Release 10.1A: OpenEdge Getting Started:
Object-oriented Programming

Defining an object reference as a variable

This is the syntax to define an object reference as a variable:

Syntax

DEFINE [ access-mode ] VARIABLE object-reference        AS [ CLASS ] type-name .

Element descriptions for this syntax diagram follow:

object-reference

The name of a variable that will contain an object reference.

access-mode

The optional access modifier (PRIVATE|PROTECTED|PUBLIC) if the variable is being defined as a data member in a class definition. In a procedure, the access-mode cannot be specified and is always private.

CLASS

The CLASS keyword is required if type-name conflicts with an abbreviation for a built in Progress data type, such as INT (INTEGER). Otherwise, it can optionally be used to clarify the readability of the statement.

type-name

The type name of the class or interface. For more information on type names, see the "Using the CLASS construct" section or the "Using the INTERFACE construct" section, respectively.

The following example shows a fragment of the Main class from the sample classes that are fully implemented in the "Sample classes" section. This fragment shows several object references defined as variables:

CLASS Main:     DEFINE PRIVATE VARIABLE rCustObj         AS CLASS acme.myObjs.CustObj NO-UNDO.     DEFINE PRIVATE VARIABLE rCustObj2         AS CLASS acme.myObjs.CustObj NO-UNDO.     DEFINE PRIVATE VARIABLE rCommonObj         AS CLASS acme.myObjs.Common.CommonObj NO-UNDO.     DEFINE PRIVATE VARIABLE rIBusObj         AS CLASS acme.myObjs.Interfaces.IBusObj NO-UNDO.     DEFINE PRIVATE VARIABLE rHelperClass         AS CLASS acme.myObjs.Common.HelperClass NO-UNDO.     CONSTRUCTOR PUBLIC Main( ):         /* Create an instance of the HelperClass class */         rHelperClass = NEW acme.myObjs.Common.HelperClass( ).         /* Create an instance of the CustObj class */         rCustObj = NEW acme.myObjs.CustObj( ).     END CONSTRUCTOR.     ...     DESTRUCTOR PUBLIC Main( ):         DELETE OBJECT rCustObj.         rCustObj = ?.         DELETE OBJECT rHelperClass.         rHelperClass = ?.     END DESTRUCTOR. END CLASS.