RESTEasy-CDI Integration

Version 10

Created by jharting on Mar 24, 2010 8:10 AM. Last modified by jharting on Oct 15, 2012 9:51 AM.

Integration between RESTEasy and CDI is provided by the resteasy-cdi module. The module has been part of the JBoss AS since version 6.0.0 M4. It can also be used to integrate RESTEasy with any other CDI-complaint application server.

What is this module for?

It is important to realize that both JAX-RS and CDI specifications introduce its own component model. On the one hand, you only need to fulfill several basic constraints for your Java class to become a CDI managed bean. On the other hand, you need to explicitly decorate your Java class with @Path or @Provider annotation for it to become a JAX-RS resource or provider. What happens when you annotate a class that is suitable for being a CDI bean with JAX-RS annotations? RESTEasy and a CDI implementation start to compete and you do not get the desired result. (You end up having a JAX-RS component not managed by CDI).

This is the reason why you need to use the resteasy-cdi module. During a web service invocation, resteasy-cdi asks the CDI container for a managed instance of a JAX-RS component. Then, this instance is passed to RESTEasy.

If a managed instance is not available for some reason (the class is placed in a jar which is not a bean deployment archive), RESTEasy falls back to instantiating the class itself.

Setting up an application

JBoss AS 6

The resteasy-cdi module has been bundled with JBoss AS since version 6.0.0 M4. Therefore, when using JBoss AS, there is no need to download the module separately or add any additional configuration.

Other JEE 6 containers

The configuration is quite straightforward. All you need to do is to add the resteasy-cdi module as a dependency.

<dependency>
     <groupId>org.jboss.resteasy</groupId>
     <artifactId>resteasy-cdi</artifactId>
     <version>${project.version}</version>
     <exclusions>
          <exclusion>
               <groupId>org.jboss.resteasy</groupId>
               <artifactId>resteasy-jaxrs</artifactId>
          </exclusion>
     </exclusions>
</dependency>

Pre-Servlet 3 containers

Furthermore, if you are running a pre-Servlet 3 container (GAE with Weld), you need to specify the following context parameter in web.xml

<context-param>
     <param-name>resteasy.injector.factory</param-name>
     <param-value>org.jboss.resteasy.cdi.CdiInjectorFactory</param-value>
</context-param>

Supported features

CDI beans can serve as root resources, subresources, providers and application subclasses
CDI beans which are JAX-RS root resources are @RequestScoped by default

CDI beans which are providers or Application subclasses are @ApplicationScoped by default

Known limitations

General limitations

if a Session Bean has more than one local interface, a random one is chosen for bean lookup

Weld(JBoss AS)-specific limitations

constructor injection does not work with Session Beans (https://jira.jboss.org/jira/browse/WELDINT-31)

Resin-specific limitations

JAX-RS property injection does not work (http://bugs.caucho.com/view.php?id=3967)
JAX-RS setter injection does not work
Session Beans do not work as JAX-RS components currently
The module does not work with Resin 4.0.9 http://bugs.caucho.com/view.php?id=4182

Download & Source

You can download the resteasy-cdi .jar from JBoss Maven repository. Source code can be obtained from RESTEasy svn repository and built using Maven.

Tested environment

The RESTEasy-CDI module has been tested with the following application servers:

JBoss AS 6 M4, M5, CR1
Caucho Resin 4.0.5
Google App Engine (see RESTEASY-392)

JBossDeveloper