WebSphere extensions to the Enterprise Java Beans specification
This article outlines extensions to the EJBs specification provided with WAS ND.
Inheritance in enterprise beans
In the Java language, inheritance is the creation of a new class from an existing class or a new interface from an existing interface. This product supports two forms of inheritance: standard class inheritance and EJB inheritance.
In standard class inheritance, the home interface, remote interface, or enterprise bean class inherits properties and methods from base classes that are not themselves enterprise bean classes or interfaces.
By contrast in enterprise bean inheritance, an enterprise bean inherits properties, uch as container-managed persistence (CMP) fields and container-managed relationship (CMR) fields, methods, and method-level control descriptor attributes from another enterprise bean.
For more information, see the documentation for the assembly tools at http://publib.boulder.ibm.com/infocenter/radhelp/v7r5mbeta/topic/com.ibm.jee5.doc/topics/cejb3.html.
Optimistic concurrency control for container-managed persistence
This product supports optimistic concurrency control of data access. See Concurrency control for more information.
Access intents for EJB persistence
This product supports the application of named data-access policies.
Sequence grouping for container-managed persistence
By designating CMP sequence groups for entity beans, we can prevent certain types of database-related exceptions from occurring during the run time of the EJB application. Within each group specify the order in which the beans update the relational database tables. See Set the run time for CMP sequence groups for instructions.
Performance enhancements
Through the lifetime-in-cache settings, this product provides a way for you to improve performance for beans that are only occasionally updated.
See the topic, "Entity bean assembly settings" located in the assembly tool documentation at http://publib.boulder.ibm.com/infocenter/radhelp/v7r5mbeta/topic/com.ibm.jee5.doc/topics/cejb3.html.
Some enterprise beans created with the assembly tools can utilize read-ahead for loading a bean and its related beans in a single database operation. An entire object graph or any part of the graph can be preloaded by configuring a finder method to use read-ahead.
Assembly and deployment extensions
This product supports IBM extensions of assembly and deployment options.
Related concepts
Concurrency control
Access intent policies
Read-ahead hints
Sequence grouping for container-managed persistence
Related tasks
Develop enterprise beans