Re: ILE Conversion

Mark wrote:
>I have been assigned the task of converting a HUGE monolith of a program
>into more manageable pieces. I have been working with RPG IV now for about
>4 years and have been creating small ILE programs utilizing
sub-procedures,
>service programs, and the rest of that good stuff for about a year. This
is
>the first very large project I will be attempting and I have a few
>questions.
>
>Regarding screen handling: The current program maintains 10 screens in one
>display file. Would it be advantageous to place each display format in
it's
>own display file or to continue to place all of the screens in one display
>file and just maintain each format in it's own module.
>...

Screen handling is a tricky subject.  Like many others here, you too
may someday have to deal with the issue of "web-enabling" your
application.  Web applications have a much different user interface
model than your typical monolithic AS/400 application.  In particular,
web apps are driven by the web server, and not by the application
itself.  If you've done any CICS programming or S/36 MRT programming,
you should be comfortable with web programming concepts.

When restructuring your app, anything dealing with the user interface
should be separated out into separate modules.  The business logic
preferably should be restructured into a set of procedures that can
be called in "batch" mode with no global data within the procedures.

There's more to it than that, obviously, but hopefully you'll start
thinking about UI-logic separation when restructuring your code.

(Note that web-based programming is a major focus for us in the
Toronto Lab, and hopefully in the future you'll see some easier ways
to web-enable your apps.)

Cheers!  Hans

Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com


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