Guide to SAS/AF Applications Development ® SAS

Guide to SAS/AF Applications Development ® SAS
Guide to SAS/AF
Applications Development
®
SAS ® Documentation
The correct bibliographic citation for this manual is as follows: SAS Institute Inc. 2011. Guide to SAS/AF® Applications Development. Cary, NC:
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Guide to SAS/AF® Applications Development
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Contents
About This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Recommended Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
PART 1
Introducing the SAS/AF Development Environment
1
Chapter 1 • The Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
What Is SAS/AF Software? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 2 • An Applications Development Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Using SAS Tools to Develop Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Steps to Developing SAS/AF Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
PART 2
Developing Applications
11
Chapter 3 • Tools for the Applications Developer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
About the SAS/AF Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Build Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Components Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Properties Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Source Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Chapter 4 • Developing Frames with Ready-Made Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Working with Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Selecting Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Re-using Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Defining Attachments to Enable Automatic Component Resizing . . . . . . . . . . . . . . . . 25
Chapter 5 • Communicating with Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Attribute Linking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Model/View Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Drag and Drop Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Chapter 6 • Adding SAS Component Language Programs to Frames . . . . . . . . . . . . . . . . . . . . 35
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Working with Frames and SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
When Frame SCL Is Not Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
When Frame SCL Is Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Constructing a Frame SCL Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Controlling the Execution of SCL Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Calling Other Entries and Opening Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Compiling and Testing Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
iv Contents
Debugging and Optimizing Your Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Saving and Storing Frame SCL Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Chapter 7 • Adding Application Support Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Implementing Custom Menus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Adding Online Help to Your Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Chapter 8 • Deploying Your Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Application Deployment Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Migrating Your Application from Testing to Production . . . . . . . . . . . . . . . . . . . . . . . . 58
Configuring a SAS Session for Your Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Enabling the Application for Your Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
PART 3
Developing Custom Components
65
Chapter 9 • Tools for the Component Developer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Class Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Resource Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Interface Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Source Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Other Development Tools and Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Chapter 10 • SAS Object-Oriented Programming Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Object-Oriented Development and the SAS Component Object Model . . . . . . . . . . . . 73
Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Event Handlers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Chapter 11 • Developing Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Creating Your Own Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Creating a Class with SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Using SCL to Instantiate Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Chapter 12 • Managing Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Implementing Methods with SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Overriding Frame Methods to Augment SCL Labeled Sections . . . . . . . . . . . . . . . . . 113
Chapter 13 • Managing Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Specifying a Component's Default Attribute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Validating the Values of Character Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Assigning an Editor to an Attribute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Adding a Custom Attributes Window to a Component . . . . . . . . . . . . . . . . . . . . . . . . 119
Assigning a Custom Access Method (CAM) to an Attribute . . . . . . . . . . . . . . . . . . . . 121
Using the Refresh Attributes Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Using List Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Chapter 14 • Adding Communication Capabilities to Components . . . . . . . . . . . . . . . . . . . . . 129
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Enabling Attribute Linking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Contents
v
Implementing Model/View Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Enabling Drag and Drop Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Modifying or Adding Event Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Chapter 15 • Deploying Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151
Managing Classes with Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Making a New Class Available for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154
Generating Class Documentation with GenDoc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
PART 4
Appendixes
161
Appendix 1 • Flow of Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
How SCL Programs Execute for FRAME Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . .163
Flow of Control for Frame SCL Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Appendix 2 • Adding Attachments to Frame Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179
Selecting the Attachment Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Initiating Define Attachment Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Selecting the Direction and Type for the Attachment . . . . . . . . . . . . . . . . . . . . . . . . . 182
Making the Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186
Defining Attachments to Sibling Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .188
Defining Attachments to Components That Have Borders . . . . . . . . . . . . . . . . . . . . . 189
Moving Multiple Components That Include Attachments . . . . . . . . . . . . . . . . . . . . . .190
Restricting Component Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190
Changing and/or Deleting an Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Displaying Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Situations in Which an Attachment Is Ignored . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .193
Errors and Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Tips for Using Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Appendix 3 • Working with SAS/AF Keys in the SAS Registry . . . . . . . . . . . . . . . . . . . . . . . . . 197
About the SAS Registry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
SAS Registry Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .197
Modifying the Registry Settings for SAS/AF Software . . . . . . . . . . . . . . . . . . . . . . . .198
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
vi Contents
vii
About This Book
Audience
SAS/AF software provides IS and IT developers the tools that they need to build
enterprise-wide applications that can be integrated with the features and functionality of
other SAS software products. Whether you are a component designer who defines the
architecture and creates class libraries, or an application developer who uses the supplied
components to create applications, this book provides a single reference to begin
developing applications with SAS software.
Requirements
To use the SAS/AF development environment requires a graphics display device capable
of displaying the Graphics Editor in SAS/GRAPH output.
You can run frame-based applications on nongraphics devices, but any graphics objects
in the frame will not be displayed, except for control objects (which are displayed as
question marks (?) by default). Text-based frames are those that do not use SAS/GRAPH
output, SAS/GRAPH fonts, graphics control boxes, or special region outlining and titles.
For detailed requirements and the most current information, see the system requirements
sheet that is shipped with SAS/AF software.
To create and run applications in FRAME entries, you need the following SAS software
products:
•
Base SAS software
•
SAS/AF software (required only for creating Frame applications; not required for
running Frame applications)
•
SAS/GRAPH software (required for creating or displaying graphics objects or
images, for using SAS/GRAPH fonts, and for printing some frame objects)
viii About This Book
ix
Recommended Reading
Other resources that may be useful to you:
•
The SAS Component Language: Reference provides detailed reference information
about the statements, functions, and other elements of SCL. Available from the
SAS/AF Product Documentation page at support.sas.com/documentation/
onlinedoc/af/.
•
The online Help for SAS/AF software. The Help system provides a complete
Component Reference, enabling you to quickly view class and property information.
•
Getting Started with SAS/AF and Frames provides a more basic introduction to using
FRAME entries and SCL. Available from the SAS/AF Product Documentation page
at support.sas.com/documentation/onlinedoc/af/.
•
SAS offers instructor-led training and self-paced e-learning courses to help you get
started with SAS/AF. For more information about the courses available, see
support.sas.com/training.
For a complete list of SAS publications, go to support.sas.com/bookstore. If you have
questions about which titles you need, please contact a SAS Publishing Sales
Representative:
SAS Publishing Sales
SAS Campus Drive
Cary, NC 27513-2414
Phone: 1-800-727-3228
Fax: 1-919-677-8166
E-mail: sasbook@sas.com
Web address: support.sas.com/bookstore
x Recommended Reading
1
Part 1
Introducing the SAS/AF
Development Environment
Chapter 1
The Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 2
An Applications Development Methodology . . . . . . . . . . . . . . . . . . . . . . . 5
2
3
Chapter 1
The Development Environment
What Is SAS/AF Software? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Overview of SAS/AF Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SAS Component Language (SCL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Mainframe Support Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
What Is SAS/AF Software?
Overview of SAS/AF Software
SAS/AF software is a set of development tools to help you create customized
applications. With its interactive development environment and rich set of objectoriented classes, you can rapidly develop and deploy portable, GUI applications that take
advantage of other SAS software products. Central to SAS/AF development is the frame,
which is an application window that contains the interface elements, such as fields,
buttons, and tables. Although the many built-in SAS/AF components are flexible, you
can extend them using SAS Component Language (SCL).
SAS Component Language (SCL)
SCL is the programming language that controls SAS/AF applications. SCL programs are
stored in separate SCL entries that can be accessed by more than one FRAME entry.
This means that an SCL program can be written once and used many times.
SCL provides complete object-oriented programming constructs for creating entire
object-oriented applications in SCL and for creating and scripting objects with the SAS
Component Object Model (SCOM).
For more information about SCOM, see “Object-Oriented Development and the SAS
Component Object Model” on page 73. For more information about SCL, see the SAS
Component Language: Reference.
Mainframe Support Issues
SAS/AF software does not support a mainframe build-time environment for FRAME
entries. However, mainframe SAS/AF developers can create and modify SCL programs
as well as build PROGRAM entries and full-screen applications.
Because SAS/AF applications are stored in SAS catalogs, they are portable to all SAS
software platforms. If your site primarily uses a mainframe, you can develop frame-
4
Chapter 1
• The Development Environment
based applications on a PC running Windows, and then port the application to your
mainframe. Users who run GUI applications on character-based display devices will see
widgets represented as characters that are typical for that host environment.
For more information, see “Porting Your Application to Different Operating
Environments” on page 59. For more information about the behavior of classes in
specific host environments, see the SAS/AF Component Reference in the online Help.
5
Chapter 2
An Applications Development
Methodology
Using SAS Tools to Develop Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Steps to Developing SAS/AF Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Step 1: Analyze the Problem or Business Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Step 2: Set Up the Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Step 3: Design and Develop Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Step 4: Develop the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Step 5: Compile and Test Your Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Step 6: Deploy Your Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Using SAS Tools to Develop Applications
The first step in building SAS applications is to determine the tool that is most
appropriate for your situation.
You can use SAS/AF software
•
to extend the functionality of another SAS software product
•
to develop an enterprise-wide application that might involve custom components and
programming
Steps to Developing SAS/AF Applications
Step 1: Analyze the Problem or Business Process
Begin a development project by conducting an analysis to discover the key issues of the
problem. Such an analysis enables you to understand and describe the problem, which
promotes the mapping of the issues and their relationships to your application's
components. The purpose of object-oriented analysis, then, is
•
to define the boundaries of the problem domain so that you know what the
application will do (and what it will not do)
•
to describe the problem domain in terms of objects and classes, and to determine
what services the objects and classes must provide
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•
to identify relationships between the objects in the problem domain, especially from
the perspective of different types of users
When you model a problem or business process, it is important to consider all potential
users of the application. Such consideration promotes cross-functional input and a more
complete understanding of the problem. The terminology and concepts that describe the
problem lead to new issues that enable you to better meet the needs of the users.
For example, consider the problems and business processes that underlie a financial
application. Users might include executives, managers, accountants, clerks, and auditors.
Concepts such as “balance sheet” and “invoice” can be easily understood, but a process
such as “consolidate balance sheets” can mean different things to different user groups.
Executives might be interested in the bottom line, whereas auditors might focus more on
the details of the consolidation process.
The outcome of an analysis phase is typically a requirements document. In some cases, it
might be important to prepare simple class diagrams that provide an overview of what
each object should do. There are many formal object-oriented methodologies as well as a
number of commercial products that can assist you in the design process.
Step 2: Set Up the Development Environment
Considerations When You Are Planning a New Application
As you begin planning a new SAS/AF application, consider the following:
•
Will you need to create a common SAS library or use a combination of new and
existing libraries to access the application, its classes, and the data that it requires?
•
How will you reference SAS catalogs and catalog entries during the development
and deployment of your application?
•
What SAS software products will end users need to license?
Creating Common SAS Libraries and Catalogs
You might consider setting up a common SAS library and appropriate catalogs for an
applications development project. Often, this makes it easier for your development team
to locate, share, and store the SAS catalog entries that your application requires.
You can store a mixture of entry types in a SAS catalog. The following table lists the
common entry types that you are likely to use in your SAS/AF applications.
Table 2.1
SAS/AF Entry Types
Entry Type
Description
CLASS
Stores the properties that define a class.
FRAME
Stores the properties that define a frame.
INTRFACE
Stores the definition of an interface, which is a group of abstract methods that
are shared by related classes.
KEYS
Stores function key settings.
PMENU
Stores the code that defines a menu.
Steps to Developing SAS/AF Applications
Entry Type
Description
RANGE
Stores the definition of a range of values. Range entries can define ranges for
both numeric text-entry fields and critical success factor (CSF) controls.
RESOURCE
Stores the definition of a resource, which typically includes a group of related
classes.
SCL
Stores SCL program code.
7
You can also use library or catalog concatenation so that you can access entries in
multiple libraries or catalogs by specifying a single library reference name (libref) or a
catalog reference name (catref). If you create a catalog concatenation, you can specify
the catref in any context that accepts a simple, nonconcatenated catref.
For example, you might need to access entries in several SAS catalogs that might be
designated as the development, test, and production areas. The most efficient way to
access the information is to logically concatenate the catalogs, which allows access to
the information without creating a new catalog. The following statement assigns the
catref app to development, test, and production catalogs:
catname app (corp.app mis.testapp projects.newapp);
In this example, corp.app is the production environment, mis.testapp is the testing
catalog, and projects.newapp is the development area.
Catalog concatenation is useful when you need to migrate catalog entries — particularly
those that have hardcoded SCL entry names such as classes — between different
environments. For details on catalog concatenation, see the SAS Language Reference:
Concepts. For information about the use of libraries and catalogs when you deploy
applications, see “Step 6: Deploy Your Application” on page 9.
Using Existing SAS Components
Your organization might already have a number of existing custom SAS components
available. If you plan to use any of these custom components in your new application,
then you should consider how the classes are grouped and made available in a resource.
For more information, see “Deploying Components” on page 151 .
Licensing SAS Software Products
When you create an application, you can use the functionality of different SAS software
products, or you can develop objects (such as a graph) that require other SAS software
products to operate. In either case, you must ensure that your end users license all the
SAS software products that they need for your application to run.
Step 3: Design and Develop Components
The object-oriented design phase of the development life cycle is often focused on the
work of component developers or “class writers.” As a component developer, you can
define how the elements of the application work. During this phase, you can detail and
describe
•
the services provided by each class.
•
the actual name, data type, and default values of class attributes.
•
any class relationships — especially inheritance.
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•
the business rules that govern object behavior.
•
other features that are specific to SAS software. See “SAS Object-Oriented
Programming Concepts” on page 71 for details.
You can construct classes in terms of their attributes and behaviors. For complete
information about using SAS/AF software to design and implement classes, see Part 3:
Developing Custom Components. For information about making the components that
you create available for use, see “Deploying Components” on page 151.
Step 4: Develop the Application
Overview of Developing Applications
This phase of the development life cycle is where application developers build the
system or application, using the objects that have been created by component
developers. For complete information about using SAS/AF software to develop
applications, see Part 2: Developing Applications.
Designing the User Interface
You can use any one of a number of modeling tools and flow chart techniques to help
determine how many windows your application will need, as well as how the user should
interact with each window and how the windows should be connected to each other.
Consider the tasks that a user needs to perform in a window, and a frame that enables the
user to complete those tasks. For information about building frames, see “Working with
Frames” on page 20.
Adding Communication Between Frames and Components
Your application design might specify that the components on a frame, or even the
frames themselves, need to work with each other. For example, you might want a
graphic object to display a specific graph when a user selects a graph from a list box. Or,
you might want the user to open another frame when a push button is selected. You can
add component and frame communication either by using SAS Component Language
(SCL) programs or by taking advantage of the features included in components that have
been built using the SAS Component Object Model (SCOM) architecture.
For more information about SCL, see “Adding SAS Component Language Programs to
Frames” on page 35. For more information about SCOM, see “Communicating with
Components” on page 27.
Designing for Reuse
If you notice that several of your frames share common traits, you can create a
composite object that includes those traits. For example, you could create a dialog box
frame that included OK, Cancel, and Help buttons. For more information about
composites, see “Re-using Components” on page 24.
Step 5: Compile and Test Your Application
Testing SCL Programs with Frames
When you use SCL programs with the frames of your application, you must compile and
test your frames. You can perform debugging and unit testing as well. Once all of the
individual pieces are working, you might also consider assembling all application
components and performing integrated testing.
Steps to Developing SAS/AF Applications
9
For information about compiling and testing, see “Compiling and Testing Applications”
on page 46.
Testing the Usability of Your Application
Although your application enables users to perform all the tasks that they need to
complete, it might still be difficult to learn or to use. Just as the early analysis phase
encourages input from users, you might want to revisit the design by having users test
the application during its development. Usability testing enables you to enhance or
correct usability issues that might arise from difficult concepts or business processes.
There are many different types of usability testing, ranging from user exploration of the
application to formal testing that assesses validity and usability.
Step 6: Deploy Your Application
Once you have designed, created, and tested your application, you are ready to deploy
your application to users. Deploying applications involves many considerations,
including how the application should appear when it opens, whether the application will
run on a stand-alone machine or a network, and what should happen when the
application closes.
For more information about application deployment issues, see “Deploying Your
Applications” on page 57.
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11
Part 2
Developing Applications
Chapter 3
Tools for the Applications Developer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Chapter 4
Developing Frames with Ready-Made Objects . . . . . . . . . . . . . . . . . . . . 19
Chapter 5
Communicating with Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Chapter 6
Adding SAS Component Language Programs to Frames . . . . . . . . . 35
Chapter 7
Adding Application Support Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Chapter 8
Deploying Your Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
12
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Tools for the Applications
Developer
About the SAS/AF Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Build Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Components Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Properties Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Source Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
About the SAS/AF Development Environment
As an applications developer, you create the frames that define application windows.
You can use the following tools from the SAS/AF development environment to create
frames:
•
the Build window
•
the Properties window
•
the Components window
•
the Components themselves
•
the Source window
When you create or open a FRAME entry, SAS/AF software opens its build-time
environment, which includes specific windows.
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Tools for the Applications Developer
Display 3.1
SAS/AF Build-Time Environment
Not every build-time environment window opens when you create or open a FRAME
entry. Some windows must be opened by the user.
You can open build-time environment windows in several ways.
Make a selection from a menu.
The menu of any active build-time window provides several options. Many options
are duplicated on pull-down and pop-up menus.
Make a selection from a pop-up menu.
A pop-up menu is available when the frame or any component on the frame is
selected. (Usually, you will not see any visual cues to indicate where pop-up menus
can be displayed.)
Enter a command at the command prompt.
Users who are more comfortable with command-driven processes can use the
command line or the command window. Refer to the SAS/AF online Help for a list
of valid commands.
Click an icon on the toolbar.
The toolbar includes icons for the Properties window, the Components window, and
the Source window.
Press a function key that has an assigned command.
You might find it useful to assign commands to function keys to create shortcuts to
both command- and menu-driven actions.
Components Window
15
Build Window
The Build window enables you to drop components onto a frame and then to manipulate
the layout and appearance of your application's user interface. Menus provide access to
commands that enable you to set component properties, to edit and compile SCL
programs, and to access other tools in the development environment. When the Build
window opens, it displays an instance of the Frame class (or a subclass of the Frame
class). When you save a frame, the contents of the Build window are stored in a FRAME
entry of a SAS catalog.
Display 3.2
SAS/AF Build Window
The Build window displays both horizontal and vertical scroll bars.
The Build window appears when you open an existing FRAME entry or create a new
FRAME entry. For more information about the Build window, see “Working with
Frames” in the SAS/AF online Help.
Components Window
The Components window enables you to view and select components that you can add
to a frame at build time. There are a number of ways to add a component to a frame. For
example, you can select the component from the Components window, and then drag the
component and drop it onto a frame. You can also double-click a component in the
Components window to make that component appear on a frame.
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Tools for the Applications Developer
Display 3.3
SAS/AF Components Window
With the Components window, you can also
•
manage resource entries for maintaining class libraries.
•
add to the classes or resources that appear in the window.
•
access Help on classes and resources. To access Help, right-click on a component
and select Help on Class.
By default, the Components window appears when you open a FRAME entry (although
you can prevent this by editing the AutoOpen property for the Components window in
the SAS Registry). You can also click the Components window icon on the toolbar or
select View ð Component Window to open the Components window.
For more information about the Components window, see “Customizing the
Components Window” in the SAS/AF online Help. For more information about the SAS
Registry, see “Modifying SAS/AF Items in the SAS Registry” in the SAS/AF online
Help.
Components
Components themselves are tools that you can use to design application windows.
SAS/AF software provides ready-made components that are stored in
sashelp.fsp.AFComponents.resource. These ready-made components appear in
the Components window by default.
Your organization might also need to create custom components to meet specific
application needs.
For information about selecting the appropriate component, see “Selecting Components”
on page 23. For information about creating custom components, see “Developing
Components” on page 95.
Source Window
17
Properties Window
The Properties window enables you to set component properties at build time. Properties
include the attributes, methods, events, and event handlers of a frame or a component.
You can view, edit, or add properties with this window.
Display 3.4
Properties Window
You can open the Properties window once you create or open a frame in the Build
window. Click the Properties window icon on the toolbar or select View ð Properties
Window.
For more information about working with the Properties window, see “Working with
Component Properties” in the SAS/AF online Help.
Source Window
The Source window provides a text editor for creating and editing SAS Component
Language (SCL) programs.
You can edit a frame's SCL entry by selecting View ð Frame SCL or by selecting
Frame SCL from the frame's pop-up menu.
You can also open the Source window by
•
double-clicking an existing SCL entry in the SAS Explorer
•
creating a new SCL entry via the BUILD command
•
clicking the Source window icon on the toolbar
•
issuing the SOURCE command from a FRAME or PROGRAM entry
Note: Avoid opening frame SCL entries in a Source window or by double-clicking them
in the SAS Explorer. Instead, open a frame SCL entry from within its respective
frame. A frame SCL entry must be compiled along with its respective frame. If you
open a frame SCL entry outside of its frame and inadvertently compile the frame
SCL entry, you will produce errors.
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Tools for the Applications Developer
Display 3.5
SAS/AF Build Window
For information about SCL, see “Adding SAS Component Language Programs to
Frames” on page 35.
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Chapter 4
Developing Frames with ReadyMade Objects
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Working with Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Opening an Existing FRAME Entry or Creating a New FRAME Entry . . . . . . . . . 20
Frame Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Frame Usage Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Specifying the Frame SCL Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Compiling Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Selecting Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Re-using Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Combining Components to Create Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Subclassing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Writing Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Defining Attachments to Enable Automatic Component Resizing . . . . . . . . . . . . . 25
Introduction
You can quickly develop GUIs by building frames and adding ready-made objects
(components) to your frames. Building a frame-based application typically consists of
the following steps:
1. Create a frame (or a set of frames) to serve as the user interface for your application.
2. Add components to each frame by dragging a selected component from the
Components window and dropping it onto the frame.
3. Modify the properties of each component with the Properties window.
4. Add frame SCL as needed to incorporate the necessary logic or business rules behind
the application.
5. Save, compile, and test the frame or frames.
Note: SAS/AF software supports a native look and feel for controls (visual components)
on a frame. This capability enables you to take advantage of best practices for user
interface design for those platforms on which you implement your application.
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Developing Frames with Ready-Made Objects
Working with Frames
Opening an Existing FRAME Entry or Creating a New FRAME Entry
Frames provide the user interface to SAS/AF applications. Frames are stored in a SAS
catalog entry of type FRAME. A frame is also an instantiation of the Frame class or one
of its subclasses.
The SAS/AF application development environment provides several ways to open an
existing FRAME entry or to create a new one:
From the Explorer window
• To open an existing frame, select a catalog, and then double-click on the FRAME
entry you want to open.
•
To create a new frame, select the catalog in which you want to store the FRAME
entry, and then select File ð New and select Frame from the New Entry dialog
box.
From the Command prompt
To open an existing frame or to create a new one, enter build
libref.catalog.framename.frame, where framename is the name of the
FRAME entry.
From the SAS/AF software development environment
To create a new frame from the SAS/AF development environment, select File ð
New.
From the Program Editor using PROC BUILD
To open an existing frame or to create a new one, submit proc build
c=libref.catalog.framename.frame; run; where framename is the name
of the FRAME entry.
The BUILD command has advantages over the BUILD procedure in that the BUILD
command enables you to open more than one BUILD session at a time and allows you to
submit other SAS procedures while the BUILD session is active.
For detailed information about working with frames, see the SAS/AF online Help.
Frame Types
You can create two types of frames: standard or dialog. Standard frames define an
application's primary window or windows. Primary windows enable you to access
secondary windows that are needed to enter, edit, collect, or display information. For
example, a primary window of a word processor might include all the menus or buttons
used to access the commands or other windows that are associated with the program.
Working with Frames
21
The following application main menu is an example of a typical frame that was created
using SAS/AF software.
Display 4.1
Example of a Standard Frame
A dialog frame is used to create secondary windows such as the dialog boxes, palette
windows, and message boxes that are accessed from a primary window. Secondary
windows are useful for specifying parameters or options, for displaying error or
information messages, and for providing a place to collect user input. Dialog frames
cannot be resized by users.
Display 4.2
Example of a Dialog Frame
In your SCL programs, you can use the DIALOG function to open a frame as a modal
window. For more information, see “Calling Dialog Boxes from an Application” on
page 45.
Note: All new frames are of type standard by default.
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Developing Frames with Ready-Made Objects
To specify whether a frame should be of type standard or dialog, set the frame's type
attribute in the Properties window.
Frame Usage Tips
The following table provides general information about working with frames. For more
information, see the SAS/AF online Help.
Table 4.1
Common Frame Tasks
Task
Solution
Setting frame properties
Use the Properties window and select the _FRAME_
object.
Adding components to a frame
Drag and drop components onto a frame from the
Components window. Or, select a component in the
Components window, and then double-click in the
frame where you want to place the component.
Positioning frame components
Use the mouse to drag and position components. Use
the Properties window to set component attributes that
specify the component's position on a frame.
Adding a menu to a frame
Use the Properties window to set the frame's
pmenuEntry attribute. You can create a new menu
with the PMENU procedure.
Storing a frame
Save the frame to a specific SAS catalog by selecting
Save or Save as from the File menu.
Frames are stored in FRAME catalog entries.
Specifying the Frame SCL Entry
Frame SCL entries provide the SCL source code to control a frame. The name of the
SCL entry that controls a FRAME entry is assigned through the frame's SCLEntry
attribute. By default, the SCLEntry attribute identifies the frame's SCL source as
*.SCL, where the asterisk (*) represents the name of the FRAME entry.
For more information about frame SCL, see “Adding SAS Component Language
Programs to Frames” on page 35.
Compiling Frames
If your frame has an associated frame SCL entry, you must compile the frame in order to
associate the frame SCL with your frame.
To compile a frame (and its frame SCL entry), select Build ð Compile from the Frame
entry's Build window.
For more information about compiling frames, see “Compiling and Testing
Applications” on page 46.
Selecting Components
23
Selecting Components
A well-designed user interface is based on a development process that focuses on users
and their tasks.
The components that you choose to place on a frame are determined by the tasks that
you want your users to perform. The following table describes common actions that your
applications might require for users to complete specific tasks. It also suggests a
SAS/AF component that you could use.
In some cases, multiple components are listed because more than one component might
suit your needs. For more information about any of the components, see the “SAS/AF
Component Reference” in the SAS/AF online Help.
Table 4.2
User Tasks and Components
If you want to...
then use a...
enable a user to indicate a yes/no, true/false, or
on/off option
check box control or radio box control
enable a user to make choices
check box control
combo box control
list box control
spin box control
visually group multiple components together
container box control
display an existing icon on your frame
desktop icon control or push button control
display an existing graph on your frame
graph output control
enable a user to execute a command
push button control
enable a user to choose only one item in a
group of possible selections
radio box control
enable a user to enter a limited amount of text
text entry control
enable a user to enter a large amount of text
text pad control
provide a label for other components or include
an uneditable line of text on your frame
text label control
include a chart or graph on your frame
chart control
critical success factor control
histogram control
map control
pie control
scatter control
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If you want to...
then use a...
provide a list of available color choices*
color list model
retrieve or access information about SAS
software files and storage utilities*
catalog entry list model
catalog list model
data set list model
library list model
SAS file list model
variable list model
variable values list model
browse or edit data
form viewer control
table viewer control
SAS data set model
access information about file and storage
utilities that were not created by or are not part
of SAS software*
external file list model
access the items contained in a list*
LIST entry list model
SLIST entry list model
* If you want to display this information in a frame, then you must use a view (such as a list box) to show
the model. Models are referred to as non-visual components. They provide data that is typically used
along with a visual control. For more information about models and views, see “Model/View
Communication” on page 29.
Re-using Components
Combining Components to Create Composites
Composites are custom components that consist of at least two existing components.
You should consider creating a composite if you find that you frequently place the same
few components together on different frames to accomplish a specific task. For example,
if you often enable your users to type in a file path value or select that file path by
clicking a browse button, you might consider creating a composite that includes a text
field and a browse button.
If you often enable users to make a color selection from a list box, you might consider
creating a composite that includes a list box and a color list.
You can save a composite if you think you might want to use it again (either in the
current application or in another application). The process of saving a composite actually
prompts you to create a new class. To use the composite again, you would create an
instance of the new composite class.
Composites can be a combination of
•
two or more visual controls, such as a check box control and a container box control
Defining Attachments to Enable Automatic Component Resizing
•
25
a visual control, such as a list box control, and a non-visual component, such as a
color list model
For step-by-step instructions on creating a composite, see “Creating Composite
Controls” in the SAS/AF online Help.
Subclassing
If you find that you consistently modify an existing component for use in one or many
applications, you might want to make a subclass of that component's class. For example,
if you want the default text in a push button control to be OK instead of Button, then
you could subclass the push button control.
For more information about subclassing, see “Creating Your Own Components” on page
95.
Writing Methods
You can write new methods that override or are added to an existing class. The method
writing process enables you to reuse an existing class by modifying it slightly for your
current needs.
For more information, see “Managing Methods” on page 109.
Defining Attachments to Enable Automatic
Component Resizing
An attachment is a connection between two or more components that controls the
placement or size of those components with respect to each other and to the frame itself.
Attachments enable you to define the spatial relationships between components and/or
between components and frames, as well as to provide support for automatic component
resizing. SAS software applications that have attachments automatically adjust
component sizing and spacing when
•
a user resizes the window that contains the component(s).
•
the window that contains the component(s) is a different size at initialization time
than it was when the FRAME entry was saved.
•
the application is ported to an environment that has different window sizes.
•
the application is displayed on a device that has a different resolution than the device
on which it was developed.
Note: Attachments are not required, but they should be used to ensure accurate
component sizing.
To define attachments, follow these steps:
1. Select a component or components.
2. Select the appropriate attachment mode. To do this, select Layout ð Attach ð
Attach Current Region or Layout ð Attach ð Attach Child Region.
3. Initiate define attachment mode. To do this, select Layout ð Attach ð Define
Attachment.
4. Select the attachment direction and type from the Define Attachments window.
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Developing Frames with Ready-Made Objects
5. Drag out your attachments between components or between components and the
frame.
6. Click OK in the Define Attachments window. This ends define attachment mode and
saves your attachments.
For more information about attachments, see “Adding Attachments to Frame Controls”
on page 179.
27
Chapter 5
Communicating with Components
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Attribute Linking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Determining When to Use Attribute Linking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Establishing an Attribute Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Model/View Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Determining When to Use Model/View Communication . . . . . . . . . . . . . . . . . . . . 30
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Drag and Drop Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Determining When to Use Drag and Drop Communication . . . . . . . . . . . . . . . . . . 32
Which Components Support Drag and Drop? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Defining Drag and Drop Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Tips for Defining Drag and Drop Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Introduction
The components in your applications must have a mechanism through which they can
communicate with each other. For example, if a frame contains a list box along with
another object whose contents are updated based on an item that is selected from the list
box, the list box must communicate to the other object that an item was selected and
which item was selected.
The SAS Component Object Model (SCOM) provides this communication, and makes it
possible for components to communicate with each other without you adding any
programming code.
As an applications developer, you can take advantage of SCOM with
•
attribute linking
•
model/view communication
•
drag and drop communication
28
Chapter 5
•
Communicating with Components
Attribute Linking
Introduction
Attribute linking enables components to interact without the need for any SAS
Component Language (SCL) code. Instead, interactions are specified with the Properties
window.
Attribute linking involves setting the Link To values of a component's attributes. For
example, if you want the text value that is entered into a text field to update a graph
output control, link the graph output control's graph attribute to the text entry control's
text attribute. You can define attribute links between attributes on the same component
or between different components on the same frame.
Determining When to Use Attribute Linking
Use attribute linking when you
•
want one component to access the value of another component without any SCL
code.
•
want to maintain consistency between components. For example, if you change the
background color of a push button, you may want every push button on the frame to
use the new background color.
•
define component communication for objects at build time.
Establishing an Attribute Link
To establish an attribute link between two attributes, you define the link on the attribute
that you want to receive the new value. Attribute linking includes the following steps:
1. Identify the component whose attribute or behavior you want to dynamically change.
For example, you may want to change whether a text entry control is enabled or
disabled.
2. In the Properties window Attribute table, find the component attribute that you want
to change. In the case of our text entry control, it would be the enabled attribute.
3. Define the link on that attribute by specifying a value in its Link To cell. For
example, you might link the text entry control's enabled attribute to the selected
attribute of a check box control that is also present on the frame.
An attribute link consists of a componentName/attributeName pair where
componentName
refers to the component that owns the above attribute
attributeName
refers to the attribute that contains the value that you want your linked attribute to
contain
Model/View Communication
29
Example
Suppose your application prompts a user to choose whether or not they receive e-mail
messages. Your frame might include a check box labeled “Do you have an e-mail
account?” If the user clicks the check box, then a text label and text entry field are
enabled so that the user can enter an e-mail address.
You can complete this type of component communication with multiple attribute links.
The following steps detail the process:
1. Create a new FRAME entry.
2. Place a check box control on the frame and change its label attribute to “Do you
have an e-mail account?”
You can use the Properties window to change the label attribute.
3. Place a text label and a text entry control on the frame.
The text label should be positioned on the left of the text entry and should be labeled
“e-mail address:”
4. Link the enabled attribute of the text entry control to the selected attribute of
the check box.
5. Link the enabled attribute of the text label object to the enabled attribute of the
text entry object.
6. Test the frame by selecting Build ð Test.
Note: This example is used to describe attribute linking only. Other tasks would be
necessary to complete this frame and make it function properly within an application.
When you select the check box, the text label and text entry objects become available.
When you deselect the check box, the text label and text entry objects become grayed
and are therefore unavailable.
Model/View Communication
Introduction
Components are often separated into two categories: those that display data (viewers)
and those that provide access to data (models). These different kinds of components
30
Chapter 5
• Communicating with Components
break the complex process of displaying data into logical parts. See “Models and
Viewers” on page 76 for more information about model/view architecture.
SAS/AF software provides an easy way for you to add model components and viewer
components to your applications. You can set model/view component communication
during application build time (that is, within the Build window) by
•
dragging a model onto a viewer
•
setting the model attribute of a viewer in the Properties window
For step-by-step information, see “Assigning Models to Viewers” in the SAS/AF online
Help.
Determining When to Use Model/View Communication
Use model/view communication when you want to attach a non-visual component
(model) to a visual component (viewer) to display specific data.
The following table lists the default models and viewers that SAS/AF software provides.
It also shows which models and viewers can be used together. Within the corresponding
sections of the table, any model on the left can be used with any viewer on the right. The
appropriate model/view combination depends on your final goal.
Table 5.1 Models and Viewers
Use any of these models...
with any of these viewers...
Catalog Entry List
Combo Box
Catalog List
List Box
Color List
Radio Box
Data Set List
Spin Box
External File List
Library List
LIST Entry List
SAS File List
SLIST Entry List
Variable List
Variable Values List
SAS Data Set
Form Viewer
SCL List
Table Viewer
Note: You can create and/or customize models and viewers within a SAS/AF
application if the models and viewers that are provided do not meet the needs of your
application. For information on creating a new model or viewer, see “Implementing
Model/View Communication” on page 133. In addition, if you plan to use a model/
view pair regularly, you might want to create a composite. For more information on
creating a composite, see “Creating Composite Controls” in the SAS/AF online
Help.
Model/View Communication
31
Examples
You can use model/view communication to display a list of color choices in a list box.
Additionally, you can set this model/view component communication by dragging and
dropping components, or by using the Properties window.
To set model/view communication by dragging and dropping components:
1. Create or open a FRAME entry.
2. Drag a List Box control from the Components window and drop it onto the frame.
3. Drag the Color List model from the Components window and drop it onto the List
Box.
To set model/view communication with the Properties window:
1. Create or open a FRAME entry.
2. Drag a List Box control from the Components window and drop it onto the frame.
3. Drag a Color List model from the Components window and drop it onto the frame.
4. Open the Properties window.
5. In the Properties window, open the Attributes table for the List Box control.
6. Set the model attribute value to the Color List model.
The above examples show that some models can return information at build time. The
list box that serves as the viewer is automatically populated with values when the model
is attached.
The following example shows that other models return information only at run time. In
this situation, the model information is not displayed in the viewer during build time.
1. Create or open a FRAME entry.
2. Place a Combo Box control and a Catalog List model on the frame.
3. Open the Properties window.
4. In the Properties window, open the Attributes table for the Combo Box control.
5. Set the model attribute value to the Catalog List model.
6. In the Properties window, open the Attributes table for the Catalog List model.
7. Set the library attribute value to an existing library.
8. Select Build ð Test to run the frame and then select the down arrow in the combo
box to see a catalog list.
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Chapter 5
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Communicating with Components
Drag and Drop Communication
Introduction
Drag and drop communication involves dragging components or objects with a mouse
(or other pointing device) and dropping them over other objects at run time to perform
an action.
A component that can be dragged is called a drag site, and a component that can receive
the dragged object is called a drop site. The data that is transferred between the
components is referred to as the dragInfo or the dropInfo.
For step-by-step information on setting drag and drop component communication, see
“Enabling Drag and Drop Functionality” in the SAS/AF online Help.
Determining When to Use Drag and Drop Communication
Use drag and drop communication when
•
you want users to be able to transfer data from one component to another by
interacting with a frame's components during application run time.
•
you cannot easily use attribute linking to transfer data from one component to
another during application run time.
Drag and drop functionality varies between different operating systems, and some
environments do not support it. If you develop an application that uses drag and drop
communication, you may want to provide an alternative process so that the action can be
performed in all environments.
Which Components Support Drag and Drop?
Most of the components in sashelp.fsp.AFComponents.resource have default
drag and drop attribute settings. Exceptions include
•
Container Box control
•
Critical Success Factor control
•
Map control
If you want to change the default drag and drop attribute settings, use the Properties
window.
Defining Drag and Drop Sites
Drag and drop sites can be defined for any component that is a subclass of the Frame
class or the Widget class, including all visual controls.
In many cases, SAS has already defined components as drag and/or drop sites. You can
use those components to perform drag and drop component communication without
having to modify them.
To define a component to function as a drag site:
Drag and Drop Communication
33
1. Set the dragEnabled attribute to Yes if you want the component to work as a
drag site by default. In most cases, setting this attribute is all you need to do to define
a drag site.
2. Specify a data representation and attribute to be passed for the drag site by setting the
dragInfo attribute.
3. Specify a drag and drop operation for the drag site by setting the dragOperations
attribute.
To define a component to function as a drop site:
1. Set the dropEnabled attribute to Yes if you want the component to work as a
drop site by default. In most cases, setting this attribute is all you need to do to define
a drop site.
2. Specify a data representation and attribute to be passed for the drop site by setting
the dropInfo attribute.
3. Specify a drag and drop operation for the drop site by setting the dropOperations
attribute.
Tips for Defining Drag and Drop Sites
When you define drag and drop sites, keep the following tips in mind:
•
Any subclass of the Widget or Frame class supports drag and drop component
communication.
•
Data from one component can be dragged to another component.
•
The drop sites and drag sites do not need to reside in the same window.
•
Components can act as both drag sites and drop sites.
•
Drag sites cannot be dragged outside the SAS software environment unless they have
a data representation of _DND_TXT.
•
Default drag and drop behavior may vary according to the host operating
environment on which your application executes.
Example
Use drag and drop communication to cause a graph to appear when you drag a specific
graph entry from a list box and drop it onto a Graph Output control.
1. Create or open a FRAME entry.
2. Place a List Box control and a Graph Output control on the frame.
3. Drag and drop the Catalog Entry List model onto the List Box control.
4. Use the Properties window to set the Catalog Entry List model's catalog attribute
to the name of a catalog that contains graphic entries (for example,
SASHELP.EISGRPH). (Optional) If you want the list box to show only one
particular type of entry, set the Catalog Entry List model's typeFilter attribute to
the appropriate entry type.
5. Use the Properties window to set the Graph Output control's borderStyle attribute
to Simple.
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Chapter 5
•
Communicating with Components
6. Use the Properties window to set the List Box control's dragEnabled attribute to
Yes and the Graph Output control's dropEnabled attribute to Yes.
7. At run time, drag a graphic entry from the list box and drop it onto the Graph Output
control. The selected graphic appears in the Graph Output control.
