OpenEdge Development:<br />Progress Dynamics Advanced Development Using ADM2 Properties and Methods in Progress Dynamics

This chapter provides an overview of the properties and methods of the Application Development Model, Version 2 (ADM2), that are essential to Progress Dynamics application builders. The overview is important so that you can:

Effectively use the Progress Dynamics framework.

Quickly distinguish the properties and methods meant for public use from those meant to support the internal workings of the framework or specialized applications.

Take advantage of useful supporting methods (internal procedures and functions) that you can call directly from your code.

Understand which methods are typically overridden and which are called directly.

The chapter also provides guidance on how methods are typically used. Some methods are simply internal procedures and functions for you to run from your code. Others are candidates for overriding, meaning that typically you write a local version of the method to extend its behavior and then invoke the standard behavior with a RUN SUPER statement. Another type of method is an event procedure. An event procedure is implemented as an internal procedure that responds to PUBLISH statements in the framework. Event procedures are localized or overridden. This chapter describes the event procedures that are the most likely candidates for localization and provides guidance on how to localize them.

The chapter organizes the information by task, but you are sure to find uses for some of the properties and methods in many other contexts. The following sections describe properties and methods in these task categories:

Getting basic information — Many properties, and some methods, return useful information about objects, their class, whether they are enabled, their contents, and so on.

Starting Progress Dynamics application windows — Understanding the sequence of events that occurs when the framework creates and initializes objects in a container allows you to intercept the process and customize or extend it for your needs. This section describes the relevant methods that you can call and properties that you can set or read to affect application startup.

Managing links in Progress Dynamics applications — This section reviews the properties and methods that the framework uses to manage the links between objects. It also describes how you can use and extend the properties and methods for your applications.

Customizing and managing queries — This section instructs you on the best ways to modify the WHERE clause of a query; determine when it is opened and closed; position and refresh queries; and so on.

Paging methods and properties — A number of properties and methods specifically support multi-page application windows, and this section reviews those.

Special functions that manage properties — Several functions let you define new properties at run time and also return information about standard object properties.

General-purpose methods — The framework provides a few special methods to set and retrieve properties whose values are complex enough that they cannot easily be used directly. This section discusses these methods.