost.
Note: You can combine entities that you create for model-driven destinations and entities for existing (not model-driven)
destinations in the same model. However, you cannot create relationships between the two types of entities.
Summary of steps
Perform the following tasks to build a model-driven client for an existing service destination:
1 Install LiveCycle Data Services and Flash Builder.
2 “Configure RDS on the server” on page 328 (Common with the Build your first model-driven application section.)
3 “Configure Flash Builder to use RDS” on page 329 (Common with the Build your first model-driven application
section.)
4 “Create a Flex project in Flash Builder” on page 329 (Common with the Build your first model-driven application
section.)
5 Import an existing service destination with a service wizard; you can import remoting, data management, and web
service destinations. (Specific to this workflow.)
6 “Building the client application” on page 372 (Common to general development.)
Import an existing remoting or data management destination
Complete these steps to generate ActionScript code for an existing Remoting Service or Data Management Service
destination on the server. The steps are slightly different for web service destinations; for more information, see
“Importing an existing web service destination” on page 368.
To import an existing Data Management Service destination configured in the data-management-config.xml file, the
destination must specify an item-class element. At least one fill-method element is required when the assembler
does not implement the Assembler interface. You cannot use this feature with destinations that use the SQL
Assembler. The following example shows a destination for an assembler that implements the Assembler interface.
<destination id="crm-company">
<properties>
<source>flex.samples.crm.company.CompanyAssembler</source>
<scope>application</scope>
<item-class>flex.samples.crm.company.Company</item-class>
<metadata>
<identity property="companyId"/>
</metadata>
</properties>
</destination>
1 From the Flash Builder Data menu, select Connect To Data/Service.
Flash Builder provides various ways to connect to the data service:
• Flash Builder Data menu
• Data/Services view Data menu
• Data/Services view context menu
2 In the Select Service Type dialog, select LCDS. Click Next.
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3 If you are prompted for a username and password, select No Password Required.
4 In the Import BlazeDS/LCDS Service dialog, select one of the listed destinations. For demonstration purposes,
select the ProductService Remoting Service destination.
5 Click Finish.
Flash Builder generates ActionScript classes that provide access to service operations from the client application.
The operations for the service are available in the Data/Services view.
Note: When connecting to a data service, Flash Builder needs to know the data type for the data returned by a service
operation. Many services define the type of returned data on the server (server-side typing). However, if the server does
not define the type, then the client application must configure the type for returned data (client-side typing). Flash
Builder indicates if this is required when you attempt to bind an operation to a user interface component. For more
information, see “Configuring return types for a data service operation” on page 376.
6 See “Building the client application” on page 372 for information on building a Flex client that uses the
ActionScript code generated from the model.
Note: You can enable client-side data management features for Flex applications that access Remoting Service
destinations. Client-side data management allows the synchronization of data updates on the server from the client
application. You can modify one or more items in a client application without making any updates to the server. You then
commit all the changes to the server with one operation. You can also revert the modifications without updating any data.
Importing an existing web service destination
1 From the Flash Builder Data menu, select Connect To Data/Service.
Flash Builder provides various ways to connect to the data service:
• Flash Builder Data menu
• Data/Services view Data menu
• Data/Services view context menu
2 In the Select Service Type dialog, select WebService. Click Next.
3 In the Specify WSDL to Introspect dialog, enter a service name.
4 Select a destination from the Destination list.
5 Under How Will Your Application Access The Web Service?, select Through A LiveCycle Data Service Proxy
Destination.
6 Click Next.
7 Select the web service operations you want to import. Click Finish.
Flash Builder generates ActionScript classes that provide access to service operations from the client application.
The operations for the service are available in the Data/Services view.
8 See “Building the client application” on page 372 for information on building a Flex client that uses the
ActionScript code generated from the model.
Manage data access from the server
Note: This content does not apply the Flex applications that use the Data Management Service in LiveCycle Data Services.
The Data Management Service provides server-side data management. This content describes client-side data
management and paging for RPC services.
Paging Paging is the incremental retrieval of large data sets from a remote service.
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For example, suppose you want to access a database that has 10,000 records and then display the data in a DataGrid
control that has 20 rows. You can implement a paging operation to fetch the rows in 20 set increments. When the user
requests additional data (scrolling in the DataGrid control), the next page of records is fetched and displayed.
Data management In Flash Builder, data management is the synchronization of updates to data on the server from
the client application. Using data management, you can modify one or more items in a client application without
making any updates to the server. You then commit all the changes to the server with one operation. You can also
revert the modifications without updating any data.
