Head First Servlets and JSP, 2nd Edition

Business tier patterns: quick review

To wrap up our discussion of business tier patterns, here’s a diagram that shows a Business Delegate, a Service Locator, and a Transfer Object in action. At the end of the chapter you’ll find a couple of summary pages for these patterns and the presentation tier patterns we’ll discuss next.

A 6-step review:

1 Register your services with JNDI.

2 Use Business Delegate and Service Locator to get the Manage Customer stub from JNDI.

3 Use the Business Delegate and the stub to get the “Customer Bean”, which in this case is a Transfer Object. Return this Transfer Object’s reference to the controller.

4 Add the bean’s reference to the request.

5 The controller forwards to the View JSP. The JSP gets the reference to the Customer Transfer Object bean from the request object.

6 The View JSP uses EL to get the Customer Transfer Object Bean’s properties it needs to satisfy the original request.