One of the greatest advantages of JavaServer Faces technology is that it offers a clean separation between behavior and presentation for web applications. A JavaServer Faces application can map HTTP requests to component-specific event handling and manage components as stateful objects on the server. JavaServer Faces technology allows you to build web applications that implement the finer-grained separation of behavior and presentation that is traditionally offered by client-side UI architectures.
The separation of logic from presentation also allows each member of a web application development team to focus on a single piece of the development process and provides a simple programming model to link the pieces. For example, page authors with no programming expertise can use JavaServer Faces technology tags in a web page to link to server-side objects without writing any scripts.
Another important goal of JavaServer Faces technology is to leverage familiar component and web-tier concepts without limiting you to a particular scripting technology or markup language. JavaServer Faces technology APIs are layered directly on top of the Servlet API, as shown in Figure 7-2.
Figure 7-2 Java Web Application Technologies
Description of "Figure 7-2 Java Web Application Technologies"
This layering of APIs enables several important application use cases, such as using different presentation technologies, creating your own custom components directly from the component classes, and generating output for various client devices.
Facelets technology, available as part of JavaServer Faces technology, is the preferred presentation technology for building JavaServer Faces technology–based web applications. For more information on Facelets technology features, see Chapter 8, "Introduction to Facelets".
Facelets technology offers several advantages.
Code can be reused and extended for components through the templating and composite component features.
You can use annotations to automatically register the managed bean as a resource available for JavaServer Faces applications. In addition, implicit navigation rules allow developers to quickly configure page navigation (see Navigation Model for details). These features reduce the manual configuration process for applications.
Most important, JavaServer Faces technology provides a rich architecture for managing component state, processing component data, validating user input, and handling events.