Data management involves coordinating several operations (create, get, update, delete) to respond to events from the
client application, such as updating an Employee record.
Enabling paging
To enable paging your data service must implement a function with the following signature:
getItems_paged(startIndex:Number, numItems:Number): myDataType
function name
You can use any valid name for the function.
startIndex
The initial row of data to retrieve.
The data type for startIndex should be defined as Number in the client
operation.
numItems
The number of rows of data to retrieve in each page.
The data type for numItems should be defined as Number in the client
operation.
myDataType
The data type returned by the data service.
When implementing paging from a service, you can also implement a count() operation. A count() operation
returns the number of items returned from the service. The count() operation must implement the following
signature:
count(): Number
function name
You can use any valid name for the function.
Number
The number of records retrieved from the operation.
Flex uses the count() operation to properly display user interface components that retrieve large data sets. For
example, the count() operation helps determine the thumb size for a scroll bar of a DataGrid control.
Some remote services do not provide a count() operation. Paging still works without a count operation, but the
control displaying the paged data might not properly represent the size of the data set.
Enable paging for an operation
This procedure assumes that you have coded both getItems_paged() and count() operations in your remote
service. It also assumes that you have configured the return data type for the operation, as explained in “Configuring
return types for a data service operation” on page 376.
1 In the Data/Services view, from the context menu for the getItems_paged() operation, select Enable Paging.
2 If you have not previously identified a unique key for your data type, specify the attributes that uniquely identify an
instance of this data type. Click Next.
Typically, this attribute is the primary key.
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3 Specify the count() operation. Click Finish.
Paging is now enabled for that operation.
In Data/Services view, the signature of the function that implements paging no longer includes the startIndex and
numItems parameters. These values are now dynamically added based on the user interface component that
displays the paged data.
Enabling client-side data management
Note: This content does not apply the Flex applications that use the Data Management Service in LiveCycle Data Services.
The Data Management Service provides server-side data management. This content describes client-side data
management.
To enable data management, implement one or more of the following functions, which are used to synchronize
updates to data on the remote server:
• Add (createItem)
• Get All Properties (getItem)
• Update (updateItem)
• Delete (deleteItem)
These functions must have the following signatures:
createItem(item:myDatatype):int
deleteItem(itemID:Number):void
updateItem((item: myDatatype):void
getItem(itemID:Number): myDatatype
function name
You can use any valid name for the function.
item
An item of the data type returned by the data service.
itemID
A unique identifier for the item, usually the primary key in the database.
myDataType
The data type of the item available from the data service. Typically, you define a
custom data type when retrieving data from a service.
Enable data management for an operation
This procedure assumes that you have implemented the required operations in your remote service. It also assumes
that you have configured the return data type for the operations that use a custom data type. See “Configuring return
types for a data service operation” on page 376.
1 In the Data/Services view, expand the Data Types node.
2 From the context menu for a data type, select Enable Data Management.
3 If you have not previously identified a unique key for your data type, specify the attributes that uniquely identify an
instance of this data type. Click Next.
Typically, this attribute is the primary key.
4 Specify the Add, Get All Properties, Update, and Delete operations. Click Finish.
Data management is now enabled for that operation.
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Configuring a data source
End-to-end model-driven development lets you generate Data Management Service destinations from models. To use
this functionality, configure a JDBC data source for each SQL database that you want to use. The RDS server uses this
data source to display database tables in the RDS Dataview panel of the Modeler. For more information about the RDS
server, see “Configure RDS on the server” on page 328.
How you configure a JDBC data source depends on the application server you use. For more information, see your
application server documentation.
On the Apache Tomcat server, you configure JDBC data sources in a context file. The default context file is
tomcat/conf/context.xml. You can also configure data sources in a context file for a specific host and web application;
for example, tomcat/conf/Catalina/localhost/web_app_name.xml file.
The following example shows a JDBC data source configuration:
<Context privileged="true" antiResourceLocking="false"
antiJARLocking="false" reloadable="true">
<Resource name="jdbc/ordersDB" type="javax.sql.DataSource"
driverClassName="org.hsqldb.jdbcDriver"
maxIdle="2" maxWait="5000"
url="jdbc:hsqldb:hsql://localhost:9002/ordersdb"
username="sa" password="" maxActive="4"/>
</Context>
Configuring RDS on the server
The lcds and lcds-samples web applications in LiveCycle Data Services include an RDS servlet that is preconfigured
but commented out in the WEB-INF/web.xml file.
