Sending messages in an IBM MQ message group

The message flow must set the following MQMD fields:

• GroupId
• MsgSeqNumber
• MsgFlags

You can use the following example of ESQL code in a Compute node, which shows how to set these fields:

DECLARE MSGNUM INT 0;
  DECLARE MSGTOTAL INT 5;
  WHILE MSGNUM < MSGTOTAL DO
    SET MSGNUM = MSGNUM + 1;
    CALL CopyMessageHeaders();
    -- Manually set the groupId since we cant ask the queue manager to generate one.
    -- the UUIDASBLOB function could be used here to generate one, but this must be done
    -- outside the loop to keep the same groupId throughout!
    SET OutputRoot.MQMD.GroupId = X'000000000000000000000000000000000000000000000001';
    SET OutputRoot.MQMD.MsgSeqNumber = MSGNUM;
    SET OutputRoot.MQMD.MsgFlags = MQMF_MSG_IN_GROUP;
    IF (MSGNUM = MSGTOTAL) THEN
      SET OutputRoot.MQMD.MsgFlags = MQMF_LAST_MSG_IN_GROUP;
    END IF;
    SET OutputRoot.XML.TestCase = MSGNUM;
    PROPAGATE;
  END WHILE;
  RETURN FALSE;

You can use the following example of Java™ code in a JavaCompute node, which shows how to set these fields:

public class mq_group_java_JavaCompute extends MbJavaComputeNode {
      public void evaluate(MbMessageAssembly assembly) throws MbException {
        MbOutputTerminal out = getOutputTerminal("out");
        int MSGTOTAL = 5;
        for(int MSGNUM = 1 ; MSGNUM <= MSGTOTAL;MSGNUM++){
           MbMessage newMessage = new MbMessage();
           MbElement root = newMessage.getRootElement();
           MbElement mqmd = root.createElementAsFirstChild("MQMD");
           mqmd.createElementAsLastChild(MbElement.TYPE_NAME_VALUE, 
           "GroupId", new byte[]{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1});
           mqmd.createElementAsLastChild(MbElement.TYPE_NAME_VALUE, "MsgSeqNumber", MSGNUM);
           if (MSGNUM == MSGTOTAL){
               mqmd.createElementAsLastChild(MbElement.TYPE_NAME_VALUE, 
               "MsgFlags", 16); // MQMF_LAST_MSG_IN_GROUP 0x00000010
           }
           else{
               mqmd.createElementAsLastChild(MbElement.TYPE_NAME_VALUE, 
               "MsgFlags", 8);  // MQMF_MSG_IN_GROUP      0x00000008
           }
           MbElement xmlnsc = root.createElementAsLastChild("XMLNSC");
           MbElement body = xmlnsc.createElementAsLastChild(MbElement.TYPE_NAME,"TestCase",null);
           body.setValue(MSGNUM);
           MbMessageAssembly newAssembly = new MbMessageAssembly(assembly,newMessage);
           out.propagate(newAssembly);
        }
    }
}