libraries/rest/src/main/java/org/qi4j/library/rest/admin/RestApplication.java

/*
 * Copyright 2008 Niclas Hedhman. All rights Reserved.
 *
 * Licensed  under the  Apache License,  Version 2.0  (the "License");
 * you may not use  this file  except in  compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed  under the  License is distributed on an "AS IS" BASIS,
 * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY KIND, either  express  or
 * implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.qi4j.library.rest.admin;

import org.qi4j.api.injection.scope.Structure;
import org.qi4j.api.injection.scope.Uses;
import org.qi4j.api.structure.Module;
import org.qi4j.api.unitofwork.*;
import org.restlet.*;
import org.restlet.data.MediaType;
import org.restlet.data.Status;
import org.restlet.resource.Finder;
import org.restlet.resource.ServerResource;
import org.restlet.routing.Router;

public class RestApplication
    extends Application
{
    public static final MediaType APPLICATION_SPARQL_JSON = new MediaType( "application/sparql-results+json", "SPARQL JSON" );

    @Structure
    private Module module;

    public RestApplication( @Uses Context parentContext )
    {
        super( parentContext );

        getMetadataService().addExtension( "srj", APPLICATION_SPARQL_JSON );

        getTunnelService().setExtensionsTunnel( true );
    }

    @Override
    public void handle( Request request, Response response )
    {
        UnitOfWork uow = module.newUnitOfWork();
        try
        {
            super.handle( request, response );
            uow.complete();
        }
        catch( UnitOfWorkException e )
        {
            uow.discard();
            response.setStatus( Status.CLIENT_ERROR_NOT_ACCEPTABLE );
            response.setEntity( new ExceptionRepresentation( e ) );
            // More info to send...
        }
        catch( ConcurrentEntityModificationException e )
        {
            uow.discard();
            response.setStatus( Status.CLIENT_ERROR_LOCKED );
            response.setEntity( new ExceptionRepresentation( e ) );
            // Info to try again...
        }
        catch( UnitOfWorkCompletionException e )
        {
            uow.discard();
            response.setStatus( Status.CLIENT_ERROR_NOT_ACCEPTABLE );
            response.setEntity( new ExceptionRepresentation( e ) );
        }
    }

    /**
     * Creates a root Restlet that will receive all incoming calls.
     */
    @Override
    public synchronized Restlet createInboundRoot()
    {
        Router router = new Router( getContext() );

        router.attach( "/entity", createFinder( EntitiesResource.class ) );
        router.attach( "/entity/{identity}", createFinder( EntityResource.class ) );

        router.attach( "/query", createFinder( SPARQLResource.class ) );
        router.attach( "/query/sparqlhtml", createFinder( SPARQLResource.class ) );
        router.attach( "/query/index", createFinder( IndexResource.class ) );

        return router;
    }

    private Finder createFinder( Class<? extends ServerResource> resource )
    {
        Finder finder = module.newObject( Finder.class );
        finder.setTargetClass( resource );
        return finder;
    }
}