JavaServer Faces

JavaServer Faces
Stable release
2.2.8 (Mojarra Reference Implementation) / May 30, 2016 (2016-05-30)
Preview release
2.3.0 Milestone 3 (Mojarra Reference Implementation) / July 21, 2015 (2015-07-21)
Written in Java
Type Web application framework
Website javaserverfaces.java.net

JavaServer Faces (JSF) is a Java specification for building component-based user interfaces for web applications.[1] It was formalized as a standard through the Java Community Process and is part of the Java Platform, Enterprise Edition.

JSF 2 uses Facelets as its default templating system. Other view technologies such as XUL or plain Java[2] can also be employed. In contrast, JSF 1.x uses JavaServer Pages (JSP) as its default templating system.

History

In 2001, the original Java Specification Request (JSR) for the technology that ultimately became JavaServer Faces proposed developing a package with the name javax.servlet.ui[3] By June 2001, JavaWorld would report on Amy Fowler's team's design of "the JavaServer Faces API" (aka "Moonwalk") – "an application framework for creating Web-based user interfaces".[4]

Versions

How it works

Based on a component-driven UI design-model, JavaServer Faces uses XML files called view templates or Facelets views. The FacesServlet processes requests, loads the appropriate view template, builds a component tree, processes events, and renders the response (typically in the HTML language) to the client. The state of UI components and other objects of scope interest is saved at the end of each request in a process called stateSaving (note: transient true), and restored upon next creation of that view. Either the client or the server side can save objects and states.

JSF and Ajax

JSF is often used together with Ajax, a Rich Internet application technology. Ajax is a combination of technologies that make it possible to create rich user interfaces. The user interface components in Mojarra (the JSF reference implementation[9]) and Apache MyFaces were originally developed for HTML only, and Ajax had to be added via JavaScript. This has changed, however:

Because JSF supports multiple output formats, Ajax-enabled components can easily be added to enrich JSF-based user interfaces. The JSF 2.0 specification provides built in support for Ajax by standardizing the Ajax request lifecycle, and providing simple development interfaces to Ajax events, allowing any event triggered by the client to go through proper validation, conversion, and finally method invocation, before returning the result to the browser via an XML DOM update.

JSF 2 includes support for graceful degradation when JavaScript is disabled in the browser.

Ajax-enabled components and frameworks

The following companies and projects offer Ajax-based JSF frameworks or component libraries:

Latest developments

Facelets (which was designed specifically for JavaServer Faces) was adopted as the official view technology for JSF 2.0. This eliminates the life-cycle conflicts that existed with JSP, forcing workarounds by Java developers.[10] Facelets allows easy component/tag creation using XML markup instead of Java code, the chief complaint against JSF 1.x.

The new JSF developments also provide wide accessibility to Java 5 annotations such as @ManagedBean, @ManagedProperty and @FacesComponent which removes the need for faces-config.xml in all cases except framework extension. Navigation has been simplified, removing the need for faces-config.xml navigation cases. Page transitions can be invoked simply by passing the name of the desired View/Facelet.

Addition of Partial State Saving and DOM updates are part of the built in standardized Ajax support.

The latest JSF release has built-in support for handling resources like images, CSS and Javascript, allowing artifacts to be included with component libraries, separated into JAR files, or simply co-located into a consistent place within the web-application. Includes logical naming and versioning of resources.

JSF 2.0 also includes a number of other changes like adding support for events, separate development, staging, and production modes, similar to RAILS_ENV in Ruby on Rails, and significantly expanding the standard set of components.

Criticism

In their January 2014 "Technology Radar" publication, ThoughtWorks wrote:[11]

We continue to see teams run into trouble using JSF -- JavaServer Faces -- and are recommending you avoid this technology. Teams seem to choose JSF because it is a JEE standard without really evaluating whether the programming model suits them. We think JSF is flawed because it tries to abstract away HTML, CSS and HTTP, exactly the reverse of what modern web frameworks do. JSF, like ASP.NET webforms, attempts to create statefulness on top of the stateless protocol HTTP and ends up causing a whole host of problems involving shared server-side state. We are aware of the improvements in JSF 2.0, but think the model is fundamentally broken. We recommend teams use simple frameworks and embrace and understand web technologies including HTTP, HTML and CSS.

Rebuttal to criticisms

In February 2014, Cagatay Civici (PrimeFaces Lead) wrote an informative post entitled: JSF is not what you’ve been told anymore. In the post, the previous criticisms are refuted, explaining that improvements in JSF over the years offer many features that embrace modern web development, providing the option to write your own JavaScript, HTML, and CSS. Also regarding state, Cagatay wrote:

JSF is a stateful framework by nature and state makes web applications easy to develop with. With improved state management techniques introduced in JSF 2.0+ (e.g. stateless mode, partial state saving), JSF can scale as well.

References

Notes

  1. ↑ JavaServer Faces Technology
  2. ↑ NoVDL: Write your JSF views in pure Java
  3. ↑ "JSR 127: JavaServer Faces". Java Community process. Oracle Corporation. 2014. Retrieved 2014-08-05. 2.6 Is there a proposed package name for the API Specification? (i.e., javapi.something, org.something, etc.) [:] javax.servlet.ui
  4. ↑ Armstrong, Eric (2001-06-06). "Java Web services: What's not to like?: Java offers end-to-end, top-to-bottom, client/server solutions". JavaWorld. JavaWorld, Inc. Retrieved 2014-08-08. The JavaServer Faces API (aka Moonwalk) promises to provide an elegant solution for implementing interactive functionality on incompatible browsers. [...] Designed by a team led by Amy Fowler, Sun's AWT and Swing architect, the JavaServer Faces API will provide a collection of GUI tools that will run on common browsers using standard HTML.
  5. ↑ Tijms, Arjan. "What's new in JSF 2.3?". Musings of a Java EE developer. Retrieved 23 March 2016.
  6. ↑ JSF 2.2 (JSR-344) is final | techscouting through the java news. Blog.oio.de. Retrieved on 2013-07-29.
  7. ↑ JSR 314 JavaServer Faces 2.1 JSF 2.1 | techscouting through the java news. Blog.oio.de. Retrieved on 2013-07-29.
  8. ↑ Bosch, Andy (2010-11-29). "Was ist neu in JSF 2.1" (in German). it-republik.de. Retrieved 2013-02-19.
  9. ↑ Ryan Lubke (5 December 2007). "Project Mojarra - the JSF RI gets a code name".
  10. ↑ Bergsten, Hans. "Improving JSF by dumping JSP". O'Reilly. Retrieved 18 August 2011.
  11. ↑ "Technology Radar" (PDF). ThoughtWorks. January 2014. p. 12.
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