RE: Data Queues

["Richard Dean" <rddean@xxxxxxx>]

Thanks for all the input from everyone.  I will give this a try.


-----Original Message-----
From: owner-java400-l@midrange.com
[mailto:owner-java400-l@midrange.com]On Behalf Of
pluta@nexgensoftware.com
Sent: Tuesday, August 24, 1999 12:48 AM
To: JAVA400-L@midrange.com
Subject: Re: Data Queues





To the Toolbox, each entry on the Data Queue is just a stream of bytes or
all
text.  When you read an entry from the DataQueue object you get a
DataQueueEntry
object.  From DataQueueEntry you getData() or getString().  If you call
getString(), the Toolbox assumes the data is all text and converts it from
EBCDIC to unicode before putting it in the String object.  If you call
getData(), the Toolbox just hands you a byte array with the data it read off
the
queue.  Your code extracts the data.  You can use a Toolbox Record object or
pull the data out using simple converters.  In your case I think the Record
object is probably more work than you need.  It would be easier to use the
AS400Text object to convert the bytes into a String.

David Wall
AS/400 Toolbox for Java
---------

The other option is to use the data structure capabilities of the Toolbox.
This
is what I do in my JDQM/400 routines.  In order to support a common
interface
between RPG servers and Java clients, I've created a set of AS/400 programs
that
wrapper the data queue calls (QSNDDTAQ and QRCVDTAQ).  RPG servers call
these
programs directly.  The Java clients call them using my JdqmSession classes,
which use data structures to break down the data queue messages.  Here's a
few
excerpts from the JdqmSession class:


DEFINE A STRUCTURE

  static AS400DataType[] dqmMsg =     {
     new AS400Text(10),
     new AS400Text(10),
     new AS400Text(2),
     new AS400Text(2),
     new AS400Text(2),
     new AS400Text(2),
     new AS400Text(2),
     new AS400ByteArray(200)
  };

  private Object[] dqmMsgJava = new Object[0];

  private AS400Structure dqmMsgCvt;


INITIALIZATION

     AS400 sys = Pbd400.getAS400();
     dqmParms = new ProgramParameter[1];
     dqmParms[0] = new ProgramParameter(230);

     dqmCRcv  = new ProgramCall(sys);
     dqmCRcv.setProgram("/QSYS.LIB/" + syslib + ".LIB/DQMCRCV.PGM",
dqmParms);

     dqmMsgCvt = new AS400Structure(dqmMsg);


RECEIVE

public Object[] receive() {

     try {

          if (dqmCRcv.run() == false) {(dqmMsg);b
               System.out.println("dqmCRcv failed.");
               System.exit(0);
          }

     } catch (Exception e) {
          System.out.println("dqmCRcv Exception: " + e.getMessage());
     }

     dqmMsg400  = dqmParms[0].getOutputData();
     return (Object[]) dqmMsgCvt.toObject(dqmMsg400, 0);
}



There's not a lot of error checking in this, but what ends up happening is
that
the receive() method returns an array of objects corresponding to the fields
defined in the structure.  For example, objectArray[0] would contain a
String
made from the first 10 bytes of the message.  I find this technique much
less
cumbersome than using the Record class.

This example and all the others are in PBD1.2P, which can be downloaded from
my
website:

http://www.zappie.net
Where the AS/400 speaks Java with an RPG accent


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