RE: Mixed RPG/Java performance (EXAMPLE CODE)

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: NGay@xxxxxxxxxxxxx
> 
> How would I make sure the server job stays open if I'm calling an RPG
> program say from within a WebSphere servlet/JSP application?  By
keeping
> the com.ibm.as400.data.ProgramCallDocument object alive?

This is one way.  The other way is to use a queued mechanism.


>  I suppose this
> could be achieved by storing the PCML object inside the WebSphere
session?
> Since two website users could access the same page at the same time
and
> these would be running in seperate threads both users could end up
> retrieving the PCML object at the same time and trying to invoke the
RPG
> program at the same time.  Surely some problems must arise trying to
do
> things like this?

No, because if you were doing this you would create one communication
object (I never use PCML, I prefer to use ProgramCall, but that's a
personal preference) per session and store it in the HttpSession.


> but this is much more based on Java code being more
> maintainable and better designed rather than any performance
decisions.

I'm glad you don't care about performance, because your performance is
going to be terrible.  And I guess I don't understand why Java is more
maintainable than COBOL.  They're programming languages, and frankly
Java sucks at processing business rules or even the simple act of doing
decimal precision mathematics; any business rules I've seen written in
COBOL are much more readable than the same code written in Java.


> But it does mean we'll have Cobol 'green screens' calling Java
programs to
> do their DB2 reads/updates in the background, and we'll also likely
have
> Java programs running in the website which are calling RPG programs
for
> their back ends.  I'm not really nervous about having a mix like this,
> just wondering if I should be :-) or if we're going to run into any
major
> performance issues.

Calls from RPG to Java are horribly expensive, especially the first one
that fires up the JVM.  Java to RPG is lightning fast.  When
communicating from RPG to Java, I almost always use data queues for
interface.

Joe