RE: Java versus RPG on iSeries

> From: Richard Dettinger
>
> I don't quite see the difference between middleware and business
> applications that you do.

I don't think our world views are really that different, Richard, especially
seeing your comments.  And you definitely centered in on my main point.


> My take on your comments is that you might be missing one small piece of
> the 'ah-ha' of OOP.
> It seems to me that you focus a lot on the object hierarchy.  My
> opinion is
> that object hierarchies are almost always
> overdone.

> A far better OO model is the use of interfaces to define types, relatively
> light object hierarchies and the use of composition over inheritance.

We DO agree!  <grin>

Actually, when I teach beginning Java, after introducing the terms that
everybody always hears - encapsulation, polymorphism, inheritance - I then
go on to say that the most powerful concept is one nobody ever seems to
mention: composition.


> It seems to me that for this reason alone, frameworks like San Francisco
> are often ill-fated to begin with.  They want
> to build a 'stack' and often there's just no 'stack' that works.

I again agree.  I'm glad to see that someone coming from the OO side has
come to the same conclusion - inheritance is not the universal panacaea
<smile>.

Anyway, I think we agree more than disagree.  I think certain features of
OO, especially that of using interfaces to hide implementation details, can
be applied successfully to business applications.  But now here's the real
kicker:

Other than inheritance and polymorphism, just about anything you can do in
OO can be implemented with RPG IV.  A few enhancements (such as expanding
the name space for procedures to include the service program name) would
make RPG IV perfectly capable of doing MOST of what you can do in OO, with
the added benefit of making it a little easier for legacy programmers to
make the transition.  Plus, the tight integration of RPG and OS/400 and
DB2/400 makes me still question whether the overhead of Java is worth the
benefits.

It really depends on your development environment (new vs. legacy), your UI
requirements (green-screen vs. thick client vs. browser) and your existing
skill set (whether your existing staff can, and want to, learn a whole new
language).

I guess my point is that OO is not a hands-down winner over good old RPG, as
some might have us believe.  Today, I think Java is best suited for the
middleware layer, with RPG for the business logic, especially as we begin to
implement more "OO-like" capabilities in our RPG code.

My two cents, for what it's worth.

Joe