Response to "Authenticator and Component XML configuration"

/*
 * This is part of a response to a question in this Restlet discussion:
 * http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447&dsMessageId=3078331
 */
package net.peierls.example.restlet.authrouting;

import org.restlet.*;
import org.restlet.data.*;
import org.restlet.routing.*;
import org.restlet.resource.*;
import org.restlet.security.*;


public class AuthRoutingExample extends Application {

    Verifier verifier;

    @Override
    public Restlet createInboundRoot(){
        Router router = new Router(getContext());

        router.attach("/", RootServerResource.class);

        router.attach("/ifaces", IfacesServerResource.class);
        router.attach("/ifaces/{ifaceId}", IfaceServerResource.class);

        router.attach("/apps", AppsServerResource.class);
        router.attach("/apps/{appId}/", authenticated(AppServerResource.class));
        router.attach("/apps/{appId}/rules", authenticated(RulesServerResource.class));
        router.attach("/apps/{appId}/rules/{ruleId}", authenticated(RuleServerResource.class));

        return router;
    }

    /**
     * Wraps a resource with a Tracer, then wraps that with a ChallengeAuthenticator.
     */
    private Restlet authenticated(Class<? extends ServerResource> targetClass) {
        Tracer tracer = new Tracer(getContext());
        tracer.setNext(targetClass);

        ChallengeAuthenticator authenticator = new ChallengeAuthenticator(
                getContext(), ChallengeScheme.HTTP_BASIC, "AndroPi");
        authenticator.setVerifier(verifier);
        authenticator.setNext(tracer);

        return authenticator;
    }

    static class RootServerResource extends ServerResource {}
    static class IfacesServerResource extends ServerResource {}
    static class IfaceServerResource extends ServerResource {}
    static class AppsServerResource extends ServerResource {}
    static class AppServerResource extends ServerResource {}
    static class RulesServerResource extends ServerResource {}
    static class RuleServerResource extends ServerResource {}
    static class Tracer extends Filter {
        Tracer(Context context) { super(context); }
    }
}