35
Chapter 6
Adding SAS Component
Language Programs to Frames
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Working with Frames and SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
When Frame SCL Is Not Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
When Frame SCL Is Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Constructing a Frame SCL Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
SCL Labeled Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
SCL Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
SCL Routines and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
SCL Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Dot Notation and SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Controlling the Execution of SCL Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Processing Custom Commands in SCL Programs . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Calling Other Entries and Opening Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Opening Other Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Calling Dialog Boxes from an Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Compiling and Testing Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Compiling FRAME Entries in Batch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Compiling FRAME Entries Automatically . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Testing Your Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Debugging and Optimizing Your Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Common SCL Debugger Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Optimizing the Performance of SCL Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Saving and Storing Frame SCL Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Introduction
SAS Component Language (SCL) is an object-oriented programming language that is
designed to facilitate the development of interactive SAS applications. In SAS/AF
software, a frame is controlled primarily by an SCL program, although it is possible to
36
Chapter 6
•
Adding SAS Component Language Programs to Frames
have a fully functional frame that has no associated SCL code. You can add code to a
FRAME entry's SCL program to
•
validate user input
•
calculate field values that are based on user input
•
change attribute values of components on a frame at run time
•
invoke methods of components on a frame
•
define custom error handling and messaging
•
provide special user interface features such as menus, graphs, selection lists, font
lists, and system information
•
link to other SAS catalog entries, including other frames
•
submit SAS programs
•
read from and write to SAS tables, SAS catalog entries, and external files
•
interact with other SAS software as well as software from other vendors
For complete reference information on SCL, refer to the SAS Component Language:
Reference. For task-oriented information on working with SCL programs, see the
SAS/AF online Help.
Working with Frames and SCL
There are several important items to remember when you are working with SCL
programs for FRAME entries:
•
The SCL for a frame (often referred to as frame SCL) is stored in a separate catalog
entry of type SCL. If you do not store the SCL entry in the same catalog as the
FRAME entry, then the frame's SCLEntry attribute must specify the four-level
name of the associated SCL entry. See “Saving and Storing Frame SCL Programs”
on page 49 for details.
•
The name of the SCL entry that controls a FRAME entry is assigned through the
frame's SCLEntry attribute. By default, the SCLEntry attribute identifies the
frame's SCL source as *.SCL, where the asterisk (*) represents the name of the
FRAME entry. For example, if your FRAME entry is named MENU.FRAME,
specifying *.SCL as the name of the SCL entry identifies MENU.SCL. Thus, the
*.SCL designates an SCL entry that has the same name as the FRAME entry and is
in the same catalog.
To check the value of the SCLEntry attribute, open the Properties window, select
the object named _FRAME_ in the Properties tree, and then scroll down to the
SCLEntry attribute.
•
You can add or edit the SCL program for a frame in the Source window. When a
frame is displayed in the Build window, select View ð Frame SCL or select Frame
SCL from the Build window's pop-up menu to open the frame's SCL program in the
Source window.
•
SCL entries must be compiled with their associated FRAME entries before you can
test or run them.
•
SCL source code is reusable, even if it is specified for a FRAME entry. Since SCL
source is stored separately from FRAME entries, you can use the same SCL source
for several FRAME entries without having to duplicate the SCL source for each one.
Constructing a Frame SCL Program
37
For example, you can develop the prototype FRAME entries
MYREPORT1.FRAME, MYREPORT2.FRAME, and MYREPORT3.FRAME.
Then, create the SCL source entry MYREPORT.SCL, and identify it as the SCL
source entry for each of the three FRAME entries by setting each frame's SCLEntry
attribute to MYREPORT.SCL in the Properties window.
When Frame SCL Is Not Required
A frame does not require an SCL program. Many components that you can add to a
frame are designed to perform tasks without additional SCL code. For example, you can
add a push button control to a frame and set its commandOnClick attribute to end. The
END command then executes when a user clicks the push button. You do not need SCL
to control this control's behavior.
Frame SCL entries do not have to control every component on a frame. When you create
your own components (or subclass those provided by SAS software), you can add
methods to perform operations. You implement these methods in an SCL entry that is
separate from the SCL entries that are used by your frames. See “Implementing Methods
with SCL” on page 109 for more information.
In addition, communication between components in your application is possible without
frame SCL. See “Communicating with Components” on page 27 for more information.
When Frame SCL Is Required
You must include an SCL program for a frame in these situations:
•
You want to use methods for a component on the frame.
•
You need to modify a component's properties at run time. For example, values that
are passed to the frame may be applied to change the attribute of a component, or
you may change the appearance of a control after a user enters input.
•
You need to perform conditional or custom processing for the selections that a user
makes or for values that a user enters.
Constructing a Frame SCL Program
Overview
A typical SCL program for a frame consists of
•
labeled sections
•
statements
•
routines and functions
•
SCL variables
This section describes how you can combine these elements to create the programs that
control SAS/AF frames.
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Chapter 6
•
Adding SAS Component Language Programs to Frames
SCL Labeled Sections
A section in SCL begins with a label and ends with a RETURN statement. SCL
programs for FRAME entries use reserved sections to process program initialization,
main processing, and termination.
INIT:
/* ...statements to initialize the application... */
return;
MAIN:
/* ...statements to process user input... */
return;
TERM:
/* ...statements to terminate the application... */
return;
In addition, you can add sections labeled with object names for each component that you
add to the frame. The labeled section for a component executes when an action is
performed on the component, such as selecting the component or changing its value. For
example, if you have a push button named okButton on your frame, you could have the
following labeled section in your SCL:
okButton:
dcl list message={'Are you sure you want to exit?'};
response=messagebox(message, '!', 'YN', 'Confirm Exit','N',”);
rc=dellist(message);
return;
The code in the okButton section automatically executes when the push button is
selected.
In general,
•
INIT executes once before the frame is displayed to the user.
•
MAIN executes immediately after the corresponding object-label section has
executed. If a corresponding object-label section does not exist, then MAIN executes
each time a user activates any object on the frame.
•
TERM executes when either your program or the user issues an END command or a
CANCEL command.
For a detailed explanation of how labeled sections are processed, see “How SCL
Programs Execute for FRAME Entries” on page 163.
SCL Statements
The labeled sections in frame SCL programs consist of one or more executable
statements that control program flow. (Declarative statements, such as DECLARE or
ARRAY, can occur anywhere in the program and do not have to exist in labeled
sections.)
You can also use the following SAS language statements in SCL programs:
•
LENGTH and ARRAY statements
•
assignment statements that use standard arithmetic, comparison, logical, and
concatenation operators
Constructing a Frame SCL Program
•
IF-THEN/ELSE and SELECT statements
•
DO groups and all forms of DO loops
•
LINK and RETURN statements
•
comment indicators, including /* comment */ and * comment;
39
For details on SCL statements, refer to the SAS Component Language: Reference.
SCL Routines and Functions
SCL provides a rich set of routines and functions that perform some action, such as the
DISPLAY routine or the OPENSASFILEDIALOG function. For detailed information
about these functions, refer to the SAS Component Language: Reference.
In addition, SCL supports nearly all of the functions of the Base SAS language. For
details on the Base SAS functions, see SAS Language Reference: Dictionary.
SCL Variables
Each variable used in an SCL entry represents a specific data type. SCL supports the
following data types:
Character
declared with the keyword CHAR
Numeric
declared with the keyword NUM
SCL List
declared with the keyword LIST
Object
declared with the keyword OBJECT or with a specific four-level class name
SCL provides several automatically defined system variables, such as
•
_FRAME_, a generic object that contains the identifier of the current active frame
•
_MSG_, a character variable that enables you to set the text to display in the frame's
message area
•
_STATUS_, a character variable that you can query to see whether a user has
cancelled or ended from a frame so that your application can either halt execution
immediately or resume processing.
See the SAS Component Language: Reference for a complete list of system variables and
their data types.
Automatic system variables like _FRAME_ and _STATUS_ are declared internally, so
you can use them without having to declare them in your SCL. Objects created on a
frame are also declared automatically, and as long as you compile the frame's SCL entry
from the frame, the SCL compiler recognizes them.
All other variables must be defined using the DECLARE statement. Consider the
following code:
DECLARE
n1 n2,
NUM
NUM
CHAR
CHAR(10)
n3[15],
c1,
c2,
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Chapter 6
•
Adding SAS Component Language Programs to Frames
LIST
OBJECT
classname
myList = {};
obj1 objs[5],
obj2;
•
The DECLARE keyword begins the variable declaration statement. You can also use
the abbreviation DCL.
•
NUM, CHAR, LIST, and OBJECT are reserved keywords that indicate the data type
of the variables that follow the keyword.
•
The variable declared as n3[15] defines a 15-item array of numeric values.
•
CHAR(n) is a notation that enables you to define the length of a character variable,
where n, a value up to 32767, is its length. By default, character variables are 200
characters long. In the declaration above, c1 is a character variable with a length of
200, and c2 is a character variable with a length of 10.
•
OBJECT indicates that the variable contains an object identifier, which enables the
SCL compiler to recognize dot notation for method calls or attribute references. The
variable declared as objs[5] is a five-item array of object identifiers.
•
classname indicates that the variable contains the object identifier of a specific class
such as sashelp.classes.cataloglist_c.class.
Dot Notation and SCL
SCL provides dot notation for direct access to component properties. Dot notation is
intended to save time, improve code readability, and reduce the amount of coding
necessary. It also improves the performance of your applications by providing additional
compile-time validation. For example, you can use it to check the method's argument
type. You can also use it to execute methods and to access component attributes without
having to use SEND or NOTIFY routines.
You can use dot notation in any of the following forms:
object.method(<arguments>);
return-value=object.method(<arguments>);
object.attribute=value;
value=object.attribute;
if (object.method(<arguments>)) then ...
if (object.attribute) then ...
where
object
specifies an object or an automatic system variable (such as _CFRAME_,
_FRAME_, or _SELF_) whose type is object.
method
specifies the name of the method to execute.
arguments
specifies one or more arguments based on the appropriate method signature.
return value
specifies the value returned by a method (if any).
attribute
specifies an attribute that exists on object.
value
specifies a value assigned to or queried from the attribute.
Controlling the Execution of SCL Programs
41
Dot notation can be used to set or query attributes. For example, suppose object1 is a
text entry control:
/*Setting the text color */
object1.textColor='yellow';
/* Querying the text color.
*/
/* object1's textColor attribute is returned */
/* to the local SCL variable 'color'
*/
color = object1.textColor;
Dot notation also is used to call methods. For example,
object._cursor();
is equivalent to
call send(object, '_cursor');
For compatibility with legacy programs, you can continue to use CALL SEND and
CALL NOTIFY to invoke methods.
You can use dot notation to call methods on objects in several ways, provided the
method contains the appropriate signature information. For example,
/* With a return variable */
cost=object1.getPrice(itemnum);
/* Without a return variable */
object1.getPrice(itemnum, cost);
/* In an IF statement */
if object1.getPrice(itemnum) > 100 then
do...
Note: Objects that are created on a frame and automatic system variables (such as
_FRAME_ ) are automatically declared as objects. You can refer to these objects in
dot notation without having to declare them in your SCL programs. To use dot
notation with legacy objects that you add to a frame, you must first select “Use
object name as ID in SCL” for those objects in the Properties window.
For more information about dot notation, refer to the SAS Component Language:
Reference and the SAS/AF online Help.
Controlling the Execution of SCL Programs
Introduction
There are several ways to control application execution in an SCL program for a frame.
You can
•
conditionally change the program flow, or branch to other sections of SCL
•
submit SAS and SQL statements (see the SAS Component Language: Reference for
details)
•
use the SYSTEM function to issue a host operating system command that performs
system-specific data management tasks or invokes an application other than SAS
42
Chapter 6
• Adding SAS Component Language Programs to Frames
•
use the CONTROL statement with the ALWAYS option or the ENTER option to
process custom commands
You can use conditional SCL statements to alter the flow of a program. For example, to
conditionally return control to the window:
object1:
/* ...SCL statements... */
if condition
then return;
/* ...SCL statements... */
return;
You can use the LINK statement to branch to a common labeled section in the same
SCL program. For example:
object1:
/* ...SCL statements... */
link computeValue;
/* ...SCL statements... */
return;
object2:
/* ...SCL statements... */
link computeValue;
return;
computeValue:
/* ...SCL statements... */
return;
The labeled section computeValue may or may not correspond to an object of the same
name. Labeled sections are not required for all objects on a frame; likewise, a labeled
section can exist with or without an associated frame object. The computeValue section
executes each time
•
object1 is activated or modified
•
object2 is activated or modified
•
an object named computeValue is activated or modified (if it exists on the frame)
For additional information on controlling application flow with SCL, refer to the topics
on submitting SAS statements and using macro variables in the SAS Component
Language: Reference.
Processing Custom Commands in SCL Programs
You can add custom command processing to your frame SCL programs to control
program flow. A custom command can be any name that does not correspond to an AF
window command or SAS global command and that you implement in the MAIN
section of your frame SCL program. A user issues commands by typing on a command
line, by pressing a function key with a defined command, or by selecting items on the
frame, including menu selections or commands that are associated with visual controls.
To implement a custom command, you must
•
select a unique command name (that is, one that differs from all AF window
commands and SAS global commands).
Controlling the Execution of SCL Programs
43
•
add a CONTROL statement to change the default behavior for command processing
during SCL program execution. Alternatively, you can set the frame's
commandProcessing attribute to Run main.
•
add code to the MAIN section of the frame's SCL program to read the custom
command from the command line, process the custom command, and prevent the
SAS command processor from evaluating the custom command.
The CONTROL statement controls the execution of labeled sections in an SCL program.
Typically, you add this statement to the INIT section of your program.
•
Use CONTROL ALLCMDS to execute the MAIN section when a procedure-specific
or custom command is issued, or when a user presses the ENTER key, even if an
error flag is in effect for an object on the frame.
•
Use CONTROL ALWAYS to execute the MAIN section when a custom command
is issued or when a user presses the ENTER key, even if an error flag is in effect for
an object on the frame.
•
Use CONTROL ENTER to execute the MAIN section when a custom command is
issued or when a user presses the ENTER key, unless an error flag is in effect for an
object on the frame.
You can use the WORD function to return the command for processing, using the syntax
command=word(n <,case>);
where command is the word that is currently in the command buffer, n is the position
(either 1, 2, or 3) of the word in the command, and case is an optional parameter that
converts the word to either uppercase ('U') or lowercase ('L').
You can use the NEXTCMD routine to remove the current command from the command
buffer, using the syntax
call nextcmd();
If you do not remove a custom command from the command buffer, SAS issues an error
message.
For example, consider a frame that contains a toolbar object on which each button is set
to issue a different command. These commands can be a mixture of valid SAS
commands or custom commands that you implement in the MAIN section of the frame's
SCL program:
dcl char(8) command;
INIT:
control always;
return;
MAIN:
command=word(1, 'u');
select command;
when ('CUSTOM1')
/* ...code to process the CUSTOM1 command... */
call nextcmd();
when ('CUSTOM2')
/* ...code to process the CUSTOM2 command... */
call nextcmd();
otherwise;
end;
return;
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Chapter 6
•
Adding SAS Component Language Programs to Frames
Calling Other Entries and Opening Windows
Introduction
You can use SCL to access other entries that you may need for your application, such as
frames and other SCL programs. You can use the DISPLAY routine to invoke another
SAS catalog entry, including FRAME, SCL, CBT, and PROGRAM entries. For
example,
call display('sasuser.mycat.myApp.scl');
invokes the SCL entry named myApp. The calling program transfers control to myApp
and waits for it to finish processing.
SCL also enables you to pass parameters between different entry types. In general, any
argument to an SCL function, routine, or method can be
•
a constant
call display('myFrame.frame', 2);
•
an SCL variable
call display('myApp.scl', myTable);
•
an object attribute
call display('dlg.frame', listBox1.selectedItem);
Character constants, numeric constants, and expressions are passed by value. You can
use any SCL variable to pass parameters by reference to another entry. To use the
DISPLAY function with a return value, you must include an ENTRY statement in the
frame SCL of the called FRAME entry. For example, consider the following SCL code:
validUser=DISPLAY('password.frame', userid);
If PASSWORD.FRAME contained a text entry control named userPassword in
which a user could provide a valid password, the frame's SCL could contain
/* FRAME SCL for mylib.mycat.password.frame */
entry userid:input:num return=num;
term:
dcl char pwd;
dcl num isValid;
/* Assume that the user ID is validated in some */
/* way to establish a value for the password.
*/
if userPassword.text = pwd
then isValid=1;
else isValid=2;
return(isValid);
For details on passing parameters to other SAS catalog entries, see the ENTRY
statement in the SAS Component Language: Reference.
Opening Other Windows
Your applications can consist of any number of windows and dialog boxes. Using the
DISPLAY routine, you can open other windows in your application as needed.
Calling Other Entries and Opening Windows
45
For example, assume that a frame contains three push button controls named Rates,
Lenders, and Recalculate. The SCL entry for that frame can call a FRAME entry
named LOANRATES.FRAME when a user clicks the Rates button, and it can call a
FRAME entry named LENDERINFO.FRAME when a user clicks Lenders. The frame
SCL also runs another SCL entry when a user clicks Recalculate.
RATES:
call display('loanRates.frame');
return;
LENDERS:
call display('lenderInfo.frame', 2, 'North', listBox1.selectedItem);
return;
RECALCULATE:
call display('sasuser.myapp.calculate.scl');
return;
You can also invoke full-screen applications from a SAS/AF frame application. For
example, the following SCL code enables a user to access the FSEDIT window and to
browse the RECORDS.CLIENTS table after clicking Clients on the active frame:
CLIENTS:
call fsedit('records.clients',”,'browse');
return;
Calling Dialog Boxes from an Application
You can present information in SAS/AF applications through dialog boxes as well as
through standard frames. Your SCL code can call dialog boxes using any of the
following:
•
the DIALOG routine or function
Much like CALL DISPLAY, the DIALOG function enables you to display a
FRAME entry. DIALOG differs from CALL DISPLAY in that it displays the frame
as a modal window, which disables all other SAS windows until the dialog frame is
closed. For example:
CALL DIALOG('verify.frame');
or
validInput=DIALOG('validate.frame', some-variable);
To use the DIALOG function with a return value, you must include an ENTRY
statement in the frame SCL of the called FRAME entry.
•
the MESSAGEBOX function
You can use the MESSAGEBOX function to display a host message window for
informational, warning, or error messages. For example:
VALIDATE:
dcl list msgList={'SAS table not specified.'};
dcl num rc;
choice=MessageBox(msgList, '!', 'OC', 'Validation');
if choice='CANCEL'
then call execcmd('end');
46
Chapter 6
•
Adding SAS Component Language Programs to Frames
rc=dellist(msgList);
return;
You can use the MESSAGEBOX function instead of the _MSG_ automatic variable
to display warnings.
•
the SCL File or Entry Dialog functions
You can use the OPENSASFILEDIALOG and SAVESASFILEDIALOG functions
to manipulate two-level SAS filenames just as you would use DIRLIST. Likewise,
you can use the OPENENTRYDIALOG and SAVEENTRYDIALOG functions to
manipulate SAS catalog entry names just as you would use CATLIST. For example,
selected=OpenEntryDialog('RANGE');
opens a catalog entry selector, displays available RANGE entries, and returns the
user's selections.
For complete information on these functions, see the SAS Component Language:
Reference.
Compiling and Testing Applications
Introduction
To compile your SCL program in the build environment, you can select Build ð
Compile. You can also enter the COMPILE command or click the Compile icon on the
toolbar. If the SCL entry was opened from within the frame, you can issue the
COMPILE command with either the FRAME entry or the SCL entry as the active
window, and both entries will be compiled.
You should also consider the following when compiling frames and their SCL entries:
•
If your FRAME entry uses an SCL program, you must compile the FRAME entry in
order to associate the compiled SCL source with the FRAME entry.
•
The compiler produces a list of errors, warnings, and notes in the Log window. Open
the Log window by issuing the LOG command or by selecting View ð Log.
Although you can compile an SCL program independently of its FRAME entry, the
compiled code is associated with the FRAME entry only if you compile the SCL source
either through the Source window that was opened from the frame or through the Build
window that contains the FRAME entry.
You can also compile FRAME entries in batch or automatically.
Compiling FRAME Entries in Batch
You can use the BUILD procedure statement to compile in batch all of the FRAME
entries in a catalog. However, you must use the ENTRYTYPE option to specify that the
FRAME entries are to be compiled. When you use the COMPILE option without an
ENTRYTYPE option, the BUILD procedure compiles only PROGRAM entries. For
example, to compile all of the FRAME entries in the PAYROLL catalog (in the library
that was assigned the libref DEPT), use the following statements:
proc build c=dept.payroll batch;
compile et=frame;
run;
Debugging and Optimizing Your Applications
47
Compiling FRAME Entries Automatically
If you set a frame's automaticCompile attribute to Yes in the Properties window, the
FRAME entry is compiled automatically when you issue the SAVE, END, or TESTAF
command from that FRAME entry.
Testing Your Application
SAS/AF software provides a testing mode that is available from within the build
environment. To test your application while your frame and SCL entry are open, you can
select Build ð Test. You can also click the TESTAF toolbar button or enter the
TESTAF command.
As long as the SCL entry was opened from within the frame, you can issue the TESTAF
command with either the FRAME entry or the SCL entry as the active window.
Note: You cannot use the TESTAF test mode if the FRAME entry is stored in a library
that is accessed with SAS/SHARE software. Also, the TESTAF command does not
process SUBMIT statements in your SCL code.
To test your application outside the build environment, you can do either of the
following:
•
Open the Explorer window, select the frame to test, and then select Run from the
pop-up menu.
•
Enter the following command:
af c=libref.catalog.catalogEntry.entryType
Testing outside the build environment has no restrictions or limitations, and frames
perform with complete functionality.
Debugging and Optimizing Your Applications
Introduction
You can use the SCL Debugger to debug your frame SCL programs. The SCL Debugger
is a powerful interactive utility that can monitor the execution of SCL programs. To use
the debugger, issue the DEBUG ON command, select Build ð Debug ð Debug On or
click the Debug toolbar button. After you turn on the Debugger, you must recompile
your SCL.
See the SAS Component Language: Reference for details on using the SCL debugger.
Common SCL Debugger Commands
The following table describes some of the common SCL Debugger commands that you
can use to track errors in your SCL programs:
48
Chapter 6
•
Adding SAS Component Language Programs to Frames
Table 6.1
Common SCL Debugger Commands
Command
Description
BREAK
sets a breakpoint at a particular executable program statement. When the
Debugger encounters a breakpoint, program execution is suspended and the
cursor is placed at the DEBUG prompt in the Debugger's Message window.
DELETE
removes breakpoints, tracepoints, or watched variables that were previously set
by the BREAK, TRACE, and WATCH commands.
DESCRIBE
displays the name, type, length, and class attributes of a variable.
EXAMINE
displays the value of a variable or an object attribute.
GO
continues program execution until a specified statement or until the next
breakpoint or end of program is encountered.
JUMP
restarts program execution at a specified executable statement, which may skip
intermediate statements.
LIST
displays all of the breakpoints, tracepoints, and watched variables that have been
set by the BREAK, TRACE, and WATCH commands.
PUTLIST
displays the contents of an SCL list.
QUIT
terminates the Debugger.
STEP
steps through the program, statement by statement. By default, the ENTER key
is set to STEP.
TRACE
sets a tracepoint. When a tracepoint is encountered, the Debugger displays
relevant information in the Message window and continues processing.
WATCH
sets a watched variable. If the value of a watched variable is modified by the
program, the Debugger suspends execution at the statement where the change
occurred. The old and new values of the variable are displayed in the Message
window.
Optimizing the Performance of SCL Code
You can optimize the performance of SCL programs in your applications with the
SAS/AF SCL analysis tools.
The following table lists the available tools and provides information about when you
might want to use each tool.
Table 6.2 SCL Tools
Use the...
when you want to...
Coverage Analyzer
monitor an executing application and access a report that
shows which lines of SCL code are not executed during
testing.
Saving and Storing Frame SCL Programs
49
Use the...
when you want to...
List Diagnostic Utility
monitor an executing application and access reports on the
use of SCL lists, including any lists that are left undeleted.
Performance Analyzer
monitor an executing application and identify any bottlenecks
in an application's SCL code.
Static Analyzer
access reports that detail SCL code complexity; variable,
function, method, and I/O usage; and error and warning
messages.
To display a menu of the SCL analysis tools, enter sclprof at the command prompt.
For detailed information about using these tools, refer to the SAS/AF online Help.
Saving and Storing Frame SCL Programs
There are several important items to remember when you are saving SCL programs for
FRAME entries:
•
If an SCL entry that is associated with a frame is saved from the Source window,
then both the FRAME entry and the SCL entry are saved.
•
Although you can compile an SCL program independently of its FRAME entry, the
compiled code is stored with the FRAME entry only if you compile the SCL source
either through the Source window or through the Build window that contains the
FRAME entry. Compiling the FRAME entry always compiles the associated SCL
entry.
•
The SCL program is automatically compiled and saved when you save the FRAME
entry if you set the frame's automaticCompile attribute to Yes.
•
When you compile a FRAME entry, the FRAME entry's SCL source is compiled,
and the compiled code is stored in the FRAME entry. Since the compiled SCL
program is stored in the FRAME entry, the SCL entry that contains the source
statements does not have to exist when you install and run the application.
•
If you change the name of a frame that has an associated SCL entry, you must also
remember to either
•
change the name of the SCL entry to match the FRAME entry if it is not *.SCL,
and then recompile the frame; or
•
edit the frame's SCLEntry attribute to use the existing frame SCL entry.
50
Chapter 6
•
Adding SAS Component Language Programs to Frames
51
Chapter 7
Adding Application Support
Features
Implementing Custom Menus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Using the PMENU Procedure to Create Menus . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Adding Online Help to Your Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Adding Help to a Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Attaching Context-Sensitive Help to Frame Components . . . . . . . . . . . . . . . . . . . . 54
Calling Help from Your Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Implementing Custom Menus
Introduction
You can create custom menus for your SAS/AF applications using the Base SAS
software PMENU procedure.
To add a menu to your application:
1. Create a PMENU catalog entry using PROC PMENU.
2. In the SAS/AF build environment, use the Properties window to set the appropriate
frame's pmenuEntry attribute to the PMENU catalog entry that you want to
display.
3. Set the frame's forcePmenuOn attribute to Yes and the frame's bannerType
attribute to None.
For additional information about PMENU entries, see the SAS/AF online Help.
Using the PMENU Procedure to Create Menus
To create the structures and commands associated with your menu, you submit a source
program that contains PMENU procedure statements. Because the source statements that
are used to create a PMENU entry are not accessible in the PMENU catalog entry, you
should save the statements in your development catalog as a SOURCE entry.
Consider the following example:
proc pmenu catalog=sasuser.corprpts;
menu main;
52
Chapter 7
•
Adding Application Support Features
item 'File' menu=menuFile mnemonic='F';
item 'View' menu=menuView mnemonic='V';
item 'Help' menu=menuHelp mnemonic='H';
menu menuFile;
item 'Open Report' selection=fileOpen mnemonic='O';
item 'Save Report' selection=fileSave mnemonic='S';
separator;
item 'End';
selection fileOpen 'openrpt';
selection fileSave 'saverpt';
menu menuView;
item 'View Table' selection=viewTbl mnemonic='T';
item 'Options' selection=viewOpts mnemonic='p';
selection viewTbl 'afa c=mylib.mycat.view.frame';
selection viewOpts 'afa c=mylib.mycat.options.frame';
menu menuHelp;
item 'Contents' selection=helpCont mnemonic='C';
item 'About...' selection=helpAbt mnemonic='A';
selection helpCont 'wbrowse "http://myintranet.com/help.htm"';
selection helpAbt 'afa c=mylib.mycat.about.frame';
run;
quit;
In this example,
•
The menu is stored in the catalog named in the PROC PMENU statement.
•
The first menu statement names the PMENU catalog entry that will contain the
menu, which in this example is sasuser.corprpts.main.pmenu.
•
Each ITEM statement specifies an item in the menu bar. The value of MENU=
corresponds to a subsequent MENU statement.
•
Each MENU= option is defined by a MENU statement, where each subsequent
ITEM statement specifies the selections that are available under the named menu in
the menu bar.
•
A separator line can be added to menus by using the SEPARATOR statement.
•
ITEM statements with no SELECTION= option indicate that the menu command is
equivalent to the value of the ITEM. For example, item 'End' in the menuFile
menu is the End command.
•
Each SELECTION= option points to a corresponding SELECTION statement to
define the command that is issued by the menu.
Note: To issue multiple commands, separate them with semicolons.
•
Commands in a SELECTION statement that do not correspond to a valid SAS
command must be implemented and trapped in the frame's SCL program.
The completed menu appears as follows:
Adding Online Help to Your Applications
53
In the PMENU example, the menuFile menu contains two SELECTION statements that
issue the custom commands openrpt and saverpt. Your frame SCL program can
process commands that are not valid SAS commands if
•
the command name is not a valid AF window command or SAS global command
•
your frame SCL includes a CONTROL ALWAYS or CONTROL ENTER option
•
the MAIN section in your frame SCL performs the processing
For example, the SCL program for the frame associated with MAIN.PMENU could
include the following code:
dcl char(8) command;
INIT:
control always;
return;
MAIN:
command=lowcase(word(1));
if command='openrpt' then do;
/* ...SCL to open reports... */
call nextcmd();
end;
else if command='saverpt' then do;
/* ...SCL to save reports... */
call nextcmd();
end;
return;
For complete information on the PMENU procedure, refer to the SAS Procedures Guide.
Adding Online Help to Your Applications
Introduction
You can add online Help to your applications to provide assistance to your users.
SAS/AF software supports help in several formats, including HTML-based Web pages
and SAS/AF CBT catalog entries. Your applications can also take advantage of contextsensitive help and tooltips.
When you implement a Help system for your application, you should consider
•
how much detail you want to add to the help
•
whether or not context-sensitive help is required (so that you can make the necessary
changes to frame and component properties)
•
what functionality the various help commands provide and how you can use them
appropriately
•
how your help files are structured and stored
54
Chapter 7
•
Adding Application Support Features
Adding Help to a Frame
You can add help to a frame by setting its Help attributes. To display the attributes in the
Help category, expand the Attributes tree in either the Properties window or the Class
Editor and select the Help node. You can set the following attributes:
CBTFrameName
Set the CBT frame name that you want to display if you are using SAS/AF CBT
entries to deliver your help information. This attribute is valid only if a CBT entry is
assigned for the frame's help attribute.
help
Set the frame's help attribute to specify the type of help and the item to display
when help is selected. If you select a SAS catalog entry as the type of help, SAS/AF
assumes that you want to display a CBT entry. Other types of help provide different
ways of displaying help in a browser. For details on the types of help, see the help
attribute in the Frame class.
showContextHelp
Set this attribute to toggle the display of the question mark control button (?) in the
window border of the frame. Set this attribute to Yes if
•
your frame's type attribute is set to “Dialog”
•
you have defined help for components on your frame
•
you want the HELPMODE command to recognize context-sensitive help
selections
Attaching Context-Sensitive Help to Frame Components
You can add context-sensitive help for components on a frame by using the “What's
This” type of help for a component, for status-line messages, and/or for tooltips. You
must set the appropriate attribute in the Properties window if you want to specify help
for a component. You can set the following attributes:
CBTFrameName
Set the CBT frame name that you want to display if you are using SAS/AF CBT
entries to deliver your help information. This attribute is valid only if a CBT entry is
assigned for the component's help attribute.
help
Set the component's help attribute to specify the type of help and the item to display
when help is selected. If you select a SAS catalog entry as the type of help, SAS/AF
assumes that you want to display a CBT entry. Other types of help provide different
ways of displaying help in a browser. For details on the types of help, see the help
attribute in the Object class.
helpText
Set the component's helpText attribute to specify a message to display on the
status bar when a user positions the cursor over the component.
toolTipText
Specify the text that you want to appear as a tooltip for the component. A tooltip
(also known as “balloon help”) is presented as pop-up text when a user positions the
cursor over the component for a particular time interval.
Adding Online Help to Your Applications
55
Calling Help from Your Application
SAS/AF software provides several commands that you can use to display help for your
application. You can add these help commands to a menu item, or you can assign one of
them as the command that is executed by a control such as a push button. You can also
attach the commands to icon buttons on a toolbar.
The commands include
HELP
The HELP command displays help for the active frame or window based on the
values of the frame's Help attributes. The Help topic or topics are displayed in the
designated help browser.
The WINDOWHELP command performs the same function as HELP.
HELPMODE
When the HELPMODE command is issued, SAS enters object help detection mode
(helpmode). In helpmode, the cursor changes to a question mark (?) and SAS waits
for the user to select an object on the active frame. When a user selects an object
while in helpmode, SAS displays the help that is defined in that object's help
attribute.
WBROWSE valid-URL
The WBROWSE command simply displays a valid URL, which can be any page that
can be displayed by the associated Web browser.
The HELP command can be used in conjunction with the HELPLOC:// protocol to
display a specific Help topic. The HELPLOC:// protocol is a mechanism defined by SAS
for displaying help files from within your application. For example, help
helploc://myapp/intro.htm opens the Help topic that is stored in the HTML file
named intro.htm.
To specify the location of the help files for your application, you must add the
appropriate path in the HELPLOC system option in the configuration file that is used to
start your application.
Note: SAS/AF software uses the HELPLOC option to identify the path it searches to
locate online Help files. The default path for SAS online Help is a format such as
!SASROOT/X11/native_help
or
!sasroot\core\help
If you modify or remove this path from the HELPLOC option in your software
configuration file (instead of in your application's configuration file), SAS software
cannot locate its associated online Help.
You can add multiple search paths to HELPLOC. The SAS Help facility replaces the
HELPLOC:// protocol with a path listed in the HELPLOC option. The paths are
searched in the order in which they are listed until the valid Help topic is found or until
there are no further paths to search. For example, if your HELPLOC option contains
('!sasroot\core\help' '!sasuser\classdoc')
you could add a path to the directory in which you stored the help for your application:
('f:\apps\myapp\help' '!sasroot\core\help' '!sasuser\classdoc')
The SAS Help facility will then search through f:\apps\myapp\help to locate a
Help topic before it searches the SAS online Help path (!sasroot\core\help).
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A path specified in the HELPLOC option does not have to be a local directory. It can
also be a path on a valid Web server or a path to a network directory. For example,
consider a HELPLOC option that is defined as
('!sasroot\core\help' 'http://mycompany.com/intranet/apphelp')
and a help call from a SAS/AF frame that uses the form
help helploc://myapp/intro.htm
In this example, the SAS Help facility will first search for the requested Help topic in the
SAS online Help path. Then it will send a fully qualified URL to the browser to locate
the Help topic at
http://mycompany.com/intranet/apphelp/myapp/intro.htm
See “Configuring a SAS Session for Your Application” on page 60 for information on
customizing the configuration file.
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Application Deployment Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Migrating Your Application from Testing to Production . . . . . . . . . . . . . . . . . . . . . 58
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Porting Your Application to Different Operating Environments . . . . . . . . . . . . . . . 59
Configuring a SAS Session for Your Application . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Specifying a Custom Configuration File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Invoking Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Enabling the Application for Your Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Application Deployment Issues
After fully testing your SAS/AF application, you can begin to implement and deploy it
to your users. Deploying an application requires you to move from the development
process of a prototype to assembling all of the parts to create a production application.
You should consider the following issues when planning to deploy a SAS/AF
application:
•
Is this a stand-alone application that will be installed on individual machines?
•
Will this application be installed on a network, with many users accessing it
simultaneously?
•
Which SAS system options should be set to establish the desired application
environment?
•
Which windowing features should be in effect?
•
When the user closes the application, where should your application return to (the
SAS display manager, another application, or the operating environment)?
The basic methodology for deploying an application should include the following steps:
1. Modify the prototype so that only the desired SAS software windows are open when
the application starts.
2. Modify the prototype so that the user is returned to the appropriate environment
when the application closes.
3. Copy the catalog or catalogs that comprise your application from the testing or
prototype location to the production location.
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4. Prepare a custom configuration file to initialize SAS for use by your application.
5. Create a command file or icon that launches the application.
Migrating Your Application from Testing to
Production
Introduction
Once you have tested your application in a development environment, you should copy
it to the area designated as a production location, where you can retest it.
Two procedures are available for copying applications:
•
the COPY procedure
•
the BUILD procedure.
The COPY procedure is a general-purpose utility for copying SAS libraries from one
device to another or from one file to another. You can copy an entire library, or you can
select or exclude members of specific types.
For example, to copy an application from a prototyping or test environment on the C:
drive to a production environment on the F: drive, you could use this code:
libname proto 'c:\test';
libname product 'f:\apps';
proc copy in=proto out=product;
run;
If your catalogs are already in the production location, then run this program simply to
reduce the size of the catalogs:
proc copy in=product out=work;
proc copy in=work out=product;
run;
Note: Although you can use operating environment commands to copy SAS files, you
should use the COPY procedure instead. After you edit catalogs in the build
environment, some entries can become fragmented. When the COPY procedure
executes, it reconstructs and reorganizes all SAS files, including data sets and
catalogs. The new files often occupy less disk space; it is not unusual for a catalog to
shrink by 50% to 75% when the COPY procedure is run on it.
You can copy either an entire catalog or selected entries with the MERGE statement in
the BUILD procedure. The general form of the MERGE statement in PROC BUILD is:
PROC BUILD C=libref.out-cat;
MERGE C=libref.in-cat options;
where
out-cat
names the output catalog.
in-cat
names the input catalog.
Migrating Your Application from Testing to Production
59
options
are options to control which entries are copied. MERGE statement options include
REPLACE
causes entries in out-cat to be replaced with like-named
entries from in-cat. The default is not to replace like-named
entries.
ENTRYTYPE=
specifies an entry type for processing. If omitted, all entries
are processed. If you want to copy entries of more than one
type, use multiple MERGE statements. You can abbreviate
the ENTRYTYPE= option as ET=.
NOEDIT
specifies that the entries being merged cannot be edited with
PROC BUILD. Be sure to save the original copy of the entry
for editing.
NOSOURCE
tells the procedure to copy only the compiled portions of
FRAME and SCL entries. You can abbreviate the
NOSOURCE option as NOSRC. The SCL code itself is
removed from SCL and PROGRAM entries.
For complete information about the MERGE statement and about the BUILD procedure,
refer to the SAS/AF online Help.
When you move your application from one library or catalog to another, be sure to check
for hardcoded librefs. Particular care must be taken to ensure that SCL code and class
references that are associated with your components refer to the proper location. See
“Deploying Components” on page 151 for more information.
Porting Your Application to Different Operating Environments
SAS/AF software enables you to create an application in one development environment
and to port that same application to the operating environments of your users.
Note: Although SAS/AF software does not support a build-time environment for
FRAME entries on a mainframe, applications can be developed in desktop
environments such as Windows and ported to run on a mainframe.
To port (or “export”) an application to another environment:
1. In the development environment, use the CPORT procedure to export a SAS library
or SAS catalog into a transport file. (You can transfer SAS tables directly from one
operating environment to another without creating a transport file.)
The basic form of the CPORT procedure is
proc cport source-type=libref<.member-name>
file=transport-fileref;
where source-type specifies a catalog, data set, or library; member-type is required if
source-type is either CATALOG or DATA; and transport-fileref specifies the
transport file to write to.
2. Copy the transport file from your development environment to the production or
end-user environment(s), using the appropriate operating system commands for a
binary file transfer such as FTP.
3. In each environment to which you want to deploy the application, use the CIMPORT
procedure to restore the transport file to its original form in the appropriate format
for the host operating environment.
The basic form of the CIMPORT procedure is
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proc cimport destination=libref<.member-name>
infile=transport-fileref;
where destination specifies a catalog, data set, or library; member-type is required if
destination is either CATALOG or DATA; and transport-fileref specifies the
transport file to read.
For details on using the CPORT or CIMPORT procedures, see the Base SAS Procedures
Guide.
When you develop a frame for use in other environments, it is recommended that you
port the frame to the target platform to test the frame, using the same display that your
users will use. The sizing of visual components on a frame can be affected by the host
environment due to differences in the system fonts in the development environment and
the run-time environments. Currently, font sizes can vary depending on the display
device that is used.
It is important to test applications on all display devices that are used in the deployment
environments. Also, keep in mind the following restrictions when developing framebased applications that you plan to deploy in multiple environments:
•
Some objects are not supported on all display devices, and some objects behave
differently when displayed in different host environments. Refer to the “Component
Reference” in the SAS/AF online Help for details.
•
Text and graphic alignment may differ between the build-time environment and the
run-time environment.
•
Certain events or functions that are supported in some environments do not work in
others, including mouse movement, drag and drop operations, double-clicking,
selecting either mouse button 2 or 3, and others.
•
Some display devices have very limited color selections. For example, when a color
such as gray is displayed on a terminal that must choose between black and white,
some visual objects on the frame may not appear or may disappear into the
background of the frame.
For additional information about a specific host operating environment and SAS
software, refer to the SAS Companion for that environment.
Configuring a SAS Session for Your Application
Introduction
There are several ways to set up a SAS session to accommodate the needs of the
applications you want to deploy. Some applications will be called by users from within a
SAS session, which requires that those users have access to the libraries that contain the
data sets and catalogs that comprise the application. Other applications may extend or
add additional capabilities to existing applications, and you can add program calls from
one application to start another.
However, most applications that you deploy, require that you provide a custom
invocation of SAS. To start a SAS session, you must have access to the SAS executable
file and to a SAS configuration file. (A standard SAS configuration file is supplied with
SAS software and is typically located in the same directory as the SAS executable file.)
The SAS configuration file specifies
Configuring a SAS Session for Your Application
61
•
the value of an environment variable, SASROOT, that contains the name of the
directory where SAS software is installed. The SAS executable and configuration
files are stored in this directory.
•
which subdirectories of the SASROOT directory to search for various SAS products.
•
the location of the files that contain warning and error messages.
•
the location of the SAS help facility and other modules that are necessary for
interactive execution (the SASHELP libref).
•
the location of a temporary directory for users' work files (the WORK libref).
•
the location of a permanent directory for users' personal files (the SASUSER libref).
•
the locations of online Help (HELPLOC) files.
•
the settings of other system options, some of which are host-specific.
Specifying a Custom Configuration File
The CONFIG system option specifies the location of the configuration file. You can
include SAS system options as part of the SAS command that is used to start a SAS
session. The configuration file that is supplied with Version 9 is called SASV9.CFG.
Here are two examples, one for a PC environment and the other for UNIX operating
environments:
sas -config c:\myApp\myConfigFile.cfg
sas -config /u/myApp/myConfigFile.cfg
Note: Your configuration file does not have to be named SASV9.CFG. If you use a
generic name for your configuration file, start with a copy of the one that is supplied
by SAS and then rename it. If you do not specify a configuration file in the SAS
command, the first file named SASV9.CFG in a predefined search path is used. For
details about host-specific system options and configuration files, see the SAS
Companion for your operating environment.
To create a configuration file, you can
1. Make a copy of the default configuration file.
2. Modify the copy by adding or changing SAS system options.
You can also specify additional windowing environment options in a custom
configuration file. For example, consider this configuration file for an application on a
Windows PC:
-AWSCONTROL TITLE NOSYSTEMMENU MINMAX
-AWSTITLE 'Corporate Reporting'
-NOAWSMENUMERGE
-SASCONTROL NOSYSTEMMENU NOMINMAX
-NOSPLASH
-SET corprept F:\apps
-HELPLOC ('!sasroot\core\help' 'F:\apps\help')
-SPLASHLOC F:\apps\images
-INITCMD "AF C=corprept.APP.MAINMENU.FRAME PMENU=YES"
where
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AWSCONTROL
specifies application workspace (AWS) features. Precede a feature with NO to
disable it.
•
TITLE indicates whether the AWS includes a title bar.
•
SYSTEMMENU indicates whether the AWS menu appears.
•
MINMAX indicates whether the minimize and maximize controls appear.
AWSTITLE
specifies the title for the AWS window if the AWSCONTROL TITLE option is set.
AWSMENUMERGE/NOAWSMENUMERGE
specifies whether the AWS menu items Options, Window, and Help appear.
SASCONTROL
specifies application window features. Precede a feature with NO to disable it.
•
SYSTEMMENU indicates whether the AWS menu appears.
•
MINMAX indicates whether the minimize and maximize controls appear.
SPLASH/NOSPLASH
specifies whether the SAS software splash screen appears while your application is
starting. You can substitute your own bitmap image for the SAS software splash
screen. For more information, see the SAS Companion for the Microsoft Windows
Environment.
SET
creates an environment variable. An environment variable that contains a pathname
can be used as a SAS libref. For networked applications, ensure that all SAS files in
this path have a read-only attribute.
HELPLOC
specifies the location of online Help files.
SPLASHLOC
specifies the location of a custom splash screen image to display when SAS starts.
Invoking Applications
You can use the INITCMD system option to launch your SAS/AF software application.
The main advantage of this option is that SAS display manager windows are not
displayed before your primary application window appears. You can add the INITCMD
option to
•
the SAS command that you use to invoke the SAS session for your application
•
the configuration file that is used in conjunction with the SAS command.
The general form of the INITCMD system option is
-INITCMD "AF-command<,SAS-windowing-environment-command>; . . .;
SAS-windowing-environment-command"
The INITCMD option
•
is specified either as part of the SAS command or in a configuration file
•
requires you to specify the DMS option
•
must follow the -DMSEXP option (unless -NODMSEXP is specified) if placed in a
configuration file
Enabling the Application for Your Users
63
•
opens the AF window first
•
does not open other SAS windowing environment windows (but they can be opened
by the application)
•
can issue additional SAS windowing environment commands
•
eliminates the need for the DM statement in an autoexec file and does not permit
execution of DM statements
•
exits SAS when the user exits the application
•
is available in most operating environments.
Enabling the Application for Your Users
Once the application is tested and ready for use in the production environment, you must
provide a mechanism for users to invoke the application. Typically, you can either create
a command file or a program item that contains the SAS command plus a reference to
the custom configuration file.
The Windows operating environment has graphical interface features for launching
application programs. In such an environment, you can create a program item for your
application and make your application accessible to users via a desktop icon or folder.
For some environments, you might want your users to access the application by using a
shell script or a batch file. For example, the following shell script starts an application in
a UNIX environment:
APPS=/u/apps
export APPS
sas -sasuser
-rsasuser
-autoexec
-printcmd nlp
-xrm
-xrm
-xrm
-xrm
-xrm
-initcmd
/u/apps/sasuser
/u/apps/autoexec.sas
'SAS.windowWidth: 80'
'SAS.windowHeight: 32'
'SAS.windowUnitType: character'
'SAS.awsResizePolicy: variable'
'SAS.sessionGravity: CenterGravity'
"af c=corprept.app.MAINMENU.FRAME"
You can give users “execute” permission to the script file, and they can simply enter the
script's name at a shell prompt to launch the application.
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65
Part 3
Developing Custom Components
Chapter 9
Tools for the Component Developer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Chapter 10
SAS Object-Oriented Programming Concepts . . . . . . . . . . . . . . . . . . . . 71
Chapter 11
Developing Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Chapter 12
Managing Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Chapter 13
Managing Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Chapter 14
Adding Communication Capabilities to Components . . . . . . . . . . . . 129
Chapter 15
Deploying Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
66
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Developer
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Class Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Resource Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Interface Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Source Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Other Development Tools and Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Introduction
The classes from which components are derived can be designed and managed in the
SAS/AF development environment with the following tools:
•
Class Editor
•
Resource Editor
•
Interface Editor
•
Source window
Other complementary development tools are also available to increase performance,
provide source management, and produce class documentation.
Class Editor
SAS/AF software provides a Class Editor for editing existing classes and for
subclassing. The Class Editor enables you to modify or add properties, including
attributes, methods, events, event handlers, and interfaces. Any time you open a CLASS
catalog entry you are using the Class Editor.
Changing any of the properties or behaviors of a class changes the property or behavior
of all instances and children of that class.
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To open the Class Editor, double-click an existing class in the SAS Explorer, or create a
new class via the SAS Explorer or the BUILD command (for example, build
work.a.a.class). For more detailed information on using the Class Editor, see
“Component Development” or “Class Editor” in the SAS/AF online Help.
Resource Editor
The Resource Editor enables you to group classes into resources. These resources can
then be added to the Components window so that you can easily use your classes at
design time.
To open the Resource Editor, double-click an existing resource in the SAS Explorer, or
create a new resource via the SAS Explorer or the BUILD command (for example,
build work.a.a.resource). For more information on the Resource Editor, see
“Managing Classes with Resources” on page 152, or “Resources” in the SAS/AF online
Help.
Interface Editor
The Interface Editor enables you to build interface objects that consist of method
definitions (the method name and method signature). The methods defined in an
interface are implemented on the classes that implement that interface. Typically,
interfaces are used by models and views to establish model/view communications.
Source Window
69
To open the Interface Editor, double-click an existing interface in the SAS Explorer, or
create a new interface via the SAS Explorer or the BUILD command (for example,
build work.a.a.intrface). For more information on how to use the Interface
Editor, see “Interfaces” in the SAS/AF online Help. For more information on using
interfaces, see “Interfaces” on page 93.
Source Window
The Source window provides a text editor for creating and editing SAS Component
Language (SCL) programs.
As a component developer, you can open the Source window by
•
double-clicking an existing SCL entry in the SAS Explorer
•
creating a new SCL entry via the SAS Explorer
•
creating a new SCL entry via the BUILD command (for example, build
work.a.a.scl)
•
issuing the SOURCE command from a FRAME or PROGRAM entry
•
selecting Source from the Class Editor's pop-up menu when any method metadata
item is selected.
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For more information about editing SCL programs, see “Implementing Methods with
SCL” on page 109.
Other Development Tools and Utilities
SAS/AF software provides several tools and diagnostic utilities that extend the
applications development environment.
Class Browser
enables you to browse through the class hierarchy, create subclasses, edit classes,
copy or delete classes, and view properties information and help for a selected class.
SCL Analysis Tools
help you optimize the performance of SAS Component Language (SCL) code in
your applications. Tools include a Coverage Analyzer, a List Diagnostic Utility, a
Performance Analyzer, and a Static Analyzer.
Source Control Manager (SCM)
provides source management for applications development with SAS software. SCM
is a full-featured source manager.
GenDoc Utility (experimental)
enables you to generate HTML files that document class, interface, resource, and
frame entries. For more information on the GenDoc Utility, see “Generating Class
Documentation with GenDoc” on page 156.
For more information about these tools, see the SAS/AF online Help.
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Programming Concepts
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Object-Oriented Development and the SAS Component Object Model . . . . . . . . . 73
Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Relationships among SAS/AF Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Types of Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Method Signatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Overloading Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Method Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Method Metadata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Attribute Metadata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Attribute Values and Dot Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Event Metadata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Event Handlers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Event Handler Metadata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Interface Properties of a Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Introduction
Object-oriented programming (OOP) is a technique for writing computer software. The
term object oriented refers to the methodology of developing software in which the
emphasis is on the data, while the procedure or program flow is de-emphasized. That is,
when designing an OOP program, you do not concentrate on the order of the steps that
the program performs. Instead, you concentrate on the data in the program and on the
operations that you perform on that data.
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Advocates of object-oriented programming claim that applications that are developed
using an object-oriented approach
•
are easier to understand because the underlying code maps directly to real-world
concepts that they seek to model
•
are easier to modify and maintain because changes tend to involve individual objects
and not the entire system
•
promote software reuse because of modular design and low interdependence among
modules
•
offer improved quality because they are constructed from stable intermediate classes
•
provide better scalability for creating large, complex systems
Object-oriented application design determines which operations are performed on which
data, and then groups the related data and operations into categories. When the design is
implemented, these categories are called classes. A class defines the data and the
operations that you can perform on the data. In SAS/AF software, the data for a class is
defined through the class's attributes, events, event handlers, and interfaces. (Legacy
classes store data in instance variables.) The operations that you perform on the data are
called methods in SAS/AF software.
Objects are data elements in your application that perform some function for you.
Objects can be visual objects that you place on the frame—for example, icons, push
buttons, or radio boxes. Visual objects are called controls; they display information or
accept user input.
Objects can also be nonvisual objects that manage the application behind the scenes; for
example, an object that enables you to interact with SAS data sets may not have a visual
representation but still provides you with the functionality to perform actions on a SAS
data set such as accessing variables, adding data, or deleting data. An object or
component is derived from, or is an instance of, a class. The terms object, component,
and instance are interchangeable.
Software objects are self-contained entities that possess three basic characteristics:
state
a collection of attributes and their current values. Two of a Push Button control's
attributes are label (the text displayed on the command push button) and
commandOnClick (the command that executes when the command push button is
pressed). You can set these values through the Properties window or through SCL.
behavior
a collection of operations that an object can perform on itself or on other objects.
Methods define the operations that an object can perform. For example, a Push
Button can set its own border style via the _setBorderStyle method.
identity
a unique value that distinguishes one object from another. In SAS/AF, this identifier
is referred to as its object identifier. The object identifier is also used as the firstlevel qualifier in SCL dot notation.
This chapter describes how object-oriented techniques and related concepts are
implemented in SAS Component Language (SCL) and in SAS/AF software.
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73
Object-Oriented Development and the SAS
Component Object Model
The SAS Component Object Model (SCOM) is an object-oriented programming model
that provides a flexible framework for SAS/AF component developers. With SCOM,
you can develop plug-and-play components that adhere to simple communication rules,
which in turn make it easy to share information between components.
A component in SCOM is a self-contained, reusable object with specific properties,
including
•
a set of attributes and methods
•
a set of events that the object sends
•
a set of event handlers that execute in response to various types of events
•
a set of supported or required interfaces
With SCOM, you can design components that communicate with each other, using any
of the following processes:
Attribute linking
enabling a component to change one of its attributes when the value of another
attribute is changed.
Model/view communication
enabling a view (typically a control) to communicate with a model based on a set of
common methods that are defined in an interface.
Drag and drop operations
enabling information to be transferred from one component to another by defining
“drag” attributes on one component and “drop” attributes on the other.
Event handling
enabling a component to send an event that another component can respond to by
using an associated event handler.
For more information on component communication with SCOM, see “Adding
Communication Capabilities to Components” on page 129.
Classes
Introduction
A class defines a set of data and the operations you can perform on that data. Subclasses
are similar to the classes from which they are derived, but they may have different
properties or additional behavior. In general, any operation that is valid for a class is also
valid for each subclass of that class.
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Relationships among SAS/AF Classes
Introduction
SAS/AF software classes support three types of relationships:
•
inheritance
•
instantiation
•
uses.
Inheritance
Generally, the attributes, methods, events, event handlers, and interfaces that belong to a
parent class are automatically inherited by any class that is created from it. One
metaphor that is used to describe this relationship is that of the family. Classes that
provide the foundation for other classes are called parent classes, and classes that are
derived from parent classes are child classes. When more than one class is derived from
the same parent class, these classes are related to each other as sibling classes. A
descendent of a class has that class as a parent, either directly or indirectly through a
series of parent-child relationships. In object-oriented theory, any subclass that is created
from a parent class inherits all of the characteristics of the parent class that it is not
specifically prohibited from inheriting. The chain of parent classes is called an ancestry.
Figure 10.1
Class Ancestry
Class
Selection
Model
All SCOM Models...
Object
Frame
Widget
Visual
Controls...
All other objects...
V6 Legacy
Widgets
Whenever you create a new class, that class inherits all of the properties (attributes,
methods, events, event handlers, and interfaces) that belong to its parent class. For
example, the Object class is the parent of all classes in SAS/AF software. The Frame and
Widget classes are subclasses of the Object class, and they inherit all properties of the
Object class. Similarly, every class you use in a frame-based application is a descendent
of the Frame, Object, or Widget class, and thus inherits all the properties that belong to
those classes.
Instantiation
In addition to the inheritance relationship, SAS/AF software classes have an instantiation
or an “is a” relationship. For example, a frame is an instance of the Frame class; a radio
Classes
75
box control is an instance of the Radio Box Control class; and a color list object is an
instance of the Color List Model class.
All classes are instances of the Class class. The Class class is a metaclass. A metaclass
collects information about other classes and enables you to operate on other classes. For
more information about metaclasses, see “Metaclasses” on page 76.
Uses
For some classes, a “uses” relationship exists. With a uses relationship, not all of the
functionality that a class needs is defined by one class. Instead, a class can use the
operations defined by another class. This process is called delegation. In SAS/AF
software classes, the “uses” relationship is defined in two ways: delegation and
composition.
delegation
With delegation, a method is automatically forwarded to a designated object (or list
of objects, in some predetermined order) when it is not recognized by the object that
initially received the message to execute the method. Each class has an optional
delegates list, which is a list of complex attribute names (or, for legacy classes,
instance variable names) to which undefined method calls are redirected. The
delegates list contains named values; each item name matches the name of a complex
attribute. When you call a method on an instance of the class and the method is not
found in the object's class nor in any ancestor class, the method call is tried on each
complex attribute (or instance variable) named in the delegates list until one of the
named objects implements the method or until the list is exhausted. The delegate
objects may, in turn, delegate the method. If none of the named objects implements
the method, then the parent class's delegates list, if it exists, is tried next, and so on.
If no delegates implement the method, there is an error.
Delegation is allowed whenever you call a method using SEND or NOTIFY
routines. However, delegation is not allowed when you use dot notation on an object
of a specific class. In order to use dot notation and delegation together, you must use
a reference to a generic object. For example, the following will work
DCL object foo; foo.delegatedMethod();
but the following will not
DCL lib.cat.someclass.class foo; foo.delegatedMethod();
composition
Objects can work together to form composite objects. Collectively, the component
objects form a composite object. The relationship that exists between the
components and the composite object is called composition. With composition, a
class implements a method by explicitly invoking that method on one or more
objects; the other objects typically are stored in complex attributes. For example,
consider a composite widget that is composed of an input field and three list boxes.
The input field and the list boxes are the components. Note that the components may
not have any explicit relationship with each other (except for the passive relationship
of all being members of the same composite).
In a composite object, methods can be forwarded to individual objects within the
composite object.
Some of the composite objects in SAS/AF software include
•
Dual Selector Control
•
Extended Input Field (legacy class)
•
Toolbar (legacy class)
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Types of Classes
Introduction
Some SAS/AF software classes are specific types of classes.
•
Abstract classes
•
Models and viewers
•
Metaclasses.
Abstract Classes
Abstract classes group attributes and methods that are common to several subclasses.
These classes themselves cannot be instantiated; they simply provide functionality for
their subclasses.
The Widget class in SAS/AF software is an example of an abstract class. Its purpose is
to collect properties that all widget subclasses can inherit. The Widget class cannot be
instantiated.
Models and Viewers
In SAS/AF software, components that are built on the SAS Component Object Model
(SCOM) framework can be classified either as viewers that display data or as models
that provide data. Although models and viewers are typically used together, they are
nevertheless independent components. Their independence allows for customization,
flexibility of design, and efficient programming.
Models are non-visual components that provide data. For example, a Data Set List model
contains the properties for generating a list of SAS data sets (or tables), given a specific
SAS library. Some models may be attached to multiple viewers.
Viewers are components that provide a visual representation of the data, but they have
no knowledge of the actual data they are displaying. The displayed data depends on the
state of the model that is connected to the viewer. A viewer can have only one model
attached to it at a time.
It may be helpful to think of model/view components as client/server components. The
viewer acts as the client and the model acts as the server.
Models that are built on the SCOM framework are enabled for model/view
communication through their support of a specified interface (such as
sashelp.classes.staticStringList.intrface). Likewise, all controls that
display items in lists have also been enabled for model/view communication by
requiring the use of the same interface.
For more information, see “Interfaces” on page 93, “Implementing Model/View
Communication” on page 133 , and the SAS/AF online Help.
Metaclasses
As previously mentioned, the Class class (sashelp.fsp.Class.class) and any
subclasses you create from it are metaclasses. Metaclasses enable you to collect
information about other classes and to operate on those classes.
Metaclasses enable you to make changes to the application at run time rather than only at
build time. Examples of such changes include where a class's methods reside, the default
values of class properties, and even the set of classes and their hierarchy.
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77
Metaclasses also enable you to access information about parent classes, subclasses, and
the methods and properties that are defined for a class. Specifically, through methods of
the Class class, you can
•
retrieve information about an application, such as information about the application's
structure, which classes are being used, and which legacy classes use particular
instance variables. Each class has a super class that is accessed by the _getSuper
method. Every class also maintains a list of subclasses that is accessed with the
_getSubclassList and _getSubclasses methods.
•
list the instances of a class and process all of those instances in some way. Each class
maintains a list of its instances. You can use _getInstanceList and _getInstances to
process all the instances.
•
create objects and classes at run time with the _new method. Instances of the
metaclass are other classes.
For more information about metaclasses, see the Class class in the SAS/AF online Help.
Methods
Introduction
In a SAS/AF software class, methods define the operations that can be executed by any
component you create from that class. In other words, methods are how classes (and
instances of those classes) do their work.
A method consists of two primary parts, its name and its implementation. You use the
method name in SCL programs to manipulate the associated component. For example, to
deselect the selections in a list box, you write an SCL statement that invokes the
_deselectAll method:
listbox1._deselectAll();
Use caution when adding new methods with a leading underscore character, which
typically indicates a method supplied by SAS and may cause conflicts with future
releases of SAS/AF software. If you attempt to name a method with both leading and
trailing underscores, SAS/AF displays a warning. Embedded underscores themselves are
allowed, but they are removed when a leading and trailing underscore trigger the name
conversion. For example, the method name _foo_Test_Foo is converted to _fooTestFoo.
Method names can be up to 256 characters long.
The implementation of the method (where the code exists) is specified in the name of a
SAS/AF entry. This entry is usually an SCL entry that is combined with an optional SCL
labeled section.
As previously mentioned, all classes inherit methods from their parent classes. Some
classes also delegate methods to other classes. In addition, SAS/AF software defines
three other types of methods:
automatic methods
are methods that automatically execute when certain events occur; you do not
explicitly call automatic methods. Automatic methods can be classified in two major
groups:
•
those that execute at build time — for example, _bInit.
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•
those that execute at run time (that is, when the FRAME entry is opened by a
TESTAF, AF, or AFA command) — for example, _select.
For more information about automatic methods, see “Flow of Control for Frame SCL
Entries” on page 169.
virtual methods
are methods that exist in a class but have no defined functionality for that class. You
add their functionality by overriding the method in a subclass. Virtual methods exist
for these reasons:
•
The functionality of the method needs to be defined, but its functionality is
specific to the subclass.
•
The presence of a virtual method serves as a reminder that the method should be
included in the subclass and that its functionality should be defined there.
The Object class contains some virtual methods — for example, _printObject. Each
object can have specific printing needs; therefore, you should define the functionality
of _printObject at the subclass level. Unless you override the definition of
_printObject, the method does nothing, but it also does not generate an error.
per-instance methods
are methods that enable you to add to or override a method for a specific object in an
application. These methods are not associated with a class but are assigned on a per
instance basis. A per-instance method that is bound to an object is not shared with or
available to other instances of the object's class. Per-instance methods do not affect
any other objects in the application.
All predefined methods for a class are listed in the class's methods list. When a
method is called, the SCL compiler searches the object class's methods list for the
method. If no matching method is found there, the compiler searches the class's
parent class, and so on. If an object has per-instance methods, the method lookup
begins in the object's list of per-instance methods.
Per-instance methods are programmatically added, changed, and deleted with these
Object Class methods:
•
_addMethod
•
_changeMethod
•
_deleteMethod
For more information about these methods, see the Object class in the Component
Reference section of the SAS/AF online Help.
Note: Although supported, per-instance methods represent a non-object-oriented
approach to SAS/AF programming. A side effect of this approach is that the
compiler cannot identify per-instance methods or attributes that have been added
programmatically via SCL. Only those per-instance methods and attributes that
have been added through the Properties window are recognized at compile time.
Method Signatures
A method's signature uniquely identifies it to the SCL compiler. A method's signature is
comprised of the method's name, its arguments, and their types and order. Precise
identification of a method based on these parameters is necessary when overloaded
methods are used (see “Overloading Methods” on page 80).
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79
For example, the following SCL METHOD statements show methods that have different
signatures:
Method1:
Method2:
Method3:
Method4:
method
method
method
method
name:char number:num;
number:num name:char;
name:char;
return=num;
endmethod;
endmethod;
endmethod;
endmethod;
Each method signature is a unique combination, varying by argument number and type:
•
The first signature contains a character argument and a numeric argument.
•
The second signature contains a numeric argument and a character argument.
•
The third signature contains a single character argument.
•
The fourth signature contains no arguments.
Signatures in SAS/AF software are usually represented by a shorthand notation, called a
sigstring. This sigstring is stored in the method metadata as SIGSTRING. For example,
the four method statements above have the following sigstrings:
Method1
Method2
Method3
Method4
sigstring:
sigstring:
sigstring:
sigstring:
(CN)V
(NC)V
(C)V
()N
The parentheses group the arguments and indicate the type of each argument. The value
outside the parentheses represents the return argument. The V character (for “void”)
indicates that no return value is used. A notation that has a value other than V indicates
that the signature has a return value of that particular type. For example, Method4,
above, returns a numeric value.
Although the optional return variable is listed as part of the sigstring, it is listed only for
convenience and should not be understood as part of the actual signature. In a sigstring,
neither the presence of a return variable nor its type affects the method signature.
When a method is called, the SAS SCL compiler matches the arguments in the call to the
arguments in the actual method. Thus, calling the method with the (CN)V signature
actually executes Method1, below. Calling the method with the (NC)V arguments
executes Method2:
/* Method1 */
/* Responds to calls using the (CN)V signature */
object.setColNum('colname', num);
/* Method2 */
/* Responds to calls using the (NC)V signature */
object.setColNum(num, 'colname');
If a method has a return value, you can execute that method and use the value that it
returns in an assignment. For example, consider an object that has a method with a
signature ()N. The following are valid operations:
dcl num returnVal;
returnVal=object.getData();
or
if object.getData() > 1 then do ...
or
if ( object.getData() ) then do ...
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Defining signatures for methods helps other developers understand the method syntax
while also offering enhanced compile-time checking and run-time efficiency. The
default signature for methods is ()V, meaning that no arguments are passed into the
method and no values are returned.
Although the SCL compiler uses the method name to help uniquely identify a method,
the name is not formally part of the signature metadata. In other words, although a
method's signature includes its name and arguments (and their types and order), the
signature metadata itself consists of
•
argument name
•
argument type
•
argument usage
•
argument description
Just like return variables, the usage and description of an argument are not used to
differentiate methods, and are not part of a method's signature, even though they are part
of the signature metadata.
Once you define a signature for a method and deploy the class that contains it for public
use, you should not alter the signature of the method in future versions of the class.
Doing so could result in program halts for users who have already compiled their
applications. Instead of altering an existing signature, you should overload the method to
use the desired signature, leaving the previous signature intact.
Overloading Methods
SAS Component Language (SCL) supports method overloading, which means that a
class can have methods of the same name as long as they can be distinguished on the
basis of their signatures (that is, as long as their arguments differ in number, order, and/
or type). If you call an overloaded method, SCL checks the method arguments, scans the
signatures for a match, and executes the appropriate code.
For example, if you had a setColor method on your class, you could define overloaded
methods with the following signatures:
Table 10.1
Overloaded setColor Methods
Method Calling Statement
Method Signature
object.setColor(color);
(C)
object.setColor(r, g, b);
(NNN)
In the example above, color is a character argument, and r, g, and b are numeric
arguments. Both methods change the object's color even though the first method takes a
color name as input and the second method takes numerical RGB values (in the range of
0255). The advantage of overloaded methods is that they require programmers to
remember only one method instead of several different methods that perform the same
function with different data.
Methods in general, not just overloaded methods, can specify only one return argument.
Each method in a set of overloaded methods can have a different return argument type,
but the method parameters must be different for each method since the return type is not
considered part of the signature. For example, you can have
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81
mymethod (NN)V
mymethod (CC)N
but not
mymethod (NC)V
mymethod (NC)N
The order of arguments also determines the method signature. For example, the
getColNum methods below have different signatures — (CN)V and (NC)V — because
the arguments are reversed. As a result, they are invoked differently, but they return the
same result.
/* method1 */
getColNum: method colname:char number:update:num;
number = getnitemn(listid, colname, 1, 1, 0);
endmethod;
/* method2 */
getColNum: method number:update:num colname:char;
number = getnitemn(listid, colname, 1, 1, 0);
endmethod;
Each method in a set of overloaded methods can have a different scope, as well.
However, the scope is not considered part of the signature (just as the return value is
not), so you may not define two signatures that differ only by scope. (See the next
section, “Method Scope”.)
In addition, a method that has no signature (that is, which has (none) as a signature)
cannot be overloaded.
Method Scope
SAS Component Language (SCL) supports variable method scope, which gives you
considerable design flexibility. Method scope can be defined as Public, Protected, or
Private. The default scope is Public. Only Public methods appear in the Properties
window at design time. In order of narrowing scope:
•
Public methods can be accessed by any other class and are inherited by subclasses.
•
Protected methods can be accessed only by the same class and its subclasses; they
are inherited by subclasses.
•
Private methods can be accessed only by the same class and are not inherited by
subclasses.
Method Metadata
In addition to a method's name, implementation, signature, and scope, SAS/AF software
stores other method metadata for maintaining and executing methods. You can query a
class (or a method within a class) to view the method metadata, and you can create your
own metadata list to add or change a method. For example, to list the metadata for a
particular method, execute code similar to the following:
init:
DCL num rc metadata;
DCL object obj;
obj=loadclass('sashelp.mycat.maxClass.class');
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/* metadata is a numeric list identifier */
rc=obj._getMethod('getMaxNum',metadata);
call putlist(metadata,'',2);
return;
Here is the returned method metadata:
(NAME='getMaxNum'
SIGNATURE=(
NUM1=(
TYPE='Numeric'
INOUT='Input'
DESCRIPTION='First number to compare'
)
NUM2=(
TYPE='Numeric'
INOUT='Input'
DESCRIPTION='Second number to compare'
)
RETURN=(
TYPE='Numeric'
DESCRIPTION='Returns the greater of two numeric values.'
INOUT='Return'
)
)
SIGSTRING='(NN)N'
ENTRY='sasuser.mycat.maxClass.scl'
LABEL='getMaxNum'
CLASS=4317
METHODID=4331
STATE='N'
DESCRIPTION='Returns the greater of two numeric values.'
ENABLED='Yes'
SCOPE='Public'
)
The method metadata contains the following named items:
Note: Because many methods are defined at the C code level, some metadata values,
such as Entry, may not provide information that you can use.
Name
is the name of the method. Method names can be up to 256 characters long.
State
specifies whether the method is new (N), inherited (I) from another class, overridden
(O), or a system (S) method.
Entry
is the name of the SAS/AF catalog entry that contains the method implementation.
Typically, this item is an SCL entry.
Example: sasuser.app.methods.scl
Label
is the name of the SCL labeled section where the method is implemented. This item
is valid only if the value of the Entry metadata item is an SCL entry. A typical
implementation of a method may look like the following:
Example: newMethod
newMethod: public method
item:input:num
return=num;
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83
/* ...more statements... */
endmethod;
Signature
is a list of sublists that correspond to the arguments in the method signature.
If an empty list is passed for this value, then SAS/AF software registers a signature
of ()V, which means that the signature contains no arguments. If you call a method
whose signature is ()V and specify any input, output, or return arguments, the
compiler reports an error.
If a missing value (.) or zero is passed for this value, then the method does not have a
stored signature. There is no compile-time checking for methods that have no stored
signature. Likewise, if a method does not have a signature (the signature is (none)), it
cannot be overloaded (although it may still be overridden). See “Overloading
Methods” on page 80 for more information.
Note: By default, legacy classes do not have signatures.
For each argument in a method signature, the following named items are stored in a
sublist that has the same name as the argument:
Type
is the argument type. Valid values are
•
Character
•
Numeric
•
List
•
Object (generic)
•
Class Name (a four-level name of a specific object)
•
an array of any valid type
Type
is the argument type. Valid values are
INOUT
determines how the argument will be used in the method.
Valid values are I | O | U | R (corresponding to Input,
Output, Update, Return).
Description
is a text description of the argument.
Return_MethodID
is the unique identifier of the method; it is assigned when
the method is created and is returned in this named item.
Scope
specifies which classes have permission to execute the method. Valid values are
Public | Protected | Private. The default scope is Public.
If Scope='Public', then any class can call the method. The method is displayed in the
component's Properties window at build time.
If Scope='Protected', then only the class and any subclasses can call the method. The
method does not appear in the component's Properties window at build time, nor can
you access the method via frame SCL.
If Scope='Private', then only the class itself can call the method. The method does
not appear in the component's Properties window at build time, nor can you access
the method via frame SCL.
Enabled
determines whether a method can be executed. Valid values are 'Yes' | 'No.' The
default value is 'Yes.'
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Description
is a description of the method.
Attributes
Introduction
Attributes are the properties that specify the information associated with a component,
such as its name, description, and color. Each attribute includes metadata information
such as Type, Value, and Scope. You can define and modify attributes for a class with
the Class Editor. You can define, modify, and create links between attributes of an
instance with the Properties window.
Attributes are divided into categories such as the “Appearance” category, which contains
attributes that control color and outline type. These categories make it easier to view and
find related items.
For example, the Push Button Control has an attribute named label that specifies the
text displayed on the button. You can create two instances of the Push Button Control on
your frame and have one display “OK” and the other display “Cancel,” simply by
specifying a different value for the label attribute of each instance.
Attribute Metadata
SAS/AF software uses a set of attribute metadata to maintain and manipulate attributes.
This metadata exists as a list that is stored with the class. You can query a class (or an
attribute within a class) with specific methods to view attribute metadata. You can also
create your own metadata list to add or change an attribute. For example, to list the
metadata for the label attribute, execute code similar to the following:
init:
DCL num rc;
DCL list metadata;
DCL object obj;
obj=loadclass('sashelp.classes.pushbutton_c.class');
rc=obj._getAttribute('label',metadata);
call putlist(metadata,'',3);
return;
The following attribute metadata is returned:
(NAME='label'
INITIALVALUE='Button'
STATE='N'
TYPE='Character'
DESCRIPTION='Returns or sets the text displayed as the label'
CATEGORY='Appearance'
AUTOCREATE=''
SCOPE='Public'
EDITABLE='Yes'
LINKABLE='Yes'
SENDEVENT='Yes'
Attributes 85
TEXTCOMPLETION='No'
HONORCASE='No'
GETCAM=''
SETCAM=''
EDITOR=''
VALIDVALUES=''
CLASS=4317
)
The attribute metadata list contains the following named items:
Name
is the name of the attribute. Attribute names can be up to 256 characters long.
State
specifies whether the attribute is new (N), inherited (I) from another class,
overridden (O), or a system (S) attribute. System attributes are supplied by SAS/AF
software. The only item in a system attribute's metadata list that you can modify is its
Initial Value.
Type
specifies the type of data being stored:
•
N = Numeric
•
C = Character
•
L = List
•
O = Object (generic)
•
Class Name = four-level name of a non-visual class (such as
sashelp.classes.colorlist_c.class)
•
An array of a specific type and the boundary for each dimension of the array. For
example, Type = sashelp.classes.colorlist_c.class (1,2,3)
represents a three-dimensional array of type colorlist_c, with the upper
boundaries for each dimension being 1, 2, and 3, respectively.
AutoCreate
specifies whether the attribute is automatically created and deleted by SAS/AF
software. This item applies only to attributes of type list (L) and specific objects
(O:classname). By default, the value is 'Yes,' which indicates that SAS/AF will
create the list or instantiate the object when the object that contains the attribute is
instantiated. SAS/AF will also delete the list or terminate the object when the object
that contains the attribute is terminated. If the value is 'No,' then it is the
responsibility of the SCL developer to control the creation and deletion of the
attribute.
InitialValue
(optional) specifies the initial value of the attribute; must be of the defined data type.
Scope
specifies which class methods have permission to get or set the value of the attribute.
Valid values are Public | Protected | Private.
•
If Scope='Public', then any method of any class can get or set the attribute value.
The attribute is displayed in the component's Properties window, and the attribute
can be queried or set with dot notation in frame SCL.
•
If Scope='Protected', then only the class or its subclasses can get or set the
attribute value in their methods. The attribute does not appear in the component's
Properties window, nor can you access the attribute via frame SCL.
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•
If Scope='Private', then only the class can get or set the attribute value in its
methods. The attribute does not appear in the component's Properties window,
nor can you access the attribute via frame SCL. Additionally, subclasses cannot
access the attribute.
Editable
indicates whether an attribute can be modified or queried.
•
If Scope='Public' and Editable='Yes', then the attribute can be accessed (both
queried and set) from any class method as well as from frame SCL program.
•
If Scope='Public' and Editable='No', then the attribute can only be queried from
any class method or frame SCL program. However, only the class or subclasses
of the class can modify the attribute value.
•
If Scope='Protected' and Editable='No', then the class and its subclasses can
query the attribute value, but only the class itself can set or change the value. A
frame SCL program cannot set or query the value.
•
If Scope='Private' and Editable='No', then the attribute value can be queried only
from methods in the class on which it is defined, but it cannot be set by the class.
Subclasses cannot access these attributes, nor can a frame SCL program. This
combination of metadata settings creates a private, pre-initialized, read-only
constant.
Note: If Editable='No', the Custom Set Method is not called (even if it was defined
for the attribute). The default is 'Yes'.
Linkable
specifies whether an attribute can obtain its value from another attribute via attribute
linking. Valid values are 'Yes' | 'No'. Only public attributes are linkable.
SendEvent
specifies whether an event should be sent when an attribute is modified. See
“Events” on page 90 for details.
When SendEvent='Yes', SAS/AF software registers an event on the component. For
example, the textColor attribute has an associated event named “textColor
Changed”. You can then register an event handler to trap the event and conditionally
execute code when the value of the attribute changes.
If you change the SendEvent value from 'Yes' to 'No', and if Linkable='Yes', you
must send the “attributeName Changed” event programmatically with the attribute's
setCAM in order for attributes that are linked to this attribute to receive notification
that the value has changed. If the linked attributes do not receive this event, attribute
linking will not work correctly. In the previous example, the setCAM for the
textColor attribute would use the _sendEvent method to send the “textColor
changed” event.
ValidValues
specifies the set of valid values for a character attribute. Use blanks to separate
values, or, if the values themselves contain blanks, use a comma as the separator. For
example:
ValidValues='North South East West'
ValidValues='North America,South America,Western Europe'
If Type='C' and a list of valid values has been defined, the values are displayed in a
drop-down list for the attribute's Initial Value cell in the Class Editor and for the
attributes Value cell in the Properties window.
Attributes 87
ValidValues is also used as part of the validation process that occurs when the value
is set programmatically using dot notation or the _setAttributeValue method. For
more information on how the ValidValues list is used as part of the validation
process, see “Validating the Values of Character Attributes” on page 116.
You can also specify an SCL or SLIST entry to validate values by starting the
ValidValues metadata with a backslash (\) character, followed by the four-level
name of the entry. For example:
ValidValues='\sashelp.classes.ItemsValues.scl';
Note: If you use an SLIST entry for validation, all items in the SLIST must be
character values. If you use an SCL entry for validation, you must ensure that the
SCL entry returns only character items.
For more information on how to use an SCL entry to perform validation, see
“Validating the Values of Character Attributes” on page 116.
Editor
specifies a FRAME, PROGRAM, or SCL entry that enables a user to enter a value
(or values) for the attribute. If supplied, the editor entry is launched by the Properties
window when a user clicks the ellipsis button (...) in the Value cell or the Initial
value cell in the Class Editor. The value that is returned from the editor sets the value
of the attribute. For more information, see “Assigning an Editor to an Attribute” on
page 117.
TextCompletion
specifies whether user-supplied values for the attribute are matched against items in
the ValidValues metadata for text completion. This item is valid only if the attribute
is Type='C' and a ValidValues list exists. For example, if ValidValues='Yes No' and
the user types 'Y', the value 'Y' becomes 'Yes' and appears in the input area.
HonorCase
specifies whether user-supplied values must match the case of items in the
ValidValues list in order to constitute a valid input value. This item is valid only if
the attribute is Type='C' and a ValidValues list is defined.
For example, if HonorCase='Yes', ValidValues='Yes No', and the user types 'yes', the
value is not matched against the valid values.
However, if HonorCase='Yes', ValidValues='Yes No', TextCompletion='Yes', and
the user enters 'Y', the value is found in the list of valid values and is expanded to
'Yes'.
GetCAM
specifies the custom access method for retrieving the attribute's value (GETCAM).
For information on how to assign a CAM, see “Assigning a Custom Access Method
(CAM) to an Attribute” on page 121.
SetCAM
specifies the custom access method for setting the attribute's value (SETCAM). For
information on how to assign a CAM, see “Assigning a Custom Access Method
(CAM) to an Attribute” on page 121.
Category
(optional) specifies a logical grouping for the attribute. This item is used for category
subsetting in the Class Editor or for displaying related attributes in the Properties
window. For example, the Properties window displays the following attribute
categories for components that are supplied by SAS:
Appearance
Misc
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Behavior
Region
Data
Model/View
Drag and drop
Size/Location
Help
System
Not all categories appear for each class.
You can also create your own category names simply by specifying a new category
name in the Class Editor. The category defaults to 'Misc' if one is not supplied.
Automatic
is used only if an instance variable (IV) is linked to the attribute. (See the IV
metadata item below.) This metadata item exists to support legacy class information
only. When an IV is linked to an attribute, the attribute's value persists on the IV
itself instead of on the attribute. If automatic is set to 'Yes,' then the IV is an
automatic instance variable as defined in SAS/AF legacy classes.
IV
specifies the name of an instance variable on which the attribute value is stored. This
metadata item exists to support legacy class information only. Components that are
based on the SAS Component Object Model (SCOM) architecture do not use
instance variables. It is recommended that you avoid using instance variables.
Description
is a short description for the attribute. This item appears as help information in the
Class Editor and in the Properties window.
Attribute Values and Dot Notation
When you use dot notation in SCL to change or query an attribute value, SAS/AF
software translates the statement to a _setAttributeValue method call (to change the
value) or to a _getAttributeValue method call (to query the value). These methods are
inherited from the Object class and provide the basis for much of the behavior of
attributes.
For example, the _setAttributeValue method
•
verifies that the attribute exists
•
verifies that the type of the attribute matches the type of the value that is being set
•
validates the value against the ValidValues metadata item if it exists for the attribute
•
invokes the custom set method (setCAM) if it exists
•
stores the value in the attribute
•
sends the “attributeName Changed” event if the attribute has a SendEvent='Yes'
metadata item
•
sends the “contents updated” event if the attribute is specified in the object's
contentsUpdatedAttributes attribute to notify components in a model/view
relationship that a key attribute has been changed
The following figures detail the flow of control for the _setAttributeValue and
_getAttributeValue methods.
Attributes 89
Figure 10.2
Flow of Control for _setAttributeValue
_setAttributeValue
executes
If attribute is
defined and is not accessed
outside its defined
scope
If attribute type is matched
If EDITABLE
attribute metadata item
= 'Yes'
If specified
VALID VALUES metadata
is working and exists
in the list
If no
No
rc=2; processing ends;
errorMessage attribute is set
No
rc=3; processing ends;
errorMessage attribute is set
No
rc=5; processing ends;
errorMessage attribute is set
rc=4;
errorMessage attribute is set
No
If setCAM exists
setCAM
executes
If setCAM
fails to execute
If
setCAM return
code <=0
No
No
If rc=0
rc=7; processing ends;
errorMessage attribute is set
rc=4 if CAM rc=4, otherwise,
rc=7; processing ends;
errorMessage attribute is set
processing ends
RC (Return Code) Key
Attribute value is set
If SENDEVENT
attribute metadata
item = 'Yes'
_setAttributeValue checks the
contentsUpdatedAttributes attribute and sends
the 'contents updated' event if the attribute is listed
rc=0
Object region is refreshed
Reserved for warning conditions returned from CAMs
successful
1
unsuccessful (an error condition); you can use the
return code to identify an error condition from a
Custom Access Method
2
attribute does not exist on the specified object or
cannot be accessed
3
type mismatch; the type of the passed value does not
match the value of the attribute you are trying to set
4
value passed to _setAttributeValue is not on attribute's
VALIDVALUES list or is otherwise invalid
5
cannot set attribute because its EDITABLE metadata
item is set to 'No.'
7
the Custom Access Method (CAM) failed to run
No
'attribute Name Changed'
event is sent
If object is a
visual control and it
is build time
<0
0
No
rc=0; processing ends
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Figure 10.3
Flow of Control for _getAttributeValue
_getAttributeValue
executes
If attribute is
defined and not accessed
outside its defined
scope
If attribute type
is matched
If no
No
No
rc=2; processing ends
rc=3; processing ends
If getCAM
is defined
getCAM
executes
No
rc=7; processing ends
Attribute value is returned
rc is propagated as the value
for the 2nd argument on the
_getAttributeValue call
Events
Introduction
Events alert applications when there is a change of state. Events occur when a user
action takes place (such as a mouse click), when an attribute value is changed, or when a
user-defined condition occurs. Event handlers then provide a response to the change.
Use the Class Editor to create events that are specific to an entire class. Use the
Properties window to create events that are specific to a single object.
SAS/AF software supports system events, which can include user interface events (such
as mouse clicks) as well as “attribute changed” events that occur when an attribute value
is updated. For system events, the State metadata item is 'S'. In order for “attribute
changed” events to be sent automatically, the component must have the SendEvent
metadata item for the attribute set to 'Yes'. See “Enabling Attribute Linking” on page
130 for details.
SAS/AF software also supports user-defined events, which can be registered to specific
classes as needed and are inherited by subclasses.
Events 91
Event Metadata
Events are implemented and maintained with metadata. You can query a class (or an
event within a class) to view the event metadata, and you can create your own metadata
list to add or change an event. For example, to list the metadata for the click event,
execute code similar to the following:
init:
dcl num rc;
dcl list metadata;
dcl object obj;
obj=loadclass('sashelp.classes.listbox_c.class');
rc=obj._getEvent('click',metadata);
call putlist(metadata,'',3);
return;
The following event metadata is returned:
(NAME='click'
STATE='S'
DESCRIPTION='Occurs on a click'
CLASS=4415
EXECUTE='System'
METHOD=''
ENABLED='Yes'
CLASS=4415
)
The event metadata list contains the following named items:
Name
is the name of the event. Event names may be up to 256 characters long.
State
is the current state of each event. Valid values are I | N | S (corresponding to
Inherited, New, or System). This is a read-only metadata item.
Execute
describes how the event is sent. Events can be sent automatically either before or
after a method. They can also be programmed manually with SCL. Valid values are:
A | B | M (corresponding to After, Before, Manual). New events default to 'After'.
The Class Editor and the Properties window display Execute metadata in the Send
column of the table.
Method
is the name of the method that triggers the event (if Execute=A | B). A method name
must be specified for new events if they are to be sent automatically. The field
remains blank if the event is sent manually (if Execute=M).
Enabled
indicates whether an event is enabled or disabled. Valid values are Y | N.
Description
is a descriptive summary of the event's purpose. For inherited and system events, the
description is forwarded from the parent class. The maximum length is 256
characters.
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Event Handlers
Introduction
An event handler is a property that determines which method to execute after an event
occurs. Essentially, an event handler is a method that executes another method after an
event is received. Use the Class Editor to create event handlers that are specific to an
entire class. Use the Properties window to create event handlers that are specific to a
single object.
Event Handler Metadata
SAS/AF software uses a set of event handler metadata to implement and maintain event
handlers. This metadata exists as a list that is stored with the class. You can query a class
(or an event handler within a class) to view the event handler metadata. You can also
create your own metadata list to add or change an event handler. For example, to list the
metadata for a particular event handler, execute code similar to the following:
init:
dcl num rc;
dcl list metadata;
dcl object obj;
obj=loadclass('sashelp.classes.listbox_c.class');
rc=obj._getEventHandler('_self_','click',
'_onClick',metadata);
call putlist(metadata,'',3);
return;
The following event handler metadata is returned:
(SENDER='_self_'
EVENT='visible changed'
DESCRIPTION='Refresh myself'
STATE='N'
METHOD='_refresh'
ENABLED='Yes'
)
The metadata contains the following named items:
State
is the current state of each event handler. Values include Inherited, New, or System,
which are represented by I, N, and S, respectively.
Sender
is the name of the object that generates the event. The default value is _self_. Valid
values are _self_, any object (*), or the name of a component on the frame.
Event
is the name of the event that is being handled.
Method
is the name of the method to execute when the event is sent.
Interfaces
93
Enabled
shows whether an event handler is enabled or disabled. Valid values are Y | N.
System events (State=S) are always enabled.
Description
is text that describes the event handler. The maximum length is 256 characters.
Interfaces
Introduction
Interfaces are collections of abstract method definitions that define how and whether
model/view communication can take place. They enable you to redirect a method call
from one component to a method call on a different component. The method definitions
are just the information that is needed to define a method; they do not contain the actual
method implementations. If two components share an interface, they can indirectly call
each others' methods via that interface.
Interfaces are stored in SAS catalog entries of type INTRFACE. For example, the
staticStringList interface is stored in the
sashelp.classes.staticStringList.intrface catalog entry.
To retrieve the methods that an interface supports, use the _getmethod or _getmethods
methods.
Interface Properties of a Class
A class can be defined to support or require one or more interfaces. For example, model/
view component communication is implemented with the use of interfaces. The model
typically supports the interface, whereas the view requires the same interface. The
interfaces for the components must match before a model/view relationship can be
established.
A class stores interface information as a property to identify whether it supports or
requires an interface. Interface data on a class consists of the following items:
State
specifies whether the interface is New or Inherited.
InterfaceName
specifies the four–level catalog entry name of the interface class (such as
sashelp.classes.staticStringList.intrface).
Status
indicates whether the interface is Required or Supported.
Although classes that support or require an interface are often used together, they are
still independent components and can be used without taking advantage of an interface.
For more information on interfaces and their use, see “Implementing Model/View
Communication” on page 133.
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Developing Components
Creating Your Own Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Subclassing Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Creating a Simple Subclass by Overriding an Attribute . . . . . . . . . . . . . . . . . . . . . . 96
Creating a Subclass by Overriding a Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Extending a Class with New Attributes and Methods . . . . . . . . . . . . . . . . . . . . . . . 99
Creating a Class with SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Converting a Class to an SCL Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Tips for Creating Classes with SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Implementing Methods Using CLASS and USECLASS Statement Blocks . . . . . 103
Using SCL to Instantiate Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Using Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Creating Your Own Components
Introduction
When an existing SAS/AF software class does not provide the behavior you desire, you
can extend the functionality of an existing class by creating a subclass. Extending a class
be as simple as creating a new frame class with a blue background or as complex as
writing your own model and view classes. By virtue of the SCOM framework, you can
take advantage of object-oriented functionality and add to or modify any of the existing
properties of a class. Subclassing and class-wide modifications are performed in the
Class Editor or with SCL class syntax.
Subclassing Methodology
When creating a subclass, you should follow these general steps:
1. Decide which class to subclass. Normally this is the class that contains the behavior
closest to the functionality you want to implement.
2. Extend the existing properties by modifying or adding attributes, methods, events, or
event handlers.
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3. Test the subclass with either of these methods:
•
Add the new class to the Components window so that it appears in the list of
available classes and can be tested on a frame.
•
Instantiate the subclass using the SCL _NEW_ or _NEO_ operators and test it
programmatically.
Creating a Simple Subclass by Overriding an Attribute
Introduction
As an example of both the methodology and the techniques that are used to create a
simple subclass, the following example demonstrates how to build a simple button class
that closes a frame. Because you include a “Close” button of some sort on nearly every
frame you build, modifying a subclass of the existing pushbutton_c class will save you
from setting the same attributes each time you want such a button. After creating the
class and adding it to the Components window, you simply drag your Close Button class
onto the frame; no coding is required, and you do not have to set its properties.
You can add or override properties using either the Class Editor or the Properties
window. Although they look alike and contain what appears to be the same information,
it is important to understand the differences between these two tools:
•
Changes that you make in the Class Editor affect all instances that are based on the
class, whether they appear on different frames or not.
•
Changes that you make in the Properties window affect only the specific instance of
the class. The Properties window displays public properties for each instance on a
frame.
Creating the Close Button Subclass
This example creates a subclass of the push button control, using the Class Editor to
override the values of the label and commandOnClick attributes. For more
information on specific tasks in this example, see the SAS/AF online Help.
To create a button that closes a frame:
1. Create a new catalog named sasuser.buttons to hold the new class.
2. Create a new class with a description of Close Button. The description is used to
identify the class in the Components window. Unique descriptions are required (if
you want to determine the difference between components with accuracy), but are
not programmatically verified.
3. Select sashelp.classes.pushbutton_c.class as the parent class.
Obviously, to know which class to subclass you must be familiar with the class
hierarchy.
4. Override the label attribute. Specify Close as the initial value of the label
attribute. The label attribute represents the text that appears on the button.
5. Override the commandOnClick attribute. Specify End as the initial value of the
commandOnClick attribute. The commandOnClick attribute represents the
command that is executed when the button is clicked.
6. Save the class. For the entry name, specify CloseButton (with no spaces).
Creating Your Own Components
97
You may also include a short description of what the class does, such as Close
frame button. This description, if provided, overwrites the description provided
in step 2 above.
Testing the Close Button Subclass
The Close Button class is now ready for use. Follow these steps to make the class
available for use and testing:
1. Create a new frame.
2. Make the Close Button available for use in the Components window by rightclicking in the Components window and selecting Add Classes. Select or enter the
sasuser.buttons.closebutton.class. The Close Button class appears in
the Components window.
3. Drag a Close Button to the frame. The button label is Close.
4. Test the functionality of the button by selecting Build ð Test. When the frame
appears, click Close to close the frame.
The example demonstrates how you can create a very useful class without any
programming.
Creating a Subclass by Overriding a Method
Introduction
When you create a new class, you must decide what unique actions you want to include
in its definition. The actions are defined by their methods. Methods from the parent class
are inherited by the subclass that you create. Although method inheritance is one of the
primary benefits of object-oriented programming techniques, there are times when you
will want to augment a class's functionality by adding new methods or overriding
inherited methods:
•
Create a new method for your subclass if you want to add behavior that is not
currently available in the parent class.
•
Override an existing method to modify the behavior of the parent class in your
subclass. An overridden method is one that extends a method that has the same name
and signature on a parent class. In effect, overridden methods add some kind of
functionality to a class, but they also call the same method on the class's parent to
ensure that the method's core functionality is preserved. When overriding a method,
you provide a new method definition, but you cannot change the method's name,
signature, or scope. You can also overload methods to complement existing
behavior. For more information on overloading, see “Overloading Methods” on page
80.
To demonstrate how you can add new behavior to a class, consider the Close Button
class that was presented above. Although the Close Button class is useful, a user of your
application might accidentally click a “Close” button. To help prevent such mistakes,
you could add a confirmation dialog box to the Close Button class. The class could have
the following behavior:
•
When the Close button is clicked, a dialog box is displayed to confirm the action.
•
If the user selects Yes, the frame closes. Otherwise, the frame remains open.
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To implement this behavior in a new class, review the existing class:
•
Does the parent class provide a behavior when the button is clicked on the frame?
After deciding to augment the behavior of a class, you must decide whether to
override an existing method or add a new one. In the Close Button class, the
_onClick method that serves as the event handler is called whenever the button is
clicked. You can override this method and have the new implementation display the
dialog box. If you override a method, you should execute the same method on the
parent by calling _super() in your code.
See the SAS/AF online Help for assistance with specific tasks.
Overriding an Existing Method
To add new behavior to the Close Button class, override the _onClick method:
1. If you created the Close Button class that was presented earlier, you must re-inherit
the commandOnClick attribute that was overridden so that the END command will
not be executed when you click the button.
2. In the Class Editor, override the inherited _onClick method. The State metadata item
changes to 'O'.
3. The _onClick Source Entry metadata item now contains the four-level name of the
SCL entry that will contain the new code:
sasuser.buttons.closebutton.scl.
4. Display the Source for the method via the pop-up menu and enter the following code
in the SCL entry:
useclass sasuser.buttons.closebutton.class;
onclick: method;
_super();
/* call onClick method on parent */
dcl num rc;
dcl list messageList = {'Close this frame?'},
char(1) sel;
sel = messageBox(messageList, '?', 'YN');
if sel = 'Y' then call execcmd('end;');
rc=dellist(messageList);
endmethod;
enduseclass;
5. Compile and close the SCL entry.
Note: For more information on methods and SCL, see “Implementing Methods with
SCL” on page 109, and “Adding SAS Component Language Programs to Frames”
on page 35.
Testing the Overridden Method
After you have created and saved the class, you can test the new behavior. If you created
the frame with the “Close” button from the last example, open that frame and test it to
see the new behavior. The changes to the Close Button class are picked up automatically
when the frame is opened and the Close Button object is instantiated.
If you do not have a frame with the Close Button object already on it, follow these steps
to test the new behavior of the Close Button:
1. Create a new frame.
Creating Your Own Components
99
2. Right-click inside the Components window and select Add Classes from the pop-up
menu to add the new class.
3. Drag a Close Button object from the Components window onto the frame.
4. Test the frame.
Extending a Class with New Attributes and Methods
Introduction
Although the Close Button class presented in the previous example is useful, you might
not always want a confirmation dialog box to be displayed when a frame is closed. To
implement this behavior, review the following question:
•
Does the parent class provide data that could be used to specify whether to display a
confirmation dialog box?
You can check attributes on the class to see whether you need to override an existing
attribute or add a new attribute to maintain this information. Since the Close Button
class does not have such an attribute, you have to add a new one to the class.
To add flexibility to the Close Button class, add an attribute to the class that enables
developers who use the object in their frames to specify whether to display the
confirmation dialog box.
To add an attribute to the Close Button class:
1. Close all frames that contain a version of the Close Button class.
2. Open the sasuser.buttons.closebutton.class class if it is not already
open.
3. Create a new attribute called displayExitDialog. This will be the attribute that
determines whether the confirmation dialog box should be displayed. Attributes keep
data on a component where it can be easily accessed by other components via SCL
or attribute linking.
4. Set the following metadata items for the new displayExitDialog attribute:
•
Type = Character
•
Initial Value = Yes
•
Valid Values = Yes,No
•
Category = Behavior
Editing the Existing Method to Query the New Attribute
Edit the existing overridden _onClick method on the Close Button class by adding four
lines of code:
useclass
sasuser.buttons.closebutton.class;
onclick: method;
_super();
/* calls the parent's _onClick method */
if upcase(displayExitDialog) = 'NO' then
call execcmd('end;');
else do;
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dcl num rc;
dcl list messageList = {'Close this frame?'},
char(1) sel;
sel = messageBox(messageList, '?', 'YN');
if sel = 'Y' then call execcmd('end;');
rc=dellist(messageList);
end;
endmethod;
enduseclass;
Testing the New Attribute and Method
After saving the class, test the new attribute:
1. Test the frame and the Close Button class as they are when the frame opens to see
the default Close Button behavior. The confirmation dialog box is displayed.
2. To see the alternate behavior of the Close Button, use the Properties window to set
the Close Button object's displayExitDialog attribute to No.
3. Re-test the frame. No confirmation dialog box is displayed.
Creating a Class with SCL
Introduction
As an alternative to creating a class interactively with the Class Editor, you can create a
SAS/AF class entirely in SCL with the CLASS/ENDCLASS statement block. You can
define all property information through SCL. When you have finished defining a class
with SCL, you must save it as a CLASS entry so that it can be used as a class.
Creating a class with SCL has several advantages:
•
Lengthy or repetitive changes to class information (such as adding or deleting the
signatures for several methods) are easier with a text editor than with the interactive,
graphical approach of the Class Editor.
•
Classes that are defined in an SCL entry can define and implement methods in one
location.
•
The CLASS block provides improved error detection at compile time, as well as
improved run-time performance.
Metadata information, such as description, is added to the class or property by
including a forward slash (/) delimiter and the appropriate metadata items enclosed in
parentheses before the semicolon (;) that ends the statement. Use a comma to separate
multiple metadata items (see description, SCL, and Label in the definition of the
add method below).
Consider the following example, which defines the Combination class in SCL:
CLASS sasuser.myclasses.Combination.class
extends sashelp.fsp.Object.class
/ (description='My Combination Class');
/* define attributes */
Public num total
Creating a Class with SCL
101
/ (description='total attribute');
Public char catstr
/ (description='catstr attribute');
/* define methods
*/
add: public method
n1: num
n2: num
return=num
/(description='Adds two numbers',
SCL='sasuser.myclasses.Combination.scl',
Label='add');
concat: public method
c1: char
c2: char
return=char
/(description='Concatenates two strings',
SCL='sasuser.myclasses.Combination.scl',
Label='concat');
ENDCLASS;
To compile the SCL program and save it as a CLASS entry:
1. Save the SCL entry. You must save an SCL entry before using Save as Class or
the SAVECLASS command.
2. From the Source window, selectFile ð Save As Class.
Alternatively, you can enter the SAVECLASS command.
Saving an SCL program as a class is equivalent to saving a class that you created
interactively with the Class Editor.
You can implement the methods directly in the same SCL as the class definition. The
following code defines the Combination class and implements its methods:
CLASS
sasuser.myclasses.Combination.class
extends sashelp.fsp.Object.class
/ (description='My Combination Class');
/* define attributes */
Public num total
/ (description='total attribute');
Public char catstr
/ (description='catstr attribute');
/* define methods
*/
add: public method
n1:num
n2:num
return=num
/(description='Adds two numbers');
total=n1+n2;
return (total);
concat: public method
c1:char
c2:char
return=char
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/(description='Concatenates two strings');
catstr=c1 || c2;
return(catstr);
ENDCLASS;
Additionally, you can create an abstract class by adding the optional reserved word
ABSTRACT before the CLASS statement. For example:
ABSTRACT CLASS myClass
EXTENDS sashelp.fsp.Object.class;
/* ...insert additional SCL here... */
ENDCLASS;
For complete information about the CLASS statement, including all valid metadata that
you can include with the class and properties definitions, see the SAS Component
Language: Reference.
Converting a Class to an SCL Entry
You can convert any SAS/AF class to an SCL entry. This enables you to view and
extend a class directly through its SCL. There are two ways to convert a class to SCL:
•
You can use the Class Editor to save a class as an SCL entry by selecting File ð
Save As and setting the Entry Type to SCL. After saving the class as SCL, open the
SCL entry to view or modify the class.
•
You can programmatically convert classes to SCL using the CREATESCL function.
The following code is an example of the CREATESCL syntax:
rc = CreateSCL ('lib.cat.yourClass.class',
'lib.cat.yourSCL.scl','description');
In this example, lib.cat.yourClass.class is the class to convert,
lib.cat.yourSCL.scl is the SCL entry to be created, and description
contains the description of the class that is stored in the SCL entry.
Tips for Creating Classes with SCL
When you create a class using SCL, there are several recommended practices that might
help your development efforts:
•
For components that might be edited in the Class Editor, it is more appropriate to
create one SCL entry for the class definition and another for the method
implementations of that class. Method implementations are not stored with a CLASS
entry. If you use the Class Editor to save a class as an SCL entry, and if the original
CLASS entry was created from an SCL entry that contained method
implementations, you may overwrite the method implementations for that class.
•
It is recommended that you implement a standard naming convention for the catalog
entries that are used to create a class. Since methods for a class are most often
implemented in an SCL entry that has the same name as the CLASS entry, you might
consider consistently appending “class” to the name of the SCL entry that defines the
class. For example, consider a class named Document that was created using SCL
and whose methods are implemented in a separate catalog entry. There would be a
total of three entries:
•
the SCL entry that defines the class
(sasuser.myclasses.Documentclass.scl)
Creating a Class with SCL
•
•
the SCL entry that implements the methods of the class
(sasuser.myclasses.Document.scl)
•
the class entry itself (sasuser.myclasses.Document.class).
103
Add values for the descriptive method-definition metadata, including Description
and all argument descriptions (such as ArgDesc1 or ReturnDesc). For example,
consider the descriptive metadata for a method named getAmount that has a
signature (C)N:
getAmount: public method
account:input:char
return=num
/(Description='Returns the amount in the specified account',
ArgDesc1='Account to retrieve',
ReturnDesc='Amount in the account');
In this example, Description is the description of the method, ArgDesc1 is the
description of the account argument, and ReturnDesc is the description of the
return argument.
For complete information, refer to the CLASS statement in the SAS Component
Language: Reference.
Implementing Methods Using CLASS and USECLASS Statement
Blocks
Introduction
The CLASS and USECLASS statements can be used to implement methods for a class
in SCL and to bind them to the class at compile time, which improves code readability,
code maintainability, run-time performance, and compile-time detection of many types
of errors. SCL users can directly reference attributes and methods in a CLASS or
USECLASS block without specifying the object ID or the system variable _SELF_. The
CLASS statement is used both for defining and for implementing methods. The
USECLASS statement is used only for implementing methods.
CLASS Statement
The CLASS statement constructs a class with SCL code, including the class definitions
and, optionally, the method implementations. The ENDCLASS statement ends the
CLASS statement block. In the following example, the method implementation is coded
inside the CLASS statement block:
class sasuser.myclasses.one.class extends sashelp.fsp.object.class;
/* define attribute */
Public num sum
/ (description='sum attribute');
_init: public Method
/ (State='O');
_super();
sum=0;
endmethod;
Sum: public method
n:Num
return=num;
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sum=sum+n;
return(sum);
endmethod;
endclass;
The approach above is appropriate for smaller projects where all class methods are
maintained by a few developers. As projects increase in complexity and the number of
developers involved grows, it is recommended that you use separate entries for class
definitions and method implementations. It is the responsibility of each component
developer to maintain an SCL entry that contains a USECLASS statement block for the
method implementations.
USECLASS Statement
The USECLASS statement is similar to the CLASS statement, except that you cannot
create class attributes or events in a USECLASS block. The ENDUSECLASS statement
ends a USECLASS statement block.
In the following example, the methods are defined and stored in one SCL entry, whereas
the method implementations are coded in a USECLASS statement block and are stored
in a separate SCL entry (sasuser.myclasses.oneCode.scl). The following SCL
code is stored in sasuser.myclasses.one.scl:
class sasuser.myclasses.one.class extends sashelp.fsp.object.class;
_init: public method
/ (state='O',
SCL='sasuser.myclasses.oneCode.scl');
/* define attribute */
Public num sum
/ (description='sum attribute');
m1: method
N:Num
Return=Num
/(SCL='sasuser.myclasses.oneCode.scl');
endclass;
The method implementations for the One class are stored in
sasuser.myclasses.oneCode.scl:
useclass sasuser.myclasses.one.class;
_init: public Method;
_super();
sum=0;
endmethod;
m1: method
N:Num
Return=Num;
sum = sum + N;
return(sum);
endmethod;
enduseclass;
Note: The _super() routine is valid only inside CLASS or USECLASS blocks. The
CALL SUPER routine can be used anywhere.
Using SCL to Instantiate Classes
105
Using SCL to Instantiate Classes
Introduction
You can instantiate a SAS/AF class with the _NEW_ operator, which combines the
actions of the LOADCLASS function with the initialization of the object with its _new
method. For example:
dcl sashelp.classes.librarylist_c.class libraries;
init:
libraries = _new_ sashelp.classes.librarylist_c();
call putlist(libraries.items, 'Libraries=', 1);
return;
You can use the _NEW_ operator with the IMPORT statement so that you can refer to a
class without having to specify its entire four-level catalog name. The IMPORT
statement specifies a search path for CLASS entry references in an SCL program. You
can also combine the _NEW_ operator with the DECLARE (or DCL) statement for
single-step declaration and instantiation:
import sashelp.classes.librarylist_c.class;
dcl librarylist_c document=_new_ librarylist_c();
Using Constructors
Introduction
The _NEW_ operator also enables you to create an instance of a class and to run a class
constructor. A constructor is a method that is automatically invoked whenever an object
is instantiated. You can use a constructor to initialize the object to a valid starting state.
The method that is used as the constructor of a class has the same name as the class. You
can specify a signature with no arguments to override the default constructor (that is, its
signature is ()V), or you can overload the constructor with signatures that use one or
more arguments. You cannot, however, specify a return type.
Consider a class that is defined as follows:
class sasuser.test.Account
extends sashelp.fsp.object.class;
/* attributes */
public num accountNumber;
public num balance;
/* constructor */
Account: public method
id:input:num;
accountNumber=id;
balance=0;
endmethod;
endclass;
When an Account object is instantiated, the constructor assigns a specific number as the
accountNumber and initializes the balance attribute to 0. For example:
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import sasuser.test.Account.class;
dcl account newAccount = _new_ account(1234);
The _NEW_ operator calls the account constructor method and passes a value 1234 to its
numeric argument. This creates a new Account object that has 1234 as its
accountNumber and a balance of 0.
You can also overload the constructor to accept a different number of arguments.
Consider a subclass of the Data Set List Model class:
class sasuser.myclasses.ourData
extends sashelp.classes.datasetlist_c.class;
OurData: public method
lib:char;
/* library is an inherited attribute */
if lib ne ''
then library=lib; /* set library attribute */
endmethod;
OurData: public method
lib:char
level:num;
/* library and levelCount are inherited attributes */
if lib ne ''
then library=lib; /* set library attribute */
if level in (1,2)
then levelCount=level; /* set levelCount attribute */
endmethod;
endclass;
You can pass one argument to the _NEW_ operator to call the constructor with one
argument in its signature. In the following example, the constructor initializes the
library attribute:
import sasuser.test.OurData.class;
dcl OurData table = _new_ OurData('sasuser');
You could also pass two arguments to the _NEW_ operator to call the constructor with
two arguments in its signature. In the following example, the constructor sets the
library and typeFilter attributes:
import sasuser.test.OurData.class;
dcl OurData table = _new_ OurData('sasuser',1);
Because the library attribute of the table object is initialized in both cases, you can
immediately query table.items to retrieve the list of SAS tables in the specified
library. If typeFilter is 1, then the items list contains only the names of the tables
and not the full two-level SAS name.
For complete information on the _NEW_ operator and constructors, see the SAS
Component Language: Reference.
Defining Constructors in the SCL for a Class
The Account class and OurData class examples above demonstrate how you can define
and implement constructors for a class within a CLASS/ENDCLASS block. There are
Using SCL to Instantiate Classes
107
several important items to remember when you define constructors in the SCL for a
class:
•
If you specify the Label metadata item in the method definition for the constructor, it
must be the same as the name of the class.
•
To override the default constructor for a class, add the STATE='O' metadata item to
the method definition. For example, you could override the default constructor for a
class named Document with the following code:
Document: public method
/(State='O',
Description='Override of the default constructor',
SCL='sasuser.myclasses.Document.scl');
Note that the default constructor has a signature of ()V.
•
If you want to use a method with the same name as the class and not have it function
as a constructor, you must specify a CONSTRUCTOR='N' metadata item in the
method definition. For example:
class sasuser.myclasses.Report
extends sashelp.fsp.Object.class;
/* constructor override with sigstring ()V */
Report: public method
/(State='O',
Description='Constructor method',
SCL='sasuser.myclasses.Report.scl');
/* method with sigstring (C)V */
Report: public method
ch:char
/(State='N',
/* optional */
Description='Report method',
SCL='sasuser.myclasses.OtherMethods.scl',
Constructor='N');
endclass;
•
By default, all constructors are stored in the CLASS entry as methods named
_initConstructor. If the method definition specifies CONSTRUCTOR='N', then the
method is stored with the same name as the class. If you add constructors to a class
that you define in SCL and save the SCL as a CLASS entry, the constructors appear
in the Methods list of the Class Editor with the same name as the class. For example,
if you opened the Report class defined above in the Class Editor, you would see two
methods: an overridden method named Report and a new method named Report.
Defining Constructors Using the Class Editor
You can also use the Class Editor to override the default constructor or to add new
constructors to a class, using the same processes that you would for any other method.
However, there are several other items you must remember when working with
constructors in the Class Editor:
•
You can override the default constructor for a class that you are editing in the Class
Editor by selecting the method with the same name as the class, then selecting
Override from the pop-up menu.
•
You can overload the class constructor by adding a new method with the same name
and providing a signature other than ()V.
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•
When you edit the class constructor in the Class Editor, the value of the SCL Label
field defaults to the name of the class. You cannot edit this value.
•
Unlike defining a constructor in SCL, if you add a method with the same name as the
class in the Class Editor, it is not stored on the class as a constructor, but rather as a
standard method.
•
If you save the class as an SCL entry from the Class Editor and view the SCL class
definition code that is generated, the constructors appear as methods with the same
name as the class. For example, if you edit a class named Document, override its
Document method in the Class Editor, and save it as an SCL entry, the SCL entry
includes the following code:
class sasuser.myclasses.Document
extends sashelp.fsp.Object.class;
Document: public method
/(State='O',
Description='Override of the default constructor',
SCL='sasuser.myclasses.Document.scl');
/* ...insert additional methods here... */
endclass;
See “Defining Constructors in the SCL for a Class” on page 106 for more
information.
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Implementing Methods with SCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
SCL and Overridden Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Using USECLASS Statement Blocks with Methods . . . . . . . . . . . . . . . . . . . . . . . 111
Improving the Performance of SCL Code in Methods . . . . . . . . . . . . . . . . . . . . . . 112
Overriding Frame Methods to Augment SCL Labeled Sections . . . . . . . . . . . . . . 113
Implementing Methods with SCL
Introduction
You can implement methods for your components with SCL code. The SCL
implementation for a method can be stored in three different places:
•
the SCL entry that is identified as the Source Entry for the method in the Class
Editor
•
the SCL entry that is identified in the SCL method declaration statement of a CLASS
block. In the following example, the SCL implementation for the m1 method is
stored in the entry named sasuser.myclasses.oneCode.scl.
Class One extends sashelp.fsp.object.class;
m1: public method
n:num
return=num
/ (SCL='sasuser.myclasses.oneCode.scl');
EndClass;
•
the SCL class definition itself, where the method is both defined and implemented.
For example:
Class One extends sashelp.fsp.object.class;
m2: public method
n:num
return=num;
dcl num total;
total=n * 2;
return total;
endmethod;
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/* ...insert additional methods here... */
EndClass;
When writing methods, keep the following tips in mind:
•
Method implementations always start with the METHOD statement and end with
ENDMETHOD.
•
Method names are not case-sensitive and can contain underscores, but not embedded
blanks or other special characters. Methods that are supplied by SAS are named
using a leading underscore, a lowercase first letter, and subsequent uppercasing of
any joined word (such as _setBackgroundColor) to promote readability, but your
methods do not have to conform to the SAS convention.
Note: Methods supplied by SAS include a leading underscore so that they can be
differentiated from user methods. If you name a new method using a leading
underscore, a warning message appears.
•
Method calls must include all arguments that you have specified in the method
signature.
•
You must either declare any variable that you use within a METHOD block, or store
the variable as a private attribute on the class. For example:
addToList: public method
item:input:char
aList:update:list;
dcl num rc;
/* rc must be declared */
rc=insertc(aList, item, -1);
/* ...insert additional SCL statements here... */
endmethod;
You can use either the DECLARE statement or its abbreviated form DCL to declare
local variables in a method.
SCL and Overridden Methods
You can write methods to override existing methods, but you should execute the method
on the parent class with the _super() routine. The _super() routine determines the current
method context and then executes the method of the same name on the parent class. The
point at which you execute the parent method can significantly affect the behavior of the
overriding method. For example, if the _super() call occurs before any other statements
in the METHOD section, the inherited behavior is executed before the overridden code
executes. In order to use _super(), you must be inside a CLASS or USECLASS block.
Some methods require you to invoke the inherited method in a particular order. Each of
the following examples is assumed to exist inside an appropriate CLASS or USECLASS
block:
•
If you override an object's _init method, you must invoke the super _init method
before any other processing:
init: public method;
_super();
/* call super */
/* ...insert additional code here... */
endmethod;
•
If you override an object's _bInit method, you must invoke the super _bInit method
before other processing:
Implementing Methods with SCL
111
bInit: public method;
_super();
/* call super */
/* ...insert additional code here... */
endmethod;
•
If you override an object's _term method, you must invoke the super _term method
as the last operation:
term: public method;
/* ...insert additional code here... */
_super();
/* call super */
endmethod;
•
If you override an object's _bTerm method, you must invoke the super _bTerm
method as the last operation:
bTerm: public method;
/* ...insert additional code here... */
_super();
/* call super */
endmethod;
Note: When overriding a method, you may not change its signature. If you require a
different signature, you should overload the method.
Using USECLASS Statement Blocks with Methods
By using USECLASS/ENDUSECLASS statements around an SCL method block, you
can use methods and attributes for the specified class without repeating the class
identifier. Due to compile-time binding, the SCL compiler can distinguish between local
variables and class attributes. Refer to the SAS Component Language: Reference for
complete details on the USECLASS statement.
You can also use the _super() routine in the implementation of a method that is
contained in a USECLASS statement block without having to specify the object
identifier.
•
Your method can execute the _super() routine without specifying a super or parent
method. The SCL compiler assumes that you want to execute the method of the same
name on the parent. For example, to override an _init method:
init: public method;
_super();
/* run _init method on parent */
/* ...insert additional code here... */
endmethod;
Note: So that any new properties you have added are saved with a class, be sure to save
a CLASS entry before compiling the SCL entry that contains its method
implementation(s).
If you override a method that has a signature of '(None)' and implement the method
inside a USECLASS/ENDUSECLASS block, you must include a signature designation
in the METHOD statement. For example, if you override the _foo method and _foo has a
signature of '(None)', your SCL code could include
USECLASS mylib.mycat.myclass.class;
foo: method/(signature='N');
/* ...insert additional code here... */
endmethod;
enduseclass;
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Any method that is implemented within a USECLASS/ENDUSECLASS block must
designate a signature.
Improving the Performance of SCL Code in Methods
Here are several tips to make the SCL code in your methods work more efficiently:
Be careful when you use recursion in methods.
You can use recursive calls such that a method can invoke itself. However, be sure to
provide an exit case so that you do not recurse infinitely. Also be sure to invoke the
inherited method with _super() and not with the form object.method(). Attempting to
use a direct call to the method when you should use _super() results either in an
infinite loop or in an out-of-memory condition.
Use the _term() method to delete objects.
If you programmatically create instances of objects in your SCL, you should always
invoke the _term() method when your application no longer needs those objects.
Objects that are no longer used are not automatically deleted while the application is
running. Invoking the _term() method deletes the object and frees the memory that it
occupies.
DCL sasuser.myclasses.myObj.class demoObj = _new_ myObj();
/* ...insert additional SCL statements here... */
demoObj._term();
Delete SCL lists that have been created by a method.
If any of your object's methods create new SCL lists, delete these lists with the
DELLIST function. SCL lists take up memory and are not always automatically
deleted. Leaving too many SCL lists open in memory can cause your application to
run out of available memory.
Do not bypass SCL method-calling functions.
Always invoke the methods in the same manner, and do not bypass the methodcalling functions that SCL provides. For example, consider a banking account class
that has two methods, deposit() and update(). The deposit() method records a deposit,
and the update() method updates a data set with the new account balance. You can
implement these methods together in a single SCL entry, ACCOUNT.SCL:
/* ACCOUNT.SCL: methods for the ACCOUNT class */
update: public method;
/* ...SCL code to update a data set with the account information... */
endmethod;
deposit: public method
amount:update:num;
/* ...code to process a deposit goes here... */
endmethod;
Since you want to perform an update after each deposit, you may need to invoke the
update operation from the DEPOSIT code. You may be tempted to call this operation
directly, either with a LINK statement or by using CALL METHOD:
/* ACCOUNT.SCL: methods for the ACCOUNT class */
deposit: method
amount:update:num;
/* ...code to process a deposit goes here... */
/* this is the wrong way to do an update! */
Overriding Frame Methods to Augment SCL Labeled Sections
113
link update;
endmethod;
or
/* ACCOUNT.SCL: methods for the ACCOUNT class */
deposit: method
amount:update:num;
/* ...code to process a deposit goes here... */
/* this is also the wrong way to do an update! */
call method('account.scl', 'update');
endmethod;
Both of these mechanisms may work when you first develop your application, but
they violate basic principles of object-oriented programming. To understand why,
consider what happens when someone decides to use your ACCOUNT class. They
decide that your account class provides most of the functionality that they want,
except that they want to record transactions in an audit trail. To do so, they override
the update() method to also update the audit trail. If your deposit() method is
implemented using either of the techniques presented above, then the new update()
method is never called when a deposit is made.
The proper way to perform the update is to call the update() method:
/* NEW ACCOUNT.SCL: methods for the NEW ACCOUNT class */
USECLASS newaccount.class;
deposit: method
amount 8;
/* ...code to process a deposit goes here... */
/* This is the correct way to do an update! */
update();
endmethod;
Then, if someone overrides the update() method, your deposit() method
automatically invokes that new update() method. Of course, the developers of the
new update() method that adds an audit trail should also invoke your original
update() code using _super().
update: method;
_super();
/* ...SCL code to update a data set */
/* with the account information... */
endmethod;
ENDUSECLASS;
Overriding Frame Methods to Augment SCL
Labeled Sections
The _initLabel, _mainLabel, and _termLabel methods of the Frame class run the
corresponding named section in the FRAME entry's SCL code. For example, the
_initLabel method runs the INIT section of the FRAME entry. This means that you can
override any of these methods and perform preprocessing and postprocessing with
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respect to the corresponding label. For example, if you want to process some information
both before and after the INIT section of a FRAME entry runs, you can override the
_initLabel method of the Frame class and write your method similar to this:
USECLASS sasuser.myclasses.newclass.class
INITLABEL: method;
/* perform preprocessing */
/* ...insert additional SCL statements here... */
/* run the INIT section of the FRAME entry */
_super();
/* perform postprocessing */
/* ...insert additional SCL statements here... */
endmethod;
ENDUSECLASS;
The _objectLabel method of the Widget class is similar to the section label methods of
the Frame class. The _objectLabel method runs an object's labeled section in the
FRAME entry's SCL code. For example, if a FRAME entry contains two objects,
Textentry1 and Textentry2, the _objectLabel method for Textentry1 runs the section
named Textentry1. Overriding this method enables you to perform preprocessing and
postprocessing with respect to the corresponding object's label.
