[jboss-dev-forums] [Design of EJB 3.0] - UserTransactedStartedListener is not implemented in EJB3

[adrian@jboss.org]

This relates to JBCTS-599 but I can explain it without reference to that.

There is a little known feature in JavaEE called lazy transaction enlistment.
It basically works with the UserTransaction where you retrieve a connection
before starting the transaction and then ut.begin() enlists the connection.


  | // BMT EJB(3) method
  | public void doSomething()
  | {
  |    DataSource ds = ...
  |    Connection c = ds.getConnection(); // Not enlisted in transaction, there isn't one
  |    UserTransaction ut = ...
  |    ut.begin(); // the connection is enlisted in the transaction
  | }
  | 

It even works across multiple transactions


  | public void doSomething()
  | {
  |    DataSource ds = ...
  |    Connection c = ds.getConnection(); // Not enlisted in transaction, there isn't one
  |    UserTransaction ut = ...
  |    ut.begin(); // the connection is enlisted in the transaction
  |    ut.commit(); // connections is unenlisted
  |    ut.begin(); connection is enlisted in the new/different transaction
  | }
  | 

The problem is that EJB3 is not firing the transaction started events
from its user transaction.

Compare EJB2/EJB3:
org.jboss.ejb.EnterpriseContext/org.jboss.ejb3.tx.UserTransactionImpl


  | 
  |       public void begin()
  |       throws NotSupportedException, SystemException
  |       {
  |          TransactionManager tm = con.getTransactionManager();
  | 
  |          int oldTimeout = -1;
  |          if (tm instanceof TransactionTimeoutConfiguration)
  |             oldTimeout = ((TransactionTimeoutConfiguration) tm).getTransactionTimeout();
  | 
  |          // Set the timeout value
  |          tm.setTransactionTimeout(timeout);
  | 
  |          try
  |          {
  |             // Start the transaction
  |             tm.begin();
  | 
  |             // HERE!!!!!!!!!!!!! notify checked out connections
  |             if (tsl != null)
  |                tsl.userTransactionStarted();
  | 
  |             Transaction tx = tm.getTransaction();
  |             if (trace)
  |                log.trace("UserTx begin: " + tx);
  | 

In fact, if you compare the two classes you'll see that the EJB3
user transaction is incomplete in other ways (such as resetting
the transaction timeout after the begin).

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