RE: Objects and such

Buck,

You can't in RPG since RPG doesn't support polymorphism or overloading.

Note the basic difference between polymorphism and overloading is that with overloading, the choice as
to which function to call is made at compile time vs. run-time with polymorphism. Though even with
polymorphism if the choice can be made at compile time, it (usually) will be for performance reasons.

To "simulate" either, you need IF/WHEN.

Creating the right abstract class _IS_ the hard part but maybe you can still make some comparisons to
creating service programs. Specifically, consider service programs that act as interfaces to
something else. Like Scott's FTPAPI and HTTPAPI or maybe service programs you've written to
encapsulate some IBM APIs. The key question you have to ask yourself, is not only what how do I need
to use this functionality now, but how may it be used in the future.

HTH,
Charles

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Buck
Sent: Friday, October 19, 2007 11:47 AM
To: rpg400-l@xxxxxxxxxxxx
Subject: Re: Objects and such

Joe Pluta wrote:
> This is the essence of polymorphism: call the same >
method for different objects and the underlying code > will
do what it's supposed to do.

How does one do that in RPG without IF or WHEN? My RPG
experience and habits didn't help take the concept to heart
and become fluent creating classes. Reading the Javadoc and
consuming a class is a lot like using a service program's
procedure in an RPG mainline, but building the foundation
classes so they can be usefully subclassed does not seem like
building an RPG service program.
--buck
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