James,

To add to Joe's comments, a lot of the infrastructure is done if you
are working in a Sevlet environment. We use an open-source
framework called Struts (http://jakarta.apache.org/struts). Struts
helps to enforce what Joe is talking about. Struts is designed to
supply a Model - View - Controller (MVC) or Model-2 structure
that is similar to what DDS and 5250 data streams provide for
green screens. Struts also provides validation and format (Tiles)
support that go beyond what you find in DDS.

Like Joe mentioned, you have to keep track of the session related
information. Separating this from the presentation (your JSP pages)
is a goal. The latest release of Struts, which is also the initial
release,
has no workflow management built in, but the latest development sources

do. That support is designed to facilitate multiple form progressions.

Overall, Struts is lightweight. If you need something more inclusive,
Expresso would be a good bet. Beyond this, you get into EJBs,
which simplify some operations, but complicate the overall design.

David Morris


>>> joepluta@PlutaBrothers.com 01/04/02 11:03AM >>>
> From: James W. Kilgore
>
> I have a dumb question: How do you keep the panels and programs
> in sync when the
> user presses the back button or jumps to a different panel in
> their history?

The way I do it is to keep a session ID and a panel sequence.  The
servlet
checks to make sure the correct panel is being returned, and if not,
redisplays the correct one.  This also allows integration with other
web
applications.  Session timeouts are another issue, either from browser
sessions ending or from called programs failing.

The truth is that there is some infrastructure work to be done, but
once you
do it, you can end up with an environment every bit as robust as your
old
5250.

Joe Pluta
www.plutabrothers.com


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