JSF 2 and CDI – a nice combo!

In JSF 2.0 there is (optional) support for annotating JSF Managed beans, via the Faces Managed Bean Annotation Specification. Both Apache MyFaces and the SUN RI implement this specification.

With the advent of these two JSRs:

There is an ongoing discussion about the right annotation for the “JSF beans”.

I agree that a JSF 2.0 application should avoid using the @ManagedBean annotation. I prefer using the stuff that 299/330 are offering. The good news is that even Spring (in Version 3.0) does actually support the @inject specification (e.g. @Named).

Using the two specifications, a simple bean could look like:

...
import javax.enterprise.context.RequestScoped;
import javax.inject.Named;

@Named
@RequestScoped
public class HelloWorldBean
{
...
}
...

For CDI there is a neat convenience annotation (@Model) that combines the two above (@Named and @RequestScoped)!

Too bad that Spring does not support CDI (JSR 299), so the @Model is not usable there… However, making something on your own (e.g. @SpringModelBean) is not hard, as you just have to combine the @Named and the @Scope(“request”) annotation, from Spring…

UPDATE: Enabling the CDI/299 Scopes in Spring is pretty simple.

One concern maybe that 299 is only usable inside of a fullblown Java EE 6 container, like Glassfish3. But that is not the case. The implementations of the 299 specification from Apache(OpenWebBeans) and JBoss (Weld) are offering support for Servlet Containers, like Tomcat.

I added a new (very) simple HelloWorld that combines CDI(299/330) and JSF 2.0 to my FacesGoodies project. The source is located here. For the implementations I picked Apache MyFaces 2.0 (the first alpha release is out; a beta is coming soon) and Apache OpenWebBean (which recently left the Apache Incubator). The combination of these two standards really matches very well. I will add more complex demos to FacesGoodies soon, but this (trivial) HelloWorld demo is just a starting point.
Note: Currently you have to build the OpenWebBeans stuff, to have the latest greatest fixes from the trunk (or, use the M3 release from the incubator repository).

Another benefit is, as my demo uses the JettyMavenPlugin, with CDI you can use the jetty:run goal. The annotations for the JSF managed bean facility do require jetty:run-exploded, which is kinda odd… See… another reason to use CDI with JSF 2.0 :-)

Apache offers great support for these with its MyFaces and OpenWebBeans project! Check em out!

HINT: You need to build Apache OpenWebBeans in order to run this example. Do the SVN checkout from this location. And run mvn install in its root-folder!

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Posted in apache, ejb, facelets, java, jetty, jsf, myfaces, spring, web², WebBeans
2 comments on “JSF 2 and CDI – a nice combo!
  1. Sven Linstaedt says:

    The problem with JSF2 (at least the reference impl I have worked with) classpath scanning works different than in CDI. This is why JSF2 fails to locate classes which are not located under target/webappname/WEB-INF/classes (webapp classpath for jetty:run-exploded), but instead target/classes (webapp classpath for jetty:run).

  2. Jon says:

    I just have to say, don’t forget about Resin’s CDI implementation! =)

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