JMS transaction between two queues

Question

Hi there,
          I have been asked to build some code that will act as an adapter
          between two legacy systems. Basically I will have to read from a
          queue, transform the information and write it to the other, then
          receive the response, transform it, and put it again back to the
          "caller" system.
          There are 4 queues implicated in this task.
          I will to use JMS Api in my code but I have found a problem. The way
          of performing a transaction in JMS is this:
          QueueSession queueSession = queueConnection.createQueueSession(true,
          0);
          "Here, the first argument means that the session is transacted; the
          second indicates that message acknowledgment is not specified for
          transacted sessions."
          As queueConnection is a connection to ONE queue, I can only perform
          transactions to ONE queue! But I don´t want to consume a message till
          I know it has been sent correctly to the other side.
          I have also read that some JMS providers support JTA transactions.
          But I don´t know if this is the right way to go.
          Can anybody bring some light to this issue.
          Thaks al lot for your attention!!
          

Answer 1

          This post has blossomed into several threads. I'm going to
          attempt a shot-gun approach to answer all questions.
          On MQSeries:
          See "How to use IBM MQ as a JMS Provider?" posts for more info.
          On transacted sessions:
          If this is ALL MQSeries, then it is up to MQSeries if a transacted
          session can span multiple queues and/or servers. WL supports this.
          MQSeries may simply prevent a session from
          spanning multiple servers and/or queues. Note that other vendors,
          that do not have their own TX monitor, very very likely do
          not have a 2PC in a transacted session that spans multiple servers
          (meaning it is not truly transactional).
          On JTA and multiple queues:
          The whole reason for being for JTA is to be able to span multiple
          operations. Yes, this is supported in WL.
          On the manuals:
          These issues are covered in great detail in the WL JMS developer's
          guide in the transactions chapter.
          On bridging:
          You do not have to write your own bridge.
          WL supplies a bridge to greatly simplify the work involved.
          WL 7.0 can even bridge two XA compliant JMS implementations transactionally.
          (Neither has to be WL JMS.) WL 6.1SP3 will have this same feature, now
          avialable as alpha code in 6.1. See "How to use IBM MQ as a JMS Provider?" posts for more
          info.
          On queuing and transactions:
          One can not include a request and its response in the same transaction. Period.
          This is the nature of queueing. One can dequeue from one queue and
          enqueue to another. I think you understand this, but it bears repeating.
          Tom
          Mac wrote:
          > I know that a recieve will not remove a message and a send will not
          > send it until the transaction is commited.
          >
          > In fact I want to do 2 transactions one for each receive-send.
          >
          > graphic again! ;)
          >
          > queue1 queue3
          > ======> =====>
          > legacy 1 Java Adapter legacy 2
          > queue2 queue4
          > <====== <=====
          >
          > In the period of time between reading from queue1 and writing to
          > queue3 the adapter could fail thus a message will be lost. The same
          > happens with queue4 and 2. Maybe this could be solved with a
          > transaction over queue1 and another one over queue4, but I'm not sure.
          >
          > I will have to decide if I use JMS or MQSeries API. MQ allows you to
          > wrap more than one queue in the same transaction if they are in the
          > same Queue Manager. So I wanted to know if JMS also allows to make a
          > transation over more than one queue and how is it done. only JTA?
          > QueueSession? impossible?
          >
          > tnx really for your help!
          >
          > "Raja Mukherjee" <[email protected]> wrote in message news:<[email protected]>...
          > > You can not. Even if you could, it's at least have to be 2 transactions.
          > > Because, if all of your work is in one transaction you will never send or
          > > receive messages, you would be blocking for ever. In order to send the
          > > message you will have to commit the transaction on the first place.
          > >
          > > .raja
          > >
          > > "Mac" <[email protected]> wrote in message
          > > news:[email protected]...
          > > > Sorry Tom, I think that I have not explained well my problem.
          > > >
          > > > The following extrange symbols are supposed to be an explaining
          > > > graphic!! ;)
          > > >
          > > >
          > > > queue1 queue3
          > > > ======> =====>
          > > > legacy 1 Java Adapter legacy 2
          > > > queue2 queue4
          > > > <====== <=====
          > > >
          > > > Legacy System 1 wants to call a service of legacy system 2, but they
          > > > can not communicate directly so we will use MQ Series as both them
          > > > support it.
          > > > For that purpose Legacy1 puts a message in queue1. The Java Adapter
          > > > transforms the message and puts it in queue3. Legacy2 processes the
          > > > request and replies with a message in queue4. The Java Adapter gets
          > > > it, transforms it and puts it in queue2. As a result legacy1 obtains
          > > > the information it was asking for.
          > > >
          > > > I'm using MQ Series 5.2 as middleware. I will not use Message Driven
          > > > Beans so I won´t have an EJB container to perform distributed
          > > > transactions.
          > > >
          > > > The question is: How can I put and get messages in the 4 queues
          > > > using de same transaction?? Can I do it somehow with JMS session or I
          > > > must use a JTA transaction?
          > > >
          > > > Thanks again for your help, and forgive me for being so insistent!
          > > > :)
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