Rajan,
If you really are trying to get a distributed transaction across two beans,
you have to choose a container manager transaction as the bean attribute.
In your case, you perhaps want to go with TX_MANDATORY(since you
always want to be in client initiated transaction context on the server side)
The server bean does not have to invoke any JTA APIs. The container
should be able to propagate the transaction context for you transparently
and ensure that bean method is invoked as part of client transaction.
BTW, you might want to check with your vendor and ensure that your
container indeed supports distributed transactions.
Good luck,
Sanjay
Rajan Desai wrote:
> Hi
>
> I am trying to play with the UserTransaction to control the CLIENT initiated
>transaction.
> Client gets begins the UserTransaction first. Then it invokes the BEAN to
> insert a record in the database. Since I am using a TX_BEAN_MANAGED stateful bean,
> I get the UserTransaction from SessionContext. I use this user transaction to begin
>()
> the transaction. I am also setting AUTO COMMIT to FALSE for the connection. If
> the INSERT is successful, I call UT.commit () else I call UT.rollback ().
>
> When control is back to the client, I REMOVE the bean.
>
> Then I try to create another instance og the same bean pointing to another database.
> NOTE THAT THE UserTransaction STARTED AT CLEINT END IS NOT YET COMMITED or
>ROLLBACKED.
>
> I then invoke the same method on the bean to insert another record in new
> database. commit or rollback is called based on the result of the INSERT operation.
>
> At the client end, I either COMMIT or ROLLBACK the UserTransaction.
>
> I AM TRYING to implement the DISTRIBUTED TRANSACTIONS here. What I had expected was
> if INSERT in first database is successful but fails in the SECOND database,
> exception will be thrown and since I ROLLBACK the client initiated USER TRANSACTION
>on
> exception, whole transaction will be rolled back ( Even the insert in the FIRST
>database)
>
> I am getting these results. Changes are still commited in the FIRST when SECOND
> operation fails?
>
> AM I DOING ANYTHING wrong here?
>
> AM I MISSING OUT ANYTHING?
>
> Any help/example will be greatly appretiated...
>
> Thanks in advance for your time
>
> Rajan Desai
>
> PS : I have included some of the code here
>
> I have a TX_BEAN_MANAGED STATEFUL session bean. Client gets the user transaction
>using JNDI as follows:
>
> CLIENT :
> // Note that I am using Tengah here.
> UserTransaction tx = ( UserTransaction )ctx.lookup( "javax.jts.UserTransaction"
>);
>
> I start the client transaction by calling
> tx.begin ();
>
> After this I get the home interface of my bean and call execute () method onit.
> engineHome = (SQLEngineHome)ctx.lookup ("sqlengine.SQLEngineHome");
> SQLEngine engine = engineHome.create ("TestPool2");
> engine.execute ("", iID, strName);
> engine.remove (); // Removes the bean
>
> // ANOTHER instance of the bean to insert data into SECOND DATABASE
> engineHome = (SQLEngineHome)ctx.lookup ("sqlengine.SQLEngineHome");
> SQLEngine engine = engineHome.create ("TestPool1"); // TESTPOOL 1 is used
> engine.execute ("", iID, strName);
> engine.remove (); // Removes the bean
>
> // commit the transaction here. (ROLLBACK if EXCEPTION is thrown)
> tx.commit ();
>
> SERVER BEAN :
>
> Execute method gets the connection using POOL NAME passed to it.
>
> try
> {
> // IS IT SAFE TO ASSUME THAT THE CONTAINER PASSES USERTRANSACTION
> // STARTED BY THE CLIENT HERE. ??????????????????
> tx = m_SessionContext.getUserTransaction ();
>
> tx.begin ();
>
> // Pool name is passed by the client while creating the bean
> // see engine.create ("Testpool1");
> con = DriverManager.getConnection("jdbc:weblogic:jts:" + m_strPoolName );
> con.setAutoCommit (false);
>
> ps = con.prepareStatement("INSERT INTO PRODUCT (PRD_PRODUCT_ID, PRD_NAME,
>PRD_DESCRIPTION) VALUES (? , ?, ?)");
> ps.setInt(1, iID);
> ps.setString(2, strName);
> ps.setString(3, "Description for " + strName );
>
> ps.executeUpdate();
>
> tx.commit ();
> }
> catch ( SQLException ex )
> {
> ex.printStackTrace ();
> tx.rollback ();
> throw new RemoteException ( ex.getMessage () );
> }
>
> I am new to the EJB development. May be I am not very clear with the concept of EJB
> and JTS? Please help :)
>
> Thanks
>
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