10.2.4. Object Models

JBoss Transaction Service supports two models for objects. Implementation of the state and concurrency controls depend on which model is used.
Single
The application only contains a single copy of the object The object resides within a single JVM, and all clients must address their invocations to this server. The single model provides better performance, but creates a single point of failure. In a multi-threaded environment, the object may not be protected from corruption if a single thread fails.
Single Object Model
Multiple
Logically, a single instance of the object exists. Copies of the object are distributed across multiple JVMs. Performance suffers compared to the single model, better failure isolation is achieved.
Multiple Object Model
The single model is the default. You can override this on a per-object basis by providing an appropriate instance of the com.arjuna.ats.arjuna.gandiva.ObjectName class when you create your object.

Note

You can change the model before any instantiation of the object There is no need for it to remain the same during the object's lifetime.
Use the following method to provide a suitable ObjectName class. Refer to Example 10.6, “Object Models” for an example.
  1. Create a new instance of ObjectName.
  2. Set the object model attribute using the com.arjuna.ats.arjuna.ArjunaNames.StateManager_objectModel() name.

Example 10.6. Object Models

{
    ObjectName attr = new ObjectName(“SNS:myObjectName”);
      
    attr.setLongAttribute(ArjunaNames.StateManager_objectModel(),
			  ObjectModel.SINGLE);
      
    AtomicObject obj = new AtomicObject(ObjectType.ANDPERSISTENT, attr);
}