Re: Calling java from RPG - how to increase performance

I think that some of this will be covered in Jon Paris's presentation at
the Washington (DC) Area Midrange's cosponsored seminar next week.
Checkout www.wash-midrange.org seminars option for details.

Don in DC



On Wed, 18 May 2005, Barbara Morris wrote:

> Larry Ducie wrote:
> > ...
> > As far as I'm aware, I only need to free objects created directly by the RPG
> > program. I assume that all objects created internally within java will be
> > garbage collected automatically once they are eligible (no non-circular
> > references). As it stands, I am freeing all objects created by RPG-to-Java
> > calls: I would class (no pun intended) a java object to be deemed created
> > via a RPG-to-Java call as any object returned to my RPG program from a *JAVA
> > procedure call. I would assume it is simply this reference that is being
> > freed - not the object itself (as it could be referenced by another object
> > within java).
>
> That's all correct.  But rather than thinking of objects being "created"
> by RPG, just think of RPG getting references to them.  Say you have a
> Java
> class that has a String object, and you have a method that returns the
> String.
> If you call that method twice from RPG, your RPG program will have two
> references
> to the String object, even though the calls didn't actually create any
> objects
> at all, since the String already existed before the calls.
>
> > ...
> > I'm going to look into creating a custom class that I simply instantiate via
> > a RPG-to-Java call - I'll get this to create the transformer and
> > StreamResult objects. I can then simply create a method that takes a byte
> > array, and I'll create the StreamSource object within java. That way I'll
> > only have one object referenced within my RPG program - my custom class.
> > This object will never be cleaned up as long as the job runs. This should
> > run quicker (I think).
> >
>
> Larry, that sounds like a good idea to use a custom Java method to do
> most of the Java code.  There is a fair amount of overhead in making a
> JNI call.  (It's an similar situation to doing several commmands using
> QCMDEXC vs calling a custom CL procedure.)
>
> Have you tried freeing your objects in groups rather than one at a
> time?  http://faq.midrange.com/data/cache/282.html
> This is mentioned in the V5R3 version of the RPG programmer guide, but
> not the V5R2 version.  Freeing them in groups should be quicker than
> doing them one at a time, and also it's easier and more reliable than
> keep tracking of every single reference.
>
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