Re: EGL and other things -- WEB400

Aaron wrote:

The reason is that the advantage of enhanced reuse afforded by
inheritance is lost in dynamic problem sets due to the extra rigidness of a
class structure. Short form: because business rules change so much, OO is a
bad choice.

I (and a lot of other developers in the world) disagree firmly here. Saying that OO is a bad choice for business logic... Well... any proof or research to back this up?

A GUI is a "natural" fit for OO. Buttons, windows, sliders and all these UI "thingies" we see naturally map to objects, that is true. But does this mean that it's a bad idea to implement BL with "objects"?

The only thing i want to say about this is that "inheritance" is to be used very sparingly. The main benefit from using "objects" is not inheritance (although a bvery nice feature but also misused a lot) but encapsulation. And i think encapsulation is always a good idea, UI or BL.

So instead, use "delegation" instead of "inheritance" in many cases, avoiding those deeply nested hierarchies which are indeed very rigid.

Of course, like always, you have to think about you design. And with an OO language, you probable have to think more up-front than with a procedural language. But i dont think this is bad.

Now i don't want to start a new thread about "inheritance" versus "delegation" here. It has been said more often by Joe e.g. That OO is good for UI, but not BL. In this respect you two seem to connect!

Jacobus

From: joepluta@xxxxxxxxxxxxxxxxx
To: web400@xxxxxxxxxxxx
Date: Sun, 16 Dec 2007 20:58:17 -0600
Subject: Re: [WEB400] EGL and other things

From: Aaron Bartell

Speaking of which, here is where I am stuck:
http://mowyourlawn.com/temp/RBDe_install.jpg. It won't let me complete
the
install. First I downloaded RAD 7.0 and installed successfully, and now
this is the RBDe portion of it. Any ideas?

Nope. Go the developerWorks and ask. Or at least post on the WDSC list
rather than here.

Here's a point, though. Would you agree that web UI is more complicated

than 5250 screen design? If so, then if EGL can let you put together a
good
looking web screen as easily as SDA lets you put together a green screen,
wouldn't by definition EGL be more productive than DDS? I'm just
saying...

I will say that it has gotten much better since I first started web
programming. But I wouldn't put it in the same overall league as 5250.

I guess I didn't make myself clear. If web UI is more complex than 5250,
and EGL can make a good looking web screen as easily as SDA can make a 5250
screen, then EGL is a more productive product. This isn't an opinion
question, it's a logical implication. If one tool makes a hard job easy,
and a second tool makes a harder job just as easy, which tool is more
productive?

Personally, I think generating HTML in RPG is just plain goofy, but

that's just me.

Generating HTML in Java would have to be just as goofy then, which is
exactly what your JSP architecture does - correct? In reality you are
talking about how well the implementation of a UI strategy is hidden.
With the current RPG Web frameworks it isn't hidden as well.

Wow. I guess we really don't connect at all. If you understood what I've
written over the years, I specifically say that static problem domains such
as generating HTML are the perfect province of OO languages, while dynamic
problem domains such as business rules are better served by procedural
languages. The reason is that the advantage of enhanced reuse afforded by
inheritance is lost in dynamic problem sets due to the extra rigidness of a
class structure. Short form: because business rules change so much, OO is a
bad choice.

If you've been talking to Barbara, then you know more about the compiler

than I do! Why ask me when you have the source?

Because I wasn't talking about features that are already public knowledge,
but instead probing to see if your interaction with the Rational team
revealed more appealing features other than being able to trim more than
spaces with the %trim() bif.

Wow. Your summary of the changes in RPG over the last decade is that %trim
removes spaces.

Wow.

You know what, Aaron? Between you, Trevor and Steve, it's possible that the
midrange mailing lists are actually becoming too toxic for me. The amount
of unbridled disdain for the tremendous work done by the IBM developers is
staggering, and I more and more I feel that any time I spend here is wasted.

I'm sorry that you're so bitter and condescending at such a young age.

Joe

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