User manual PROGRESS ABL VIDEOS INTRODUCTION TO ABL CLASSES

[. . . ] ABL Videos: Introduction to ABL Classes Developing with ABL Classes in OpenEdge 10 This series of short video presentations introduces the support for classes and objectoriented programming in OpenEdge 10, and is intended for ABL developers who have not worked in an object-oriented environment before. [. . . ] The Interface definition serves as a contract ­ enforced by the ABL compiler -- that classes implementing the Interface must adhere to, assuring consistency of access to the behavior defined in the Interface. Using Inheritance and Super Classes ­ Part 1 This video is the first of two parts that show the use of inheritance of common behavior using the INHERITS phrase in a class definition. First we take an existing class that operates on the AutoEdge Employee table, and create a similar class that does the same job for the Customer table. Having seen the code duplication that results from this copy, paste, and edit operation, we start the process of identifying common code and factoring it out into a new class. Part two of the inheritance presentation completes the job of removing common code from multiple classes that implement the same Interface and do the same data management job for different database tables. The new class that the code goes into becomes a super class for both of the table-specific subclasses, which specify in ABL syntax that they INHERIT from the super class. The example also shows how to override a method in a subclass, so that the method's definition is divided between common behavior in the super class and table-specific code in the subclass. [. . . ] The video series is accompanied by a single document that summarizes the presentations, without duplicating the full discussion, and shows the complete code samples used in the videos. Programming with Classes in ABL in OpenEdge 10 (paper) Generated by Clearspace on 2010-12-27-05:00 3 [. . . ]