RE: Business Logic Servers ( was: MVC in RPG?)

[<matt.haas@xxxxxxxxxxx>]

Jake,

This topic isn't really language specific coupled with the number of RPG
developers who would buy such a book is why there isn't one of this
topic. 

Taking this approach, you need to break the problem down into functional
areas and create servers to work with those functional areas (in an
order entry program, you're going to have functional areas like dealing
with customer info, prices, rights, shipping, tax, and inventory) and
each one of these server programs must be able to operate independently
of one another. Any dependencies (like needing to check rights before
prices) would be handled at a higher level than each server.

Another way of looking at this is that you would have a program that
deals with screen I/O and that program would in turn call the functional
servers that you've created to do individual functions.

Matt

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Jake Bruster
Sent: Thursday, October 04, 2007 12:32 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: Business Logic Servers ( was: MVC in RPG?)

The "how to" of writing an UI agnostic business logic server from
scratch is
exactly the process that I'm trying to understand. Although I've seen
many
references to the use of these servers, I've not been able to find an
article, book, or CBT course that fully describes the implementation
details
and the process for creating one of these servers using ILE RPG best
practices.

My original question was an attempt to derive the scope of the server.
Is
there a one-to-one relationship between the server and the traditional
monolithic green-screen program or should the server be more
generic with some type of "controller" program sitting between it and
the
UI?


On 10/3/07, Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx> wrote:
> Yes and no, Jake.  While you can take an existing program and turn it
into
> a
> server using this technique, you can also write the server program
from
> scratch to be UI agnostic.  The nice thing about the approach in the
> article
> is that it provides a quick way to turn an existing monolithic program
> into
> an interim server, giving you an opportunity to immediately start
working
> on
> the UI portion of the system even before you have your long-term
server
> architecture in place.
>
> In any event, I'm tickled that you found that old article; it shows
that
> I've been saying pretty much the same thing for a decade or more now
> <grin>.
>
> Joe