ResourceListingResource.java

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Application;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.sun.jersey.api.model.AbstractResource;
import com.sun.jersey.api.model.AbstractResourceMethod;
import com.sun.jersey.api.model.AbstractSubResourceMethod;
import com.sun.jersey.server.impl.modelapi.annotation.IntrospectionModeller;

@Path("/resources")
public class ResourceListingResource
{
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response showAll( @Context Application application,
                             @Context HttpServletRequest request)
    {
        String basePath = request.getRequestURL().toString().replace("/resources", "");
        // http://stackoverflow.com/questions/13484350/find-a-list-of-all-jersey-resource-methods-in-my-app

        ObjectNode root = JsonNodeFactory.instance.objectNode();
        ArrayNode resources = JsonNodeFactory.instance.arrayNode();

        root.put( "resources", resources );

        for ( Class<?> aClass : application.getClasses() )
        {
            if ( isAnnotatedResourceClass( aClass ) )
            {
                AbstractResource resource = IntrospectionModeller.createResource( aClass );
                ObjectNode resourceNode = JsonNodeFactory.instance.objectNode();
                String uriPrefix = resource.getPath().getValue();

                for ( AbstractSubResourceMethod srm : resource.getSubResourceMethods() )
                {
                    String uri = uriPrefix + "/" + srm.getPath().getValue();
                    addTo( resourceNode, uri, srm, joinUri(basePath, uri) );
                }

                for ( AbstractResourceMethod srm : resource.getResourceMethods() )
                {
                    addTo( resourceNode, uriPrefix, srm, joinUri( basePath, uriPrefix ) );
                }

                resources.add( resourceNode );
            }

        }


        return Response.ok().entity( root ).build();
    }

    private void addTo( ObjectNode resourceNode, String uriPrefix, AbstractResourceMethod srm, String path )
    {
        if ( resourceNode.get( uriPrefix ) == null )
        {
            ObjectNode inner = JsonNodeFactory.instance.objectNode();
            inner.put("path", path);
            inner.put("verbs", JsonNodeFactory.instance.arrayNode());
            resourceNode.put( uriPrefix, inner );
        }

        ((ArrayNode) resourceNode.get( uriPrefix ).get("verbs")).add( srm.getHttpMethod() );
    }

    public static String joinUri( String... parts )
    {
        StringBuilder result = new StringBuilder();
        for ( String part : parts )
        {
            if ( result.length() > 0 && result.charAt( result.length() - 1 ) == '/' )
            {
                result.setLength( result.length() - 1 );
            }
            if ( result.length() > 0 && !part.startsWith( "/" ) )
            {
                result.append( '/' );
            }
            result.append( part );
        }
        return result.toString();
    }


    private boolean isAnnotatedResourceClass( Class rc )
    {
        if ( rc.isAnnotationPresent( Path.class ) )
        {
            return true;
        }

        for ( Class i : rc.getInterfaces() )
        {
            if ( i.isAnnotationPresent( Path.class ) )
            {
                return true;
            }
        }

        return false;
    }

}