Put 2 Messages with Unique CorrelId and Get 1 Message by CorrelId

On StackOverflow, someone asked a question about putting 2 messages on a queue with unique correlation ids and then retrieve a message with a particular correlation id.

Here is a fully functioning Java/MQ program that will put 2 messages on a queue with unique correlation ids and then retrieve a message with a particular correlation id (i.e. “0002”).

You can download the source code from here.

import java.io.IOException;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Hashtable;

import com.ibm.mq.MQException;
import com.ibm.mq.MQGetMessageOptions;
import com.ibm.mq.MQMessage;
import com.ibm.mq.MQPutMessageOptions;
import com.ibm.mq.MQQueue;
import com.ibm.mq.MQQueueManager;
import com.ibm.mq.constants.CMQC;

/**
 * Program Name
 *  MQTest11B
 *
 * Description
 *  This java class will connect to a remote queue manager with the
 *  MQ setting stored in a HashTable, put 2 message on a queue with unique CorrelIds
 *  and then retrieve the message with a  CorrelId of "0002".
 *
 * Sample Command Line Parameters
 *  -m MQA1 -h 127.0.0.1 -p 1414 -c TEST.CHL -q TEST.Q1 -u UserID -x Password
 *
 * @author Roger Lacroix
 */
public class MQTest11B
{
   private static final SimpleDateFormat  LOGGER_TIMESTAMP = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS");

   private Hashtable<String,String> params;
   private Hashtable<String,Object> mqht;
   private String qMgrName;
   private String outputQName;

   /**
    * The constructor
    */
   public MQTest11B()
   {
      super();
      params = new Hashtable<String,String>();
      mqht = new Hashtable<String,Object>();
   }

   /**
    * Make sure the required parameters are present.
    * @return true/false
    */
   private boolean allParamsPresent()
   {
      boolean b = params.containsKey("-h") && params.containsKey("-p") &&
                  params.containsKey("-c") && params.containsKey("-m") &&
                  params.containsKey("-q") &&
                  params.containsKey("-u") && params.containsKey("-x");
      if (b)
      {
         try
         {
            Integer.parseInt((String) params.get("-p"));
         }
         catch (NumberFormatException e)
         {
            b = false;
         }
      }

      return b;
   }

   /**
    * Extract the command-line parameters and initialize the MQ HashTable.
    * @param args
    * @throws IllegalArgumentException
    */
   private void init(String[] args) throws IllegalArgumentException
   {
      int port = 1414;
      if (args.length > 0 && (args.length % 2) == 0)
      {
         for (int i = 0; i < args.length; i += 2)
         {
            params.put(args[i], args[i + 1]);
         }
      }
      else
      {
         throw new IllegalArgumentException();
      }

      if (allParamsPresent())
      {
         qMgrName = (String) params.get("-m");
         outputQName = (String) params.get("-q");

         try
         {
            port = Integer.parseInt((String) params.get("-p"));
         }
         catch (NumberFormatException e)
         {
            port = 1414;
         }
         
         mqht.put(CMQC.CHANNEL_PROPERTY, params.get("-c"));
         mqht.put(CMQC.HOST_NAME_PROPERTY, params.get("-h"));
         mqht.put(CMQC.PORT_PROPERTY, new Integer(port));
         mqht.put(CMQC.USER_ID_PROPERTY, params.get("-u"));
         mqht.put(CMQC.PASSWORD_PROPERTY, params.get("-x"));

         // I don't want to see MQ exceptions at the console.
         MQException.log = null;
      }
      else
      {
         throw new IllegalArgumentException();
      }
   }

   /**
    * Connect, open queue, write a message, close queue and disconnect.
    *
    */
   private void testSendAndReceive()
   {
      MQQueueManager qMgr = null;
      MQQueue queue = null;
      int openOptions = CMQC.MQOO_INPUT_SHARED | CMQC.MQOO_OUTPUT | CMQC.MQOO_FAIL_IF_QUIESCING;
      MQPutMessageOptions pmo = new MQPutMessageOptions();
      pmo.options = CMQC.MQPMO_NO_SYNCPOINT | CMQC.MQPMO_FAIL_IF_QUIESCING;
      MQGetMessageOptions gmo = new MQGetMessageOptions();
      gmo.options = CMQC.MQGMO_NO_SYNCPOINT | CMQC.MQGMO_WAIT | CMQC.MQGMO_CONVERT | CMQC.MQGMO_FAIL_IF_QUIESCING;
      gmo.matchOptions = CMQC.MQMO_MATCH_CORREL_ID;
      gmo.waitInterval = CMQC.MQWI_UNLIMITED;
      MQMessage sendmsg;
      String msgData;
      DecimalFormat df = new DecimalFormat("0000");

      try
      {
         qMgr = new MQQueueManager(qMgrName, mqht);
         logger("successfully connected to "+ qMgrName);

         queue = qMgr.accessQueue(outputQName, openOptions);
         logger("successfully opened "+ outputQName);
         
