RESTEasy Guice Provider

Question

I'm having a small problem when trying to use Guice with ContainerRequestFilter, it throws a NullPointerException. I did a little digging into RESTEasy and it would appear that it can't find a constructor for MyFilter due to the @Context annotation not being present, the NullPointerException is thrown when trying to instantiate a null constructor.

My filter:

@Provider
@PreMatching
public class MyFilter implements ContainerRequestFilter {
    private Dependency d;

    @Inject
    public MyFilter(Dependency d) {
        this.d = d;
    }

    @Override
    public void filter(ContainerRequestContext containerRequestContext) throws IOException {
        if (d.doSomething()) {
            Response r = Response.status(Response.Status.INTERNAL_SERVER_ERROR).build();
            containerRequestContext.abortWith(r);
        }
    }
}

I've added the filter to my Application class:

@ApplicationPath("")
public class Main extends Application {
    private Set<Object> singletons = new HashSet<Object>();
    private Set<Class<?>> c = new HashSet<Class<?>>();

    public Main() {
        c.add(Dependency.class);
    }

    @Override
    public Set<Class<?>> getClasses() {
        return c;
    }

    @Override
    public Set<Object> getSingletons() {
        return singletons;
    }
}

My Guice configuration:

public class GuiceConfigurator implements Module {
    public void configure(final Binder binder) {
        binder.bind(Dependency.class);
    }
}

My web.xml:

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
         http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <display-name>My App</display-name>

    <context-param>
        <param-name>resteasy.guice.modules</param-name>
        <param-value>com.example.GuiceConfigurator</param-value>
    </context-param>

    <listener>
        <listener-class>
          org.jboss.resteasy.plugins.guice.GuiceResteasyBootstrapServletContextListener
        </listener-class>
    </listener>
</web-app>

This configuration is working for injecting my dependencies into resources, but I get a NullPointerException when trying to use it on a provider.

Any help would be appreciated.

Answer 1

It seems that even with RESTeasy/JAX-RS components, you still need to register it with the Guice binder. I wasn't sure at first, but looking at the test cases, it seems we still need to register our resources and providers with Guice to make it work.

I test it after adding the filter to the Guice module, and it works as expected.

public class GuiceConfigurator implements Module {
    public void configure(final Binder binder) {
        binder.bind(MyFilter.class);
        binder.bind(Dependency.class);
    }
}

To test, I went off the example from the RESTeasy project, added a filter with the constructor injection, and added the filter to the module binder. And it worked when adding the filter to the module and failed when not added.