How to get resource method matched to URI before Jersey invokes it?

Question

I'm trying to implement a ContainerRequestFilter that does custom validation of a request's parameters. I need to look up the resource method that will be matched to the URI so that I can scrape custom annotations from the method's parameters.

Based on this answer I should be able to inject ExtendedUriInfo and then use it to match the method:

public final class MyRequestFilter implements ContainerRequestFilter {

    @Context private ExtendedUriInfo uriInfo;

    @Override
    public ContainerRequest filter(ContainerRequest containerRequest) {

        System.out.println(uriInfo.getMatchedMethod());

        return containerRequest;
    }
}

But getMatchedMethod apparently returns null, all the way up until the method is actually invoked (at which point it's too late for me to do validation).

How can I retrieve the Method that will be matched to a given URI, before the resource method is invoked?

---

For those interested, I'm trying to roll my own required parameter validation, as described in JERSEY-351.

Answer 1

Actually, you should try to inject ResourceInfo into your custom request filter. I have tried it with RESTEasy and it works there. The advantage is that you code against the JSR interfaces and not the Jersey implementation.

public class MyFilter implements ContainerRequestFilter
{
    @Context
    private ResourceInfo resourceInfo;

    @Override
    public void filter(ContainerRequestContext requestContext)
            throws IOException
    {
        Method theMethod = resourceInfo.getResourceMethod();
        return;
    }
}