When overriding a method, remember that you cannot change its name, scope, or
signature.
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Specifying a Component's Default Attribute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Validating the Values of Character Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Assigning an Editor to an Attribute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Creating a Custom Attribute Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Adding a Custom Attributes Window to a Component . . . . . . . . . . . . . . . . . . . . . 119
Assigning a Custom Access Method (CAM) to an Attribute . . . . . . . . . . . . . . . . . 121
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
CAM Naming Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Avoiding Unnecessary CAM Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Avoiding CAM Recursion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Using the Refresh Attributes Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Using List Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Specifying a Component's Default Attribute
Every component has a defaultAttribute attribute that is inherited from the Object
class. A component's defaultAttribute is set to the attribute whose value is most
often needed from that component. For example, the defaultAttribute attribute for
a combo box control is selectedItem, which is the item that is selected from the list
that the combo box displays.
The defaultAttribute attribute also affects some behaviors of the Class Editor and
the Properties window. Actions that prompt for an attribute are initially set to the value
of a component's defaultAttribute. For example, when you specify an attribute
link, the value of Link to defaults to the value of the source component's
defaultAttribute attribute. The dragInfo and dropInfo values that pass information
between objects during drag and drop processes also use the value of the
defaultAttribute attribute.
Many SAS classes, including most visual components, have values specified for
defaultAttribute.
To specify or change the value of the defaultAttribute attribute for a particular
class using the Class Editor:
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1. Select the Attributes node, and then select the defaultAttribute attribute.
2. Right-click and select Override from the pop-up menu.
3. In the Initial Value field, select an attribute from the drop-down list. Note that the list
contains only attributes that are currently defined on the class.
4. Save the class.
You can also specify the value of defaultAttribute at build time using the
Properties window. Valid selections are limited to the attributes that are currently
defined for the instance of the class.
Validating the Values of Character Attributes
Attributes in SAS/AF software enable you to perform data validation without having to
add code to your frame SCL entries. The process behind attribute validation depends on
the attribute type and on how you specify some of the attribute metadata.
You can assign a list of valid values to a character attribute. Valid values restrict the
value of an attribute to a set of values that you specify for the attribute. The values are
stored in the ValidValues metadata item for the attribute. The validation occurs when
some action attempts to set the attribute value (that is, when the _setAttributeValue
method runs). At build time, the validation is performed when you set the attribute value
with the Properties window. At run time, the validation occurs when you assign a new
value from SCL code. For example, specifying Yes and No as the valid values for an
attribute ensures that only those two values are used at build time and run time.
To define valid values for a component's attribute using the Class Editor:
1. Select the Attributes node, and then select the character attribute for which you
want to add valid values.
Note: If the attribute is inherited, you must override it by selecting Override from
the pop-up menu.
2. In the Valid Values cell, enter the list of valid values. Use either a space or a comma
to separate single-word items, and use a comma (,) to separate multiple-word items.
For example,
Red Blue Green
or
Crimson Red, Midnight Blue, Forest Green
You can also use the Valid Values editor to add valid values. Click the ellipsis (...)
button to open the Valid Values editor.
See the SAS/AF online Help for more information on adding valid values in the Class
Editor. For more information on the ValidValues metadata item, see “Attributes” on
page 84.
Although the Class Editor displays the defined valid values in the combo box that is
displayed when you select the Initial Values cell of an attribute, no validation is
performed on the initial value that you select. It is the responsibility of the component
developer to assign a valid value to the InitialValue metadata item.
Assigning an Editor to an Attribute
117
You may want to use an SCL entry to perform programmatic validation or to match
values against items in an SLIST entry. To assign an SCL or SLIST entry to perform
validation for a character attribute, use the Class Editor to set Valid Values to the
appropriate entry name. Note that you must preface the catalog entry name with a
backslash (\) character.
For example, the defaultAttribute attribute that all components inherit from
sashelp.fsp.Object.class has its ValidValues metadata item set to
sashelp.classes.defaultattributevalues.scl to run the specified SCL
entry when the value of defaultAttribute is set. The SCL entry contains the
following code, which returns a list of all attributes that are defined on the object:
/* Include this ENTRY statement to process ValidValues */
entry list:list
optional= objectId:object
attributeName:char
environment:char(2);
dcl num rc;
INIT:
attributesList=makelist();
objectID._getAttributes(attributesList, 'Y');
do i=1 to listlen(attributesList);
rc=insertc(list, nameitem(attributesList,i), -1);
end;
rc=dellist(attributeList, 'Y');
rc=sortlist(list);
return;
The defaultattributevalues.scl entry executes when the
defaultAttribute attribute of any object is set. For details on the ENTRY statement
used in this example, see “Creating a Custom Attribute Editor” on page 118.
You can also use a custom access method to process valid values for an attribute. For
more information on custom access methods, see “Assigning a Custom Access Method
(CAM) to an Attribute” on page 121.
Assigning an Editor to an Attribute
Introduction
An editor is a SAS/AF catalog entry that provides assistance when a user tries to set an
attribute's value. Typically, an editor is implemented as a FRAME entry that is defined
as a dialog box. You can specify an editor to assign an attribute value, which can make
build-time operations easier and can decrease the chance of input error. Editors are
usually reserved for broad ranges, where valid values presented in a drop-down list
would not accurately or completely represent valid input. For example, instead of
making users remember and correctly input numeric RGB or hexidecimal color values,
or even color names, you could assign the Color Editor
(sashelp.classes.colorEditor.frame) to the attribute to simplify the selection
of color values. An editor that is specified for an attribute is stored in the attribute's
Editor metadata item.
To assign an editor for a component attribute using the Class Editor:
1. Select the Attributes node, and then select the attribute for which you want to
assign an editor.
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Note: If the attribute is inherited, you must first override it by selecting Override
from the pop-up menu.
2. Select the Editor cell, and then click the ellipsis (...) button.
3. Specify the catalog entry that you want to use as the editor.
You can also use the Properties window to define an editor for a specific instance of a
component. In the New Attributes dialog box that appears when you add an attribute in
the Properties window, select the Value/CAMs tab, and then click the ellipsis (...) button
next to the Editor field to add an editor.
SAS/AF software provides several ready-to-use editors that you can specify to modify
attribute values in components that you develop. For a complete list of supplied editors,
see the SAS/AF online Help.
Creating a Custom Attribute Editor
You can create your own frame or SCL entry to use as an attribute editor. The frame or
SCL entry functions just like other frames or SCL programs, except that you must
include an ENTRY statement with an OPTIONAL= option before the INIT label. The
ENTRY statement can include the following arguments:
objectID
is the object identifier of the current object for entries that are invoked from the
Properties window. For entries that are invoked from the Class Editor, the object
identifier is 0.
classID
is the object identifier of the class that is used to create the current object for entries
that are invoked from the Properties window. For entries that are invoked from the
Class Editor, classID is the object identifier of the class that is currently loaded
and displayed.
environment
is a two-character value that contains CE for entries invoked from the Class Editor
and PW for entries invoked from the Properties window.
frameID
is the object identifier of the active frame that contains the object for entries that are
invoked from the Properties window. For entries that are invoked from the Class
Editor, frameID is 0.
attributeName
is a character variable (char(32)) that contains the name of the selected attribute.
attributeType
is a character variable (char(83)) that contains the type of the selected attribute,
which can be Character, List, Numeric, Object, or the four-level name of a
specific CLASS entry.
value
is either a character or numeric variable that can contain the value of the attribute.
mode
is a character variable (char(1)) that can be set to E if the attribute is editable.
For example, in the Font Editor that is provided in SAS/AF software, the complete SCL
program for the editor is:
Adding a Custom Attributes Window to a Component
119
entry optional=
objectId:object classId:object environment:char(2)
frameId:object attributeName:char(32) attributeType:char(83)
value:char mode:char(1);
INIT:
value=fontlist(”, 'N', 1, 'Select a font.', 'N');
if value ne ' ' then value = scan(value,1,' ');
return;
The program simply calls the SCL FONTLIST function, but by including the ENTRY
statement, you can wrap that functionality inside an attribute editor.
You can specify just those arguments that you need to either process information in the
editor or to return to the Class Editor or the Properties window. For example, you would
include the environment parameter in the ENTRY statement if you needed to
determine whether the entry was called when a user was modifying an attribute in the
Class Editor or the Properties window.
Adding a Custom Attributes Window to a
Component
An editor is used to set a single attribute value. By contrast, a custom attributes window
(which is also known as a “customizer”) can be used to set attribute values for an entire
component. You can add a custom attributes window to a class to provide an alternate
way to set attribute information (that is, to replace the use of the Properties window for a
specific class) or to provide another way to access specific attributes by appending the
custom window to the Properties window.
You must first create a frame to serve as your custom attributes window. The SCL for
the frame must contain an ENTRY statement. For example:
entry optional= objectID:object;
init:
/* ...insert SCL for your frame... */
return;
In this example, the objectID argument that is passed represents the current object that
is being edited. This object argument enables you to use dot notation in the SCL code
that sets attribute values based on the selections a user makes in the custom attributes
window.
To specify a FRAME entry to use as a custom attributes window for a component:
1. In the Class Editor, select View ð Class Settings.
2. Select Use Custom Attributes Window, and then enter the name of the frame you
want to use as the custom window.
3. Select Append to include the custom attributes window with the Properties window,
or select Replace to use the custom attributes window instead of the Properties
window.
4. Click OK.
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If you select Append, a user of your component can access your custom attributes
window by selecting the row labeled (Custom) in the Properties window and clicking the
ellipsis (...) button in the Value cell.
If you select Replace, a user of your component will see the custom attributes window
instead of the Properties window. It is the responsibility of the component developer to
account for all attribute values in the design of the frame and in the SCL code that
processes the frame. The SCL for a custom attributes window that “replaces” the
Properties window must still include the ENTRY OPTIONAL= statement described
above.
Consider a component that is a subclass of
sashelp.classes.graphoutput_c.class. You could create a frame named
sasuser.test.attrgrph.frame that could provide a simple interface for setting
values for the major attributes in the component. This frame could be appended to the
Properties window.
The frame SCL must contain the following code:
/* sasuser.test.attrgrph.scl */
entry optional= objectID:object;
init:
/* ...insert SCL that initializes the values... */
/* ...of the controls in your frame... */
return;
/* ...insert additional SCL code here... */
term:
/* SCL must set the value of the attributes for objectID.
/* Assume that the following object names are the names
/* of the controls on the frame:
/*
- graphName is the text entry control
/*
- graphSize is the radio box control
/*
- scrollbarsCheckBox is the check box control
/* set graph name */
objectID.graph=graphName.text;
/* set resizeToFit or magnify */
if graphSize.selectedIndex=1
then objectID.resizeToFit='Yes';
else if graphSize.selectedIndex=2
then objectId.magnify=50;
/* set the scrollbars option */
*/
*/
*/
*/
*/
*/
Assigning a Custom Access Method (CAM) to an Attribute
121
objectID.scrollbars=scrollbarsCheckBox.selected;
return;
To create the subclass of the graph output control that uses the custom attributes
window:
1. Create a new class whose parent is sashelp.classes.graphoutput_c.class
and whose description is Graph Output Control with Customizer.
2. Select View ð Class Settings to view the Class Settings dialog box. Select Use
Custom Attributes Window, and then enter sasuser.test.attrgrph.frame
as the frame. Select Append, and then click OK to close the dialog box.
3. Save the class as sasuser.test.CustomGraphOutput.class, and then close
the Class Editor.
If you add this class to a frame, you can then use either the custom attributes window or
the Properties window to set the graph, resizeToFit, magnify, and/or
scrollbars attributes. You can open the custom attributes window from the
Properties window by selecting the row labeled (Custom) and clicking the ellipsis (...)
button in the Value cell.
Assigning a Custom Access Method (CAM) to an
Attribute
Introduction
A custom access method (CAM) is a SAS/AF software method that is associated with an
attribute. The CAM is automatically executed to perform additional processing when the
attribute's value is queried (with either dot notation or a direct _getAttributeValue call)
or set (with either dot notation or a direct _setAttributeValue call). You can use the Class
Editor to assign a CAM to a class attribute.
CAMs operate just like any other method, with a few special considerations:
•
You should never call a CAM directly; instead, rely on the _getAttributeValue or
_setAttributeValue methods to call it automatically.
•
CAMs in SAS classes are protected methods to help enforce indirect execution via
the _getAttributeValue and _setAttributeValue methods. Component developers are
encouraged to create all CAMs as Scope=Protected methods to encourage the use
of dot notation and to inhibit the direct calling of CAMs by developers who use the
component.
•
A CAM always has a single signature and should not be overloaded. The CAM
signature contains a single argument that is the same type as its associated attribute.
A CAM always returns a numeric value as a return code that indicates success or
failure. For example, if a CAM is specified for a character variable, its signature is
(C)N.
•
The CAM must be defined for the object that contains the attribute that calls it. In
other words, if object.myAttribute calls a CAM named
setcamMyAttribute, then setcamMyAttribute must be a method on
object.
•
CAMs may be added only to New or Overridden attributes.
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•
Default names for custom access methods in SAS classes follow this format:
•
_setcamAttributeName
•
_getcamAttributeName
See “Attribute Values and Dot Notation” on page 88 for more information about CAMs
and about the flow of control for the _setAttributeValue and _getAttributeValue
methods.
For example, consider an object that has an attribute whose value is set to a SAS catalog.
You can add a CAM to that attribute to determine whether the value is an existing SAS
catalog as follows:
1. Create a new class whose parent is sashelp.fsp.object.class and whose
description is Document Object.
2. Save the class as sasuser.test.document.class.
3. In the Attributes node of the Class Editor, select New Attribute from the pop-up
menu and add a character attribute named catalogToRead.
4. In the Set CAM cell for the catalogToRead attribute, select the
setcamCatalogToRead method from the drop-down list. When you are prompted
to add the method, click Yes.
5. In the New Method dialog box, click Source and add the following code to the
sasuser.test.document.scl entry:
USECLASS sasuser.test.document.class;
/* ...other methods can be defined here... */
setcamCatalogToRead: Protected method
name:input:char(83)
return=num;
if name eq ” then return(0);
if cexist(name) eq 0 then
do;
/* set the errorMessage attribute */
errorMessage = 'ERROR: Catalog does not exist.';
put errorMessage;
return(1);
end;
else return(0);
endmethod;
enduseclass;
6. Compile and save the SCL, close the Source window and the New Method dialog
box, and then close the Class Editor.
When the attribute is set via SCL (for example, document.catalogToRead =
'sasuser.myclasses';), the setCAM is called, verifying that the catalog is a valid
SAS catalog. If the catalog that is specified is an invalid SAS catalog name or does not
exist, an error message is generated and the setCAM program halts.
The same CAM could be expanded to do more than simple validity checking. For
example, you could add processing to the CAM to read information from the selected
catalog and to store that information in a list attribute named contents when the
catalogToRead attribute is set:
Assigning a Custom Access Method (CAM) to an Attribute
123
USECLASS sasuser.test.document.class;
/* ...other methods can be defined here... */
setcamCatalogToRead: Protected method
name:input:char(83)
return=num;
dcl num rc;
if name eq ” then return(0);
if cexist(name) eq 0 then
do;
/* set the errorMessage attribute */
errorMessage = 'ERROR: Catalog does not exist.';
put errorMessage;
return(1);
end;
else do;
/* use the catalog entry list model to read the catalog */
/* and return the four-level name of each entry in it
*/
dcl sashelp.classes.catalogentrylist_c.class catobj;
catobj = _new_ sashelp.classes.catalogentrylist_c();
catobj.catalog=name;
rc=clearlist(contents);
contents = copylist(catobj.items);
catobj._term();
return(0);
end;
endmethod;
enduseclass;
CAM Naming Conventions
CAM naming follows method-naming rules and conventions in several ways:
•
CAM names can be up to 256 characters long. However, keep in mind that the
USECLASS command can only accommodate method names up to 32 characters
long. For easy maintenance, the method name is used as the SCL label in the
METHOD statement.
•
CAM names may contain only alphanumeric characters and the underscore
character. The Class Editor does not support modifications to methods whose names
contain special characters. Be sure to remove special characters from method names
when converting legacy classes.
•
In SAS classes, CAMs and other methods are named with a leading underscore.
Users should not use leading underscores in names of methods or CAMs.
This format makes it easy to differentiate between CAMs and regular methods. For
example, the method _setBorderStyle is easily distinguished from the associated CAM
_setcamBorderStyle. Developers should follow the same format, without the leading
underscore:
•
setcamAttributeName
•
getcamAttributeName
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When you add a CAM to an attribute, the Class Editor automatically provides the CAM
name in the format of setcamAttributeName or getcamAttributeName.
You should adhere to these naming formats to eliminate confusion between CAMs and
regular methods. Doing so will ensure that CAMs are not accessed directly.
Avoiding Unnecessary CAM Execution
The ease with which dot notation enables you to get and set attribute values may lead
you to write code similar to the following:
obj.color = obj2.text;
/* Assuming obj2.text contains a valid color value. */
This is perfectly valid code. However, setCAMs and getCAMs may be executing in the
background each time code like this is run. Of particular concern is a getCAM that is
associated with the right-hand side of an assignment.
Use caution when repeatedly evaluating a right-hand value, thus repeatedly running
_getAttributeValue and any associated getCAM. The following code illustrates the
potential inefficiency of repeatedly evaluating the right-hand side of an assignment:
do x = 1 to
listlen(someList);
/* Assigns the values and runs obj2._getcamAttribute2 each time. */
obj.attribute[x] = obj2.attribute2;
end;
Even if no getCAM is executing each time the value of attribute2 is queried, a better
way to implement such code would be to assign the value to a third variable and to use
the variable in the loop, avoiding any getCAM code that runs for each iteration of the
loop:
/* Assigns the value and runs _getcamAttribute2 once. */
dcl newVariable = obj2.attribute2;
do x = 1 to listlen(someList);
/* Assigns the values without running _getcamAttribute2. */
obj.attribute[x] = newVariable;
end;
Avoiding CAM Recursion
Do not set other attribute values from within getCAM code. It is possible to
inadvertently create an infinite loop when setting the value of another attribute while
inside the execution of a getCAM method. For example:
1. The getCAMX method is called when the value of the X attribute is queried.
2. In the course of its code, getCAMX sets the value of the Y attribute.
3. The Y attribute has a setCAM that queries the value of the X attribute, which starts
the process again at step 1.
Using the Refresh Attributes Event
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Using the Refresh Attributes Event
Introduction
When you develop a component, it may be designed such that its attributes are
dependent on each other. In other words, a change to the value of one attribute can cause
the value of one or more attributes to change as well. For example, the list box control
has several attributes that are dependent on each other, two of which are
selectedIndex and selectedItem. When a user sets the value for either attribute
using the Properties window, the value of the other attribute is updated to keep them
synchronized. The behavior that updates other attributes is typically implemented in the
attribute's setCAM.
Consider what happens when a user sets the value of selectedIndex to 5. The
setCAM for the selectedIndex attribute executes and sets the new value for the
selectedItem attribute. If a user were to update selectedItem, its setCAM would
update selectedIndex.
If any of these attributes are changed at build time while the Properties window is open,
the “refresh Attributes” event can be sent to notify the Properties window that it should
refresh its display to reflect the new attribute values. The Properties window is designed
to listen for the “refresh Attributes” event.
It is the responsibility of the component developer to send the event. Typically, you can
send this event in the setCAM following any code that changes the other attribute values.
For example:
if frameID.buildTime='Yes' then
_sendEvent('refresh Attributes', attributeList);
where attributeList is a list that contains information that the Properties window uses to
update its displayed attribute values. For performance reasons, the event should be sent
only if the frame is displayed at build time. There is no reason to update the Properties
window at run time.
The format of the list represented by attributeList can be one of the following:
•
a list with no named items that is passed with the event. All items in the list are
processed for the currently selected objects. The items in the list correspond to the
attributes whose values must be refreshed.
If a user selects multiple objects on a frame and updates a common attribute in the
Properties window, the “refresh Attributes” event is sent to all selected objects.
Sample list: ('borderColor', 'backgroundColor', 'borderStyle')
•
a list with named items, where the named items represent the object identifiers that
should be refreshed. A named item can point to an attribute or to a list of attributes
that should be refreshed for the object that is represented by the identifier. If the
named item is set to 0, a period (missing value), or ( ), then all of the attributes are
refreshed for the object that is represented by the identifier.
When you use a list of object identifiers, the event can be sent to all valid objects on
the frame. An object does not have to be selected.
For example, a list can include
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(2324= 0, 3345=('selectedItem', 'items', 'comboboxStyle'),
7272='text')
All attributes would be refreshed for the object whose identifier is 2324;
selectedItem,items, and comboxStyle would be refreshed for the object
whose identifier is 3345; and text would be refreshed for the object whose
identifier is 7272. Invalid attribute names would be ignored.
If no list parameter is passed with the event, then the entire list of attributes is refreshed
for the selected object.
Note: It is the responsibility of the component developer to use the “refresh Attributes”
event appropriately. For example, you should not refresh the attribute that the
setCAM is updating, because the _setAttributeValue method call will not be
completed during the CAM operation.
Example
As an example of using the “refresh Attribute” event due to a change in another
attribute, consider a subclass of sashelp.fsp.object.class that has a character
attribute named testMode and a numeric attribute named newValue. If the
testMode attribute is set to Test, then the attribute value of newValue should be set
to 999and its editable status should be changed to No. If the value of testMode is set to
anything other than Test, then newValue should be Editable=Yes and its value should
remain unchanged.
To create the setCAM that sends the “refresh Attributes” event to implement the class:
1. Create a new class whose parent is sashelp.fsp.object.class and whose
description is Testing Object.
2. Save the class as sasuser.test.testing.class.
3. In the Attributes node of the Class Editor, select New Attribute from the pop-up
menu and add a character attribute named testMode. Add a numeric attribute
named newValue.
4. In the Set CAM cell, select the setcamTestMode method from the drop-down list.
When you are prompted to add the method, click Yes.
5. In the New Method dialog box, click Source and add the following code to the
sasuser.test.testing.scl entry:
USECLASS sasuser.test.testing.class;
setcamTestMode: method
attrval:char return=num;
dcl list changeAttrList = makelist();
dcl list refreshList = makelist();
dcl num rc;
/* set value and change editable status if value='Test' */
if (upcase(attrval)='TEST') then do;
rc = insertc(changeAttrList,'No',-1,'editable');
_setAttributeValue('newValue',999);
end;
else
rc = insertc(changeAttrList,'Yes',-1,'editable');
_changeAttribute('newValue',changeAttrList);
/* refresh datalist displayed in Property Window */
Using List Attributes
127
rc = insertc(refreshList,'newValue',-1);
_sendEvent('refresh Attributes',refreshList);
rc = dellist(refreshList);
return (0);
endmethod;
enduseclass;
6. Compile and save the code, close the Source window, and then close the New
Method dialog box.
7. Save the class as sasuser.test.testing.class and close the Class Editor.
You could then use the Testing class in a frame:
1. In the SAS Explorer, select a catalog, and then select File ð New and specify a
FRAME entry.
2. In the Components window, right-click and select Add Classes from the pop-up
menu to add sasuser.test.testing.class. If the Components window is not
displayed when the new frame appears in the Build window, then select View ð
Components Window to display the Components window.
3. Drag an instance of the Testing object and drop it onto the frame.
4. Select View ð Properties Window and select the testing1 component in the
tree.
5. Test the CAM:
•
Change the value of testMode to Test. The value of newValue changes to
999 and the attribute is not editable.
•
Change the value of testMode to any value other than Test. The value of
newValue is editable.
Using List Attributes
SCL list functions such as INSERTC and GETITEMN do not perform explicit “set” and
“get” assignments. That is, when you use one of these SCL functions to manipulate a list
attribute, the _setAttributeValue method is not invoked for the attribute. The value of the
attribute might be changed, but the other actions that occur when an attribute value is
changed in a _setAttributeValue call do not execute. The value cannot be validated, the
“attributeName changed” event is not sent, and custom access methods do not run. Your
SCL code must use explicit assignment operations, such as
object.attribute=value, in order to invoke the expected attribute value setting
behavior.
For example, consider a frame that contains a list box control named listbox1. If you
want to write SCL that adds items to the list box, it might seem logical to write:
/* frame SCL */
dcl num rc;
init:
rc=insertc(listbox1.items, 'Red', -1);
rc=insertc(listbox1.items, 'Blue', -1);
rc=insertc(listbox1.items, 'Green', -1);
return;
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However, because the INSERTC function does not invoke the _setAttributeValue
method for items, the “items changed” event is never sent, and the list box is not
updated on the frame.
Instead, you can use a list variable and set the items attribute to the value of the list.
For example:
dcl list localList=makelist();
init:
localList=listbox1.items;
rc=insertc(localList, 'Red', -1);
rc=insertc(localList, 'Blue', -1);
rc=insertc(localList, 'Green', -1);
listbox1.items=localList;
return;
The _setAttributeValue method runs for the itemsattribute when the dot notation call
sets the value of items. The list box in the frame displays the updated list.
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Capabilities to Components
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Enabling Attribute Linking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
What Happens When Attributes Are Linked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Implementing Model/View Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
What Happens during Model/View Communication . . . . . . . . . . . . . . . . . . . . . . . 133
Creating Your Own Models and Viewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Enabling Drag and Drop Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
What Happens during a Drag and Drop Action . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Adding Drag and Drop Functionality to Your Components . . . . . . . . . . . . . . . . . 142
Drag and Drop Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Modifying or Adding Event Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
What Happens during Event Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Adding Events and Event Handlers to Your Components . . . . . . . . . . . . . . . . . . . 149
Introduction
When you create components using the SAS Component Object Model (SCOM)
framework, you can take advantage of four distinct processes that enable components to
communicate with each other.
Attribute linking
enabling a component to change one of its attributes when the value of another
attribute is changed.
Model/view communication
enabling a viewer (typically a control) to communicate with a model, based on a set
of common methods that are defined in an interface.
Drag and drop operations
enabling information to be transferred from one component to another by defining
“drag” attributes on one component and “drop” attributes on the other.
Event handling
enabling a component to send an event that another component can respond to by
using an associated event handler.
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This section describes how you can add these communication processes to your
components.
Enabling Attribute Linking
Introduction
In SAS/AF software, attributes can facilitate communication between components. You
can enable one component to automatically update the value of one of its attributes when
the value of another component attribute is changed. In the SAS Component Object
Model, this interaction is called “attribute linking,” and you can implement it without
any programming.
As a component developer, you can decide whether the components you design support
attribute linking. You can use the Class Editor to add attribute linking capabilities.
•
To enable an attribute to receive its value via an attribute link, simply set the
attribute's Linkable metadata item to “Yes.”
•
To enable an attribute to function as a source attribute (that is, the attribute to which
you link), you must set the attribute's SendEvent metadata item to “Yes.”
Most attributes on SAS classes are linkable.
What Happens When Attributes Are Linked
Introduction
During build time, you can use the Properties window to add attribute links. When you
add an attribute link, the component's _addLink method runs. The _addLink method
specifies the attribute to which you want to link, the object you are linking from, and the
source attribute for the link.
Similarly, when an attribute link is removed, the _deleteLink method runs. The
component's _deleteLink method specifies the name of the attribute whose link you want
to delete, the source object, and the source attribute for the link.
Note: You could also write SCL code that uses _addLink or _deleteLink to
programmatically add or delete an attribute link at run time.
The definitions of your component's attribute metadata determine what happens during
attribute linking.
1. When a source attribute with SendEvent=“Yes” is modified, it sends an
“attributeName Changed” event. The event passes an instance of
sashelp.classes.AttributeChangedEvent.class that contains
information about the event.
2. The target component has an event handler method with a single argument whose
type is object. The argument receives the AttributeChangedEvent instance from the
event.
3. The _onAttributeChange method queries the AttributeChangedEvent object for the
name and the value of the attribute that has been changed, as well as for the object
identifier of the source object. The _onAttributeChange method then invokes the
_setAttributeValue method on the target attribute, which updates the value of the
target attribute.
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4. At build time, the _onAttributeChange method sends the “refresh Attributes” event.
See “Using the Refresh Attributes Event” on page 125 for more information.
For details on the flow of control for the _setAttributeValue method, see “Attribute
Values and Dot Notation” on page 88.
If you enable attribute linking, developers who use your components do not have to
write any code to establish communication between components.
How the Attribute Changed Event Component Works
The Attribute Changed Event component
(sashelp.classes.AttributeChangedEvent.class) provides an object
container for passing the information that is used in attribute linking. The information is
stored in the following attributes of the Attribute Changed Event component:
attributeName
is the name of the changed attribute.
value
is the value of the changed attribute. This attribute is a complex attribute whose type
is sashelp.classes.type.class, which contains the following attributes:
type
represents the type of the attribute value (Character, Numeric,
List, Object). Based on the value of type, you can query the
appropriate “value” attribute.
characterValue
stores the character value if type is “Character”.
listValue
stores the SCL list if type is “List”.
numericValue
stores the numeric value if type is “Numeric”.
objectValue
stores the object identifier if type is “Object”.
objectID
is the identifier of the source object whose attribute was changed.
For complete information on the AttributeChangedEvent component, see the “SAS/AF
Component Reference” in the SAS/AF online Help.
Example
Sometimes setting an attribute link between two attributes does not provide the complete
behavior that your component or application needs. In these situations, you might want
to define your own event handler to listen for an “attributeName Changed” event and to
perform the desired behavior in the event handler method.
For example, consider a frame with a list box that contains the names of columns in a
SAS table. A text entry control is also on the frame. As a user of the frame selects one or
more columns in the list box, the text entry control displays a string that contains the list
of selected columns, with blank characters separating the column names. The standard
attribute linking functionality cannot handle this requirement because of the type
mismatch of the attributes that are involved. (The list box stores selected columns as list
items in its selectedItems attribute. The text entry control displays the text as a
character string in its text attribute.) You must write code to convert the list of items in
selectedItems to a concatenated character string that can be displayed in the text
entry control.
The following example demonstrates how you can create a subclass of the text entry
control to provide such functionality:
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1. Using the Class Editor, create a new class whose parent is
sashelp.classes.textentry_c.class and whose description is Smart
Text Entry.
2. Save the class as sasuser.myclasses.SmartTextEntry.class.
3. Right-click on the Event Handlers node and select New Event Handler. Add an
event handler whose Event Generator is “Any Object (*)”. Set the Event Name to
selectedItems Changed and the Method Name to
onSelectedItemsChanged.
4. When you are prompted to add the new method, click Yes. In the New Methods
dialog box, click the ellipsis (...) button to modify the Signature field. In the
Signature dialog box, click the Add button to add a new argument whose type is a
specific class name, and then enter
sashelp.classes.attributechangedevent. Click OK, and then click OK
again to close the New Method dialog box and return to the Class Editor.
5. Select the Methods node, and then select the new onSelectedItemsChanged method.
Right-click and select Source from the pop-up menu, and then add the following
SCL code:
useclass sasuser.myclasses.SmartTextEntry.class;
onSelectedItemsChanged: public method
eventObj:sashelp.classes.attributeChangedEvent.class;
dcl char(500) textstr,
num i,
list localList;
localList = eventObj.value.listValue;
do i = 1 to listlen(localList);
textstr = textstr||' '||getitemc(localList,i);
end;
text=textstr;
/* set the text attribute */
endmethod;
enduseclass;
Compile and save the SCL entry.
6. Save the class and close the Class Editor.
You can then use the new Smart Text Entry component in conjunction with a list box
control. To create a frame that hosts the Smart Text Entry component:
1. Create a new frame.
2. Add the text entry subclass to the Components window by selecting Add Classes
from its pop-up menu. Select or enter
sasuser.myclasses.SmartTextEntry.class.
The class named Smart Text Entry appears in the Components window.
3. Drag a list box control onto the frame. Open the Properties window and set the list
box control's selectionMode attribute to “Multiple Selections”.
4. Drag and drop a Variable List Model component onto the list box to establish a
model/view relationship. In the Properties window, set the model's dataSet
attribute to a valid SAS table such as sashelp.prdsale.
The list box should immediately be populated with the column names in the table.
5. Drag and drop a Smart Text Entry component onto the frame. Resize the component
as necessary.
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6. Select Build ð Test to test the frame.
As you make multiple selections from the list box, the text entry control is automatically
updated to display a string of selected items. Because the list box control's
selectedItems attribute was defined in the class with SendEvent=Yes, the
selectedItems Changed event is sent each time the attribute value is changed. The event
also includes an instance of the Attribute Changed Event component that contains
information about the attribute and its value. The event handler on the Smart Text Entry
component retrieves the new value of the Attribute Changed Event component that is
passed to the method. The method then loops through the items in the list to create a
string of column names that are displayed in the text entry.
Implementing Model/View Communication
Introduction
When you perform the object-oriented analysis for your application, you can separate the
problem domain from the design of the application's user interface. The problem domain
provides a perspective on what the application should do, including all business rules.
Objects that represent the problem domain serve as models and are typically non-visual
components. Viewers are components that display data to the user or provide access to
the information in the model. To enable communication between the model components
and viewer components, you can implement model/view communication.
Although models and viewers are typically used together, each is nevertheless an
independent component. Their independence allows for customization, design flexibility,
and efficient programming. The use of a model/view architecture also
•
enables you to develop stable models that do not change much over time
•
enables you to customize viewers based on the preferences of different users who
might need to work with the same problem domains presented in the models
•
simplifies application maintenance because the user interface is separated from the
problem domain
As a component developer, implementing model/view communication can possibly
require you to add a significant amount of SCL code. However, users of the models and
viewers that you create do not have to do any programming to perform component
communication.
Interfaces are designed to help implement model/view communication by providing a
kind of relationship between the model and the viewer. An interface essentially defines
the rules by which two components can communicate with each other. The interface that
is used between a model and a viewer ensures that the viewer knows how and when to
communicate with the model to access the data it needs.
What Happens during Model/View Communication
The following items describe the flow of control for model/view communication:
1. When the model attribute of a viewer is set, an event handler is established on the
viewer to listen for the “contents updated” event to be sent from the model. The
event handler is the _onContentsUpdated method. In addition, the _setcamModel
method executes when the viewer's model attribute is set, both at build time and at
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run time. The _setcamModel method includes a call to a method that is both
implemented on the model and defined in the interface.
2. The “contents updated” event is sent by the model when one of the attributes in its
contentsUpdatedAttributes attribute changes or when the model specifically
sends the event.
The model's contentsUpdatedAttributes attribute contains the name of one
or more other attributes. These attributes have been identified as critical components
on the component. They affect the contents of the model, and the viewer must be
notified when their values change. The “contents Updated” event passes the name of
the changed attribute as an input argument to the _onContentsUpdated method.
3. The viewer's event handler, which is the _onContentsUpdated method, calls back to
the model to retrieve updated information. The viewer is able to communicate with
the model due to the methods defined in the interface.
For example, consider a frame that has a list box control that you want to use to present a
list of standard color names (such as Red, Green, and Blue). The Color List Model
component provides this list of names based on values that are supported by SAS
software. You can establish a model/view relationship between a list box and an instance
of the Color List Model component by dragging the model from the Component window
and dropping it onto the list box in the frame.
At the point where the drop occurs on the list box, the SAS/AF classes have been
designed to verify whether the two objects know how to communicate with each other
via model/view communication using a common interface. If the model has a supported
interface that matches a required interface on the viewer, the model is “attached” to the
viewer. In this case, the color list model supports the
sashelp.classes.staticStringList interface, and the list box requires the
same interface, so a model/view relationship exists. Two types of processing occur once
the model/view relationship is established:
1. The model attribute on the viewer is set to the name of the model, which executes
the setCAM for the attribute (_setcamModel). In the list box/color list model
example, the implementation of the _setcamModel method for the list box contains
code that queries the model and retrieves a list of items using a _getItems call, which
is a supported method in the interface. The CAM then sets the value of the viewer's
items attribute to the list that is returned by _getItems.
2. When the “contents Updated” event is sent by the model, the viewer's
_onContentsUpdated method executes. This method's implementation is similar to
the _setcamModel in that it queries the model using methods supplied in the
interface, and it retrieves the model's information to update the viewer. In the list box
example, a _getItems call is used to retrieve the list of colors each time the model is
updated.
Creating Your Own Models and Viewers
Introduction
To implement model/view communication, you need to examine the design of the
model, the viewer, and the interface to set the appropriate actions. Consider the
following steps when designing components for model/view:
1. Decide whether an existing interface provides the design you need.
If it does not, you can create a new interface.
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2. Add the interface as a supported interface for your model.
3. Create or identify the key attributes on the model. Modify the model's
contentsUpdatedAttributes attribute to include the key attributes.
4. Implement the methods for the model specified by the interface. Ensure that the
method or methods query or update the key attributes that you identified.
5. Add the interface as required for the viewer.
6. Override the viewer's _onContentsChanged and _setcamModel methods. Typically,
the implementation invokes methods that have been defined in the interface and
implemented in the model to retrieve new information from the model. This new
information is used to update attributes or to perform an action on the viewer. The
_onContentsChanged method handles the “contents Updated” event, and the
_setcamModel method retrieves the initial values from the model when the viewer is
instantiated.
Defining a Model Based on the StaticStringList Interface
The most simple example of implementing model/view involves providing support for
an existing interface. Using the steps outlined above, you can:
•
Provide support for the methods defined in
sashelp.classes.staticStringList.intrface so that you do not have to
create a new interface.
•
Add the _getItems method and implement code that populates an items attribute on
the model.
•
Work with an existing viewer that requires the staticStringList interface, such as a
list box.
To create the model:
1. Using the Class Editor, create a new class whose parent is
sashelp.fsp.Object.class and whose description is My Model.
2. Save the class as sasuser.myclasses.myModel.class.
3. On the Interfaces node in the tree, right-click and select New Interface from the
pop-up menu. Specify sashelp.classes.staticStringList.intrface for
the interface and set Status to Supports.
The Class Editor prompts you to add the methods that are defined in the interface.
Click Yes.
Note: Although this example may not provide implementation for each method that
is defined in the interface, it is a recommended practice to implement in your
class all methods that are specified in the interface. You do not necessarily know
which methods the viewer might invoke.
4. Right-click on the Attributes node and select New Attribute. Add an attribute
named items and assign it as a List type. Save the class.
5. Select the Methods node. Select the _init method with the signature of ()V, and then
right-click and select Override from the pop-up menu. Select the _getItems method,
and then right-click and select Source from the pop-up menu. Add the following
SCL code to implement both methods in the entry named
sasuser.myclasses.myModel.scl that is created for you:
useclass sasuser.myclasses.myModel.class;
/* Override of _init method */
init: public method (state="0");
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dcl num rc;
dcl list temp=makelist();
_super();
rc=clearlist(items);
temp=items;
rc=insertc(temp, 'One', -1);
rc=insertc(temp, 'Two', -1);
rc=insertc(temp, 'Three', -1);
items=temp;
endmethod;
getItems: public method return=list;
return(items);
endmethod;
enduseclass;
Compile the code, and then close the Source window and return to the Class Editor.
6. Close the Class Editor.
Once the model is complete, you can create a frame and test the model with a control
that requires the same interface. For example, you could use a list box control since it
requires the staticStringList interface:
1. Create a new frame.
2. Add your new model to the Components window by selecting Add Classes from its
pop-up menu. Select or enter sasuser.myclasses.myModel.class.
The class named My Model appears in the Components window.
3. Drag a list box control onto the frame, and then drag and drop a My Model
component onto the list box to establish a model/view relationship. Regardless of the
version of SAS that you are using, test the frame using the TESTAF command to see
that the list box populate correctly.
The list box should immediately be populated with the values that you specified in
the model's _getItems method.
Creating a Model/View Relationship Based on a New Interface
If existing interfaces do not provide the necessary relationship for a model and a viewer
to communicate, you can create a new interface. This example demonstrates how you
can:
•
create a new interface.
•
implement the methods defined in that interface for a new model class that supports
the interface.
•
provide support in a viewer for the required interface by overriding the viewer's
_onContentsUpdated and _setcamModel methods.
To create the interface:
1. Use the Interface Editor to create a new interface whose description is My
Interface.
2. Right-click and select New Method from the pop-up menu, and then add a method
named getColumnData with a signature ()L.
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3. Close the Interface Editor and save the new interface as
sasuser.myclasses.MyInterface.intrface.
Alternatively, you can use SCL to create an INTRFACE entry:
interface sasuser.myclasses.MyInterface;
getColumnData: public method return=list;
endinterface;
You can use the SAVECLASS command to save the SCL code as an interface. For more
information, see SAS Component Language Reference.
To create the model:
1. Using the Class Editor, create a new class whose parent is
sashelp.fsp.Object.class and whose description is Column Data Model.
2. Save the class as sasuser.myclasses.ColumnDataModel.class.
3. In the Interfaces node of the Class Editor, right-click and select New Interface from
the pop-up menu. Specify the model that you created above
(sasuser.myclasses.myInterface.intrface) for the interface and set
Status to Supports.
The Class Editor prompts you to add the method that you defined in the interface.
Click Yes.
4. In the Attributes node of the Class Editor, add an attribute named columnData and
assign it as a List type. Add an attribute named table and assign it as a Character
type. Add a third attribute named columnName and assign it as a Character type.
5. Select the attribute named contentsUpdatedAttributes, and then select
Override from the pop-up menu. Select the Initial Value cell, and then click the
ellipsis button (...) to edit the values. In the dialog box, select columnName and
table, and then click OK.
6. Save the class.
7. In the Methods node of the Class Editor, select the getColumnData method, and
then right-click and select Source from the pop-up menu. Add the following SCL
code to the entry named sasuser.myclasses.ColumnDataModel.scl that is
created for you:
useclass sasuser.myclasses.ColumnDataModel.class;
getColumnData: public method
return=list;
dcl num rc dsid levels;
/* reset the existing items attribute */
rc=clearlist(columnData);
/* open the SAS table specified in the table attribute */
dsid = open (table);
if dsid ne 0 then do; /* process if table exists */
if varnum (dsid, columnName) > 0 then do;
levels=0;
rc=lvarlevel(dsid,columnName,levels,columnData);
rc=revlist(columnDataModel);
end;
end;
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rc=close(dsid);
return(columnData);
endmethod;
enduseclass;
Compile and save the SCL code, and then close the Source window and return to the
Class Editor.
8. Close the Class Editor.
Next, you can create a subclass of the list box control that requires the MyInterface
interface that you created:
1. Use the Class Editor to create a subclass of the List Box control
(sashelp.classes.listbox_c.class). Name your class My List Box.
2. Select the Interfaces node in the Class Editor tree and add a new interface. Specify
the sasuser.myclasses.myInterface.intrface interface.
3. Save the class as sasuser.myclasses.myListBox.class.
4. In the Methods node of the Class Editor, select the _onContentsUpdated method,
and then right-click and select Override from the pop-up menu. Select the
_setcamModel method, and then right-click and select Override from the pop-up
menu. Right-click and select New Method from the pop-up menu, and then add a
method named getModelData. Right-click and select Source from the pop-up menu
to add the following SCL code, which implements all three methods:
useclass sasuser.myclasses.myListBox.class;
getModelData: public method;
/* This method retrieves the data from the model.
/* modelID is an attribute inherited from Object
/* that contains the identifier of the model when
/* the viewer's model attribute is set.
items=modelID.getColumnData();
endmethod;
*/
*/
*/
*/
onContentsUpdated: public method
colItems:char;
getModelData();
endmethod;
setcamModel: protected method
attributeValue:update:char
return=num;
_super(attributeValue);
getModelData();
endmethod;
enduseclass;
Compile the SCL and save the entry.
5. Close the Class Editor.
Once the model is complete, you can create a frame and test the model with a control
that requires the same interface:
1. Create a new frame.
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139
2. Add your new model and the list box subclass to the Components window by
selecting Add Classes from its pop-up menu. Select or enter
sasuser.myclasses.ColumnDataModel.class and
sasuser.myclasses.myListBox.class.
The Column Data Model and My List Box classes appear in the Components
window.
3. Drag a My List Box onto the frame, and then drag and drop a Column Data Model
component onto the list box to establish a model/view relationship.
Note that the list box is not populated until you set the table and columnName
attributes on the model. Use the Properties window to set columnDataModel1's
table attribute to a valid SAS table such as sashelp.prdsale. Set
columnDataModel1's columnName attribute to a valid column name in the table.
For example, Region is a column in the sashelp.prdsale table.
Enabling Drag and Drop Functionality
Introduction
You can add drag and drop functionality to your components. Drag and drop is a user
interface action that involves dragging components or objects using a pointing device
and dropping them over other objects on the frame, which results in some action. For
example, a text entry control that contains the name of a SAS table could be dragged
onto a data table component and then dropped to display the contents of the SAS table in
the data table. Drag and drop also works between objects on different frames.
Components that can be dragged are called drag sites, and components that can receive a
dropped object are called drop sites. When an object is dropped, data is passed to the
drop site and an action occurs. The action is determined by:
•
the form in which the data is passed, called the data representation
•
the type of drop operation
The data representation is the form of data that a drag site is capable of transferring and a
drop site is capable receiving. The data can be as simple as a string of text or as complex
as an SCL list. SAS/AF components that are based on the SAS Component Object
Model (SCOM) use
characterData
a generic representation to indicate when a character string is passed as the data
numericData
a generic representation to indicate when numeric values are passed as the data
Legacy objects support three default data representations, all of which provide data in a
character string:
•
_DND_TEXT for text
•
_DND_FILE for an external file
•
_DND_DATASET for a SAS table
Additional data representations enable you to drag items from the SAS Explorer and to
drop them onto a frame. These representations include
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•
EXPLORER_DATASET_NAME for SAS tables. The data is provided in a character
string that contains the two-level SAS table name, such as sasuser.fitness.
•
EXPLORER_CATALOG_NAME for SAS catalogs. The data is provided in a
character string that contains the two-level SAS catalog name, such as
sashelp.classes.
•
EXPLORER_ENTRY_NAME for a specific catalog entry. When the selection
includes a single entry, the data is provided in a character string that contains the
four-level entry name, such as work.a.a.scl. When the selection includes two or
more entries, the data is provided in a list in which each item is a character string that
contains the four-level entry name.
•
EXPLORER_MEMBER_NAME for multiple selections from a SAS library. When
the selection includes a single entry, the data is provided in a character string that
contains a two-level member name for catalogs or a three-level member name for
SAS tables (including those of type VIEW). When the selection includes two or
more members, the data is provided in a list in which each item is a character string.
Note that multiple selections of SAS tables or SAS catalogs are sent in an
EXPLORER_MEMBER_NAME data representation.
If you create a component based on SCOM architecture, you can define your own data
representations if characterData and numericData do not meet your needs.
A data representation is essentially a “verbal contract” between two components. As a
component developer, you must name the data representation. For example, the
characterData representation states that whatever component uses this as its drag
representation, the drag site will send a valid character value as the data. The drop site
then expects to receive a character value and can react accordingly.
It is recommended that component developers fully document their data representations
so that other developers can know how to use them. See “How the Drag and Drop
Component Works” on page 144 for more information about the data representation.
Drop operations define actions that are performed on the data representation:
Copy
Data is provided with no post-processing.
Link
Some mechanism synchronizes the source and destination.
Move
Data is provided and the source is removed.
Copy is the default.
Drag and drop operations in SAS/AF software have the following limitations:
•
You cannot drag objects outside the SAS environment.
•
Slider and scroll bar components do not support drag and drop operations.
•
The behavior of drag and drop operations may vary according to the host
environment.
What Happens during a Drag and Drop Action
SAS/AF software performs several operations to enable drag and drop functionality
between two components. When the object is instantiated, SAS/AF checks to see
whether the object's dragEnabled or dropEnabled attributes are set to “Yes.” If
either of these attribute values is “Yes”, then:
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1. the object is queried for its respective dragInfo or dropInfo attribute values.
•
For drag sites, SAS/AF reads the value or values of the dragInfo attribute's
dataRepresentation and invokes the _addDragRep method to register each drag
data representation that is supported by the object.
•
For drop sites, SAS/AF reads the value or values of the dropInfo attribute's
dataRepresentation and invokes the _addDropRep method to register each drop
data representation that is supported by the object.
2. the object is queried for its dragOperations and/or dropOperations settings.
•
For drag sites, the _addDragOp method is invoked to register the supported drag
operations for the object.
•
For drop sites, the _addDropOp method is invoked to register the supported drop
operations for the object.
SAS/AF permits a drop action to occur between two objects only when the two objects
have a shared data representation and a shared operation. For example, consider an
object named listbox1 that is enabled as a drag site using the characterData
representation. A second object named listbox2 is enabled as a drop site using the
characterData representation. A user can successfully complete a drag and drop action
between the two objects if they share a common operation such as “Copy.” Objects that
do not have a matching data representation and a matching operation will not permit a
drop action to occur.
When a valid drag and drop action occurs between two objects, SAS/AF takes the value
of an attribute on the drag site and sets it as the value of another attribute on the drop
site. Several methods are invoked automatically, passing an instance of
sashelp.classes.DragAndDrop.class:
1. The _startDrag method is invoked on the drag site. An instance of the Drag and Drop
component is created.
2. The _respondToDragOnto method is invoked on a drop site as the cursor passes over
a valid drop site.
3. The _respondToDragOff method is invoked on a drop site as the cursor moves off of
a valid drop site.
4. The _getDragData method is invoked on the drag site after the user has released the
drag item on a valid drop site. The implementation of this method prepares the data
that is passed between the drag site and the drop site. It also sets the values of the
appropriate attributes (including attributeName and attributeValue) on an
instance of the Drag and Drop component before passing the object. The default
implementation of _getDragData
•
determines whether an attributeName is defined for the associated dragInfo
data representation that was selected for the drop
•
retrieves the current value of the named attribute and sets its name on the drag
and drop object's attributeName attribute
•
retrieves the current value for that attribute and sets the value of the drag and
drop object's attributeValue attribute
If no attributeName is specified as part of the dragInfo data representation, then
you can override the _getDragData method to set the value of the drag and drop
object's attributeValue attribute.
5. The _validateDropData method is invoked on the drop site to perform any validation
that may be required.
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6. The _completeDrag method is invoked on the drag site to complete any processing.
7. The _drop method is invoked on the drop site. The default implementation of the
_drop method
•
retrieves the attributeName from the drop site's dropInfo attribute based on
the selected data representation
•
sets the value of the attribute identified in attributeName using the
attributeValue that was passed in the drag and drop object
If no attributeName exists on the drop site, you can override the _drop method
and implement the desired drop behavior.
Adding Drag and Drop Functionality to Your Components
Defining Drag and Drop Properties
For most of your applications, you will likely find it sufficient to implement drag and
drop functionality simply by setting attribute values.
You can define drag and drop properties for any component that is a subclass of the
Widget class or the Frame class. To implement drag and drop, you define the drag
properties of the component that you designate as a drag site, as well as the drop
properties of another component that you want to behave as a drop site. A component
can act as both a drag site and a drop site.
The following attributes must be defined for drag sites. You might want to review these
attribute settings if you encounter problems with a drag site, or if you want more
information on a drag site's behavior.
dragEnabled
sets the state that determines whether the object can be dragged when selected. In
many cases, setting this attribute to “Yes” is all that is needed to implement a drag
site that uses default values for dragInfo and dragOperations.
dragInfo
sets the information that defines what information is transferred from the object. The
dragInfo attribute is a list that includes a named item for each drag representation:
•
the dataRepresentation, which is a name that describes the type of data that a
drag site is capable of transferring. The data can be as simple as a string of text or
as complex as an SCL list.
•
the attributeName, which is the name of the attribute whose value is passed to the
drop site. (The drop site value is specified in the dropInfo attribute.)
A component becomes a drag site when its data representation is defined. More than
one data representation can be defined for the drag site. When a component is
dropped onto another component, the system checks through the list of
representations for each component and chooses the first matching representation.
This matching representation enables the drag site to format the data in the required
representation. The drop site is then given its data, which it processes accordingly.
dragOperations
enables the object to indicate the action that occurs following the drag: Copy, Move,
and/or Link. By default, an object allows the COPY action.
The following attributes must be defined for drop sites. You might want to review these
attribute settings if you encounter problems with a drop site, or want more information
on a drop site's behavior.
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143
dropEnabled
sets the state that determines whether the control can serve as a drop site. In many
cases, setting this attribute to Yes is all that is needed to implement a drop site using
default values for dropInfo and dropOperations.
dropInfo
sets the information that defines what information is transferred to the object. The
dropInfo attribute is a list that includes a named item for each drop representation:
•
the attributeName, which is the name of the attribute whose value is set by the
value of attributeName in the dragInfo attribute. (The _setAttributeValue
method is called on the drop site's attribute, using the value of the attribute
specified in the dragInfo attribute.)
•
the dataRepresentation, which is a name that describes the type of data that a
drop site is capable of receiving. The data can be as simple as a string of text or
as complex as an SCL list. It is compared to the drag site's dataRepresentation. If
a match exists, the drop action occurs.
More than one data representation can be defined. The last representation defined
is given the highest priority.
dropOperations
defines the drag actions that the drop site can handle: Copy, Move, and/or Link. By
default, an object allows the Copy action. In addition to the drag actions, you can
specify the associated method that runs when the drop occurs, as well as the pop-up
menu text that is displayed for non-default drag and drop processing.
Overriding Drag and Drop Methods
SAS/AF software implements the drag and drop process by automatically executing
several methods. Although you can override these methods to add functionality, you
cannot directly call them from an SCL program.
Table 14.1
Drag and Drop Methods to Overrride
Override this
method...
To...
_startDrag
change the appearance or other state of the drag site when the drag
begins. The code that you add runs when the user begins dragging
from the drag site.
_respondToDragOnto
change the appearance or other state of the drop site as the dragged
item passes over it. For example, you could change the drop site's
color to indicate that a drop action is valid.
_respondToDragOff
change the appearance or other state of the drop site as the dragged
item moves off of the drop site. For example, you could change the
drop site back to its normal appearance if it was changed by
_respondToDragOnto.
_getDragData
prepare the data that you want to pass to the drop site by setting
attributes of the drag and drop object that is passed between all drag
and drop methods.
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Override this
method...
To...
_validateDropData
perform any validation that you require before the drop action occurs.
For example, you can verify the range of data that is passed and then
set the completeDrag attribute of the drag and drop object to either
“Yes” or “No” to indicate whether the drop can occur. If
completeDrag is set to “No,” then the drop is cancelled, the _drop
method does not run, and no attribute values are set on the drop site.
_completeDrag
complete processing on the drag site. For example, consider two list
boxes on a frame that have the same data representation and a “Move”
operation. When the item is dragged from the first list box and
dropped onto the second, the “Move” operation indicates that the item
should be removed from the first list box. You can override
_completeDrag to implement the “Move” operation and delete the
item from the drag site.
Note: The _completeDrag method runs even if the drag and drop
object's completeDrag attribute is set to “No.” If necessary, check the
value of this attribute before executing the code.
_drop
process the drop action. This method executes only if the
completeDrag attribute of the drag and drop object is set to “Yes.”
Typically, you override this method to perform some action other than
setting the appropriate attribute value on the drop site. For example,
you may want to display a message box that confirms the success of
the drag and drop action.
How the Drag and Drop Component Works
All drag and drop methods contain signatures that accept an object as their only
argument. This object is an instance of the Drag and Drop Component (that is,
sashelp.classes.DragAndDrop.class). It provides a container for the standard
drag and drop information that is passed between a drag site and a drop site. The
information is stored in the following attributes of the Drag and Drop component:
attributeName
is the name of the attribute that is passed from the drag site to the drop site.
attributeValue
is the value of the attribute that is passed from the drag site. This attribute is a
complex attribute whose type is sashelp.classes.type.class, which
contains the following attributes:
type
represents the type of the attribute value (Character, Numeric,
List, Object). Based on the value of type, you can query the
appropriate “value” attribute.
characterValue
stores the character value if type is “Character.”
listValue
stores the SCL list if type is “List.”
numericValue
stores the numeric value if type is “Numeric.”
objectValue
stores the object identifier if type is “Object.”
For example, your method override could contain code as follows:
drop: public method
dndObj:input:object;
Enabling Drag and Drop Functionality
if dndObj.attributeValue.type = 'Character' then
do;
/* Retrieve dndObj.attributeValue.characterValue,
/* then add any other code.
end;
else if dndObj.attributeValue.type = 'Numeric' then
do;
/* Retrieve dndObj.attributeValue.numericValue,
/* then add any other code.
end;
/* and so forth... */
endmethod;
145
*/
*/
*/
*/
completeDrag
is a character attribute that you can optionally set to indicate whether a drop can
successfully occur. For example, you can perform validation in an override of the
_validateDropData method, and you can cancel the drop action by setting this
attribute to “No”. You can also query this value in an override of the _completeDrag
method to verify whether the drop will actually occur before performing some action
on the drag site.
dataOperation
is the selected drag operation; corresponds to one of the operations specified in the
dragOperations attribute that is set on the drag site.
dataRepresentation
is the form of the data that is passed between sites; corresponds to the particular list
item in the dragInfo attribute that is set on the drag site
dragSiteID
is the object identifier of the drag site
dragSiteLocation
indicates whether the drag started inside or outside of the current frame
XLocation
specifies the x location of the drag site or drop site
YLocation
specifies the y location of the drag site or drop site
For components that are based on the SCOM architecture, the data specified in the data
representation (such as characterData or EXPLORER_MEMBER_NAME) is stored in
the attributeValue complex attribute of the Drag and Drop component. If one item
is dragged, then the data is stored in the characterValue attribute of the
attributeValue object. If two or more items are dragged, then the data is stored in the
listValue attribute as separate character items.
For complete details on the Drag and Drop component, see “SAS/AF Component
Reference” in the SAS/AF online Help.
Drag and Drop Example
To demonstrate how drag and drop functionality works, consider an example that defines
two subclasses of the list box control. The first subclass defines an object that is a drag
site. The second defines an object that is a drop site. (Of course, it is entirely possible to
have a single object that is both a drag site and a drop site.)
To create the first list box subclass:
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1. Using the Class Editor, create a new class whose parent is
sashelp.classes.ListBox_c.class and whose description is Source
List Box.
2. Select the Attributes node, and then set the following values for attributes:
•
Select the dragEnabled attribute, and then right-click and select Override from
the pop-up menu. Set the Initial Value to Yes.
•
Select the dragOperations attribute, and then right-click and select Override
from the pop-up menu. Click the ellipsis (...) button in the Initial Value field. In
the dragOperations dialog box, deselect the Enabled check box for Default
Copy Operation and then select the Enabled check box for Default Move
Operation. Click OK to return to the Class Editor.
3. Save the class as sasuser.test.SourceListBox.class.
4. Select the Methods node, and then select the second _completeDrag method in the
list (with the O:SASHELP.CLASSES.DRAGANDDROP.CLASS signature). Rightclick and select Override from the pop-up menu, and then select Source from the
pop-up menu. Add the following SCL code to
sasuser.test.SourceListBox.scl:
USECLASS sasuser.test.SourceListBox.class;
/* Override of the _completeDrag method */
completeDrag: method dndobj:sashelp.classes.draganddrop.class;
dcl num rc;
/* If the rep is one that is not understood, call super. */
if ( upcase(dndobj.dataRepresentation) = 'CHARACTERDATA' ) then
do;
/* Check the status of the completeDrag attribute. */
if ( ( upcase(dndobj.completeDrag) = 'YES' ) AND
( upcase(dndobj.dataOperation) = 'MOVE' ) ) then
do;
/* Remove the selected item from the items list. */
if (selectedIndex ^= 0 ) then
do;
/* Delete the item from the items attribute. */
rc = delitem(items, selectedIndex );
/* Set the items attribute equal to itself to */
/* update this list box.
*/
items = items;
end;
end;
end;
else
_super( dndobj );
endmethod;
enduseclass;
5. Compile and save the code, and then close the Source window.
6. Close the Class Editor.
To create the second list box subclass:
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147
1. Using the Class Editor, create a new class whose parent is
sashelp.classes.ListBox_c.class and whose description is Target
List Box.
2. Select the Attributes node, and then set the following values for attributes:
•
Select the dropEnabled attribute, and then right-click and select Override from
the pop-up menu. Set the Initial Value to Yes.
•
Select the dropInfo attribute, and then right-click and select Override from the
pop-up menu. Click the ellipsis (...) button in the Value field. In the Drop Info
dialog box, click Add, and then set the Drop Attribute to a blank value and the
Drop Representation to CHARACTERDATA.
•
Select the dropOperations attribute, and then right-click and select Override
from the pop-up menu. Click the ellipsis (...) button in the Value field. In the
dropOperations dialog box, deselect the Enabled check box for Default Copy
Operation and then select the Enabled check box for Default Move Operation.
3. Save the class as sasuser.test.TargetListBox.class.
4. Select the Methods node, and then select the second _drop method in the list (with
the O:SASHELP.CLASSES.DRAGANDDROP.CLASS signature). Right-click and
select Override from the pop-up menu. Select the second _validateDropData method
in the list (with the O:SASHELP.CLASSES.DRAGANDDROP.CLASS signature).
Right-click and select Override from the pop-up menu, and then select Source from
the pop-up menu. Add the following SCL code to implement both methods in
sasuser.test.TargetListBox.scl:
USECLASS sasuser.test.TargetListBox.class;
/* Override of the _validateDropData method */
validateDropData: method dndobj:sashelp.classes.draganddrop.class;
/* If the rep is one that is not understood, call super. */
if ( upcase(dndobj.dataRepresentation) = 'CHARACTERDATA' ) then
do;
/* Ensure that the type is 'Character' and that the */
/* value is not blank. If either of these checks
*/
/* fail, then do not let the drop happen.
*/
if ( ( upcase(dndobj.attributeValue.type) ^= 'CHARACTER' ) OR
^length( dndobj.attributeValue.characterValue ) ) then
dndobj.completeDrag = 'No';
end;
else _super( dndobj );
endmethod;
/* Override of the _drop method */
drop: method dndobj:sashelp.classes.draganddrop.class;
dcl num rc;
/* If the rep is one that is not understood, call super. */
if ( upcase(dndobj.dataRepresentation) = 'CHARACTERDATA' ) then
do;
/* Ensure that the attributeValue is the correct type. */
/* If so, then insert it at the end of the items list. */
if ( upcase(dndobj.attributeValue.type) = 'CHARACTER' ) then
do;
dcl num rc;
rc = insertc( items,dndobj.attributeValue.characterValue, -1 );
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/* Set the items attribute equal to itself in order to */
/* update this list box.
*/
items = items;
end;
end;
else _super( dndobj );
endmethod;
enduseclass;
5. Compile and save the code, and then close the Source window.
6. Close the Class Editor.
You could then use two classes in a frame:
1. In the SAS Explorer, select File ð New then select a FRAME entry.
2. In the Components window, right-click and select Add Classes to add
sasuser.test.SourceListBox.class and
sasuser.test.TargetListBox.class. If the Components window is not
displayed when the new frame appears in the Build window, then select View ð
Components Window to display it.
3. Drag an instance of the Source List Box object and drop it onto the frame, and then
drag an instance of the Target List Box object and drop it onto the frame.
4. Select Build ð Test to test the frame. Drag an item from the source list box and drop
it onto the target list box.
In the Target List Box class, the _validateDropData method verifies that the data
representation is CHARACTERDATA. Its _drop method queries the
attributeValue attribute that is passed in the drag and drop object and adds the
value to its items attribute. Finally, the _completeDrag method on the Source List Box
verifies that a drop has successfully occurred by querying the completeDrag attribute
on the drag and drop object. It then removes the item from the list of items displayed in
the list box to complete the MOVE action.
Modifying or Adding Event Handling
Introduction
Events provide flexible, loosely coupled communication between objects. The SAS/AF
event model is implemented through global event registration, which means that
different components can listen to and provide handlers for events that are generated by
other objects in the current application, objects in any other SAS/AF application that is
also running, or the SAS session itself.
Events notify applications when a resource or state changes. Event handlers manage the
corresponding response to any changes. Events occur when a user action takes place
(such as a mouse click), when an attribute value is changed, or when a user-defined
condition occurs.
SAS/AF software supports system events, which can include user interface events (such
as mouse clicks) as well as “attributeName Changed” events that occur when an attribute
value is updated. For system events, the value of the State metadata item is “S.” For
“attributeName Changed” events, the component must have the SendEvent metadata
Modifying or Adding Event Handling
149
item for the attribute set to “Yes.” See “Enabling Attribute Linking” on page 130 for
details.
SAS/AF software includes a SAS Session component that provides access to changes
made within the SAS environment. For example, SAS sends a system event when a new
libref has been assigned or when a new catalog entry has been added. You can create an
instance of the SAS Session component and implement handler methods for the events
you want to process. For complete information on the SAS Session component, refer to
the SAS Session component topic in the SAS/AF online Help.
What Happens during Event Handling
The SAS/AF event model is straightforward: objects “listen” for events that are sent by
the system, by other objects, or by the object itself. If the object has an event handler that
is defined to perform some action, then that action occurs when the object receives
notification of the event.
Adding Events and Event Handlers to Your Components
SAS/AF software also supports user-defined events, which can be registered to specific
classes as needed and can be inherited by subclasses. You can use the Class Editor to
add user-defined events and event handlers for a class, or you can use the Properties
window to add events and event handlers for an instance of a class. For details on how to
work with events and event handlers, see “Adding an event,” “Adding an event handler,”
and “Working with events and event handlers in the Class Editor” in the SAS/AF online
Help.
You can also add events and event handlers programmatically. To do so, your SCL code
should use the _addEventHandler method to indicate that an object should be notified
when a certain event occurs and to specify which method should be invoked as the event
handler. You would also invoke the _sendEvent method on the appropriate object to
send the event and to run the event handling method that you specify in the
_addEventHandler call.
The methods that support event communication are part of the Object class. In addition
to _sendEvent and _addEventHandler, you can use _deleteEventHandler to indicate that
an object should no longer be notified of a particular event.
For more information about these methods, refer to the Object class in the SAS/AF
online Help.
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Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Managing Classes with Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Synchronizing Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Analyzing Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Merging Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Renaming Class Catalogs and Libraries in a Resource . . . . . . . . . . . . . . . . . . . . . 154
Making a New Class Available for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Associating Resources with FRAME Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Modifying the Components Key of the SAS Registry . . . . . . . . . . . . . . . . . . . . . . 156
Generating Class Documentation with GenDoc . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Tips for Writing Meaningful Metadata Descriptions . . . . . . . . . . . . . . . . . . . . . . . 157
What the GenDoc Utility Creates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Making Class Documentation Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Introduction
After you finish designing and implementing your components, you need to consider
how applications developers will use them. In many cases, it is helpful to create specific
class libraries for your organization or for a specific project. SAS/AF software uses
RESOURCE entries to organize and manage classes.
In general, you can follow these steps to make your components available to other
developers:
1. Create a RESOURCE entry to group your components together, based on how
developers will use them. See “Managing Classes with Resources” on page 152.
2. Move classes from your component development and testing location to the library
and catalog that are being used for applications development. Update the SCL source
as necessary. See “Renaming Class Catalogs and Libraries in a Resource” on page
154.
3. Instruct applications developers to add the resource that contains your components to
the Components Window. See “Making a New Class Available for Use” on page
154.
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4. (Optional) Use the experimental GenDoc utility to generate documentation for your
components. Copy the documentation files to the appropriate directory, and instruct
your component users to update their HELPLOC system option to include a path to
this directory. See “Generating Class Documentation with GenDoc” on page 156.
Managing Classes with Resources
Introduction
A RESOURCE entry, or simply resource, stores information about a set of classes. This
information controls the classes that can be instantiated by a frame when that frame is
initialized. Therefore, when you browse, edit, or execute a frame, it must be able to
access the RESOURCE entry that was used when the frame was created.
SAS/AF software also uses resources to load classes efficiently. When a resource is
loaded with a frame, SAS performs a single catalog I/O operation to load all appropriate
class information into memory. If you were to instantiate each class at run time using
separate LOADCLASS or _NEW_ functions, SAS would perform a catalog I/O
operation for every class.
The SAS/AF classes are stored in sashelp.fsp.AFComponents.resource, and
the SAS/AF legacy classes are stored in sashelp.fsp.build.resource.
Organizing and manipulating resources and the classes that they contain is an important
part of project management. You can create custom RESOURCE entries to
•
make your components available for use in a specific project or application
•
make your components available to specific groups of developers
•
arrange related classes in a manner that makes sense for your needs
•
reduce the number of classes that a frame is required to load by removing classes that
you know are not needed
Multiple resources help you maintain and organize class libraries for development in
SAS/AF software. For example, you could use the RESOURCE entry containing the
standard classes provided by SAS (sashelp.fsp.AFComponents.resource), the
resource containing SAS legacy classes (sashelp.fsp.build.resource), a
resource entry containing classes that were developed for a particular project, and a
resource containing classes that you are developing. When you are ready to deploy the
components, however, you could create a single resource that contains only those classes
used by the application.
You can use the Resource Editor to create, organize, and manipulate resources, as well
as the classes that the resources contain. The Resource Editor is invoked when you open
an existing RESOURCE entry or when you create a new RESOURCE entry.
You can also use the Resource Editor to specify which classes in a resource you want to
display when the resource is displayed in the Components window. You can select a
class and toggle its display status by selecting the Toggle Display Status check box.
Although the resource should contain all classes that the application will use, only those
components that can be dropped onto a frame should be set to display. For more
information about resources and the Components window, see “Associating Resources
with FRAME Entries” on page 155.
Managing Classes with Resources
153
For complete information about working with the Resource Editor, see the SAS/AF
online Help.
Synchronizing Resources
Each RESOURCE entry contains a complete, static copy of its classes, which means that
a resource does not reread the underlying class information as it loads them. To update
information in a resource when you change one of its classes, you must synchronize the
RESOURCE entry. Synchronizing a resource requires the class metadata of the original
classes, updating the version of the class that is stored within the resource. You must
synchronize a resource whenever you change a class name, location, or description, or
whenever you change property metadata information that is stored in a CLASS entry,
such as an attribute's valid values or the location of SCL method code. You do not have
to synchronize a resource if you modify the SCL code of methods on a class.
For example, suppose you create a resource that includes a class named
mylib.myclasses.Demo.class and then save that resource and close the Resource
Editor. You then edit the class to add a method. After you save the class, you need to
synchronize the resource so that the changes you made to the class are included.
To synchronize a RESOURCE entry from within the Resource Editor, select Tools ð
Synchronize.
You can also edit a class directly from the Resource Editor, which enables you to
automatically synchronize the class and the resource after you commit the changes to the
CLASS entry. That is, if you edit a class from within the Resource Editor, you do not
have to synchronize the resource. To edit a class from within the Resource Editor,
selectEdit ð Edit Class or click the Edit toolbar button.
Analyzing Resources
The Resource Editor enables you to analyze a resource by displaying all of the classes
that the resource contains, their ancestors, and the search path that is needed to find the
classes. To analyze a resource in the Resource Editor, select Tools ð Analyze.
Here is a sample analysis of a simple resource as it appears in the SAS log:
Analysis of resource entry:
SASUSER.TESTCATALOG.TESTRES.RESOURCE
SASHELP.CLASSES.CHECKBOX_C.CLASS
Parent = SASHELP.CLASSES.AFCONTROL.CLASS
Parent = SASHELP.FSP.WIDGET.CLASS
Parent = SASHELP.FSP.OBJECT.CLASS
SASUSER.TESTCATALOG.NBUTTON.CLASS
Parent = SASHELP.CLASSES.PUSHBUTTON_C.CLASS
Parent = SASHELP.CLASSES.AFCONTROL.CLASS
Parent = SASHELP.FSP.WIDGET.CLASS
Parent = SASHELP.FSP.OBJECT.CLASS
Current search path is:
SASHELP.CLASSES
SASUSER.TESTCATALOG
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Merging Resources
The Resource Editor enables you to merge classes that are referenced by another
resource into the currently open resource. Merging several smaller resources into a
single, larger resource can help improve performance by reducing the catalog I/O that
SAS/AF performs. Note that the actual class information is merged, not the copy of the
class information in the merged resource.
To merge resources from within the Resource Editor, select Tools ð Merge Resource
and then select the resource that you want to merge.
Classes with identical aliases are not merged. An alias is a reference that is used by a
RESOURCE entry. It is created by concatenating the class name and its closest abstract
parent class. As a result, when resources reside in different libraries and/or catalogs and
two classes have the same name and type, the resulting aliases will be identical. If you
try to merge classes that have identical aliases, the class in the imported resource will not
be merged.
Renaming Class Catalogs and Libraries in a Resource
A resource must accurately reflect all CLASS entry information, as well as the library
and catalog in which the class is stored. If you move or copy the classes that are
referenced in a resource to another catalog or library, you will need to change the class
information in the resource to the new location. To rename the library and catalog
references for a resource using the Resource Editor, select Rename Libraries or
Rename Catalogs from the pop-up menu in the Resource Editor window.
You can use the Resource Editor not only to rename the library and catalog references
for its classes, but also to update the library and catalog references in all affected CLASS
entries. To apply the rename action to all classes in the resource, check the Apply
changes to class entries check box in the Rename Libraries or Rename Catalogs dialog
box.
Note: Applying renamed library and catalog references to classes via the Resource
Editor does not update any hardcoded object references or other library and catalog
names in the method SCL for a class. If you use SCL to create classes with the
CLASS/ENDCLASS syntax, the library and catalog names in the SCL also are not
affected by changes in the Resource Editor.
You can also use the CATNAME statement to logically combine one or more catalogs
by associating them with a catref (shortcut name). See “Step 2: Set Up the Development
Environment” on page 6 for more information.
Making a New Class Available for Use
Introduction
After a class has been created and is ready to be used on a frame for testing or
production, you can make it available for use from the Components window. The
Components window loads resources and individual classes that can be added to a frame
at design time. All classes in a resource that are set to “Display” (via the Toggle Display
Status check box in the Resource Editor) are shown in the Components window,
including
Making a New Class Available for Use
•
all visual controls and subclasses of visual controls
•
non-visual components that work in conjunction with visuals, such as models
•
legacy objects that are subclasses of sashelp.fsp.Widget.class
155
Components that are designed to be instantiated at run time should be included in a
resource, but you do not have to consider their use in the Components window.
Developers can use the _NEW_ operator in their SCL code to add these components to
their applications.
Associating Resources with FRAME Entries
The applications developers who use your components to create frames must have
access to those components. You can make the components available for drag and drop
operations from the Components window, or developers can explicitly associate a
resource with a frame.
You can control the contents of the Components window that appears in the build
environment in any of the following ways:
•
Add individual classes to the Components window to test those classes. To add an
individual class to the Components window, select Add Classes from the pop-up
menu inside the Components window.
•
Add classes to a resource, and then add that resource to the Components window to
organize several classes. This process is recommended for deploying most
components. To add a resource to the Components window, select Add Resources
from the pop-up menu inside the Components window.
•
Add classes or resources to the Components key of the SAS Registry to change the
default contents of the Components window. See “Modifying the Components Key
of the SAS Registry” on page 156 for details.
The Components window displays any classes and resources that are defined in the
Components key of the SAS Registry. Resources that are used by any open FRAME
entries are also temporarily added to the Components window while those frames are
open. The default resource settings include
sashelp.fsp.AFComponents.resource and
sashelp.fsp.build.resource.
When you open a frame, the Components window displays the resource that was used to
create the frame. Classes that are used by the frame and are not contained in the resource
are loaded individually by the frame but do not necessarily appear in the Components
window.
The resource that was used when the frame was created is stored with the FRAME entry.
By default, a new frame uses the resource specified in the Resource value of the
Products\AF\Design Time\Frame key. You can explicitly change the active
resource for the current frame from the default frame resource in either of the following
ways:
•
Enter the RESOURCE resource-name command.
•
Include a RESOURCE=resource-name option as part of the BUILD command. For
example:
build work.a.a.frame resource=sashelp.fsp.afcomponents.resource
To see which resource is used by the current frame, you can enter the RESOURCE
command without a specified resource. The active resource is displayed on the SAS
status bar.
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Modifying the Components Key of the SAS Registry
The SAS Registry contains a key that stores the settings for the Components window.
The values defined in this key specify the resources and/or classes that are displayed
when the Components window is opened. You can add values to this key or modify
existing values on the key to change the default setting.
To change the Components key:
1. Enter the REGEDIT command to open the SAS Registry.
2. Expand the registry to view Products\AF\Design Time\Component Window
\Components.
3. Select New String from the pop-up menu to add a new value, or select the name of
the value you want to modify and then select Modify from the pop-up menu.
4. Enter the changes for Value Data as required. (The value of Value Name is not
significant.) Click OK.
5. Exit from the SAS Registry.
For more information on the SAS Registry, see “Working with SAS/AF Keys in the SAS
Registry” on page 197 .
Generating Class Documentation with GenDoc
Introduction
SAS/AF software includes GenDoc, an experimental documentation utility that enables
you to generate HTML files that document class, interface, resource, and frame entries.
The generated HTML files can be viewed with most Web browsers. You can use the
documentation produced by the GenDoc utility to provide assistance to developers who
use the components that you develop.
You can start the GenDoc utility in any of the following ways:
•
In the Class Editor, select File ð Save As HTML.
•
In the Interface Editor, select File ð Save As HTML.
•
In the Resource Editor, select File ð Save As HTML.
•
In the Build window while editing a frame, select File ð Save As HTML.
•
At the command prompt, enter
afa c=sashelp.aftools.scl2html.frame
You can use the interface to select the entry and entry type you want to document.
•
Use the experimental SCL function CreateDoc:
CreateDoc('catalog-entry-name', 'output-directory');
where catalog-entry-name is the name of the class, interface, frame, resource, or
catalog you want to document, and output-directory is the local directory to which
you want to direct the HTML output.
Generating Class Documentation with GenDoc
•
157
Use the SCL Static Analyzer and add the HTMLDIR= option to the CROSSREF
statement. In the following example, output-directory is the local directory to which
you want to direct the HTML output:
proc build batch;
crossref proj=lib.cat HTMLDIR='output-directory';
run;
Tips for Writing Meaningful Metadata Descriptions
Because GenDoc reads the metadata that is associated with a class or interface, the
quality and usefulness of the generated documentation depends on how much
information you provided in your class or interface definitions. Complete and accurate
descriptions of metadata items also make class maintenance and debugging easier, and
they aid other developers who use your classes.
Before you use the GenDoc utility to generate documentation, be sure to include values
for the Description metadata items in the following properties and/or property elements:
Attributes
In your description, include a clause that begins “Returns or sets...”. Since the
elements describe things rather than actions or behaviors, it is also appropriate to
omit a subject and verb and to simply use a noun phrase. For example, instead of
“This attribute is a button label”, you could use “A button label”.
Methods
Since methods implement an operation, they usually use a verb phrase. While this
may make methods “self-documenting,” you should try to extend this action with
additional detail. Method descriptions typically begin with a verb such as “Deletes,”
“Updates,” “Sets,” or “Returns.”
Method Arguments
Provide a description that begins with “Specifies” (when INOUT is “Input” or
“Update”) or “Returns” (when INOUT is “Output” or “Return”), depending on how
the argument is used in the method.
Method Return Argument
Provide a description that starts with “Returns.” Descriptive text that you supply for
method return arguments appears only in documents that are generated by the
GenDoc utility.
Events
Provide a description that indicates when or how the event occurs, such as “Occurs
when ...”. “Attribute changed” events are automatically included for each attribute
you add. These events are assigned a description in the form “Occurs when the ___
attribute is changed.”
Event Handlers
Provide a description that indicates how the event handler performs. Since event
handlers respond to events, most event handlers use the form “Executes when the
___ event occurs.”
You may also consider these additional style guidelines:
•
Use phrases instead of complete sentences for property descriptions.
•
Use third person declarative rather than second person imperative. For example, a
description should read “Gets the label” instead of “Get the label.”
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What the GenDoc Utility Creates
By default, the GenDoc utility stores the HTML files that it creates in the directory that
includes a classdoc subdirectory in the HELPLOC option. The HELPLOC option is a
SAS system option that is defined or set in the SAS configuration file or in an
AUTOEXEC file. You can also edit the HELPLOC option for the current SAS session
by selecting Tools ð Options ð System. You can then expand the Environment
control and Help nodes to modify the HELPLOC option.
The HELPLOC option should include at least two directory paths if you want to provide
component documentation. One directory path identifies the online Help files that are
shipped with SAS software. For example:
!sasroot\core\help
The second path must end with a directory named classdoc. For example:
d:\My SAS Files\classdoc
SAS must be able to write to this directory in order for GenDoc to create HTML files.
Since you cannot have two classes with the same name within a catalog, the GenDoc
utility creates a subdirectory for the library and catalog under the classdoc directory
that is listed in the HELPLOC option. The first subdirectory specifies the library. A
second directory is created under the library directory and is named for the catalog
containing the element that you want documented. For example, if you generated
documentation for sasuser.myclasses.SalesObject.class, GenDoc creates
the directory /sasuser/myclasses under classdoc.
The following list describes the types of information generated by GenDoc and the
filenames of the resulting HTML documents:
Table 15.1
GenDoc File Output
Documentation for...
Contains...
Class Entry
parent or ancestor information and all properties (attributes, methods,
events, event handlers, and supported or required interfaces) defined
for the class.
HTML file: classname.htm
Interface Entry
parent or ancestor information and all methods defined for the
interface.
HTML file: interfacename-intrface.htm
Resource Entry
all class entries and interface entries included in the resource.
HTML files: resourcename-resource.htm, plus an HTML
file for each class and interface in the resource
Frame Entry
frame information and general attributes, the associated resource, and
instance information for all visual and nonvisual components on the
frame.
HTML file: framename-frame.htm
Generating Class Documentation with GenDoc
Documentation for...
Contains...
Catalog
all class, interface, and frame entries stored in the catalog.
159
HTML files: catalogname-index.htm, plus an HTML file for
each class, interface, and frame entry stored in the catalog
For example, if HELPLOC is set to d:\My SAS Files\classdoc and you generate
documentation for sasuser.myclasses.SalesObject.class, the following
HTML file is created:
d:\My SAS Files\classdoc\sasuser\myclasses\SalesObject.htm
You can edit the HTML files to add other information, such as a complete description of
a component.
GenDoc creates an index file that contains links to other files when you generate
documentation for a resource or catalog. However, you can create your own HTML file
to use an index if you want a more customized collection. To document a project or
application, you can also create an HTML file that contains links to all of the necessary
documents, or to the documentation for the catalogs and/or resources that are used by the
project.
Making Class Documentation Available
After you have used GenDoc to create documentation for your components, you can
make that documentation available to users of your components. Instruct your
component users to include a path in their HELPLOC system option to the classdoc
directory where you generated the class documentation. Depending on your system
environment, you may have to copy the files to a new location that is accessible to all
appropriate users.
After they set their HELPLOC options, they can access the generated documentation
through the Class Editor, Properties window, Components window, and Class Browser
in the same manner that help is displayed for SAS classes. For example, if you make
documentation available for myorg.classes.SalesObject.class and the class
has been included in a RESOURCE entry that is displayed in the Components window, a
user can select the class in the Components window and then select Help on Class from
the pop-up menu to display the documentation in a Web browser.
Of course, you can simply copy the generated HTML files to an accessible location on a
Web server to make the class documentation available to any developer at any time,
regardless of whether SAS is running. If you copy the HTML files, be sure to preserve
the directory structure that GenDoc creates for the library-name and catalog-name that
are associated with the class, interface, or resource. Unless this location is defined in a
developer's HELPLOC option, the interactive help features will not work.
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Part 4
Appendixes
Appendix 1
Flow of Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Appendix 2
Adding Attachments to Frame Controls . . . . . . . . . . . . . . . . . . . . . . . . . 179
Appendix 3
Working with SAS/AF Keys in the SAS Registry . . . . . . . . . . . . . . . . . 197
162
163
Appendix 1
Flow of Control
How SCL Programs Execute for FRAME Entries . . . . . . . . . . . . . . . . . . . . . . . . . 163
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Processing the INIT Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Processing Labeled Sections for Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Processing the MAIN Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
Processing the TERM Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Automatic Termination of SCL Objects When an Application Ends . . . . . . . . . . . 167
Flow of Control for Frame SCL Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
FRAME Entries and Automatic Methods at Build Time . . . . . . . . . . . . . . . . . . . . 169
Build-Time Order of Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
FRAME Entries and Automatic Methods at Run Time . . . . . . . . . . . . . . . . . . . . . 172
Run-Time Order of Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Changing Frame Components and Frame SCL Programs . . . . . . . . . . . . . . . . . . . 177
How SCL Programs Execute for FRAME Entries
Introduction
SCL programs for FRAME entries use code sections that are named with reserved labels
to process the phases of program initialization (INIT), main processing (MAIN), and
termination (TERM).
Processing the INIT Section
Statements in the INIT section typically perform actions such as
•
initializing variables
•
importing values through macro variables
•
displaying initial messages on the window's message line
•
opening SAS tables and external files that are used by the entry
•
processing parameter values that are passed to the FRAME entry
By default, INIT executes only once, before the entry's window opens, for each
invocation of a FRAME.
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Processing Labeled Sections for Components
Introduction
Sections of frame SCL programs that are named with object labels execute when an
action is performed on the component, such as selecting the component or changing its
value. The CONTROL LABEL statement in SCL controls the execution of labeled
sections. CONTROL LABEL is on by default for FRAME entries, making it easier to
create labeled statement sections to execute when you perform an action on a
component. For details on the CONTROL LABEL statement, see the SAS Component
Language: Reference and the _setControl method of the Frame class in the SAS/AF
online Help.
Order of Processing for Multiple Window Components
When a frame needs to process more than one component, a predefined order (known as
the window order) controls the processing order. The window order starts from the top
row of the window and moves to the bottom row. Additionally, window order moves
from left to right in each row.
However, if one component (such as a container box) contains other components, then
all the contained components are processed as a group before other components on the
right are processed.
Some hosts and display devices also honor the window order when you use the TAB key
to move the cursor between fields. See “Setting the Tab Order” in the SAS/AF online
Help for more information.
Note: There is an exception to the window order. When the _preTerm,_postInit, and
_refresh methods are run, all extended tables in the frame are processed before any
other components.
Example: Order of Processing for Multiple Window Components
Consider the following FRAME entry:
How SCL Programs Execute for FRAME Entries
165
The order of processing for this window is FIELD1, FIELD2, FIELD3, FIELD4,
FIELD5, FIELD6, BOX, FIELD7, FIELD8, FIELD9, FIELD10, TABLE, FIELD11,
FIELD12, FIELD13, and FIELD14.
Note carefully the order of processing components in the container box labeled Box and
the extended table labeled Table, as well as the fields within them. For example,
FIELD10 is not processed until after FIELD7, FIELD8, and FIELD9 are processed
because they are contained in Box, which appears before FIELD10. Also, FIELD11 and
FIELD12 are processed before FIELD13 because they are contained in Table, which
starts in the row above FIELD13.
Processing the MAIN Section
Introduction
Statements in the MAIN section typically perform actions such as:
•
validating field values
•
calculating values for computed variables that are based on user input
•
displaying selection lists that are developed through SCL functions
•
submitting Base SAS software code
•
invoking secondary windows
•
querying and executing commands that are issued by users
•
retrieving values from SAS tables or from external files
By default, MAIN executes each time the follows occurs:
•
a user presses ENTER or RETURN (or any function key) after modifying one or
more fields or text entry controls, provided that the modified fields contain valid
values. After you modify fields and press ENTER, all modified fields are checked to
verify that their values satisfy their attribute specifications. (However, the
required attribute is not checked until you attempt to end from the entry.)
•
you activate a control by modifying or selecting it.
Each of these actions first runs the labeled section that is associated with the object and
then runs MAIN. The new values of the window variables are then displayed in the
corresponding fields.
To override the default behavior of when MAIN executes, use the CONTROL statement
in SCL. (For details, see the SAS Component Language: Reference.)
Forcing MAIN to Execute
Although the default behavior is for MAIN to execute only when all field or component
values are valid, you can force MAIN to execute even when some fields or components
contain invalid values or when an application-specific command is issued. SCL provides
CONTROL ENTER, CONTROL ERROR, CONTROL ALLCMDS, and CONTROL
ALWAYS statements that cause the MAIN section to execute whenever you press
ENTER or RETURN, even if no fields are modified or if modified fields do not contain
valid values. If the FRAME entry contains no selectable or modifiable objects, then
MAIN cannot execute unless a CONTROL ENTER or CONTROL ALWAYS statement
is in effect.
To enable MAIN to execute even if a field is in error, you must specify CONTROL
ERROR or CONTROL ALWAYS. The _setControl method of the Frame class also
modifies how the FRAME entry processes errors and input events.
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• Flow of Control
See the SAS Component Language: Reference for information about CONTROL
statement options.
Handling Invalid Values in MAIN
If a modification to a text entry control introduces an attribute error, the labeled section
for that control does not execute. However, the labeled sections for other controls that
are also modified will execute.
If an attribute error is detected, MAIN does not execute. Instead, fields or controls that
contain invalid values are highlighted and an error message is displayed. The error
attributes that you specified determine what is flagged as an error. You can enable users
to correct an attribute error in the window. If the program contains CONTROL ERROR
and CONTROL LABEL, or if the _setControl method has put these statements into
effect, you can include statements in the labeled section that make a correction, as shown
in the following example:
INIT:
control error;
return;
TEXTENTRY1:
if error(textentry1) then do;
textentry1.text=.;
erroroff textentry1;
_msg_='Value was invalid. It has been reset.';
end;
return;
Processing the TERM Section
Introduction
Statements in the TERM section typically perform actions such as
•
updating and closing SAS tables and external files that were opened by the entry
•
exporting values of SCL variables to macro variables for later use
•
branching to another entry in the application by using the DISPLAY routine
•
submitting Base SAS software code for execution
•
deleting SCL lists or SCL objects that are created in the FRAME entry
TERM executes when you issue either an END command or a CANCEL command.
Processing an END Command
If you issue the END command,
•
The SCL system variable _STATUS_ is set to E.
•
Modified fields are checked for valid values.
•
Statements in the MAIN section execute if fields are modified and their values are
valid.
•
Required fields are checked to verify that they are not blank.
•
Any SCL statements in the TERM section execute.
•
The _term method runs for the frame and for all components.
How SCL Programs Execute for FRAME Entries
•
167
The window closes and control returns to the parent or calling entry.
Note: If any fields contain invalid values when MAIN executes, MAIN processing
highlights the errors and returns control to the application. In that case, TERM does
not execute.
If any empty fields have the required attribute, TERM does not execute. Instead, the
empty required fields are highlighted and an error message is displayed. You must
provide values for all required fields and issue the END command again before the
TERM section will execute.
After all these conditions are satisfied, the SCL statements in TERM execute. After the
TERM section executes, the window closes and the entry terminates. Control returns to
the SAS process that invoked the entry.
Processing a CANCEL Command
If you issue the CANCEL command,
•
The SCL system variable _STATUS_ is set to C.
•
No field validation is performed.
•
Sny SCL statements in the TERM section execute.
•
The _term method runs for the frame and for all components.
•
The window closes and control returns to the parent or calling entry.
Processing an ENDSAS, BYE, or System Closure Command
If you issue the ENDSAS or BYE command, or if you use the system closure menu
when the FRAME entry is running without the SAS Application Work Space (AWS),
then:
•
The SCL system variable _STATUS_ is set to ' ' (blank).
•
Statements in the TERM section do not run.
•
The _term method runs for the frame and for all components.
•
The window closes.
Note: The SAS AWS is the container window for SAS software.
Automatic Termination of SCL Objects When an Application Ends
Introduction
When an application ends, the software scans for any remaining SCL objects that have
not yet been deleted and sends a _term method to them. In most cases, this is completely
benign. In a few cases, it might indicate a defect in your application; that is, perhaps you
did not delete something that you should have, or perhaps your _term method omitted a
SUPER(_self_,'_term_');.
Sometimes an application cannot delete an object because it does not know whether the
object is still in use; the AUTOTERM feature deletes such objects by running the _term
method.
Using the AUTOTERM= Option to Control the AUTOTERM Feature
If the AUTOTERM feature causes problems in your application, you can disable it by
adding the AUTOTERM= option to your AF, AFA, or AFSYS command:
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• Flow of Control
AF C=lib.cat.member.name AUTOTERM=term-value
AFA C=lib.cat.member.name AUTOTERM=term-value
AFSYS AUTOTERM term-value
(You can use the AFSYS command once an application is running.) Values for termvalue are
ON
enables the AUTOTERM feature. AUTOTERM is on by default. Use this value to
enable the feature if it is turned off.
OFF
disables the AUTOTERM feature, which means that the software does not invoke
the _term method on objects when a task is terminated. This value makes the
AUTOTERM feature compatible with earlier releases of SAS/AF software.
VERBOSE
prints a note and dumps the object list of each object that still exists when a task is
terminated. This value works even if AUTOTERM is OFF; it serves as a debugging
aid to identify which objects still exist but whose _term method has not run.
NOVERBOSE
disables the VERBOSE option. NOVERBOSE is the default.
You cannot combine options in one string; use separate AUTOTERM= options on the
command line, or use separate AFSYS commands.
Using the VERBOSE Value to Help Debug Your Application
Use the VERBOSE value when you invoke your application or while the application is
running. With VERBOSE, the software displays a note about any object that still exists
at task termination, and it dumps the object list to the log before sending the _term
method. Without VERBOSE, _term is invoked and no note is displayed in the log. Using
VERBOSE as you develop your applications is helpful because it can highlight objects
that your application fails to delete.
In a few rare cases, you might begin to see program halts as your application completes.
These halts are often caused when one object is deleted and another object that
references it does not know that it has been deleted. For example, consider a class named
Manager that maintains a list of instances of Message File objects. The Manager class
has a _term method that unconditionally sends _term to each item in its list of Message
File objects:
term: private method;
dcl num i;
do i=1 to listlen(msgObjs);
dcl object msgObj;
msgObj=getitemn(msgObjs,i);
msgObj._term();
end;
_self_._super();
endmethod;
However, when a task ends, AUTOTERM may send _term to a Message File object
before running the Manager's _term, so the Manager's list becomes stale (that is, it
contains object identifiers of deleted Message File objects). The proper fix in this and
similar situations is to verify other dependent objects in the _term before sending
methods to them. (In this case, the Message File object is not aware of the Manager and
therefore cannot ask the Manager to remove the object identifier from the Manager's list
of Message File objects.)
Flow of Control for Frame SCL Entries
169
To determine whether a number is a valid list identifier, use
LISTLEN(number) > -1
Then, to determine whether a list identifier is an object identifier, use
HASATTR(listid, 'O')
(The 'O' is a letter O as in Object.) For example, the Manager's _term method is more
correctly implemented as follows:
term: private method;
dcl num i;
do i=1 to listlen(msgObjs);
dcl object msgObj;
msgObj=getitemn(msgObjs,i);
if listlen(msgObj) > -1 and hasattr(msgObj,'O') then
msgObj._term();
end;
_self_._super();
endmethod;
Note: As an alternative to the above solution, when _term is run on a Message File
object, the Message File object could send an event. The manager would then have a
handler for the event and could remove the object from its list.
Flow of Control for Frame SCL Entries
Introduction
There is a specific flow of control for frame SCL. In general, the INIT section runs
before the window opens, the MAIN section executes after a field is modified or a
component is selected, and the TERM section runs when the window closes. Because the
FRAME entry allows additional statements to run for components as well as for multiple
extended tables via SCL methods, there are additional points of interest in the flow of
control in FRAME entry programs.
After each SCL section runs, if the FRAME entry's status has been set to H (for Halt),
execution halts. You can set the status to H either by assigning the _STATUS_ variable
in the SCL or by calling the FRAME entry's _setStatus method. Likewise, a STOP
statement in the frame SCL program can halt the frame application, interrupting the
normal flow of control. However, in both of these cases, all _term methods execute.
FRAME Entries and Automatic Methods at Build Time
When you build a frame, an instance of a frame is created. When a frame or frame SCL
is used at build time, specific methods are automatically called. You can override these
automatic methods at build time, if necessary.
Although frames and frame SCL entries are typically executed at run time, there are
some cases where you might actually use an existing frame and its frame SCL entry at
build time. For example, you might have created a custom editor for use during the
development of other frames.
The following table provides information about automatic build time methods. For more
information about these methods, refer to the SAS/AF online Help.
170
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• Flow of Control
Table A1.1
Automatic Build-time Methods
Method
Class
Description
_bInit
Frame
a _bInit method that runs at build time when you open
the FRAME entry, first for the frame, and then for each
component. The Frame object and each component
must successfully execute this method (and its parent's
definition) to be usable.
_bInit
Object
initializes each object in the FRAME entry.
_bPostInit
Frame
performs postprocessing after the _bInit method for the
Frame object. Also runs the _bPostInit for all the
components; _bPostInit for non-visual components runs
first, followed by _bPostInit for visual components.
_bPostInit
Object
performs postprocessing on objects after the _bInit
method. You should override this method rather than
_bInit if your initialization code refers to any objects
besides _SELF_.
_bUpdate
Frame, Widget
updates the Frame object or widget with any values that
you might have changed in the Attributes window. For
your own GUI subclasses, you might need to override
this method to execute code after the user closes the
Attributes window.
This method is used only by legacy classes. Any object
that uses the Properties window or a custom Properties
window does not invoke this method.
_bTerm
Object
terminates the components in the FRAME entry at build
time. You only need to override this method for cleanup
purposes. For example, you might need to delete SCL
lists or non-visual components that you create during
_bInit or _bPostInit.
_bTerm
Frame
terminates the Frame object at build time. You only
need to override this Frame class method for cleanup
purposes. For example, you might need to delete SCL
lists or non-visual components that you create during
_bInit or _bPostInit.
Build-Time Order of Program Execution
The following figure illustrates the order in which the automatic methods are invoked at
build time and the circumstances under which they are invoked.
Flow of Control for Frame SCL Entries
Figure A1.1
171
Automatic Methods and Build-Time Order of Program Execution
Open FRAME
• Instantiate objects
• Run setCAMs for
non-default attributes
• Install system event
handlers
_binit for FRAME
_binit from all components
_bpostinit for FRAME
• Initialization after all
objects are created
• Synchronize links
_bpostinit for all components
If SAS V6
object selected
Objects
Attributes
ATTR
If SCOM
object selected
1
PW
2
Properties
Window
END or CANCEL
Close
CANCEL
_STATUS_ = 'C'
FRAME
is displayed
END
_STATUS_ = 'E'
_bupdate
for object
_bterm for FRAME
_bterm for
non-visual components
Delete objects
1 Issuing the ATTR command or
opening the Attributes window.
2 Issuing the PW command or
_bterm for all components
opening the Properties window.
Refer to the SAS/AF online Help for
more information.
Close FRAME
Note: Events are not sent during _bInit and _init, including attributeName changed
events sent by _setAttrValue as well as events sent by _sendEvent. The reasoning
behind this behavior is that it is impossible to know which objects exist when your
_init is running. Therefore, not all objects that are listening for your event will be
notified. You can not be sure that all objects exist until your _postInit runs.
172
Appendix 1
• Flow of Control
FRAME Entries and Automatic Methods at Run Time
When a frame or frame SCL executes at run time, specific methods are automatically
called. The following table provides information about automatic run-time methods. For
more information about these methods, refer to the SAS/AF online Help.
Table A1.2
Automatic Run-time Methods
Method
Class
Description
_init
Frame
initializes all components for the frame.
_init
Object
initializes the Frame object and all components.
_initLabel
Frame
runs the INIT section of the FRAME entry's SCL
program.
_postInit
Frame
performs additional processing for the Frame object
after _initLabel has run. Also runs the _postInit for all
components; non-visual components are run first,
followed by visual components.
_postInit
Object
performs additional processing on all widgets after the
INIT section has run.
_objectLabel
Widget
runs the object label section in the FRAME entry's SCL
program.
_select
Widget
responds to a user selection or modification.
_mainLabel
Frame
runs the MAIN section of the FRAME entry's SCL
program.
_refresh
Widget
redraws a widget without updating its data.
_preTerm
Frame
performs additional processing before _termLabel is
run.
_preTerm
Widget
performs additional processing before the TERM
section runs.
_termLabel
Frame
runs the TERM section of the FRAME entry's SCL
program.
_term
Frame
deletes the Frame object. Also runs the _term for nonvisual components. The _term for visual components
should have already run by this point. If this method
runs the _term for visual components, then a problem
exists with the visual components and a warning
message appears.
_term
Object
deletes an object and the SCL list that is used to
represent the object.
Flow of Control for Frame SCL Entries
173
Run-Time Order of Program Execution
The following figure illustrates the order in which the automatic methods are invoked at
run time and the circumstances under which they are invoked.
174
Appendix 1
Figure A1.2
• Flow of Control
Automatic Methods and Run-Time Order of Program Execution
Open Window
_init for FRAME
1
_init from all components
2
_initLabel for FRAME
Yes
User
Input
_STATUS_= 'H'
3
No
_postinit for FRAME
_postinit for all components
Attribute links synchronized
5A
4
FRAME
is displayed
9
9A
_objectLabel for widget
Process all user input
END or CANCEL
Yes
_STATUS_= 'H'
_preterm for all components
_preterm for FRAME
5B
Yes
_STATUS_= 'H'
5
No
_select for widget
No
Yes
Yes
No
_STATUS_= 'H'
_STATUS_= 'R'
Loop Complete
No
6
Yes
Any components
in error
9B
7
_termLabel for FRAME
9C
Yes
No
_STATUS_= 'H'
8
No
_term for all widgets
_term for FRAME
Yes
_mainLabel for FRAME
Yes
_STATUS_= 'R'
If errors
and not CONTROL
ALWAYS, CONTROL ENTER
or CONTROL
ALLCMDS
No
_refresh for all components
_term for all widgets not
already _term'd
Close Window
1
The _init methods for the FRAME entry and its components execute. The _init for
non-visual objects is run first, followed by the _init for visual objects. The _init for
visual objects follows a specific window order. See “Example: Order of Processing
for Multiple Window Components” on page 164 for more information.
Flow of Control for Frame SCL Entries
175
Event handlers are installed and drag and drop sites are also set up at this point.
2
The statements in the INIT section of the SCL program execute via the _initLabel
method.
3
The _postInit methods for the FRAME entry and its components execute. Any
attribute links are also synchronized at this point. That is, _getAttribute is invoked on
the source attribute (to access the attribute value), and then _setAttrValue is called
on the target attribute.
•
For extended tables that are being used as selection lists, the _setSelection
method executes for all components in the row.
•
The _getRowLabel method and the _getRow method run for each row of each
extended table until the table fills (or until the _endTable method is called, for
dynamic tables).
Note: Because an object cannot be initialized twice, the _init and _postInit methods
are not permitted after the object is initialized. After the first _init method is sent
to an object, any subsequent _init methods result in an SCL program halt. After
the first _postInit method is sent to an object, the FRAME entry will not send
additional _postInit methods, but instead sends _refresh methods.
4
When one of these conditions is met:
•
a field is modified
•
a component is selected
•
a command is issued and CONTROL ALWAYS, CONTROL ALLCMDS, or
CONTROL ENTER is in effect.
The following steps occur (these steps are not illustrated in the figure):
5
•
If the modified component is in an extended table that is being used as a selection
list, the _selectRow method executes.
•
If a field is modified, the field's informat is applied. If the value does not match
the informat, the field is flagged as being in error. If a field within an extended
table is modified, the corresponding row of the extended table is also marked as
modified.
•
If the modified field matches the informat, the field's _validate method is queued
to run. If the validation fails, the field is flagged as being in error.
•
The _objectLabel method for the object that is modified or selected is queued to
run, unless CONTROL NOLABEL is in effect. CONTROL LABEL is the
default for FRAME entries.
•
If the component that is modified or selected is in an extended table, the
_putRowLabel method is queued to run immediately after the _objectLabel
methods for all modified components in that row. The _putRow method for the
row that is modified or selected is queued to run after the _putRowLabel method.
The _objectLabel method of the extended table is queued to run immediately
after all _putRowLabel and _putRow methods.
All methods that were queued in step 4 execute. (Only 5A and 5B are illustrated in
the figure.)
•
5A) The _objectLabel method for each modified component executes. For
example, if you modify the PRICE field in one or more rows of an extended
table, the PRICE label executes once for each modified field, and the
_CURROW_ system variable is updated with the number of the updated row
each time.
176
Appendix 1
• Flow of Control
•
5B) If a modified field is not in error or if CONTROL ERROR is in effect, the
_select method is invoked for the selected or modified component. The default
_select method submits the SAS command that is assigned to that component.
•
5C) Any _putRowLabel methods that are queued execute in order after all labels
for components within the row execute. If the component is in an extended table,
the _CURROW_ system variable is updated to reflect the row number.
•
5D) The _putRow method for the extended table containing modified
components executes after all other labels and methods for that row execute.
•
5E) The _objectLabel method for the extended table executes, and then the
extended table receives a _select method after all _putRowLabel and _putRow
methods run.
6
If any component is marked as being in error (after the labels or the _select,
_putRowLabel, or _putRow methods execute) and CONTROL ALWAYS,
CONTROL ALLCMDS, or CONTROL ENTER is not in effect, the FRAME entry
returns control to the user and awaits the next modification or command.
7
Unless one of the following conditions is met, the statements in the _mainLabel
method execute:
8
•
one or more fields are in error
•
a CANCEL, ENDSAS, BYE, or RETURN command is issued
•
neither CONTROL ALLCMDS, CONTROL ALWAYS, CONTROL ENTER, or
CONTROL ERROR is in effect
If the FRAME entry is not ending, each FRAME entry component that has been
modified or marked as needing refreshment is refreshed by invoking its _refresh
method. An object cannot receive a _refresh method unless it is completely
initialized (that is, the object's _init and _postInit methods must have run). If a
_refresh method is sent to an object before its _postInit method runs, the _refresh
method is converted to a _postInit method. When you use a REFRESH statement or
send a _refresh method to a FRAME entry before the FRAME entry receives a
_postInit method, a _postInit method is sent to the FRAME entry, and then the
refreshment proceeds.
Extended tables receive the _refresh method first, and then the other objects receive
a _refresh method. Extended tables are refreshed by executing their _getRowLabel
and _getRow methods and refreshing all components within the rows. This action is
performed either for all rows or only for rows that have been modified, depending on
the settings of the table's Putrow Options attribute. The extended table updates
the _CURROW_ system variable to reflect the logical row number for each row that
it processes. _CURROW_ is added as an automatic instance variable of both the
extended table and the objects within the table.
9
•
For extended tables with the selectionList attribute, the _setSelection
method executes for all components on the row.
•
When an extended table is refreshed, it executes the _getRowLabel method.
•
The _getRow method for the extended table executes.
•
The table executes the _update method for the objects in the current row.
•
If the end of a table is reached, the _hide method is called for the remaining
objects in the rows that are still visible.
If you issue the END, CANCEL, ENDSAS, BYE, or RETURN command, program
termination begins.
Flow of Control for Frame SCL Entries
177
•
9A) The _preTerm methods for the Frame object and all components are executed
unless the command is BYE or ENDSAS. This enables objects to set the entry's
_STATUS_ system variable to R (to resume rather than terminate) under certain
circumstances. For example, empty required fields are not allowed, and they prevent
normal program termination except after a CANCEL, ENDSAS, BYE, or RETURN
command.
•
9B) If no _preTerm method sets the _STATUS_ variable to R or H via the _setStatus
method of the Frame class, the _termLabel method is executed. If a statement in the
TERM section sets _STATUS_ to R, the program resumes instead of terminating,
unless the command issued is ENDSAS, BYE, CANCEL, or RETURN. The TERM
label does not execute if an ENDSAS, BYE, or ENDAWS command is issued.
•
9C) If the program termination is not stopped by an R status, the FRAME entry
window closes and the _term method executes for each object in the entry and for the
FRAME entry itself.
Note: Once the _term methods begin, the components are deleted. _term methods
should not attempt to apply methods to other components in the FRAME entry.
Also, any value assigned to _STATUS_ is ignored once _term methods begin
since the FRAME window is closed.
Changing Frame Components and Frame SCL Programs
You can change the attributes, location, and appearance of components in a FRAME
entry without recompiling the SCL source program. Only the following changes require
you to recompile:
•
changing the name of a component
•
changing the type of a component from character to numeric and vice versa
•
changing the length of a component
•
changing the SUBMIT replacement string from the Attributes window
•
adding a new component
•
deleting an existing component
•
changing the SCL source entry
•
modifying the SCL source
When you are in the build environment, this message appears when you need to
recompile:
NOTE: Intermediate code has been removed.
178
Appendix 1
• Flow of Control
179
Appendix 2
Adding Attachments to Frame
Controls
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Selecting the Attachment Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Initiating Define Attachment Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Selecting the Direction and Type for the Attachment . . . . . . . . . . . . . . . . . . . . . . . 182
Making the Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Defining Attachments to Sibling Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Defining Attachments to Components That Have Borders . . . . . . . . . . . . . . . . . . 189
Moving Multiple Components That Include Attachments . . . . . . . . . . . . . . . . . . . 190
Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Restricting Component Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Changing and/or Deleting an Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Displaying Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Situations in Which an Attachment Is Ignored . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Errors and Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Tips for Using Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Introduction
Attachments are connections between two or more components on a frame. These
connections can control the placement and size of components. Component placement
and size may be affected by attachments when a component is resized or moved, or
when the component's frame is resized.
Attachments remain valid even if automatic component resizing becomes necessary.
Automatic component resizing occurs when you resize either components themselves or
the frame on which your components exist.
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• Adding Attachments to Frame Controls
Selecting the Attachment Mode
Before you begin defining attachments, you need to decide how you want to define
them. You can focus on defining attachments for one particular component (such as a
push button) or on defining attachments for a parent component and its child
components (such as a container box that includes check boxes). The following figures
illustrate the difference between child component attachment and current component
attachment modes.
Figure A2.1 Child Attachment Mode
Initiating Define Attachment Mode
Figure A2.2
181
Current Attachment Mode
In either mode, attachments can be defined for the components that appear with sections
drawn within them. In child attachment mode, all child components of the selected
parent component are divided into sections, and their attachments are displayed. For
current attachment mode, only the selected component is divided into sections, and only
its attachments are displayed. In addition, other components on the frame may be hidden
while you are defining attachments for a specific component.
Child attachment mode is the default, and it enables you to attach child components of a
specific parent component to each other (sibling attachment) or to the parent component.
To initiate child attachment mode, select Layout ð Attach ð Attach child region.
Note: This technique is equivalent to the RM ATTACH KIDS command.
Before initiating the next step (Initiating Define Attachment Mode), select the parent
component that contains the child components for which you want to define attachments.
Current attachment mode enables you to attach the currently selected component to its
parent component or to its sibling components.
To initiate current region attachment mode, select Layout ð Attach ð Attach current
region.
Note: This technique is equivalent to the RM ATTACH SELF command.
Before initiating the next step (Initiating Define Attachment Mode), select the
component for which you want to define attachments.
Initiating Define Attachment Mode
After you specify the attachment mode by designating whether you want to work in
child component or current region attachment mode, you can turn on define attachment
182
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•
Adding Attachments to Frame Controls
mode. To initiate define attachment mode, select Layout ð Attach ð Define
Attachment.
Note: This technique is equivalent to the RM ATTACH command.
The Define Attachments window opens, showing the default attachment of singledirection and absolute type:
The cursor shape changes to a focus icon, which looks like a magnifying glass in some
operating environments.
Selecting the Direction and Type for the
Attachment
The direction and type for attachments define how you want the connection between two
components to be interpreted when one of the components moves or is resized. There are
two basic types of attachments, absolute and relative:
Table A2.1 Attachment Types
The type ...
Is represented
by ...
And maintains an attachment value of ...
absolute
a fixed number of pixels between the connection
points of the attached components
relative
a percentage of the parent component's space
between the connection points of the attached
components. If the size of the parent component
changes, the space between the components
remains proportional.
Unless the size of the parent component changes, absolute attachments and relative
attachments produce the same effect.
While you are working in define attachment mode, you can move or resize any
component from which you are defining attachments. When you do this, the values of
any affected attachments are modified. This enables you to move components closer
together or farther apart without having to temporarily remove any existing attachments.
Selecting the Direction and Type for the Attachment
183
To demonstrate the difference between absolute and relative attachments, this example
shows two components attached to their common parent.
Figure A2.3 The top item uses an absolute attachment and the bottom uses a relative
attachment.
Figure A2.4 If the size of the common parent grows from either the right or left side, the
absolute attachment preserves the actual distance between the top item and the left edge
of the parent, and the relative attachment preserves the percentage distance between the
bottom item and the left edge of the parent.
The attachment direction controls which component is affected when the attached
component is resized or moved. Attachments can be single directional or bidirectional:
184
Appendix 2
• Adding Attachments to Frame Controls
Table A2.2
Attachments
Attachment Type
Direction
Effect
bidirectional
Both components respond to resizing or moving
either component.
single directional
The component that the arrow points to responds
to resizing or moving the component that is
anchored by the end node.
is the default.
Resizing or moving a component is considered to be propagated by an attachment if
resizing or moving a component, combined with the attachment, results in another
component being resized or moved. An attachment is considered to be honored if
resizing or moving a component is propagated because of the attachment.
In the following window, components a, b and c have a common parent component and
are all attached to the right side of their parent with absolute attachments.
Figure A2.5 a's attachment is bidirectional; b's attachment is single directional going out of b;
and c's attachment is single directional going into c.
Figure A2.6 If the right side of the common parent is moved further to the right, only a and c
move because the parent generated the initial resize event and the direction of a's and c's
Selecting the Direction and Type for the Attachment
185
attachments allowed the attachment to be honored. The attachment associated with b,
however, was given a new value.
Figure A2.7 Notice that if b moves to the left, the right hand side of the parent region is
pulled to the left since b's attachment is honored only from b. Resizing the parent results in
honoring the attachments to a and c. If a is moved, the parent will also move because a's
attachment is bidirectional.
Figure A2.8 If c is moved, only c moves. Because the attachment associated with c is
honored only coming into c, resizing c is not propagated (that is, resizing c does not move
186
Appendix 2
• Adding Attachments to Frame Controls
or resize other regions). Note that the attachment from the parent region to c is given a
new value in this case.
Making the Attachments
After you initiate define attachment mode, you actually define the attachments by
clicking the mouse button in one component and dragging it to another. Each component
can be attached at one of five different points: each side of a component and its center.
You can define only one attachment from each of these points. However, you can create
many attachments to a single component section by defining the attachments at an
attachment point from another component.
The section that owns the attachment is the section from which you initiate the drag.
This section is referred to as the defining section. Knowing which section defines that
attachment is important when you perform certain actions on the attachment. For
example, to delete an attachment, you select {pseudo} in the Define Attachments
window and then click in the defining section for that attachment.
Attaching the components from the side and from the center causes different results:
Table A2.3 Attachment Points
To...
Attach the regions from the...
resize the child component when the parent
component is resized
side
move the child component when the parent
component is resized
center
You can use side attachments to control component size, as explained in the following
example:
Making the Attachments
187
Figure A2.9 Both a and b have their right sides attached to their common parent's right side,
and b also has its bottom attached to its parent's bottom.
Figure A2.10 If the parent grows from the right side, the right side of both a and b move
along with the parent's right side, but the left sides of a and b do not.
188
Appendix 2
• Adding Attachments to Frame Controls
Figure A2.11
as well.
If the parent grows by moving the bottom down, the bottom of b moves down
Defining Attachments to Sibling Components
Attachments can be further classified by whether they attach the defining component to
its parent or to a sibling component. Sibling attachments connect a component to one of
its siblings. All of the previous examples have shown parent attachments.
Sibling attachments can often simplify a set of attachments by making it visually easier
to interpret the attachment logic. In addition, this type of attachment sometimes results in
fewer attachments.
Defining Attachments to Components That Have Borders
189
Figure A2.12 a, b, and c should all follow the right side of their common parent. This can be
accomplished by attaching all regions to the parent directly, but using sibling attachments
is easier to understand.
Figure A2.13 If the right side of the parent grows to the right, all of the sibling regions move
to the right as well.
Defining Attachments to Components That Have
Borders
Some components may have special outlines or scroll bars. By default, when an
attachment is attached to the side of a component, the actual attachment point is
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• Adding Attachments to Frame Controls
considered to be the edge of the component itself. This point is along the inside edge of
any special outline that the component may have. It is also inside any attached scroll
bars that may be associated with the component.
External attachments enable you to create attachments with attachment points on the
outer edge of the component dressing. This type of attachment is often necessary when
the component dressing is a fixed number of pixels, as it is with component outlines and
component attached scroll bars. To create an external attachment, you should initiate
rubber-band line mode with an extended drag operation instead of a normal drag.
External attachments look different from other attachments. They use a thicker line, and
the terminating point of the directed arrow is the component border instead of the
component itself.
Moving Multiple Components That Include
Attachments
When more than one component is selected and moved at the same time, the attachments
between these components, or between these components and other components, are not
honored. Instead, attachments are temporarily ignored while the components are moved
to their new locations. Attachment values are then recalculated and reset so that they are
correct for the new location.
Example
Three push buttons are placed horizontally in a row. Push button 1 is bidirectionally
attached on its right side to the left side of push button 2. Push button 2 is bidirectionally
attached on its right side to the left side of push button 3. Additionally, there are two
pixels between each push button.
If you select push button 1 and push button 2 and move them to the left by two pixels,
push button 3 will not grow to the left by two pixels to keep an appropriate distance
between itself and the selected push buttons. Instead, push button 1 and 2 are moved to
the left and the distance between them is recalculated. Push button 3 now has four pixels
between itself and push button 2 instead of two pixels. Now, when either push button 2
or push button 3 is moved by itself, the attachment maintains a four-pixel distance
instead of a two-pixel distance.
Restricting Component Size
You can restrict component resizing by displaying a pop-up menu for a component while
you are in define attachment mode. You can make the component size fixed absolute or
fixed relative, or you can reset the fixed status of the component (remove any restrictions
on resizing). There are separate horizontal and vertical settings, so it is possible to set a
size restriction for a component in only one direction. By default, the size of components
is not restricted.
If a component is fixed absolute, then its size may not change in the direction (either
horizontal or vertical) that is fixed. If the component is fixed relative, then its size will
be maintained as a certain percentage of its parent component's size in the appropriate
direction.
Restricting Component Size
191
The resize restrictions absolute and relative look similar to absolute and relative
attachments.
The following figures illustrate a common use of fixed absolute and fixed relative
component size restrictions.
Figure A2.14 d is fixed absolute and side attached absolutely to the right side of its parent.
This attachment causes d to move with the right side of its parent and is equivalent to
attaching to d's center. Using this method instead of center attachment is a matter of
personal preference. a, b, and c share the expansion of the parent equally.
Notice in this case that the fixed relative restrictions are required in order to achieve the
desired result. If they are left off, then the right side of c will be resized, and the distance
between c and b will be set correctly, but the actual size of c will be undefined.
Figure A2.15 If the right side of the parent is grown, a, b, and c grow in proportion to the
parent, and their respective positions are relatively preserved. d moves along with the right
side of the parent.
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Figure A2.16 By contrast, without any relative size restrictions on a, b, and c, resizing the
parent causes the right sides of both c and d to move to the right, preserving the relative
and absolute distances respectively.
However, since there are no size restrictions, the left side of each component is not
relocated. The distance between b and c is adjusted, but the right side of b moves since
the direction of the attachment is into b. The same effect occurs for a. The distances
between the components are maintained as required due to the attachments, but the
resultant component sizes are not clearly defined.
Changing and/or Deleting an Attachment
You can correct your attachment definition by deleting the current attachment and
defining a new attachment in its place.
When you want to delete an attachment, open the Define Attachment window and select
the delete attachment symbol (O—|).
Then click in the section that defines the attachment.
Displaying Attachments
If you click within a section while in define attachment mode and an attachment is
defined from that section, a message reports exactly what kind of attachment it is. This
information is useful when the connection points are so close together that it is difficult
to determine the attachment type and direction from the visual indicator. For example, if
you click on the right side of the d component in the previous window, the following
message is displayed:
NOTE: Relative attachment (in) of right to right of parent.
You can also view the attachments for a component or a component's child components
without entering define attachment mode. To do this, issue the following command:
rm showatt [all|kids]
Errors and Error Handling
193
If you issue just the RM SHOWATT command, the attachments for the current
component are shown. An arrow shows the attachments, and the message line displays
the following message:
NOTE: Press any key to return.
If you issue RM SHOWATT KIDS, the attachments for all of the active component's
child components are shown. If you specify RM SHOWATT ALL, all attachments for
all components that are descended from the current component are shown.
After you use RM SHOWATT, the visual attachment indicators remain displayed until
you press a mouse button or a keyboard key.
Situations in Which an Attachment Is Ignored
These situations cause an attachment to be ignored:
•
The component is resized only horizontally, and the attachment is vertical in nature,
or vice versa.
•
The attachment is attached to the side of a sibling, and the location of that side has
not changed.
•
The component that is currently being resized is attached to the component that was
originally moved or resized to propagate the event.
•
The attachment is single directional coming into the component instead of going out
of the component.
•
The actual distance in pixels between the two attached components is within one-half
character of the desired distance. This situation applies to both absolute and relative
attachments. This shortcut is taken when a component is resized only if the
component to be adjusted must be aligned on a character cell boundary or if the
attachment has been previously synchronized.
•
The attachment is between one component in a group of multiple-selected
components and another component, and the group of multiple-selected components
is moved.
•
The attachment is associated with a component that uses the conformSize
attribute. Attachments have the potential to conflict with the conformSize
attribute.
Errors and Error Handling
Whenever the region manager detects an error during the resizing of a component, the
components are all restored to the location and size that they had before the component
was resized. Here are the most common reasons that resizing a component fails:
•
When the component is resized, the component becomes too small for the object that
it contains.
•
An attachment cannot be honored. Check all your attachments for conflicts.
•
Honoring an attachment requires resizing the master component. The master
component can only initiate a resize event and cannot be resized as a result of
resizing another component. Check all your attachments to the master component.
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•
Resizing the component results in a component being placed outside of the
boundaries of its parent (unless its parent is a viewport component, as used by the
work area object). This typically implies that a required attachment is missing.
•
Resizing the component results in a component being smaller than allowed by the
region manager (eight pixels). This situation does not necessarily imply that the
attachments are in error. You may simply be attempting to shrink the original
component too much.
•
Resizing the component causes components that contain text objects to overlap,
which usually implies an error in the way the attachments are defined.
If, after examining the attachments and the results of attempted resizes, you do not
understand the attachment problem, use the region manager to trace the handling of the
resizing by issuing the command RM GROW DEBUG. The next time you try to resize
the component, diagnostic messages will be sent to the Log window.
Tips for Using Attachments
By far the most important aspect of defining attachments for a FRAME entry is to
carefully think about how you want various components and contained components to
react to the appropriate resize event.
Carefully examine the components and determine which components should absorb the
gain or loss of space. Examine the horizontal and vertical dimensions separately; it is
fairly common for each dimension to handle resizing differently.
•
Use only the attachments.
When a component is resized, all attachments are checked; therefore, unnecessary
attachments may affect performance. Also, attachment information is stored with the
FRAME entry, so unnecessary attachments increase the size of the stored entry.
The same is not true for component size restrictions. Virtually no overhead is paid
for these settings. Sometimes, you may want to turn on a fixed size restriction, even
if only for documentation purposes; that is, if the attachments are viewed by another
person at a later date, they will be more understandable.
•
Remember that the master component always resizes from the lower right.
This is true even if the master component is grown from the upper left of the
window. Therefore, absolute attachments to the top or the left of the master
component are unnecessary. Note that this is not true of components in general, only
of the master component.
•
Take advantage of Move Only situations.
If you know that a container or group component will only be moved and not resized
due to attachments to its siblings and parent, then you do not need to define any
attachments to the child components of the container or group.
•
Keep the attachment logic simple.
If the attachments are getting too complicated, consider creating a container box just
to hold a set of related components. Attach the container to its parent and siblings
and set up attachments (if necessary) to the container's children.
•
Avoid mixing absolute and relative attachments in the same direction.
It is easy to create a situation that cannot be satisfied when mixing absolute and
relative attachments in the same direction. Sometimes such situations are
Tips for Using Attachments
195
appropriate, but you should take a second look to make sure this is really what you
need.
•
Avoid relative attachments with text-based objects that must be aligned on a row/
column boundary.
Usually the desired placement of a component after honoring a relative attachment
does not exactly align on a row/column boundary, which necessitates a shift of the
component to attain the required alignment. This situation can create odd visual
effects, and it significantly increases the chance that textual objects will overlap. If
you feel you must use relative attachments with text-based objects, be sure to leave
space around each component to allow for shifting without creating an overlap
situation.
A related problem occurs when a container contains character-aligned objects
(widgets) and the container is relatively attached. The container is not character-cell
aligned, and when the master component is resized, the widgets often shift within the
container.
You can avoid this shifting by creating a dummy character-cell-aligned component
(for example, a one-character text field that is protected and nondisplayable). Attach
this dummy component to the master component relatively, and then attach the
container to the dummy component absolutely. Make sure the absolute attachment is
short so that the resulting location of the container is as close to relatively correct as
possible.
When the master component is resized, the dummy component will be positioned
relatively, and then it will align to a character-cell boundary. Then, the absolute
attachment between it and the container will be honored. No shifting will occur
within the container either since the net movement of the container is guaranteed to
be an integral number of character cells. This guarantee is possible because the
master component is always an integral number of character cells in size and the
dummy component is always character-cell aligned.
•
Remember that you can resize in define attachment mode.
Remember that you can still resize any component without attachments being
honored by entering define attachment mode and performing the desired move or
resize. This action causes any associated attachments to be redefined instead of
honored.
•
Create small and allow for growth.
In general, results are usually better when honoring the growth rather than the
shrinkage of the master component. You are better off defining your window to be as
close to the smallest allowable size and ensuring that you handle size increases
gracefully through attachment. The primary reason for this is that if you create a
window too large and then try to shrink it, the master component may become too
small, and the containing component may also become too small to hold other
components.
•
Be careful when using very short attachments.
Avoid very short attachments to a component that contains a component that must be
character-cell aligned. These attachments are most likely to be ignored because of
the one-half character rule mentioned earlier. Short attachments are acceptable if
placement or size variations within ½ character are insignificant and if propagation is
not an issue. Such attachments are a concern only when you are attaching to a
component that contains an object that must be character-cell aligned.
•
Test your attachments.
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You can test all attachments while in build mode. Position the components, create
the attachments, and save the entry so that the desired placement is not lost (in case
the attachments do not work as you expect them). If the attachments do not work,
then cancel them, re-edit the frame, and change the attachments appropriately.
•
Use single-directional attachments in most cases.
Single-directional attachments are usually most appropriate, especially for
attachments from parent to child. Sibling attachments can also be made single
directional, but be sure to analyze how resizing the master component will affect
subcomponents so that you define sibling attachments in the correct direction.
•
Use relative component size restrictions to reduce the number of attachments
required.
If you want a component to maintain a relative size, attach one side to the parent
relatively and set the component-size restriction to fixed relative, instead of attaching
both sides relatively. This technique results in significantly fewer attachments if you
have many components that are being sized relatively in this manner.
•
Check the kind of attachment for a component if you are not sure what kind is
defined.
To determine the kind of attachment that is defined for a section, click in the section
while you are in define attachment mode. A message will be displayed indicating
what kind of attachment is defined there and what it is attached to.
197
Appendix 3
Working with SAS/AF Keys in the
SAS Registry
About the SAS Registry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
SAS Registry Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Keys and Key Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Modifying the Registry Settings for SAS/AF Software . . . . . . . . . . . . . . . . . . . . . . 198
About the SAS Registry
The SAS Registry stores configuration data about the SAS session and about specific
applications, such as SAS/AF software.
You can use the SAS Registry to customize your SAS session as well as SAS
applications. Customization involves modifying configuration data, key values, or both.
For example, you can use the SAS Registry to customize whether the Components
window appears by default when you open a frame in SAS/AF software.
You can access the SAS Registry with the SAS Registry Editor or with PROC
REGISTRY. The information in this appendix is based on using the SAS Registry
Editor. For more information on PROC REGISTRY, see the Base SAS Procedures
Guide.
SAS Registry Editor
Introduction
The SAS Registry Editor enables you to view and modify the SAS Registry. It provides
a graphical alternative to PROC REGISTRY. To open the SAS Registry Editor, select
Solutions ð Accessories ð Registry Editor or issue the REGEDIT command.
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• Working with SAS/AF Keys in the SAS Registry
You can use the SAS Registry Editor to complete a number of tasks, including
•
viewing the contents of the registry, which shows keys and key values
•
adding, modifying, and deleting keys and key values.
Keys and Key Values
Values in the registry are stored in keys. Keys look like folders in the SAS Registry
Editor, and appear on the left hand side (the tree view) of the window. The values stored
in the currently selected key are displayed on the right hand side (the list view) of the
window. If a key contains only subkeys, it has a plus sign (+) next to its folder.
You can expand or collapse a key to show or hide its subkeys by selecting the key's
expansion icon (either a + or - sign), which is located to the left of the key's folder.
Note: In some operating environments, you can select an expansion icon by positioning
the cursor on it and pressing the ENTER key.
Modifying the Registry Settings for SAS/AF
Software
You can use the SAS Registry to modify settings that control the SAS/AF software
design-time and run-time environments.
Modifying the Registry Settings for SAS/AF Software
199
For example, you may want to change the resource that is associated with the
Components window by default, or you may want the Properties window to appear
without its navigation tree.
To set SAS/AF registry settings:
1. Open the SAS Registry Editor.
2. Expand the Products\AF\Design Time or Products\AF\Run Time key.
3. Select a key in the left pane of the window.
4. Select a key value in the right pane of the window, and then right-click to open the
pop-up menu.
5. Select the appropriate command from the pop-up menu. Some commands invoke
dialog boxes that enable you to edit the key value.
200
Appendix 3
• Working with SAS/AF Keys in the SAS Registry
201
Glossary
application workspace
a window that contains other windows or from which other windows can be invoked,
but which is not contained within any parent window that is part of the same
software application. Short form: AWS.
attribute
a property of a SAS/AF component that specifies the data that is associated with a
component, such as its color, size, description, or other information that is stored
with the component. Although similar to instance variables, attributes can contain
additional data.
attribute linking
a feature of the SAS/AF graphical user interface that enables you to designate values
to be shared by multiple components without writing any SCL code. You can define
attribute links between attributes of the same component or between different
components within the same frame.
automatic instance variable
an instance variable whose value is automatically copied into the corresponding SCL
variable when an SCL method executes, and is copied back into the object when the
method returns. Assigning the automatic status to an instance variable makes writing
new methods for a class easier because the SCL method can access the automatic
instance variable directly instead of accessing it indirectly with SCL list functions.
See also instance variable.
AWS
See application workspace.
CAM
See custom access method.
catalog entry
See SAS catalog entry.
catalog reference
a name that is temporarily associated with a catalog or with concatenated catalogs.
You use a CATNAME statement to assign a catref. Short form: catref.
catref
See catalog reference.
202
Glossary
class
a template for an object. A class includes data that describes the object's
characteristics (such as attributes or instance variables), as well as the operations
(methods) that the object can perform. See also subclassing and object.
complex attribute
an attribute whose type is either Object (O) or a fully qualified SAS/AF class name
such as sashelp.classes.draganddrop.class. Using an object as an attribute enables
you to use a single attribute to store a set of information. In SCL, you can access the
attributes of a complex attribute object by 'stringing' together the dot notation that
queries or sets the attribute. The objects that are used as complex attributes can have
their own methods. A complex attribute must be a non-visual component (that is, one
that is not based on sashelp.classes.widget.class).
component
a self-contained class that has specific properties, which can include attributes,
methods, events, event handlers, and interfaces.
control
another term for visual component. See also visual component.
custom access method
a method that is automatically executed when an attribute is accessed. Short form:
CAM. See also getCAM and setCAM.
data representation
the type of data that a drag site is capable of transferring or receiving. The data can
be as simple as a string of text or as complex as an SCL list. See also drag site, drag
and drop (DND), and drop operation.
dimension
a group of closely related hierarchies. Different hierarchies within a single dimension
typically represent different measurements of a single concept. For example, a Time
dimension might consist of two hierarchies: (1) Year, Month, Date, and (2) Year,
Week, Day.
DND
See drag and drop.
drag and drop
a user interface action that involves dragging objects with a mouse (or other pointing
device) and dropping them over other objects at run time, and having some action
occur. On systems that do not use a mouse or other pointing device, you can drag an
object by using the WDRAG command and cursor-key input to position the object
and complete the drag action. Short form: DND.
drag site
a component that can be dragged. See also drag and drop.
drop operation
any of the following actions that can be performed on a data representation: (1) copy,
when data is provided with no post- processing; (2) link, when some mechanism
synchronizes the source and destination; (3) move, when data is provided and the
source is removed.
Glossary
203
drop site
a component that can receive a dragged object. See also drag and drop.
entry type
a characteristic of a SAS catalog entry that identifies the catalog entry's structure and
attributes to SAS. When you create a SAS catalog entry, SAS automatically assigns
the entry type as part of the name. See also SAS catalog entry.
event
a property of a SAS/AF component that notifies components or applications when a
resource or state changes. An event occurs when a user action (such as a mouse
click) occurs, when an attribute value is changed, or when a user-defined condition
occurs. An event handler then provides a response to the change.
event handler
a property of a SAS/AF component that determines the response to an event.
Essentially, an event handler is a method that executes after an event is received.
field
a window area in which users can view, enter, or modify a value.
field validation
the process of checking user-entered values either against attributes that have been
specified for a field or against conditions that have been specified in an SCL
program.
getCAM
a method that is associated with an attribute and that is automatically executed when
the attribute's value is queried. See also custom access method and setCAM.
global command
a command that is valid in all of a particular SAS software product's windows.
graphics object
a graphical window element that displays a variety of graphics output created
dynamically from specified data.
inheritance
in object-oriented methodology, the structural characteristic of class definitions by
which methods and attributes of a class are automatically defined in its subclasses.
instance
another term for object. See also object.
instance variable
a characteristic that is associated with an object, such as its description, its color or
label, or other information about the object. All objects that are created from the
same class automatically contain the instance variables that have been defined for
that class, but the values of those variables can change from one object to another. In
addition, objects can contain local instance variables (that is, variables that are local
to a particular instance of a class). Beginning in Version 8, the use of attributes
reduced the need for instance variables. See also automatic instance variable and
attribute.
204
Glossary
interface
a type of class that specifies the rules that are used for model/view communication.
Interfaces are collections of abstract method definitions that enable you to redirect a
method call from one component to a method call on a different component. The
method definitions are just the information that is needed to define a method; they do
not contain the actual method implementations. If two components share an
interface, they can indirectly call each others' methods via that interface.
KEYS entry
a type of SAS catalog entry that contains function key settings for interactive
windowing procedures.
legacy class
any SAS/AF class that does not use the SAS Component Object Model (SCOM),
including classes that were supplied in Version 6 of SAS/AF Software.
library reference
See libref.
libref
a name that is temporarily associated with a SAS library. The complete name of a
SAS file consists of two words, separated by a period. The libref, which is the first
word, indicates the library. The second word is the name of the specific SAS file. For
example, in VLIB.NEWBDAY, the libref VLIB tells SAS which library contains the
file NEWBDAY. You assign a libref with a LIBNAME statement or with an
operating system command.
local environment list
a list that contains data that is available only to SCL entries that are invoked in the
same SCL application. This list is deleted when the application ends.
member
a SAS file in a SAS library.
member name
a name that is assigned to a SAS file in a SAS library.
metadata
a description or definition of data or information.
method
a property of a SAS/AF component that defines an operation that the component can
execute.
model
a type of non-visual component that provides attributes and methods for querying
and modifying underlying data abstractions. For example, a Data Set List model
contains methods for reading and manipulating SAS tables.
model/view
an abstract relationship between a model, the internal logic of applications, and a
viewer. You can set model/view component communication during application build
time (that is, within the Build window) either by dragging a model onto a viewer or
by setting the 'model' attribute of a viewer in the Properties window. See also model,
view, and viewer.
Glossary 205
non-visual component
any component that is not visible in an application's graphical user interface.
object
an instantiation or specific representation of a class. For example, a list box on a
frame is an instantiation of sashelp.classes.Listbox_c.class. The terms instance and
object are synonyms.
overload
to define multiple methods that have the same name but different signatures within
the same class. If you call an overloaded method, SCL checks the method arguments,
scans the signatures for a match, and executes the appropriate code. See also
signature.
override
to replace the definition of an inherited method or the default value of an instance
variable in a subclass.
parameter
(1) in SAS/AF and SAS/FSP applications, a window characteristic that can be
controlled by the user. (2) in SCL, a value that is passed from one entry in an
application to another. For example, in SAS/AF applications, parameters are passed
between entries by using the CALL DISPLAY and ENTRY statements. (3) a unit of
command syntax other than the keyword. For example, NAME=, TYPE=, and
COLOR= are typical command parameters that can be either optional or required.
parent class
the class from which another class is derived. The parent class is also known as a
super class.
property
any of the characteristics of a component that collectively determine the component's
appearance and behavior. Attributes, methods, events, and event handlers are all
types of properties.
region manager
the portion of SAS that allows windows to consist of regions. The region manager
controls the operations performed on regions.
resource
another term for RESOURCE entry. See also RESOURCE entry.
RESOURCE entry
a type of SAS catalog entry that stores information about a set of classes. This
information determines which classes can be instantiated by a frame when that frame
is initialized. Therefore, when you browse, edit, or execute a frame, the frame must
be able to access the RESOURCE entry that was used when the frame was created.
resource list
the list of classes and sets of attributes that can be used to build objects and execute
FRAME entries. Resource lists are stored in RESOURCE entries.
SAS catalog
a SAS file that stores many different kinds of information in smaller units called
catalog entries. A single SAS catalog can contain different types of catalog entries.
See also SAS catalog entry.
206
Glossary
SAS catalog entry
a separate storage unit within a SAS catalog. Each entry has an entry type that
identifies its purpose to SAS. Some catalog entries contain system information such
as key definitions. Other catalog entries contain application information such as
window definitions, Help windows, SAS formats and informats, macros, or graphics
output. See also entry type.
SAS Component Language
a programming language that is provided with SAS/AF and SAS/FSP software. You
can use SCL for developing interactive applications that manipulate SAS data sets
and external files; for displaying tables, menus, and selection lists; for generating
SAS source code and submitting it to SAS for execution; and for generating code for
execution by the host command processor. Short form: SCL.
SAS Component Object Model
a framework for developing SAS/AF applications that provides developers with
model/view communication, drag and drop communication, and attribute linking.
Short form: SCOM. See also model/view, drag and drop, and attribute linking.
SAS data set
a file whose contents are in one of the native SAS file formats. There are two types
of SAS data sets: SAS data files and SAS data views. SAS data files contain data
values in addition to descriptor information that is associated with the data. SAS data
views contain only the descriptor information plus other information that is required
for retrieving data values from other SAS data sets or from files that are stored in
other software vendors' file formats.
SCL
See SAS Component Language.
SCOM
See SAS Component Object Model.
scope
a value that indicates whether a property can be called by all classes, by only the
parent class, or only by subclasses. Scope is set to Public, Private, or Protected.
Scope also determines whether properties are displayed at build time. For example,
only public attributes are displayed in the Properties window. By default, the scope
of a property is Public.
selection list
a list of items in a window, from which users can make one or more selections.
Sources for selection lists are LIST entries, special SCL functions, and extended
tables.
setCAM
a method that is associated with an attribute and that is automatically executed when
the attribute's value is set. See also custom access method and getCAM.
signature
the name, order, and type of arguments for a method.
sigstring
a short notation that indicates a method signature.
Glossary 207
source code
programming code that must be compiled before it can be executed.
source entry
a SAS catalog entry that contains the source code for a method. Source entries
typically have an entry type of SCL.
state
a value that indicates whether a property is new, inherited, or overridden, or whether
it is a system property.
subclassing
the process of deriving a new class from an existing class. A new class inherits the
characteristics (attributes or instance variables) and operations (methods) of its
parent. It can also possess custom attributes (or instance variables) and methods. See
also class, attribute, instance variable, and method.
super method
a method that is replaced by an overridden method. The super method can be
invoked from the overridden method with a CALL SUPER statement.
type
the data type of a variable, an attribute, or a method argument.
view
a particular way of looking at a model's data.
viewer
a component that provides a visual representation of a model's data.
visual component
a component such as an icon, a push button, a check box, or a frame that forms part
of the graphical user interface of an application. Visual components are also referred
to as controls.
widget
an element of a graphical user interface that displays information or that accepts user
input. For example, a text entry field is a widget that is used for displaying and
entering text, and a chart is a widget that is used for displaying information.
208
Glossary
209
Index
Special Characters
_completeDrag method 143
_drop method 143
_getAttributeValue method
definition 88
flow of control 88
_getDragData method 143
_initLabel method 113
_mainLabel method 113
_objectLabel method 114
_respondToDragOff method 143
_respondToDragOnto method 143
_setAttributeValue method
definition 88
flow of control 88
_startDrag method 143
_super() routine 110
_termLabel method 113
_validateDropData method 143
A
absolute attachments 182
abstract classes 76
application window features, enabling/
disabling 62
application workspace (AWS) 62
attachment mode, selecting 180
attachments 25
changing 192
defining 179
deleting 192
displaying 192
error handling 193
ignoring 193
tips for using 194
attachments, adding to frame controls 179
absolute attachments 182
attachment mode, selecting 180
bidirectional attachments 183
child attachment mode 180
components, moving multiple 190
components, restricting size of 190
creating 186
current attachment mode 180
define attachment mode, initiating 181
defining sections 186
direction, selecting 182
for components with borders 189
for sibling components 188
ownership 186
propagation 183
relative attachments 182
single directional attachments 183
type, selecting 182
Attribute Changed Event component 131
attribute editors 117, 118
assigning 117
creating your own 118
attribute links 28
Attribute Changed Event component
131
definition 28
enabling 130
establishing 28
example 29, 131
uses for 28
attribute metadata items
AutoCreate 85
Automatic 88
Category 87
definition 84
Description 88
Editable 86
Editor 87
GetCAM 87
HonorCase 87
InitialValue 85
IV (instance variable) 88
Linkable 86
Name 85
Scope 85
210
Index
SendEvent 86
SetCAM 87
State 85
TextCompletion 87
Type 85
ValidValues 86
attributes
adding 99
attributeName 144
CBTFrameName, context sensitive help
in frames 54
CBTFrameName, online Help in frames
54
completeDrag 145
custom access methods (CAMs),
assigning 121
dataOperation 145
dataRepresentation 145
dataSiteID 145
defaultAttribute, specifying 115
definition 84
dependencies 125
dot notation 88
dragEnabled 142
dragInfo 142
dragOperations 142
dropEnabled 143
dropInfo 143
dropOperations 143
getting 88
help, context-sensitive help in frames
54
help, online Help in frames 54
helpText 54
list attributes 127
metadata 84
refresh Attributes event, example 126
refresh Attributes event, using 125
showContextHelp 54
toolTipText 54
validating character values 116
values, getting and setting 88
XLocation 145
YLocation 145
attributes, setting
for entire component 119
singly 117, 118
with attribute editors 117, 118
with custom attributes windows 119
with dot notation 88
AutoCreate attribute metadata item 85
Automatic attribute metadata item 88
AUTOTERM feature 167
AUTOTERM= option 167
AWS (application workspace) 62
See also application workspace (AWS)
AWSCONTROL system option 62
AWSMENUMERGE system option 62
AWSTITLE system option 62
B
bidirectional attachments 183
BUILD procedure, deploying SAS/AF
applications 58
Build window 15
BYE command 167
C
CAMs (custom access methods) 121
See also custom access methods
(CAMs)
CANCEL command 167
catalogs, creating SAS
SAS/AF applications 6
Category attribute metadata item 87
child attachment mode 180
child classes 74
CIMPORT procedure, deploying SAS/AF
applications 59
Class Browser 70
class catalogs, renaming 154
class constructors
adding 107
defining with Class Editor 107
defining with SCL 106
overriding 107
overview 105
class documentation
generating 156
making available 159
Class Editor 67
defining constructors 107
CLASS statement 103
classes 73
abstract 76
ancestry 74
child 74
composite objects 75
composition 75
converting to SCL entries 102
creating with SCL 100
definition 73
delegation 75
descendents 74
documenting 156
editing 67
extending 99
families 74
grouping into resources 68
inheritance 74
Index
instantiating with SCL 105
instantiation 74
making available 154
merging 154
metaclasses 76
models 76
naming conventions 102
parents 74
relationships among SAS/AF classes 74
siblings 74
types of 76
uses relationships 75
views 76
classes, from older SAS releases 72
See also legacy classes
Close buttons, creating 96
communication 27
See also component communication
See also component-frame
communication
See also drag and drop communication
compiling
frames 22
SAS/AF applications 8
SCL programs 46
completeDrag attribute 145
component communication 27
See also attribute links
See also drag and drop communication
adding to components 129
for data access 29
for data display 29
models, definition 29
models, example 31
models, uses for 30
SAS Component Object Model (SCOM)
27
viewers, definition 29
viewers, example 31
viewers, uses for 30
component development
attributes, adding 99
Class Browser 70
class constructors, adding 107
class constructors, defining with Class
Editor 107
class constructors, defining with SCL
106
class constructors, overriding 107
class constructors, overview 105
Class Editor 67
CLASS statement 103
classes, converting to SCL entries 102
classes, creating with SCL 100
classes, instantiating with SCL 105
classes, recommended practices 102
211
Close buttons, creating 96
creating your own components 95
extending classes 99
GenDoc Utility, deploying components
156
Interface Editor 68
methods, adding 99
methods, implementing 103
Resource Editor 68
SAS/AF applications 7
SCL analysis tools 70
SCL programs, creating 69
Source Control Manager 70
Source window 69
subclassing, by overriding attributes 96
subclassing, by overriding methods 97,
98
subclassing, methodology 95
testing components 97
testing new attributes 100
testing new methods 100
testing overridden methods 98
text editor 69
tools and utilities for 70
tools for 67
USECLASS statement 104
component properties, setting 17
component-frame communication 8
components
adding 22
combining 24
composite 24
default attributes 115
dropping in frames 15
functions, table of 23
provided by SAS 7
re-using 24
SAS/AF software 16
selecting 15, 23
subclassing 25
supporting drag and drop
communication 32
viewing 15
components, deploying 151
See also deploying components
components, positioning 22
See also attachments
components, sizing 25
See also attachments
Components window 15
composite, definition 24
composite objects 75
composition 75
CONFIG system option 61
configuration files
definition 60
212
Index
naming 61
specifying 61
constructors 105
defining with Class Editor 107
defining with SCL 106
controls, adding to windows 95
See also subclassing
COPY procedure, deploying SAS/AF
applications 58
Coverage Analyzer tool 48
CPORT procedure, deploying SAS/AF
applications 59
current attachment mode 180
custom access methods (CAMs) 121
assigning to attributes 121
limiting execution of 124
naming conventions 123
recursion, avoiding 124
custom attributes windows 119
custom commands, in SCL programs 42
custom configuration files 61
custom menus, creating in SAS/AF 51
customizers 119
D
dataOperation attribute 145
dataRepresentation attribute 145
debugger commands 47
debugging applications 168
debugging SCL programs 47
defaultAttribute, specifying 115
define attachment mode, initiating 181
defining sections 186
delegation 75
deploying components 151
class documentation, generating 156
class documentation, making available
159
classes, making available 154
metadata descriptions 157
resources, analyzing 153
resources, associating with FRAME
entries 155
resources, merging 154
resources, overview 152
resources, renaming class catalogs 154
resources, renaming libraries 154
resources, synchronizing 153
SAS Registry Components key,
modifying 156
deploying SAS/AF applications 57
See also SAS sessions, configuring
BUILD procedure 58
CIMPORT procedure 59
COPY procedure 58
CPORT procedure 59
deployment issues 57
MERGE statement 58
migrating from testing to production 58
to different operating environments 59
descendents 74
Description
attribute metadata item 88
event handler metadata item 93
event metadata item 91
dialog boxes, calling 45
dialog frames 20
dot notation 40, 88
drag and drop communication 32
See also component communication
adding to components 139
components supporting 32
data representation 140
defining properties for 142
definition 32
drag sites, defining 32, 33
drag sites, definition 32
dragInfo 32
drop sites, defining 32, 33
drop sites, definition 32
dropInfo 32
example 33, 145
flow of control 140, 144
uses for 32
drag sites
defining 32, 33
definition 32
dragEnabled attribute 142
dragInfo 32
dragInfo attribute 142
dragOperations attribute 142
drop sites
defining 32, 33
definition 32
dropEnabled attribute 143
dropInfo 32
dropInfo attribute 143
dropOperations attribute 143
E
Editable attribute metadata item 86
Editor attribute metadata item 87
END command 166
ENDSAS command 167
ENTRY statement 118
environment argument 118
environment variables, creating 62
event handler metadata items
definition 92
Description 93
Index
Enabled 93
Event 92
Method 92
Sender 92
State 92
event handlers 72, 92
event handling
adding to components 148, 149
flow of control 149
modifying 148
event metadata items
definition 91
Description 91
Enabled 91
Execute 91
Method 91
Name 91
State 91
events 90
adding to components 149
definition 90
Execute event metadata item 91
F
families of classes 74
flow of control
_getAttributeValue method 88
_setAttributeValue method 88
AUTOTERM feature 167
AUTOTERM= option 167
BYE command 167
CANCEL command 167
debugging applications 168
drag and drop communication 140, 144
END command 166
ENDSAS command 167
event handling 149
example of order processing 164
frame components, changing 177
FRAME entries and automatic methods,
build time 169
FRAME entries and automatic methods,
run time 172
frame SCL components, changing 177
INIT section 163
labeled sections 164
MAIN section 165
MAIN section, forcing execution of
165
MAIN section, handling invalid values
166
MAIN section, overview 165
model/view communication 133
multiple window components 164
order of execution, build-time 170
213
order of execution, run-time 173
SCL objects, terminating on application
end 167
system closure command 167
TERM section 166
VERBOSE value 168
frame components, changing 177
FRAME entries
and automatic methods, at build time
169
and automatic methods, at run time 172
compiling automatically 47
compiling in batch 46
how SCL programs execute for 163
overriding frame methods 113
frame SCL 36
changing components 177
entries, flow of control 169
frame-component communication 8
frameID argument 118
frames 19
See also SCL (SAS Component
Language)
adding menus 22
and SCL programs 36
attachments 25
compiling 22
components, adding 22
components, automatic resizing 25
components, combining 24
components, composite 24
components, positioning 22
components, re-using 24
components, selecting 23
components, subclassing 25
dialog 20
documenting 156
dropping components in 15
help, context sensitive 54
help, online 54
methods, writing 25
SCL entries, specifying 22
SCL programs for 37
SCL requirements 37
setting properties 22
source code 22
standard 20
storing 22
tips for using 22
types of 20
frames, opening from
command prompt 20
Explorer window 20
Program Editor 20
SAS/AF software development
environment 20
214
Index
G
GenDoc Utility
definition 70
deploying components 156
output of 158
GetCAM attribute metadata item 87
H
help, calling from applications
HELP command 55
HELPLOC:// protocol 55
HELPMODE command 55
overview 55
WBROWSE command 55
help, context-sensitive
attaching to frames 54
tooltip help 54
help, online
adding to applications 53
adding to frames 54
help attribute
context sensitive help in frames 54
online Help in frames 54
HELP command 55
help files, specifying location of 62
HELPLOC:// protocol 55
HELPLOC system option 62
HELPMODE command 55
helpText attribute 54
HonorCase attribute metadata item 87
I
inheritance 74
INIT section 163
INITCMD system option 62
InitialValue attribute metadata item 85
instance variables 72
instantiation of SAS/AF classes 74
Interface Editor 68
interface properties of classes
definition 93
InterfaceName item 93
State item 93
Status item 93
InterfaceName item 93
interfaces, definition 93
IV (instance variable) attribute metadata
item 88
L
labeled sections 164
legacy classes 72
Linkable attribute metadata item 86
list attributes 127
List Diagnostic Utility 48
M
MAIN section
forcing execution of 165
handling invalid values 166
overview 165
menus
adding to frames 22
creating 51
MERGE statement
deploying SAS/AF applications 58
metaclasses 76
metadata descriptions 157
Method
event handler metadata item 92
event metadata item 91
method metadata 81
method names, case sensitivity 110
method signatures 78
methods 77
_getAttributeValue, definition 88
_getAttributeValue, flow of control 88
_setAttributeValue, definition 88
_setAttributeValue, flow of control 88
adding 99
automatic execution 77
definition 77
having same name 80
naming conventions 77, 110
overloading 80
overriding 110
per-instance 78
recursion 112
scope 81
sigstrings 79
storing 109
subclassing 78
virtual 78
writing 25
methods, implementing
with CLASS statement 103
with SCL 109
with USECLASS statement 103, 111
model components
definition 29
example 31
uses for 30
model/view communication 29
creating a new interface 136
determining when to use 30
examples 31
flow of control 133
implementing 133
Index
models, basing on StaticStringList
interface 135
models, creating 134
models, defining 135
problem domains 133
setting by dragging and dropping
components 31
viewers, creating 134
models 76
multiple window components 164
N
Name attribute metadata item 85
Name event metadata item 91
naming conventions
configuration files 61
custom access methods (CAMs) 123
methods 77, 110
NOAWSMENUMERGE system option
62
NOSPLASH system option 62
O
object-oriented programming (OOP) 71
See also attributes
See also classes
See also events
See also methods
and SAS Component Object Model
(SCOM) 73
application design 72
attributes 72
definition 71
instance variables 72
legacy classes 72
nonvisual objects 72
objects 72
OOP (object-oriented programming) 71
See also object-oriented programming
(OOP)
optimizing SCL programs 48
overloading methods 80
overriding
attributes, to create subclasses 96
class constructors 107
drag and drop methods 143
frame methods 113
overriding methods
and scope 114
SAS Component Language (SCL) 110
testing the overrides 98
to create subclasses 97, 98
215
P
parent classes 74
per-instance methods 78
Performance Analyzer 48
PMENU 51
PROC BUILD, deploying SAS/AF
applications 58
PROC CIMPORT, deploying SAS/AF
applications 59
PROC COPY, deploying SAS/AF
applications 58
PROC CPORT, deploying SAS/AF
applications 59
PROC PMENU, creating menus 51
procedures
BUILD 58
CIMPORT 59
COPY 58
CPORT 59
PMENU 51
properties
component, setting 17
drag and drop communication 142
frame, setting 22
properties of classes
definition 93
InterfaceName item 93
State item 93
Status item 93
Properties window 17
R
recursion 112
avoiding with CAMs 124
refresh Attributes event
example 126
using 125
relative attachments 182
Resource Editor 68, 153
RESOURCE entries 152
See also resources
resources 152
analyzing 153
associating with FRAME entries 155
merging 154
overview 152
renaming class catalogs 154
renaming libraries 154
synchronizing 153
S
SAS catalogs, creating
SAS/AF applications 6
SAS Component Language (SCL)
216
Index
See SCL (SAS Component Language)
SAS Component Object Model (SCOM)
See SCOM (SAS Component Object
Model)
SAS language statements, supported by
SCL 38
SAS libraries, creating
SAS/AF applications 6
SAS libraries, renaming 154
SAS Registry
key values 198
keys 198
overview 197
SAS/AF settings 198
SAS Registry Components key,
modifying 156
SAS Registry Editor 197
SAS sessions, configuring 61
application window features, enabling/
disabling 62
application workspace (AWS) 62
configuration files, definition 60
configuration files, naming 61
configuration files, specifying 61
environment variables, creating 62
help files, specifying location of 62
invoking applications 62
overview 60
SAS software splash screen, displaying
at startup 62
SAS system options for 61
splash screens, specifying location of
62
SAS software splash screen, displaying at
startup 62
SAS system options
AWSCONTROL 62
AWSMENUMERGE 62
AWSTITLE 62
CONFIG 61
HELPLOC 62
INITCMD 62
NOAWSMENUMERGE 62
NOSPLASH 62
SASCONTROL 62
SET 62
SPLASH 62
SPLASHLOC 62
SAS/AF applications 3
compiling 8
component development 7
component-frame communication 8
configuration file, specifying 61
definition 3
deploying 9, 57
designing for reuse 8
development environment, setting up 6
frame-component communication 8
invoking with INITCMD system option
62
launching 63
licensing SAS software products 7
mainframe support issues 3
migrating from testing to production 58
planning 5
porting to different operating
environments 59
SAS catalogs, creating 6
SAS libraries, creating 6
SAS sessions, configuring 60
testing 8
usability testing 9
user interface development 8
uses for 5
using existing SAS components 7
SAS/AF classes 73
abstract classes 76
attribute metadata 84
attribute values 88
attributes 72, 84
automatic methods 77
composition 75
constructors 105
converting to an SCL Entry 102
creating with SCL 100
creating with SCL, recommended
practices 102
delegation 75
dot notation 88
event handler metadata 92
event handlers 72, 92
event metadata 91
events 72, 90
extending 99
implementing methods using the
CLASS statement 103
implementing methods using the
USECLASS statement 103
inheritance 74
instantiation 74
interface properties 93
interfaces 72, 93
metaclasses 76
method metadata 81
method scope 81
method signatures 78
methods 72
methods, definition 77
methods, flow of control 88
methods, implementing with SCL 109
methods, overriding 110
model/view components 76
Index
models 76
overloading methods 80
per-instance methods 78
relationships among 74
SCOM (SAS Component Object Model)
73
subclass, creating by overriding a
method 97
subclass, creating by overriding an
attribute 96
subclassing methodology 95
types of 76
uses relationships 75
viewers 76
virtual methods 78
SAS/AF software 13
attribute editors, creating 117
attribute linking 130
attribute validation 116
Build window 15
class browser 70
Class Editor 67, 107
component development 95
components 16
Components window 15
custom access methods (CAMs) 121
custom attribute editors, creating 118
custom attributes window 119
custom menus, creating 51
development environment 13
drag and drop, enabling 139
GenDoc Utility 70
Interface Editor 68
model/view communication 29, 133
models, creating 134
Properties window 17
Resource Editor 68
SAS Registry 198
SCL analysis tools 70
Source Control Manager (SCM) 70
Source window 17, 69
viewers, creating 134
SASCONTROL system option 62
SCL (SAS Component Language)
_NEW_ operator 105
analysis tools 70
automatic methods, order of execution
at build time 170
automatic methods, order of execution
at run time 172
calling dialog boxes 45
calling other entries 44
calling SAS catalog entries 44
class constructors, defining 106
CLASS statement 103
compiling 46
217
compiling FRAME entries
automatically 47
compiling FRAME entries in batch 46
constructing a program 37
constructors 105
controlling execution of 41
converting a class to an SCL Entry 102
creating 17, 69
creating a class 100
creating classes, recommended practices
102
custom commands 42
data types supported 39
debugger commands 47
debugging 47
definition 3
dot notation 40, 88
ENDUSECLASS statement 111
entries, specifying 22
flow of control 163
FRAME entries and automatic methods
169
functions 39
IMPORT statement 105
INIT section processing 163
instantiating classes 105
labeled sections 38, 113
list functions 127
MAIN section processing 165
method blocks 111
method scope 81
method signatures 78
METHOD statements 78
methods, implementing 109
objects, terminating on application end
167
opening windows 44
optimizing 48
order of execution, build time 170
order of execution, run time 173
overloading methods 80
overriding frame methods 113
overriding methods 110
performance 112
programs 35
requirements for programs 37
routines 39
SAS language statements supported 38
saving programs 49
Source window 17, 69
statements 38
storing programs 49
TERM section processing 166
testing 46, 47
USECLASS statement 104, 111
variables 39
218
Index
working with frames 36
SCM (Source Control Manager)
See Source Control Manager (SCM)
SCOM (SAS Component Object Model)
27, 73
attribute linking 28, 129
attribute linking, enabling 130
drag and drop, enabling 139
drag and drop communication 32
drag and drop operations 129
event handling 129
model/view communication 29, 129
models 76
OO programming model 73
processes 129
viewers 76
Scope attribute metadata item 85
scope of methods
definition 81
in overridden methods 114
Sender event handler metadata item 92
SendEvent attribute metadata item 86
SET system option 62
SetCAM attribute metadata item 87
showContextHelp attribute 54
sibling classes 74
sigstrings 79
single directional attachments 183
Source Control Manager (SCM) 70
Source window 17, 69
splash screens, specifying location of 62
SPLASH system option 62
SPLASHLOC system option 62
standard frames 20
State
attribute metadata item 85
event handler metadata item 92
event metadata item 91
Static Analyzer 48
Status item 93
subclassing 95
by overriding attributes 96
by overriding methods 97, 98
components 25
methodology 95
methods 78
system closure command 167
TESTAF command 47
testing
components 97
new attributes 100
new methods 100
overridden methods 98
SAS/AF applications 8
SCL programs 46, 47
text editor 69
TextCompletion attribute metadata item
87
tooltips 54
toolTipText attribute 54
Type attribute metadata item 85
U
underscore (_), in method names 77
usability testing, SAS/AF applications 9
USECLASS statement 104
user interface development
Interface Editor 68
SAS/AF applications 8, 15
uses relationships 75
V
validating character values 116
ValidValues 86
value argument 118
VERBOSE value 168
viewer components 76
definition 29
example 31
uses for 30
virtual methods 78
W
WBROWSE command 55
windows, opening 44
X
XLocation attribute 145
Y
YLocation attribute 145
T
TERM section 166
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