Re: How many active Jobs ?

The number of jobs depends on how you call the program.

   One choice is to have a central / single Java job that catches the
   requests then call the COBOL program via JNI.  When you use JNI all
   processing stays on the same thread.  If you have a thread for each user
   then you have only one job, just a lot of threads.  If you use this
   model you have two important considerations.  (1) Identity -- by
   default, each call to the COBOL program will run under the user profile
   of the java job.  If you need to preserved the identity of the user then
   you have to swap the identity of the thread before calling the program.
   (2) Thread safety -- your COBOL program will be called multiple times in
   the same job.  Is it thread and object safe?  For example, if the COBOL
   program creates an object in QTEMP, the QTEMP will be the same for each
   thread (there is only one QTEMP per job).  You could easily have object
   collisions.

   Another choice is to have the central Java job use the Toolbox
   ProgramCall object to call the COBOL program.  ProgramCall is performed
   via an OS/400 server.  There is one server job per Toolbox AS400 object
   so you can control the number of jobs.  For example, through connection
   pooling you can put a limit on the number of connections (jobs).  If
   your threshold is reached, new reqeusts would wait until an active one
   completes.  If you don't use connection pooling there will be one active
   job for each concurrent program call.  The good news is since each
   server is in its own job, you have thread safety.  Also, since the
   Toolbox preserves identity, each program can run as a different user.
   The bad news is there will be more jobs.

   Another choice is one Java job for each user.  With this case you can
   preserve identity and it will be thread safe.  Besides having more jobs,
   another thing to watch for here is the performance of starting the Java
   job.  It can take measurable time to start the JVM.

Hope this helps,

David Wall
AS/400 Toolbox for Java


"Atul Ghanekar" <atul.ghanekar@mphasis.com> on 06/21/2000 11:48:07 PM

Please respond to JAVA400-L@midrange.com

To:   JAVA400-L@midrange.com
cc:
Subject:  How many active Jobs ?




Hi

I am posed with a problem :
I am supposed to make one As/400 based legacy system Web enabled but by
making use of existing COBOL programs logic.
So only choice is to call Cobol program from a JAVA program (Wrapper).
Our problem is there are 100's of users who will be making calls to this
cobol program
so does that mean that many active jobs are there on AS/400. Like in JAVA
single thread
will take care of such situation. What happens on AS/400 ?

Regards,

Atul

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