Re: Help calling java from RPG

[James Perkins <jrperkinsjr@xxxxxxxxx>]

Well, from this it's tough to tell you what your error is. I'm don't call
Java from RPG very often, but nothing from this code is jumping out at me.

I am curious to know why you would use JPA form RPG? The reason for JPA in
Java is because there is not native DB interface which RPG has.

I'm not even sure how you would get JPA to properly work in RPG. Using RPG
to create Java objects isn't really a good idea. The JVM doesn't do GC
automatically with these objects. From the manual:

"Normally, Java does its own garbage collection, detecting when an object is
no longer needed. When you create objects by calling Java constructors from
your non-native RPG procedure, Java has no way of knowing that the object
can be destroyed, so it never destroys them. You can enable garbage
collection for several objects at once by calling the JNI functions
described in Telling Java to free several objects at
once<http://publib.boulder.ibm.com/infocenter/iadthelp/v7r0/topic/com.ibm.etools.iseries.pgmgd.doc/c0925076177.htm#wrpsevobj>.
If you know you are not going to need an object any more, you should tell
this to Java by calling the JNI function described in Telling Java you are
finished with a temporary
object<http://publib.boulder.ibm.com/infocenter/iadthelp/v7r0/topic/com.ibm.etools.iseries.pgmgd.doc/c0925076177.htm#wrpfintmp>
."


So, I guess IMHO I wouldn't even try it. It just seems like you would be
doing a lot of work to get something to work that RPG already handles
better.
--
James R. Perkins
http://twitter.com/the_jamezp


On Mon, Aug 24, 2009 at 08:00, Chris Beck <CBeck@xxxxxxxxxxxx> wrote:

> Hello,
>
> I am creating a RPG program that calls multiple Java method from RPG and am
> having problems with one of them.  In the code snippet below I am wondering
> how to set the hxplvl6Class field to the propper value? in Java I would just
> use the following: "Hxplvl6 hxplvl6 = em.find(Hxplvl6.class, l6number);"
>
>     D em...
>     D                 S               O   CLASS(*JAVA:
> 'javax.persistence.En+
>     D                                     tityManager' )
>
>     D HxpLvl6         S               O   CLASS(*JAVA : 'java.lang.Object'
> )
>
>     D hxplvl6Class    S               O   CLASS(*JAVA : 'java.lang.Class' )
>     D l6Number        S               O   CLASS(*JAVA : 'java.lang.Object'
> )
>
>     D find            PR              O   CLASS(*JAVA : 'java.lang.Object'
> )
>     D                                     EXTPROC(*JAVA :
> 'javax.persistence+
>     D                                     .EntityManager' : 'find' )
>     D  pmClass                        O   CLASS(*JAVA : 'java.lang.Class' )
>     D  pmKey                          O   CLASS(*JAVA : 'java.lang.Object'
> )
>
>
>      /Free
>        HxpLvl6 = find(em:hxplvl6Class:l6Number)
>
> Thanks for any help,
>
> Chris
>
>
> This email transmission and any documents, files or previous
> email messages attached to it may contain information that is
> confidential or legally privileged. If you are not the intended
> recipient, you are hereby notified that any disclosure, copying,
> printing, distributing or use of this transmission is strictly
> prohibited. If you have received this transmission in error,
> please immediately notify the sender by telephone or return
> email and delete the original transmission and its attachments
> without reading or saving in any manner.
>
> The Evangelical Lutheran Good Samaritan Society.
>
> --
> This is the Java Programming on and around the iSeries / AS400 (JAVA400-L)
> mailing list
> To post a message email: JAVA400-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/java400-l
> or email: JAVA400-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/java400-l.