What is facelets?

Answer 1

Facelets is a view technology for JSF that replaces the standard view handler which deals with JSP pages. All of the standard JSF components are available with Facelets plus some extras provided by Facelets itself. One can also use third party component libraries with Facelets (like Tomahawk, ICEFaces and RichFaces) although you may need to provide a tag library definition as configuration if the library does not.

Many of the original reasons for Facelets have been obviated in JSF 1.2 with the addition of the Unified EL. However, Facelets still provides some benefits including better templating support, more lightweight than JSPs; actually, here's the list from the Facelets documentation:

* Works with JSF 1.1 and JSF 1.2, including Sun's RI and Apache MyFaces.

* Zero Tag development time for UIComponents

* Fast Templating/Decorators for Components and Pages

* The ability to specify UIComponent trees in separate files (UICompositions)

* Line/Tag/Attribute precise Error Reporting

* Specify Tags in Separate Files, even packaged with Jars

* Full EL support, including Functions

* Build-time EL Validation

* XML configuration files aren't necessary

* Reserves the 'jsfc' attribute which acts the same as Tapestry's jwcid (Example: <input id="bar" type="text" jsfc="h:inputText" value="#{foo.bar}"/>)

* Plugable Decorators to really make designer's job easy (Example: transform <input type="text"/> to <h:inputText/> at compile time)

* Works with any RenderKit

* Facelet APIs aren't dependent on a Web Container

See the Facelets home page for more detail:

https://facelets.dev.java.net/

By RaymondDeCampo