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Transaction manager services
The following diagrams show example interactions between the client, the BES
Partition, and how the BES Partition locates the right transaction service based on the
above configuration. All of the beans are assumed to have container-managed
transactions.
Example 1PC usage
1 The client calls a method of UserSesEJB. This is an implementation of the method that
creates users in the database.
2 Before the call is actually invoked, as shown below, the Partition uses its in-process
Transaction Manager to begin the transaction.
3 The session bean does some database work.
4 When the call is over, the Partition issues commit.
5 The Transaction Manager calls commit_one_phase() on the database resource.
Figure 19.1
Example of 1PC usage
Example 2PC usage
1 The client calls OrderSesEJB.create() method to create a new order.
2 Since the bean is configured to use the OTS engine named TwoPhaseEngine, the
container locates the right transaction service named TwoPhaseEngine, and uses it
for beginning the transaction.
3 The session bean does some database work, and sends a message to a JMS
queue.
4 When the call is over, the Partition issues commit.
5 The OTS engine coordinates the transaction completion with the database and the
JMS resources.
Chapter 19: Transaction management 173