Self-Reference

A method can refer to the current object using the %This system variable.

Due to subtyping, %This is an object of either the method's class or a subclass of the method's class.

In PeopleCode, the methods and properties of the class cannot be used without an object qualification.

In the following code example, the line in bold indicates an error. You can't call the class this way: you must use %This.

class FactorialClass
   method factorial(&I as number) returns number;
end-class;

method factorial
   if &I <= 1 then
      return 1;
   end-if;

   return &I * factorial(&I - 1); /* error - factorial undefined */

   return &I * %This.factorial(&I - 1); /* okay */
end-method;

One of the implications of this is that when you're writing a method, there isn't any way to guarantee you'll access your own class' version of a public method (rather then a subclass') as it might be overridden by a subclass. The only way to make sure that you can access your own method is to make it private.

If you have some action that you also want to make public, and you want guaranteed access to it, you can make the action a private method, then define a public method for it that calls the private one.

In the following example, factorial is the public method that can be used by other classes. myFactorial is the private action.

class FactorialClass
   method factorial(&I as number) returns number;
private
   method myFactorial(&I as number) returns number;
end-class;

method factorial
   return myFactorial(&I);
end-method;

method myFactorial
   if &I <= 1 then
      return 1;
   end-if;
   
   return &I * %This.myFactorial(&I - 1);
   
end-method;

If you declare an instance variable as private you can still access it as a private property in another instance of the same class. For example, given the following declaration:

class Example

   private

      instance number &Num;

end-class;

A method of Example could reference another Example instance's &Num instance variable as follows:

&X = &SomeOtherExample.Num;

class Base
   method Base();
   method Test();
   method CallTest();
   property string sTestResult;
end-class;

method Base
   %This.Test();
end-method;

method Test
   &sTestResult = "BASE_METHOD_CALLED";
end-method;

method CallTest
   %This.Test();
end-method;

import PACKAGE:Base;

class Extend extends PACKAGE:Base;
   method Extend();
   
   method Test();
end-class;

method Extend
   %Super = create PACKAGE:Base();
end-method;

method Test
   /+ Extends/implements PACKAGE:Base.Test +/
   %This.sTestResult = "EXTENSION_METHOD_CALLED";
end-method;