/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.apache.shindig.social.opensocial.service;

 import com.google.inject.Inject;

 import com.google.inject.Provider;

 import com.google.common.collect.ImmutableMap;

 import com.google.common.collect.Maps;

 import java.util.Map;

 /**

  * Default implementation of HandlerDispatcher.  Provides default

  * bindings for the person, activity, and app data handlers.

  */

 public class StandardHandlerDispatcher implements HandlerDispatcher {

   private final Map<String, Provider<? extends DataRequestHandler>> handlers;

   /**

    * Creates a dispatcher with the standard handlers.

    * @param personHandlerProvider provider for the person handler

    * @param activityHandlerProvider provider for the activity handler

    * @param appDataHandlerProvider provider for the app data handler

    */

   @Inject

   public StandardHandlerDispatcher(Provider<PersonHandler> personHandlerProvider,

       Provider<ActivityHandler> activityHandlerProvider,

       Provider<AppDataHandler> appDataHandlerProvider) {

     this(ImmutableMap.of(

         DataServiceServlet.PEOPLE_ROUTE, personHandlerProvider,

         DataServiceServlet.ACTIVITY_ROUTE, activityHandlerProvider,

         DataServiceServlet.APPDATA_ROUTE, appDataHandlerProvider));

   }

   /**

    * Creates a dispatcher with a custom list of handlers.

    * @param handlers a map of handlers by service name

    */

   public StandardHandlerDispatcher(Map<String,Provider<? extends DataRequestHandler>> handlers) {

     this.handlers = Maps.newHashMap(handlers);

   }

   /**

    * Gets a handler by service name.

    */

   public DataRequestHandler getHandler(String service) {

     Provider<? extends DataRequestHandler> provider = handlers.get(service);

     if (provider == null) {

       return null;

     }

     return provider.get();

   }

   /**

    * Adds a custom handler.

    */

   public void addHandler(String service, Provider<? extends DataRequestHandler> handler) {

     handlers.put(service, handler);

   }

 }