JavaServer Faces

From Wikipedia, the free encyclopedia

JavaServer Faces (JSF) is a Java-based Web application framework intended to simplify development of user interfaces for Java EE applications. Unlike other traditional request-driven MVC web frameworks, JSF uses a component-based approach. The state of UI components is saved when the client requests a new page and then is restored when the request is returned. Out of the box, JSF uses JavaServer Pages (JSP) for its display technology, but JSF can also accommodate other display technologies (such as XUL). JSF includes:

The JSF specification was developed under the Java Community Process as JSR 127, which defined JSF 1.0 and 1.1, and JSR 252 which defined JSF 1.2. Upcoming JSF 2.0 is being developed as JSR 314.

Contents

[edit] JSF versions

  • JSF 1.0 (2004-03-11) — the initial release of the JSF specification.
  • JSF 1.1 (2004-05-27) — bug fix release. There were no spec or HTML renderkit changes.
  • JSF 1.2 (2006-05-11) — latest release.
    • enhancements to provide an interim solution to the content-interweaving problem described at http://www.onjava.com/pub/a/onjava/2004/06/09/jsf.html
    • provide XML Schema for the config files, instead of using DTD
    • enhancements to allow faces applications to handle multi-frame, or multi-window UI designs
    • enhancements to the f: tag library for improved TCK coverage, f:view lifetime events, and other small features
    • enhancements to the decorator support for API objects
    • security enhancements for client side state saving
    • solve the "duplicate button press" problem
    • re-organize the spec into normative, and non-normative sections, to make implementation easier
    • portlet related bug-fixes
    • bug fixes that require minimal specification changes
  • JSF 2.0 (expected in 2008) - major revision of the specification under development. Planned to coincide with Java EE 6.

[edit] Comparison to other Web-GUI Frameworks

[edit] Struts

Main article: Apache Struts

Struts is a popular Model 2 MVC framework from the Apache Software Foundation. It provides page-at-a-time MVC and does not have a component model in the style of JSF. Pages are mapped to models with a dispatch servlet (controller) piping input to actions. Struts applications use JSPs to render views and are amenable to mix-and-match jsp taglib use. (See also Apache Beehive)

[edit] WebObjects / Wotonomy

Main articles: WebObjects and Wotonomy

WebObjects is the earliest known web-application framework and was originally developed by NeXT Software, Inc. then acquired by Apple Computer when it acquired NeXT. It contains an MVC architecture with a component and event model and lifecycle similar to JSF. It is deployable without J2EE (its original configuration), or can be deployed in a servlet container — its dispatcher object acting as the entry-point of a J2EE web application. Unlike JSF's default case, components are not defined in JSP files but are in .wo directories containing any or all of html/xml/wml template files, a .wod file to map fields and actions to Java code, and a .java class. A template file provides the rendering/layout and may include other WebObjects components, rather than the delegated RenderKit approach used by default in JSF. It is a halfway-point between the delegated and directly-rendered approaches used in JSF.

WebObjects also includes a layered architecture with one of the earliest Object-Relational Mapping frameworks, Enterprise Objects Framework.

Wotonomy is a clean-room, open-source re-implementation of the WebObjects frameworks licensed under LGPL. It attempts to implement all parts of WebObjects, and has implemented the whole MVC web-GUI stack. As a clone of WebObjects, it differs from JSF in identical ways, except where it is incomplete.

[edit] Apache Tapestry

Main article: Tapestry (programming)

Tapestry is an open-source framework for creating dynamic, robust, scalable web applications in Java. Tapestry builds upon the standard Java Servlet API, and so it works in any servlet container or application server. Unlike JSF, Tapestry does not use JSP as the default view technology — instead preferring an alternate templating engine that allows for easy html preview and editing (similar to the JSF-based Facelets).

[edit] Microsoft ASP.NET

Main article: ASP.NET

JSF features a component based approach to WebApplication development similar to ASP.NET from Microsoft. In ASP.NET v1, component rendering code was bundled with the UI component, unlike JSF, where rendering and component interfaces can be separated, thus allowing for customization of the renderer. ASP.NET v2 introduced the control adapter framework allowing the default rendering to be overridden by third-party code.

Business code is connected to the UI components by subscribing to events generated by the components and stored in a separate file ("code behind"). Thus a typical ASP.NET page consists of a (HTML) file describing the visual page layout (design), and a file with the page logic (code). Both files are treated as one single entity by the Microsoft development tools.

According to the author of the book Core JSF, JSF offers a means for Java to compete with ASP.NET/Visual Studio in the area of Rapid application development (RAD). The addition of the Sun Java Studio Creator IDE provides a RAD environment similar to Visual Studio 2005, potentially lowering development cost and other barriers to entry.

[edit] JSF and Ajax

JSF is often mentioned together with Ajax, a Rich Internet application technology. Ajax is a combination of technologies that makes it possible to create richer user interfaces. The user interface components in the JSF reference implementation and MyFaces were originally developed in HTML. Because JSF supports multiple output formats, Ajax-enabled components can easily be added to improve the quality of JSF-based user interfaces. The JSF 2.0 specification intends to improve support for Ajax by allowing UI logic to run partly on the client and not only on the server, and by providing support for graceful degradation when JavaScript is disabled in the browser.

[edit] Ajax-enabled JSF components and frameworks

The following companies and projects offer Ajax-based JSF implementations or blueprints:

[edit] See also

[edit] References

[edit] Books

[edit] External links

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