JavaServer Faces Technology - The J2EE 1.4 Tutorial

JavaServer Faces Technology

JavaServer Faces technology is a server-side user interface component framework for Java technology-based web applications.

The main components of JavaServer Faces technology are as follows:

An API for representing UI components and managing their state; handling events, server-side validation, and data conversion; defining page navigation; supporting internationalization and accessibility; and providing extensibility for all these features
Two JavaServer Pages (JSP) custom tag libraries for expressing UI components within a JSP page and for wiring components to server-side objects

The well-defined programming model and tag libraries significantly ease the burden of building and maintaining web applications with server-side UIs. With minimal effort, you can

Wire client-generated events to server-side application code
Bind UI components on a page to server-side data
Construct a UI with reusable and extensible components
Save and restore UI state beyond the life of server requests

As shown in Figure 17-1, the user interface you create with JavaServer Faces technology (represented by myUI in the graphic) runs on the server and renders back to the client.

Figure 17-1 The UI Runs on the Server

The JSP page, myform.jsp, is a JavaServer Faces page, which is a JSP page that includes JavaServer Faces tags. It expresses the user interface components by using custom tags defined by JavaServer Faces technology. The UI for the web application (represented by myUI in the figure) manages the objects referenced by the JSP page. These objects include

The UI component objects that map to the tags on the JSP page
The event listeners, validators, and converters that are registered on the components
The objects that encapsulate the data and application-specific functionality of the components

This chapter gives an overview of JavaServer Faces technology. After going over some of the primary benefits of using JavaServer Faces technology and explaining what a JavaServer Faces application is, it lists the various application development roles that users of this technology fall into. It then describes a simple application and specifies which part of the application the developers of each role work on. The chapter then moves on to summarizing each of the main features of JavaServer Faces technology and how the various pieces of an application that uses these features fit together. Finally, this chapter uses a page from a simple application to summarize the life cycle of a JavaServer Faces page.

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