• Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

transaction in mdb

 
zb cong
Ranch Hand
Posts: 416
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
hello
i write a message driven bean,that monitor the weblogic message queue,when a "Order" object is witten to the queue,the mdb get it and write it to a entity bean "Orderinfo".all of above logic is within the "onMessage" method of the mdb.
i want to encapsulate the flow in a transaction,see my code snippet of the onMessage method:

ObjectMessage objMsg = (ObjectMessage) msg;
OrderVO orderVO = (OrderVO) objMsg.getObject();
System.out.println(orderVO.booklist);
OrderinfoHome orderinfoHome = (OrderinfoHome) ctx.lookup(
"java:/comp/env/orderinfo");
Orderinfo orderinfo = orderinfoHome.create(orderVO.orderID);
orderinfo.setAddress(orderVO.address);
orderinfo.setCustname(orderVO.custName);
orderinfo.setEmail(orderVO.email);
orderinfo.setBooklist(orderVO.booklist);
orderinfo.setPrice(new BigDecimal(orderVO.price));

and deploy descriptor snippet(ejb-jar.xml):

<assembly-descriptor>
.............
............
<container-transaction>
<method>
<ejb-name>orderMDB</ejb-name>
<method-name>*</method-name>
</method>
<trans-attribute>Required</trans-attribute>
</container-transaction>
</assembly-descriptor>

i think during this transaction,there are two action:geting the object from the queue and saving it to entity bean.in order to test the transaction,i modify the jndi name of entity bean in the code to a WRONG one.redeploy my program,and send a message to the queue,the mdb is activated,then the exception is thrown because of the wrong jndi name.after that,i check the message queue,find that it is empty.why?i think if the second action of the transaction is fail,the transaction should roll back,the message should be send BACK to the queue.
i also ty to use the "javax.transaction.UserTransaction" in the onMessage method,but the follwing exception is thrown:

javax.transaction.NotSupportedException: Another transaction is associated with this thread.................................

who can help me,if any wrong with me,and how to use the transaction with the message driven bean?
thank you.
 
Lasse Koskela
author
Sheriff
Posts: 11962
5
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Isn't the exception thrown by the JNDI lookup not a system exception? Anyway, I would explicitly call setRollbackOnly() just to be sure (and have the code communicate better that the transaction is being rolled back).
Btw. You can only use container-managed transactions with MDBs -- that's why you couldn't use UserTransaction.
 
Chris Mathews
Ranch Hand
Posts: 2712
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Originally posted by Lasse Koskela:
Btw. You can only use container-managed transactions with MDBs -- that's why you couldn't use UserTransaction.

Actually, you can use BMT with MDBs also. However, that still doesn't allow you to use UserTransaction if your MDB is marked as CMT.
 
Lasse Koskela
author
Sheriff
Posts: 11962
5
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Duh. Can't believe I just passed SCBCD
 
Brian Tinnel
Ranch Hand
Posts: 69
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
In WebLogic, unless you configure it otherwise, a message that is rolled back is dropped. That is because the default redelivery limit is -1 (meaning no retry) and the error destination is (None). Assuming you set up an Error Destination (just a different queue), your message should appear there after you roll it back. If you set the redelivery limit to a value X, your MDB should be called X times and then the message will appear in the Error Destination.
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic