Presentation of the Sample Application

Summary

This chapter presented a J2EE banking program that was constructed from the Duke’s Bank sample application and showed its organization into projects and packages. This allowed us to explore its architecture and design comprehensively. After reading this chapter, you should now have a basic understanding of the design problems of this application and the ways in which AOP can resolve them.

The next two chapters present a detailed account of the use of AOP with this sample application, tier by tier. Although design elements may affect several tiers, it is best to concentrate on one at a time when implementing a design pattern. This allows the projects corresponding to each of the layers to remain independent of each another.

For each of the tiers, we will evaluate the improvements offered by AOP according to three criteria:

• • Improvements in the implementation of th e design patterns used, concentrating on J2EE design patterns

• • Improvements to a design element that is re cognized as being crosscutting, but that is not an identified design pattern or does not fit within the documented context of a design pattern

• • Improvements whereby the design depends le ss on the J2EE technologies, especially EJBs

As far as the business layer is concerned, we will also evaluate the possibility of replacing automatic integration with a solution using AOP.