For local development, you can use the RDS servlet without configuring application server security. However, this is
not recommended for any other type of deployment.
The following example shows an RDS servlet configuration in the WEB-INF/web.xml file with an init-param setting
that bypasses application server security:
<servlet>
<servlet-name>RDSDispatchServlet</servlet-name>
<display-name>RDSDispatchServlet</display-name>
<servlet-class>flex.rds.server.servlet.FrontEndServlet</servlet-class>
<init-param>
<param-name>useAppserverSecurity</param-name>
<param-value>false</param-value>
</init-param>
<load-on-startup>10</load-on-startup>
</servlet>
<servlet-mapping id="RDS_DISPATCH_MAPPING">
<servlet-name>RDSDispatchServlet</servlet-name>
<url-pattern>/CFIDE/main/ide.cfm</url-pattern>
</servlet-mapping>
By default, the RDS server uses application server security, and you configure a role named rds and assign a user to
that role.
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The following example shows the default RDS servlet configuration in the WEB-INF/web.xml file. Uncomment this
part of the file.
<servlet>
<servlet-name>RDSDispatchServlet</servlet-name>
<display-name>RDSDispatchServlet</display-name>
<servlet-class>flex.rds.server.servlet.FrontEndServlet</servlet-class>
<load-on-startup>10</load-on-startup>
</servlet>
<servlet-mapping id="RDS_DISPATCH_MAPPING">
<servlet-name>RDSDispatchServlet</servlet-name>
<url-pattern>/CFIDE/main/ide.cfm</url-pattern>
</servlet-mapping>
How you configure application server security depends on the application server you use. For more information, see
your application server documentation.
On the Apache Tomcat server, by default you configure users and roles in the tomcat-users.xml file in the tomcat/conf
directory. The following example shows a user and role configured for RDS in a tomcat-users.xml file:
<?xml version='1.0' encoding='utf-8'?>
<tomcat-users>
<role rolename="rds"/>
<user username="rdsuser" password="rdspassword" roles="rds"/>
</tomcat-users>
You must also configure custom authentication. For example, on Apache Tomcat, complete the following steps:
1 Locate the Tomcat security resource libraries under install_root/resources/security/tomcat. Place the flex-tomcat-
common.jar and flex-tomcat-server.jar files in the tomcat/lib directory.
2 Create or edit a context file for your web application. For example, for the lcds-samples web application, create or
add to an existing tomcat-root/conf/Catalina/localhost/lcds-samples.xml file. In that file, add the following line:
<valve classname="flex.messaging.security.TomcatValve"></valve>
3 For non-turnkey installations, make sure the TomcatLoginCommand is active in the <SECURITY> section of the
services-config.xml file:
<security><login-command server="Tomcat"></login-command>
...
</security>
Building the client application
Use the Flash Builder code editor to create a user interface. You can use the editor either in Design view or Source view.
You can also generate a form from service operations in the Data/Services view. You can generate a simple Flex form
or a model-driven form that takes advantage of advanced application modeling technology features provided on the
LiveCycle Data Service server.
Important: The model-driven form is a developer productivity aid only. It is not a general solution for RIA form
generation and development. Regenerating a model-driven form overwrites the existing form.
After laying out the components for the application, generate event handlers as needed for user interaction with the
application.
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Using Flash Builder Design view to build an application
In Design view of the MXML editor drag-and-drop components from the Components view into the Design Area.
Then arrange the components and configure their properties. After designing the application layout, bind data
returned from the data service to the components.
Controls
Flex provides a rich set of user-interface components such as Button, TextArea, and ComboBox controls. You place
controls in containers. Containers are user-interface components that provide a hierarchical structure for controls and
other containers.
Flex provides various data-driven controls that are ideal for displaying sets of data in lists, tables, or trees.
Data Controls
DataGrid
AdvancedDataGrid
OLAPDataGrid
List
TileList
Tree
Binding service operations to controls
There are several ways to bind a service operation to a control component. You can drag service operation from the
Data/Service view onto a component in Design view. You can also open the Bind to Data dialog to select an operation
to bind to a component.
When you bind a service operation to a control component, Flash Builder generates MXML and ActionScript code to
access the service operation from the client application.
Bind a service operation to a DataGrid control (drag-and-drop)
This procedure assumes that you have connected to a data service. It also assumes that you have configured the data
return type for a service operation so it returns a set of items.
