Re: Call Back information

[Barbara Morris <bmorris@xxxxxxxxxx>]

"Bartell, Aaron L. (TC)" wrote:
> 
> I am not sure if I should post this here or in the Java list.
> 
> I have done a little of calling Java methods from an RPG program, but not
> enough to know the answer to my question.  Can RPG do a call back to a Java
> method?  The calling Java program must first be able to pass in a "pointer"
> to the method that should be used for the call back.  Then the RPG program
> would make a call to that method, but would that be the same object in
> memory or would it create a new one?  First off can Java pass a pointer of a
> method to an RPG program, and second, can RPG accept and call a pointer to a
> method vs. a procedure or class?
> 

Aaron, I don't know of any way for Java to pass a method pointer.  But
say you have a class C with a method m.  You could have subclasses C1
and C2 with their own versions of method m, and pass RPG either a C1 or
C2 object.  RPG would prototype extproc(*java:'C':'m'), and the call to
'm' for a subclass C1 object would get the C1 method m().  Same as if
you did this in Java:

  C c = new C1();
  c.m();  <--- calls method m() in subclass C1