Lightweight local operational mode for entity beans
WebSphere Application Server provides a special operational mode called lightweight local mode, which can improve the performance of entity bean methods. We can decide which entity beans in your application to run in this mode.
In lightweight local mode, the container streamlines the processing that it performs before and after every method on the local home interface and local business interface of the bean. This streamlining can result in improved performance when entity bean operations are called locally from within an application. Because some processing is skipped when running in lightweight local mode, this mode can be used in certain scenarios only.
Lightweight local mode is patterned somewhat after the Plain Old Java Object (POJO) entity model introduced in the Enterprise JavaBeans (EJB) 3.0 specification. Using lightweight local mode, we can obtain some of the performance advantages of the POJO entity model without having to convert your existing EJB 2.x application code to the new POJO model. We can apply lightweight local mode to both container-managed persistence (CMP) and bean-managed persistence (BMP) entity types that meet the specific criteria.
For more information about EJB containers, see Enterprise beans: Resources for learning .
When to use the lightweight local mode
Lightweight local mode is designed for entity beans that are created, found, and called using the Session Facade pattern. Under this pattern, entity bean local home and local business methods are called from within methods of a stateless session bean or stateful session bean. The session bean methods, which can be called remotely or locally, provide security control and transaction demarcation for the entity beans that are accessed by the session bean.
You can apply lightweight local mode only to an entity bean that meets the following criteria:
- The bean implements an EJB local interface.
- No security authorization is defined on the entity bean local home or local business interface methods.
- No run-as security attribute is defined on the local home or local business methods.
- The classes for the calling bean and the called entity bean are loaded by the same Java classloader.
- The entity bean methods do not call the WebSphere Application Server-specific Internationalization Service or Work Area Service.
The first criterion prevents CMP 1.x beans from supporting lightweight local mode, because the 1.x beans cannot have local interfaces.
In addition, lightweight local mode provides its fullest performance benefits only to entity bean methods that do not need to start a global transaction. This condition is true if you ensure that your entity bean also meets the following criteria:
- A global transaction is already in effect when the entity bean home or business method is called. Typically, this transaction is started by the calling session bean.
- The local business interface methods and the local home methods of the entity bean use the following transaction attributes only: REQUIRED, SUPPORTS, or MANDATORY.
If an entity bean method that is running in lightweight local mode must start a global transaction, the bean still functions normally but only a partial performance benefit is realized.
We can mark an entity bean that defines a remote interface or a TimedObject interface, in addition to the local interface, for lightweight local mode. However, the performance benefit is apparent only when the bean is called through its local interface.
Related concepts
Enterprise beans Related tasks
Applying lightweight local mode to an entity bean Manage EJB containers Related reference
Enterprise beans: Resources for learning