         /*
          * Code to send 2 messages with a specific CorrelId.  i.e. 0001 and 0002
          */
         for (int i=0; i < 2; i++)
         {
            // Define a simple MQ message, and write some text
            sendmsg = new MQMessage();
            sendmsg.format = CMQC.MQFMT_STRING;
            sendmsg.messageId = CMQC.MQMI_NONE;
            sendmsg.correlationId = df.format(i+1).getBytes();

            // Write message data
            msgData = "This is a test message from MQTest11B. CorrelID is "+new String(sendmsg.correlationId);
            sendmsg.writeString(msgData);

            // put the message on the queue
            queue.put(sendmsg, pmo);
            logger("Sent: Message Data>>>" + msgData);
         }
         
         /*
          * Code to receive a message with a specific CorrelId.  i.e. 0002
          */
         
         // Define a simple MQ message, and write some text
         MQMessage receiveMsg = new MQMessage();
         receiveMsg.messageId = CMQC.MQMI_NONE;
         receiveMsg.correlationId = "0002".getBytes();

         // get the message on the queue
         queue.get(receiveMsg, gmo);

         if (CMQC.MQFMT_STRING.equals(receiveMsg.format))
         {
            String msgStr = receiveMsg.readStringOfByteLength(receiveMsg.getMessageLength());
            logger("Received: Message Data>>>" + msgStr);
         }
         else
         {
            byte[] b = new byte[receiveMsg.getMessageLength()];
            receiveMsg.readFully(b);
            logger("Received: Message Data>>>" + new String(b));
         }
      }
      catch (MQException e)
      {
         logger("CC=" +e.completionCode + " : RC=" + e.reasonCode);
      }
      catch (IOException e)
      {
         logger("IOException:" +e.getLocalizedMessage());
      }
      finally
      {
         try
         {
            if (queue != null)
            {
               queue.close();
               logger("closed: "+ outputQName);
            }
         }
         catch (MQException e)
         {
            logger("CC=" +e.completionCode + " : RC=" + e.reasonCode);
         }
         try
         {
            if (qMgr != null)
            {
               qMgr.disconnect();
               logger("disconnected from "+ qMgrName);
            }
         }
         catch (MQException e)
         {
            logger("CC=" +e.completionCode + " : RC=" + e.reasonCode);
         }
      }
   }

   /**
    * A simple logger method
    * @param data
    */
   public static void logger(String data)
   {
      String className = Thread.currentThread().getStackTrace()[2].getClassName();

      // Remove the package info.
      if ( (className != null) && (className.lastIndexOf('.') != -1) )
         className = className.substring(className.lastIndexOf('.')+1);

      System.out.println(LOGGER_TIMESTAMP.format(new Date())+" "+className+": "+Thread.currentThread().getStackTrace()[2].getMethodName()+": "+data);
   }

   /**
    * main line
    * @param args
    */
   public static void main(String[] args)
   {
      MQTest11B write = new MQTest11B();

      try
      {
         write.init(args);
         write.testSendAndReceive();
      }
      catch (IllegalArgumentException e)
      {
         logger("Usage: java MQTest11B -m QueueManagerName -h host -p port -c channel -q QueueName -u UserID -x Password");
         System.exit(1);
      }

      System.exit(0);
   }
}

And the output will look like:

2021/07/02 14:01:59.316 MQTest11B: testSendAndReceive: successfully connected to MQA1
2021/07/02 14:01:59.332 MQTest11B: testSendAndReceive: successfully opened TEST.Q1
2021/07/02 14:01:59.332 MQTest11B: testSendAndReceive: Sent: Message Data>>>This is a test message from MQTest11B. CorrelID is 0001
2021/07/02 14:01:59.347 MQTest11B: testSendAndReceive: Sent: Message Data>>>This is a test message from MQTest11B. CorrelID is 0002
2021/07/02 14:01:59.347 MQTest11B: testSendAndReceive: Received: Message Data>>>This is a test message from MQTest11B. CorrelID is 0002
2021/07/02 14:01:59.347 MQTest11B: testSendAndReceive: closed: TEST.Q1
2021/07/02 14:01:59.347 MQTest11B: testSendAndReceive: disconnected from MQA1

Regards,
Roger Lacroix
Capitalware Inc.