1 In Design view, drag a DataGrid control from Components view to the editing area.
2 Drag an operation from the Data/Services view onto the DataGrid control.
The DataGrid control changes to show the fields retrieved from the database.
3 Customize the display of the DataGrid control.
4 Save and run the application.
Bind a DataGrid control to a service operation (Bind to Data dialog)
This procedure assumes that you have connected to a data service and the data return types for operations are
configured.
1 In Design view, drag a DataGrid control from Component view to the editing area.
2 Open the Bind to Data dialog using one of the following methods:
• Select Bind to Data from either the Flash Builder Data menu or the DataGrid context menu.
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• Select the Bind to Data button in the Property Inspector.
3 Select New Service Call, then select a Service and Operation.
4 (Optional) Select Change Return Type:
Select Change Return Type if you want to reconfigure the return type for the service operation.
If the return type for the operation has not configured appropriately, select Configure Return Type to continue.
5 Click OK.
The DataGrid control changes to show the fields retrieved from the service.
6 Customize the display of the DataGrid control.
7 Save and run the application.
Generating a form for an application
Flash Builder can generate several types of forms for accessing data services.
Form
Description
Custom data type
Contains entries for each field of a custom
data type for a service
Master -detail form
Contains entries for a selected item in a
data control, such as a DataGrid or a List
Service call
Displays the data returned from a service
call
When generating forms, specify which fields to include and whether to make the form editable. You can also specify
the type of user interface control to represent the form items.
When working with end-to-end model-driven development, you can generate a model-driven form that takes
advantage of advanced application modeling technology features provided on the LiveCycle Data Service server.
Important: The model-driven form is a developer productivity aid only. It is not a general solution for RIA form
generation and development. Regenerating a model-driven form overwrites the existing form.
Generating a form for a service call
This procedure assumes that you have connected to a data service and that you are in Design view of the MXML Editor.
This procedure shows how to generate a form for a service call. The procedure for generating other types of forms are
similar.
1 There are several ways to run the Generate Form wizard:
• From the Data/Service view, select an operation from the context menu. Select Generate Form.
• From the Flash Builder Data menu, select Generate Form or Generate Details Form.
• Select a Data Control in Design view. From the context menu, select Generate Details Form.
2 In the Generate Form wizard, select Generate Form For Service Call.
3 Select New Service Call, then specify the Service and Service Operation.
4 Configure the return type (or change the return type) for the selected operation if necessary.
The return type for the operation must be configured before you can generate the form. If you previously
configured a return type, you have the option to change the return type.
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See “Configuring return types for a data service operation” on page 376.
5 Specify whether to include forms for input parameters and return type.
6 Specify whether to make the form editable. Click Next.
7 In the Property control Mapping dialog, select which fields to include in the form and the type of control to
represent the data.
8 Click Finish.
Generating a model-driven form
Important: The model-driven form is a developer productivity aid only. It is not a general solution for RIA form
generation and development. Regenerating a model-driven form overwrites the existing form.
Follow this procedure to generate a model-driven form that takes advantage of advanced application modeling
technology features provided on the LiveCycle Data Services server.
A model-driven form that has a *-to-one association to a non-model-driven assembler generates a line of code similar
to the following, in which you must manually enter valid fill parameters:
var accountCategoryToken:AsyncToken = new
AccountCategoryService().fill(INSERT_CORRECT_FILL_PARAMETERS_HERE);
If you try to compile the application without entering fill parameters, the compiler issues the following error:
Access of undefined property INSERT_CORRECT_FILL_PARAMETERS_HERE
This procedure assumes that you have connected to a data service and that you are in Design view of the MXML Editor.
This procedure shows how to generate a form for a data type. The procedure for generating other types of forms are
similar.
1 Right-click a DataGrid control to which you have bound data and select Generate Details Form.
2 Select Model Driven Form and click OK to generate a Form.
3 Reposition the form so that it is not covering the DataGrid control.
4 Run the application. The DataGrid control should fill with data; the productService.getAll() function is called
in the DataGrid control’s creationComplete event handler.
Note: Calling the getAll() function results in a call to the fill() method of the underlying DataService instance.
5 Select a row in the DataGrid control to display details in the form.
Using global styles with a model-driven form
If you generate a model-driven form for an entity with a property that uses a global style, at run time the form label for
that property is replaced with the style's caption text. The default caption message is "Caption." To work around this
issue, you can use one of three options:
• Delete the caption message of the global style in Source view
• Use an inline style instead of a global style
• Use a bundle and key instead of the caption text property
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Using required properties with a model-driven form
When a model-driven form is generated from an entity that contains a required property, the generated ActionScript
code does not check for empty strings. To ensure that a property is required and that empty data is not sent to the
server, in the model set required attribute of the property to true and also use a constraint element that constrains the
length of the property to a minimum length.
Generating event handlers
When you bind a data service operation to a component, Flash Builder generates an event handler that retrieves data
from the service to populate the component.
For example, if you bind an operation such as getAllItems() to a DataGrid control, Flash Builder generates a
creationComplete event handler.
<DataGrid creatonComplete="getAllItemsResult.token = productService.getAllItems()" ... >
When you run the application, once the DataGrid control has been created, it populates itself with data retrieved from
the service.
You can accept the generated event handlers or replace them with others according to your needs. For example, you
can replace the creationComplete event handler on the DataGrid control with a creationComplete handler on the
Application.
You can also generate or create event handlers for controls that accept user input, such as Buttons or Text. Do either
of the following to generate event handlers:
• From the Data/Services view, drag an operation onto the control.
Flash Builder generates an event handler for the default event for the component. For example, for a Button, the
event handler would be the Click event.
• In Design view, select the control and then in the Property Inspector, click the generate event icon.
Flash Builder opens the Source view of the editor and generates a stub for the event handler.
Fill in the remaining code for the event handler. Flash Builder provides Content Assist to help you code the event
handler.
Configuring return types for a data service operation
When connecting to a data service, Flash Builder needs to know the data type for the data returned by a service
operation. The data types supported are those types recognized by AMF.
Many services define the type of returned data on the server (server-side typing). This is always the case when working
Data Management Service destinations. However, if the server does not define the type, then the client application
must configure the type for returned data (client-side typing).
When configuring return types for client-side typing, the data type can be an ActionScript data type, a custom data
type representing complex data, or void to indicate the operation does not return any data. The following table lists
possible data types for client-side typing.
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Data Type
Description
ActionScript types
Boolean
Boolean[]
Date
Date[]
int
int[]
Number
Number[]
String
String[]
No data returned
void
User-defined type
CustomType
CustomType[]
Typically, you define custom data types for service operations that return complex data.
Flash Builder code generation
Flash Builder generates client code that provides access to remote service operations. Flash builder generates code in
the following circumstances:
• Saving a model in a Flash Builder project.
• Refreshing the data service in Data/Services view
• Configuring a return type for an operation
• Binding a service operation to a user interface control
• Enabling client-side paging for a service operation. Does not apply to Data Management Service applications.
• Enabling client-side data management for a service operation. Does not apply to Data Management Service
applications.
Service classes
When you connect to a service, Flash Builder generates an ActionScript class file that provides access to the service
operations.
Flash Builder bases the name of the generated class file on the name you provided for the service in the service wizard.
By default, Flash Builder places this class in a package under src. The name of the package is based on the service name.
For example, Flash Builder generates the following ActionScript classes for an EmployeeService class.
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- project
|
- src
|
+
|
|
|
-
(default package)
services.employeeservice
_Super_EmployeeService.as
EmployeeService.as
The super class contains the implementation for the EmployeeService class.
Never edit the super class, which is a generated class. Modifications you make to the super class can be overwritten.
Any changes you make to the implementation might result in undefined behavior.
In this example, use EmployeeService.as to extend the generated super class and add your implementation.
Classes for custom data types
Many remote data services provide server-side typing. These services return complex data as a custom data type.
For remote data services that do not return typed data, Flash Builder provides client-side typing. With client-side
typing, you use the Flash Builder Configure Operation Return Type dialog to define and configure the data type for
complex data returned by the service. For example, for a service that returns employee database records, you define
and configure an Employee data type.
Flash Builder generates an ActionScript class for the implementation of each custom data type returned by the service.
Flash Builder uses this class to create value objects, which it then uses to access data from the remote service.
For example, Flash Builder generates the following ActionScript classes for an Employee class:
- project
|
|
+
|
|
|
-
src
(default package)
services.employeeservice
_Super_Employee.as
Employee.as
The superclass contains the implementation for the Employee custom data type.
Never edit the superclass, which is a generated class. Modifications you make to the superclass can be overwritten. Any
changes you make to the implementation might result in undefined behavior.
In this example, use Employee.as to extend the generated superclass and add your implementation.
Note: Applications that use generated value objects but not generated service wrappers, should call the object’s
_initRemoteClassAlias() method before retrieving any instances of the object from the server, if there are no other
references to the object prior to the retrieval.
