Transaction in mdb

Question

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.

Answer 1

Hi,
A failure to lookup a jndi name will throw NamingException and this will not rollback
the tx. To rollback the tx, you need to explicity set the tx context status to
rollbackonly or throw a system exception ( which will discard that MDB instance).
Application exceptions do not rollback the tx.
In your scenario, the tx started on invoking onMessage routine and infects the
Entity beans business method. You can either throw a system exception in either
the onMessage routine or the entity beans business method or explicity set the
tx status to rollbackonly to rollback the tx.
ram
"zhebincong" <[email protected]> wrote:
>
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.