3 Replies Latest reply on Jan 25, 2008 9:39 AM by Adrian Brock

    Recover Exception after Rollback in JMS

    Tomas Pollak Newbie

      Hello, I have the following problem.
      I'm using a JMS Queue and a MDB to process asynchronous operations. The MDB runs in a transaction environment, so that the operations are committed or rolled back automatically.

      If the process raises an exception, being transactional, the JMS Message is redelivered automatically and the MDB flags the involved entities with an error state. However, I am unable to determine the Exception that caused the JMS Message to be redelivered. I need this, in order to store the error condition in the entities, so that the users can see this info.

      I have tried setting the exception as a property in the JMS Message, but I get MessageNotWriteableException (makes sense).

      Is there a way to achieve this? Either get the Exception that cause the JMS Message to be redelivered, or to attach some extra information to the JMS Message, so that it is available upon redelivery?

      Thanks everybody for your help!
      Tomas

        • 1. Re: Recover Exception after Rollback in JMS
          Elias Ross Master

          It's not really supported.

          If you want to do this, one way is to create a new message (copy?), using a non-transacted JMS connection and send it back to the same queue (or a separate queue) with the exception.

          • 2. Re: Recover Exception after Rollback in JMS
            Tomas Pollak Newbie

            Hello Elias,

            Thanks for your answer. I had considered some similar approaches like the one you propose.

            However, if I include a non-transactional component in the design, there is the possibility to introduce a race condition.

            Imagine this scenario:
            1) The JMS message is delivered for the first time, and starts transaction T1 to process Object A.
            2) During the process, a business error is detected and an exception with the message is thrown.
            3) As this exception is thrown, somewhere a handler sends also a non-transacitonal message to the process queue.
            4) The JMS message is redelivered in T2, and the MDB has to flag this process as failed (and maybe update Object A to a new state?).
            5) At the same time, the second message is processed in T3, that has to update Object A to attach the error message to it.

            In this hypothetical case, it would be very unlikely that this race condition materializes to a real threat, because we would take care that T2 and T3 will not update the same objects. However, this is not valid for a more general case. Maybe if I don't find a better solution I will have to settle for this.

            Regards,
            Tomas

            • 3. Re: Recover Exception after Rollback in JMS
              Adrian Brock Master

              Like I always say, JMS is not a database.
              It only supports add (send) and delete (receive). There is no update or select, etc.