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Binding a service operation to a user interface control
“Binding service operations to controls” on page 373 shows how you can bind data returned from service operations
to a user interface control. When you bind a service operation to a control, Flash Builder generates the following code
when you use Flex SDK 4. For Flex SDK 3.4, the same functionality is achieved using Flex SDK 3.4 syntax.
• Declarations tag containing a CallResponder and service tag
• Event handler for calling the service call
• Data binding between the control and the data returned from the operation
Note: The Declarations tag and CallResponder object do not apply to Flex SDK 3.4.
Declarations tag
A Declarations tag is an MXML element that declares non-default, non-visual properties of the current class. When
binding a service operation to a user interface, Flash Builder generates a Declarations tag containing a CallResponder
and a service tag. The CallResponder and generated service class are properties of the container element, which is
usually the Application tag.
The following example shows a Declarations tag providing access to a remote EmployeeService:
<fx:Declarations>
<s:CallResponder id="getAllItemsResult"/>
<employeesvc:EmployeeSvc id="employeeSvc" destination="ColdFusion"
endpoint="http://localhost:8500/flex2gateway/"
fault="Alert.show(event.fault.faultString)" showBusyCursor="true"
source="EmployeeService.EmployeeSvc"/>
</fx:Declarations>
Call Responder
A CallResponder manages results for calls made to a service. It contains a token property that is set to the Async token
returned by a service call. The CallResponder also contains a lastResult property, which is set to the last successful
result from the service call. You add event handlers to the CallResponder to provide access to the data returned
through the lastResult property.
When Flash Builder generates a CallResponder, it generates an id property based on the name of the service operation
to which it is bound. The following code sample shows CallResponders for two operations of an EmployeeService. The
getAllItems operation is bound to the creationComplete event handler for a DataGrid control. The delete operation is
bound to the selected item in the DataGrid control. The DataGrid control displays the items retrieved from the
getAllItems service call immediately after is created. The Delete Item Button control removes the selected record in the
DataGrid control from the database.
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<fx:Declarations>
<s:CallResponder id="getAllItemsResult"/>
<employeeservice:EmployeeService id="employeeService" destination="ColdFusion"
endpoint="http://localhost:8500/flex2gateway/"
fault="Alert.show(event.fault.faultString)"
showBusyCursor="true" source="CodeGenCF.CodeGenSvc"/>
<s:CallResponder id="deleteItemResult"/>
</fx:Declarations>
<mx:DataGrid id="dg" editable="true"
creationComplete="getAllItemsResult.token =
employeeService.getAllItems()"dataProvider="{getAllItemsResult.lastResult}">
<mx:columns>
<mx:DataGridColumn headerText="emp_no" dataField="emp_no"/>
<mx:DataGridColumn headerText="last_name" dataField="last_name"/>
<mx:DataGridColumn headerText="hire_date" dataField="hire_date"/>
</mx:columns>
</mx:DataGrid>
<s:Button label="Delete Item"
click="deleteItemResult.token = employeeService.deleteItem(dg.selectedItem.emp_no)"/>
Event handlers
When you bind a service operation to a user interface component, Flash Builder generates an inline event handler for
the CallResponder. The event handler manages the results of the operation. You can also create an event handler in an
ActionScript code block, and reference that event handler from a property of a user interface component.
Typically, you populate controls such as Lists and DataGrids with data returned from a service. Flash Builder, by
default, generates a creationComplete event handler for the control that executes immediately after the control is
created. For other controls, Flash Builder generates a handler for the control’s default event. For example, for a Button,
Flash Builder generates an event for the Button’s click event.
Flash Builder generates inline event handlers. The ActionScript code for the event handler is set directly in the event
property of the control. The following example shows the generated creation complete event handler for a DataGrid
control:
<mx:DataGrid id="dg" editable="true"
creationComplete="getAllItemsResult.token = employeeService.getAllItems()"
dataProvider="{getAllItemsResult.lastResult}">
<mx:columns>
<mx:DataGridColumn headerText="emp_no" dataField="emp_no"/>
<mx:DataGridColumn headerText="last_name" dataField="last_name"/>
<mx:DataGridColumn headerText="hire_date" dataField="hire_date"/>
</mx:columns>
</mx:DataGrid>
You can also create event handlers in ActionScript blocks and reference the event handler from the event property of
the control. The following example shows the same event handler for a DataGrid control implemented in an
ActionScript block.
