Mastering PowerBuilder

General Purpose Classes

Classes that place all potentially required functionality in one ancestor class belong to this category. That means, methods are defined for all possible functionality for that object. When the developer uses this class, he turns on and off the functionality in one of the following ways:

• Call the method with arguments with TRUE/FALSE values. (In the ancestor class, the code uses IF...ELSEIF statement to check the argument value and acts accordingly)
• Call separate functions to turn on/off the functionality and then call the actual method. (In the ancestor class, boolean instance variables are defined and in the method’s code IF...ELSEIF statements are used to check the instance variable values for on/off.).

A typical example of a general-purpose class is a DataWindow with all the functionality, as shown in the following picture:

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