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List:       jboss-user
Subject:    [JBoss-user] [Messaging, JMS & JBossMQ] - Message redelivery failing for BMT MDBs
From:       tmjkeeney <nukes () jboss ! org>
Date:       2004-08-31 20:17:08
Message-ID: 2827756.1093983428388.JavaMail.root () ads ! jboss ! org
[Download RAW message or body]

I am running BMT MDBs under JBoss 3.2.3 using the JBossMQ Provider and have noticed a \
problem with BMT MDBs failing to redeliver JMS messages when the MDB throws a system \
exception, a condition that violates the EJB spec section 18.3.3.  I have created a \
patch for the problem and tested it with both BMT and CMT MDBs (After patching the \
code, any system exception will force redelivery until max retries, then the message \
goes to the DLQ).  Before I apply this patch to my production codebase, I wanted to \
confirm with the JBoss developers if this is an appropriate solution that will not \
impact other parts of the system.

I tracked the message redelivery failure for BMT MDBs to the exception handler for \
the code block beginning on line 1100 in the JMSContainerInvoker.onMessage() method:


  | 
  |          try
  |          {
  |             Transaction tx = tm.getTransaction();
  | 
  |             // DLQHandling
  |             if (useDLQ && // Is Dead Letter Queue used at all
  |                message.getJMSRedelivered() && // Was message resent
  |                dlqHandler.handleRedeliveredMessage(message, tx)) //Did the DLQ \
handler take care of the message  |             {
  |                // Message will be placed on Dead Letter Queue,
  |                // if redelivered to many times
  |                return;
  |             }
  |             
  |             invoker.invoke(id,                    // Object id - where used?
  |                            ON_MESSAGE,            // Method to invoke
  |                            new Object[]{message}, // argument
  |                            tx,                    // Transaction
  |                            null,                  // Principal                    \
  |                            null);                 // Cred
  |                            
  |          }
  |          catch (Exception e)
  |          {
  |             log.error("Exception in JMSCI message listener", e);
  |          }
  |          
  | 

If you modify the exception handler to rethrow any system exceptions, the \
StdServerSession can set the transaction for rollback.  So here's the patch:


  | 
  |          try
  |          {
  |             Transaction tx = tm.getTransaction();
  | 
  |             // DLQHandling
  |             if (useDLQ && // Is Dead Letter Queue used at all
  |                message.getJMSRedelivered() && // Was message resent
  |                dlqHandler.handleRedeliveredMessage(message, tx)) //Did the DLQ \
handler take care of the message  |             {
  |                // Message will be placed on Dead Letter Queue,
  |                // if redelivered to many times
  |                return;
  |             }
  |             
  |             invoker.invoke(id,                    // Object id - where used?
  |                            ON_MESSAGE,            // Method to invoke
  |                            new Object[]{message}, // argument
  |                            tx,                    // Transaction
  |                            null,                  // Principal                    \
  |                            null);                 // Cred
  |                            
  |          }
  |          catch (Exception e)
  |          {
  |             log.error("Exception in JMSCI message listener", e);
  |             
  | >            // rethrow system exceptions as an EJBException
  | >            if (e instanceof RuntimeException || e instanceof RemoteException) {
  | >              throw new EJBException("Encountered system exception.", e);
  | >            }            
  |          }
  | 
  | 

As said above, this patch works fine for CMT and BMT MDBs.  The only problem I see is \
that CMT MDBs will setRollbackOnly twice: once in the \
AbstractInterceptor.invokeNext() method, line 105, and once in the \
StdServerSession.onMessage(), line 275.  This could be fixed by wrapping line 275 in \
StdServerSession with a check to see if the transaction Status is already \
STATUS_MARKED_ROLLBACK.  Correct?

Any comments on the problem/solution would be much appreciated!

Thanks in advance.
--Tom

View the original post : \
http://www.jboss.org/index.html?module=bb&op=viewtopic&p=3846794#3846794

Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&p=3846794



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