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<mx:Script>
<![CDATA[
import mx.events.FlexEvent;
import mx.controls.Alert;
protected function dg_creationCompleteHandler(event:FlexEvent):void
{
getAllItemsResult.token = employeeService.getAllItems();
}
]]>
</mx:Script>
. . .
<mx:DataGrid id="dg"
creationComplete="dg_creationCompleteHandler(event)"
dataProvider="{getAllItemsResult.lastResult}">
<mx:columns>
<mx:DataGridColumn headerText="emp_no" dataField="emp_no"/>
<mx:DataGridColumn headerText="last_name" dataField="last_name"/>
<mx:DataGridColumn headerText="hire_date" dataField="hire_date"/>
</mx:columns>
</mx:DataGrid>
You can also generate event handlers for controls that respond to user events, such as Buttons. The following example
shows a generated event handler for a Button that populates a DataGrid control:
<mx:Button label="Delete Item" click="deleteItemResult.token =
employeeService.deleteItem(dg.selectedItem.emp_no)"/>
You can also implement the event handler for the Button in an ActionScript block:
<mx:Script>
<![CDATA[
import mx.controls.Alert;
protected function delete_button_clickHandler(event:MouseEvent):void
{
deleteItemResult.token =
employeeService.deleteItem(dg.selectedItem.emp_no);
}
]]>
</mx:Script>
. . .
<mx:Button label="Delete Item" id="delete_button"
click="delete_button_clickHandler(event)"/>
Data binding
Flash Builder generates code that binds the data returned from a service operation to the user interface control that
displays the data. The following example code that Flash Builder generates to populate a DataGrid control. The
getAllItems operation returns a set of employee records for the custom data type, Employee.
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The dataProvider property of the DataGrid control is bound to the results stored in the CallResponder,
getAllItemsResult. Flash Builder automatically updates the DataGrid control with DataGridColumns corresponding
to each field returned for an Employee record. The headerText and dataField properties of each column are set
according to the data returned in an Employee record.
<mx:DataGrid creationComplete="datagrid1_creationCompleteHandler(event)"
dataProvider="{getAllItemsResult.lastResult}" editable="true">
<mx:columns>
<mx:DataGridColumn headerText="gender" dataField="gender"/>
<mx:DataGridColumn headerText="emp_no" dataField="emp_no"/>
<mx:DataGridColumn headerText="birth_date" dataField="birth_date"/>
<mx:DataGridColumn headerText="last_name" dataField="last_name"/>
<mx:DataGridColumn headerText="hire_date" dataField="hire_date"/>
<mx:DataGridColumn headerText="first_name" dataField="first_name"/>
</mx:columns>
</mx:DataGrid>
Enabling client-side paging for a service operation
Note: This content does not apply the Flex applications that use the Data Management Service in LiveCycle Data Services.
The Data Management Service provides server-side data management. This content describes client-side data
management and paging for RPC services.
When you enable paging, Flash Builder modifies the implementation of the generated service. When you populate a
data control (such as a DataGrid or a List) with paged data, Flash Builder determines the number of records visible in
the data control and the total number of records in the database. Flash Builder provides these values as arguments to
the service operation that you used to implement paging.
You do not have to modify any client application code after paging is enabled.
See “Enabling paging” on page 369 for more information.
Enabling client-side data management for a service
Note: This content does not apply the Flex applications that use the Data Management Service in LiveCycle Data Services.
The Data Management Service provides server-side data management. This content describes client-side data
management and paging for RPC services.
In Flash Builder, data management is the synchronization of a set of updates to data on the server. You can enable data
management for custom data types returned from the service. With data management enabled, you can modify one or
more items in a client application without making any updates to the server. You can then commit all the changes to
the server with one operation. You can also revert the modifications without updating any data on the server.
“Enabling client-side data management” on page 370 shows how to implement this feature.
When you enable data management, Flash Builder modifies the implementation of the generated service class and the
generated class for custom data types. Flash Builder creates a DataManager to implement this functionality.
When you call service operations for a managed data type, the changes are reflected in the client application. However,
data on the server is not updated until you call the DataManager’s commit() method. The DataManager also provides
a revertChanges() method that restores the data displayed in the client application to the values retrieved from the
server before the last commit() call.
