We are almost finished! The remaining piece of the puzzle is to coordinate activity between the web browser, database, domain objects, JDOM producers, and XSLT stylesheets. This task lies in the servlet implementation and related classes. In an XSLT-driven web application, the servlet itself really does not do all that much. Instead, it acts as a mediator between all of the other actions taking place in the application.
Figure 7-9 shows the UML class diagram for the
com.oreilly.forum.servlet package. This design
consists of a few key classes along with numerous subclasses of
subclasses are very repetitive in nature, which is indicative of the
highly structured application design that XML and XSLT facilitate.
Figure 7-9. Servlet design
A single-servlet design has been adopted for this application. In
this approach, the
intercepts all inbound requests from clients. The requests are then
delegated to subclasses of
handle requests for individual pages. Once the request has been
processed, a subclass of
Renderer selects the XML
and XSLT stylesheet.
XSLTRenderHelper does the
actual XSLT transformation, sending the resulting XHTML back to the
This is not designed to be a heavyweight web application framework. Instead, it is just a simple set of coding conventions and patterns that help keep the ...