Learn Java for Web Development

150 CHAPTER 3: Best Practices in Java EE Web Development

Figure 3-10 shows the structure of the Front Controller pattern.

Client

Front

Controller

Request

Delegates requestDispatches request

Servlet Container

Dispatcher View

Figure 3-10. Front Controller class diagram

The components of the Front Controller pattern are as follows:

   Controller

   Dispatcher

   View

Controller

The controller is the initial point for handling a request and coordinates with a dispatcher component.
The controller manages the following:

   Handling the request, including invoking security services such as authentication

and authorization

   Delegating to the business service

   Handling errors

Dispatcher

The dispatcher is responsible for view management and navigation.

View

The view represents and displays information to the client.

Figure 3-11 illustrates the sequence diagram of the front controller.