9.2.6. The Transaction Protocol Engine

The transaction protocol engine is represented by the AtomicAction class, which uses StateManager to record sufficient information for crash recovery mechanisms to complete the transaction in the event of failures. It has methods for starting and terminating the transaction. For those situations where programmers need to implement their own resources, methods for registering them with the current transaction are also provided. Because JBoss Transaction Service supports subtransactions, if a transaction is begun within the scope of an already executing transaction, it is automatically nested.