Chapter 9: Advanced EJB Persistence and Optimization

Download CD Content

Overview

WebSphere Application Server Version 5.0 contains a number of features and optimizations that make the already compelling value of EJB 2.0 applications even more exciting. Container-managed entity beans are the preferred method of data persistence in J2EE 1.3. To the developer, CMP simply means that the EJB container handles interactions with database. However, CMP means a bit more to the vendor that is implementing the container. It means not only that is there a responsibility upon the container vendor, but it also provides a certain amount of opportunity for the vendor to differentiate itself from the competition and to provide additional value to the customer.

This chapter will introduce the value-added features that IBM has provided in its implementation of the EJB container for CMP, including:

• An introduction to the concept of Access Intent

• An introduction to the Application Profile service

• EJB Persistence Support

• EJB QL extensions

• Transactions

• Unit-of-work scoping

  Important

  Beyond basic access intent and local transactions, most of the features discussed in this chapter are part of the Enterprise Edition of the WebSphere Application Server.

A more detailed summary of features applicable specifically in the base WebSphere Application Server and specifically in the Enterprise Edition is found as part of the Summary at the end of this chapter.

Some of these features introduce new programming interfaces and make the applications created with them specific to WebSphere. Other features, however, can be applied to applications declaratively without impacting on the portability.