12.2. Direct Use of the StateManager Class

The examples throughout this manual derive user classes from the LockManager class. There are two reasons for this.
  • Most importantly, the serializability constraints of atomic actions require it.
  • It reduces the need for programmer intervention.
However, if you only require access to the persistence and recovery mechanisms of JBoss Transaction Service, you can directly derive a user class from StateManager.
Classes derived directly from StateManager must make use of its state management mechanisms explicitly, rather than relying on LockManager. You need to make appropriate use of the activate, deactivate, and modified methods, since the constructors of StateManager are effectively identical to those of LockManager.

12.2.1. The activate Method

boolean activate ()
boolean activate (String storeRoot)
The activate method loads an object from the object store. The object’s UID needs to already be set via the constructor, and the object must exist in the store. If the object is successfully read, the restore_state method is called to build the object in memory. The activate method operates such that once an object has been activated, further calls are ignored. The parameter represents the root name of the object store to search for the object. If the value is null, the default store is used.