Using a Transaction

You can use a transaction object to group multiple service calls into an atomic action, maintaining data integrity within your application logic. You obtain a transaction from a session pool with the method:

  Transaction trans = ssPool.startTransaction(timeout);

where the transaction object trans holds the reference to the transaction, ssPool is the SessionPool or ServletSessionPool object, and the timeout argument for the transaction is specified in seconds.

Once a transaction obtains a session, that session cannot be used by other transactions until the transaction is committed, aborted, or times out. The session may, however, still be used by single requests that are not part of a transaction. If a transaction fails to obtain a session from the pool, this method throws a bea.jolt.pool.TransactionException. If the session pool is suspended, the method throws a bea.jolt.pool.SessionPoolException.

Each time your application uses the call() method, you should supply the transaction object as the last parameter. For example:

  ssPool.call("svcName", request, trans);

You can make multiple calls in the same transaction. The calls will not complete until you either commit or roll back the transaction using the methods of the transaction object. The trans.commit() method completes the transaction. This method returns 0 if the commit was successful, or throws a TransactionException if the transaction failed to commit.

If you need to abort the transaction, use the Transaction.rollback() method. This method attempts to abort the transaction. It returns 0 if successful; otherwise it throws a TransactionException.

Handling Exceptions

Errors or failures that may occur when Jolt initiates a Tuxedo service call are reported to your application through Java exceptions. Always enclose the call() method within a try / catch block and attempt to deal with any exceptions appropriately. The call() method can throw any of the following exceptions for the following reasons: