[WDSCI-L] Re: Installing a web change (was: importing a rpg orsqlrpg)

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: Buck Calabro
>
> >OK, I'm trying to understand the pieces here. Assume
> >I webface my system. My "system" means everything
> >that's on my iSeries now, shipping, receiving,
> >order entry, purchasing, accounting, HR, etc.
> >I deploy this in WebSphere on my iSeries.
>
> Yes.  The WF tool has an option to bundle up the entire lot of converted
> panels as a WAR or EAR file, which WAS imports as a native Java app.

This is one of the problems with WebFacing, IMHO.  The integrated WAR/EAR
file does not coordinate very well with the production environment of most
shops, where programs are independent entities to be modified, tested and
promoted.


> >Each screen has one (or more?) JSPs. Servlets too? And a JAR?
>
> Each record format has several JSP files with corresponding servlets.  The
> exact number depends on whether the rcdfmt is input, output or both.  The
> only JAR is the WF runtime.  The MVC model is implemented by JSP-View,
> Servlet-Model, WFRun.jar-Controller.  Don't quote me precisely on
> the name, but you get the idea.

This is a fundamental flaw in the architecture.  PSC/400 has one JSP and one
XML file per program, and a common servlet for all programs.  Not only does
this make it easy to integrate into change management systems, it's also
works with standard development practices: you can update a single program
independent of all the other programs.


> >What restarts when I make a change to a set of programs? The
> >"web module"?  What is that? When that gets restarted what
> >is lost? Sessions? Whose? All my users? Only those in an
> >"application"? What is an application? AR? Accounting?
>
> I can't answer these parts.  Maybe I'll get the time to fire up
> WAS and try it.

This gets tricky.  Normally, updating an application means stopping and
starting the web server for that application, which brings down all
sessions.  Unless somebody can tell me different, I equate a web module with
an interactive subsystem - when you bring it down, everything comes down.
This is the problem with the WAR/EAR model, and why it really has no place
in a production environment.  It's great for deployment, hell on
maintenance.

And, as you might guess, PSC/400 doesn't have this problem.  At most you
must shut down sessions currently using that application, just like you
would if you were modifying a display file.

Joe