JMS XA with JTA Example

This example shows you how to use JTA interfaces to control transactions with HornetQ. JTA provides facilities to start and stop a transaction and enlist XA resources into a transaction.

HornetQ is JTA aware, meaning you can use HornetQ in a XA transactional environment and participate in XA transactions. It provides the javax.transaction.xa.XAResource interface for that purpose. Users can get a XAConnectionFactory to create XAConnections and XASessions.

In this example we get a transaction manager from JBoss JTA to control the transactions. First we create an XASession for receiving and a normal session for sending. Then we start a new xa transaction and enlist the receiving XASession through its XAResource. We then send two words, 'hello' and 'world', receive them, and let the transaction roll back. The received messages are cancelled back to the queue. Next we start a new transaction with the same XAResource enlisted, but this time we commit the transaction after receiving the messages. Then we check that no more messages are to be received. In each transaction a dummy XAResource is also enlisted to show the transaction processing information.

Example step-by-step

To run the example, simply type mvn verify from this directory. It will download the JBoss JTA jars before it launches the example.

1. First we need to get an initial context so we can look-up the JMS connection factory and destination objects from JNDI. This initial context will get it's properties from the client-jndi.properties file in the directory ../common/config

           InitialContext initialContext = getContext(0);
        

2. We look-up the JMS queue object from JNDI

           Queue queue = (Queue) initialContext.lookup("/queue/exampleQueue");
        

3. We perform a lookup on the XA Connection Factory

           XAConnectionFactory cf = (XAConnectionFactory) initialContext.lookup("/XAConnectionFactory");
        

4. We create a JMS XAConnection

           connection = cf.createXAConnection();
        

5. We Start the connection

           connection.start();
        

6. We create a JMS XASession

          XASession xaSession = connection.createXASession();
       

7. We create a normal session

          Session normalSession = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
       

8. We create a normal Message Producer

           
           MessageProducer normalProducer = normalSession.createProducer(queue);
           
       

9. We get the JMS Session

          Session session = xaSession.getSession();
       

10. We create a message consumer

          MessageConsumer xaConsumer = session.createConsumer(queue); 
       

11. We create two Text Messages

          
          TextMessage helloMessage = session.createTextMessage("hello");
          TextMessage worldMessage = session.createTextMessage("world");
          
       

12. We get the Transaction Manager

          javax.transaction.TransactionManager txMgr = TransactionManager.transactionManager();
       

13. We start a transaction

          txMgr.begin();
       

14. We get the JMS XAResource

          XAResource xaRes = xaSession.getXAResource();
       

15. We enlist the resources in the Transaction work

          
          Transaction transaction = txMgr.getTransaction();
          transaction.enlistResource(new DummyXAResource());
          transaction.enlistResource(xaRes);
          
       

16. We send two messages.

          
         normalProducer.send(helloMessage);
         normalProducer.send(worldMessage);
          
       

17. We receive the messages

          
          TextMessage rm1 = (TextMessage)xaConsumer.receive();
          System.out.println("Message received: " + rm1.getText());
          TextMessage rm2 = (TextMessage)xaConsumer.receive();
          System.out.println("Message received: " + rm2.getText());
          
       

18. We roll back the transaction

          txMgr.rollback();
       

19. We create another transaction

          
          txMgr.begin();
          transaction = txMgr.getTransaction();
          
       

20. We enlist the resources to start the transaction work

                   
          transaction.enlistResource(new DummyXAResource());
          transaction.enlistResource(xaRes);
          
       

21. We receive those messages again

           
           rm1 = (TextMessage)xaConsumer.receive();
           System.out.println("Message received again: " + rm1.getText());
           rm2 = (TextMessage)xaConsumer.receive();
           System.out.println("Message received again: " + rm2.getText());
            
       

22. We commit

          txMgr.commit();
       

23. We check that no more messages are received.

          
          TextMessage rm3 = (TextMessage)xaConsumer.receive(2000);
          if (rm3 == null)
          {
             System.out.println("No message received after commit.");
          }
          else
          {
             result = false;
          }
          
       

24. And finally, always remember to close your JMS connections and resources after use, in a finally block. Closing a JMS connection will automatically close all of its sessions, consumers, producer and browser objects

           finally
           {
              if (initialContext != null)
              {
                initialContext.close();
              }
              if (connection != null)
              {
                 connection.close();
              }
           }