Destination bridge

[gquintana]

Hello,

Is it possible to create "destination bridges" in JBoss MQ: every JMS message sent to the bridge is forwarded to another Queue or Topic on another JMS server as soon as it is available.

Other J2EE servers already do this

• 
  
• Bea Weblogic: http://edocs.beasys.com/wls/docs70/adminguide/msgbridge.html
  
• Joram (Jonas): http://joram.objectweb.org/current/doc/Joram-4.3-en.pdf , chapter 10
  
  Does JBoss have a similar feature?
  
  Thanks for your help,
  Gérald
  

[genman]

No. But I imagine it would be fairly simple to code using an MDB.

[gquintana]

Fairly easy?

• Handle all message types: Text, Map, Object, Bytes...
  
• Handle header properties
  
• Handle sending options: priority, time to live, delivery mode
  
  
  I guess I am not the only one who needs such a behaviour. JBoss can not do this in generic way?

[gquintana]

I followed your advice and wrote a MDB:

 public void onMessage(Message sourceMessage) {
 Connection connection = null;
 try {
 connection = getTargetConnectionFactory().createConnection();
 Session session = connection.createSession(true, Session.AUTO_ACKNOWLEDGE);

 // Body
 Message targetMessage;
 if (sourceMessage instanceof TextMessage) {
 // Text
 TextMessage sourceTextMessage = (TextMessage) sourceMessage;
 targetMessage = session.createTextMessage(sourceTextMessage.getText());
 } else if (sourceMessage instanceof BytesMessage) {
 // Bytes
 BytesMessage sourceBytesMessage = (BytesMessage) sourceMessage;
 BytesMessage targetBytesMessage = session.createBytesMessage();
 byte[] bytes = new byte[getByteBufferSize()];
 int byteCount;
 while((byteCount=sourceBytesMessage.readBytes(bytes))>0) {
 targetBytesMessage.writeBytes(bytes, 0, byteCount);
 }
 targetMessage = targetBytesMessage;
 } else if (sourceMessage instanceof MapMessage) {
 // Map
 MapMessage sourceMapMessage = (MapMessage) sourceMessage;
 MapMessage targetMapMessage = session.createMapMessage();
 Enumeration mapNameEnum = sourceMapMessage.getMapNames();
 while (mapNameEnum.hasMoreElements()) {
 String mapName = (String) mapNameEnum.nextElement();
 targetMapMessage.setObjectProperty(mapName, sourceMapMessage.getObject(mapName));
 }
 targetMessage = targetMapMessage;
 } else if (sourceMessage instanceof ObjectMessage) {
 // Object
 ObjectMessage sourceObjectMessage = (ObjectMessage) sourceMessage;
 targetMessage = session.createObjectMessage(sourceObjectMessage.getObject());
 } else if (sourceMessage instanceof StreamMessage) {
 // Stream
 StreamMessage sourceStreamMessage = (StreamMessage) sourceMessage;
 StreamMessage targetStreamMessage = session.createStreamMessage();
 byte[] bytes = new byte[getByteBufferSize()];
 int byteCount;
 while((byteCount=sourceStreamMessage.readBytes(bytes))>0) {
 targetStreamMessage.writeBytes(bytes, 0, byteCount);
 }
 targetMessage = targetStreamMessage;
 } else {
 targetMessage = null;
 }

 if (targetMessage == null) {
 log.error("Message couldn't be copied");
 } else {
 // Header
 Enumeration propertyNameEnum = sourceMessage.getPropertyNames();
 while (propertyNameEnum.hasMoreElements()) {
 String propertyName = (String) propertyNameEnum.nextElement();
 targetMessage.setObjectProperty(propertyName, sourceMessage.getObjectProperty(propertyName));
 }

 // Message producer
 MessageProducer messageProducer = session.createProducer(getTargetDestination());
 messageProducer.setDeliveryMode(sourceMessage.getJMSDeliveryMode());
 messageProducer.setPriority(sourceMessage.getJMSPriority());
 final long timestamp = sourceMessage.getJMSTimestamp();
 if (timestamp>0) {
 final long expiration = sourceMessage.getJMSExpiration();
 if ((expiration>0)&&(expiration>timestamp)) {
 messageProducer.setTimeToLive(timestamp);
 }
 } else {
 messageProducer.setDisableMessageTimestamp(true);
 }
 messageProducer.send(targetMessage);
 }
 } catch(JMSException jmsExc) {
 log.error("Bridge message", jmsExc);
 } finally {
 if (connection != null) {
 try {
 connection.close();
 } catch (JMSException e) {
 }
 }
 }
 }

I couldn't find an easier way to do it, could you?

[genman]

The JBoss messages support a clone via "myClone()" so you can use that method instead of copying by hand from JBoss -> to some other provider. Or use the "SpyEncapsulatedMessage" to copy from other provider -> JBoss.

It's not that elegant, I admit.