To access the commit() and revertChanges() methods for a managed type, first get the DataManager for the type,
and then call the methods. For example, if you have an instance of employeeService and enabled data management for
the Employee data type, then you would do the following:
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employeeService.getDataManager (employeeService.DATA_MANAGER_EMPLOYEE).revertChanges();
employeeService.getDataManager (employeeService.DATA_MANAGER_EMPLOYEE).commit();
You can also call the commit() method directly from the employeeService instance. Calling the commit() method
directly from the service instance commits all changes for all managed data types.
employeeService.commit();
Note: You cannot call revertChanges() directly from the service instance.
Using server-side logging with the Model Assembler
As an extension of the Hibernate Assembler, the Model Assembler passes back any errors as is. The Model Assembler
provides additional validation on instances and throws errors when validation fails. To log messages from the Model
Assembler, use the Service.Data.Fiber logging filter pattern in the logging section of the services-config.xml file. For
additional information from the Hibernate Assembler, use the Service.Data.Hibernate filter pattern. For information
about server-side logging, see “Logging” on page 420.
Setting Hibernate properties for a model in a Hibernate
configuration file
The Model Assembler lets you set Hibernate properties in an annotation by prefixing the Hibernate property name
with hibernate. You can also set Hibernate properties for a specific model by creating a file with the property settings.
The file must use the following naming convention:
modelName.hibernate.cfg.xml
where modelName is the name of the model. You must create the file in the WEB-INF/classes directory of your
LiveCycle Data Services server.
The WEB-INF/classes directory can contain other Hibernate configuration files, such as the global configuration file,
hibernate.cfg.xml. The Model Assembler only searches for the configuration file for the model; it does not use the
global configuration file.
More Help topics
“Hibernate configuration files” on page 278
Configuring the model deployment service
The model deployment service deploys models when the LiveCycle Data Services server starts up. By default, the
service uses the WEB-INF/datamodel directory in the web application. You can configure an alternative storage
directory. If you change the directory, use a full directory path.
The following example shows all possible elements of a model deployment service configuration in the servicesconfig.xml file:
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<service class="fiber.data.services.ModelDeploymentService" id="model-deploy-service">
<properties>
<model-persistence-class>
fiber.data.services.FilePersistence
</model-persistence-class>
<model-persistence-directory>
/path/to/model/directory
</model-persistence-directory>
</properties>
</service>
Note: The default file persistence mechanism is not supported for WAR file (unextracted) web application deployment.
Entity utility
The entity utility, fiber.runtime.entity.EntityUtility, provides server-side (Java) access to behavioral aspects of an entity
object that represents an application modeling technology entity and to metadata of the relevant entity. Behavioral
aspects include derived property calculation, validation with respect to constraints and validations (in styles), and
availability of properties inside variants. The property proxy of the entity utility provides APIs for getting and setting
properties of an entity object, which enables the entity utility to deal with many varying representations of entity
objects.
The Model Assembler uses the entity utility for validation checking before every create and update operation. This
happens automatically. Only data properties are sent across the wire to the server so these are the only properties
populated on the entity object available to the Model Assembler. Before committing this object to the database, the
Model Assembler checks its validity. During validation calculation, the Model Assembler may use other entity utility
functions, such as derived property calculation and availability calculations.
If you use the Model Assembler, the entity utility cannot perform validation calculations that involve function and
method calls unless implementations of those functions and methods are provided on the server. You can plug in your
own function and method implementations.
If you use a custom assembler that extends the Model Assembler, you can use all other functionality of the entity utility.
You must use the property proxy of the entity utility to set and get values on entity objects. If you write your own
server-side implementation that does not use the Model Assembler or extend it, you can utilize all of the functionality
of the entity utility.
The property proxy lets the entity utility handle different representations of entity objects. For example, the Model
Assembler uses byte-code-generated Hibernate beans to represent entity instances.
Functions of the entity utility
Validation
The fiber.runtime.entity.EntityUtility interface defines validation of constraints and validation expressions in the
following methods. For more information, see the Javadoc API documentation for the EntityUtility interface.
• A validate() method that evaluates all of the constraints of the entity object that is passed in. The method returns
true only if they are all valid.
• A validate() method that evaluates all of the constraints of the entity object passed in except those whose names
are included in a set of constraints to exclude. The method returns true only if the non-excluded constraints are
valid.
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• A validateSubsetOfConstraints() method that evaluates only the constraints whose names are included in a
collection of constraints to evaluate. The method return true only if all of the named constraints are valid.
Derived property calculation
The fiber.runtime.entity.EntityUtility interface defines several versions of the populateDerivedProperties()
methods for calculating the derived properties of an entity object. Consumers can perform the following operations:
• Pass in an entity object and a property name to request a single derived property