You now have a solid application backbone in place. You may be expecting another five or ten chapters detailing how to write a GUI or HTML interface, servlets and JavaServer Pages for application logic, a web services interface, or any number of other layers. However, the Building Java Enterprise Applications series is geared at teaching you solid application design. For that reason, this chapter marks the end of this volume, and leaves discussion of application front-ends for Volumes II and III.
If this doesn’t make much sense to you, consider that any application backbone, like the Forethought application used throughout the book, should be easily segregated into several discrete layers. Figure 10-1 illustrates this, and should remind you of the discussions from Chapter 2.
Figure 10-1. Application layering
As you can see, a web services front-end relies on the same back-end as does a traditional J2EE web application (servlets, JSP, etc.). If you design your application backbone specifically for presentation through a web application, then using that same backbone for a web application can become awkward and kludgy. By the same token, a backbone built to work specifically with a web services presentation layer can cause problems when converting or adding a web presentation layer using HTML, WML, and other markup languages. The best approach, then, is ...