content: //
  // 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 com.cloud.network.resource;
  
  import java.util.Hashtable;
  import java.util.Set;
  
  import org.reflections.Reflections;
  
  import com.cloud.agent.api.Answer;
  import com.cloud.agent.api.Command;
  import com.cloud.resource.CommandWrapper;
  import com.cloud.resource.RequestWrapper;
  import com.cloud.resource.ServerResource;
  
  public class NiciraNvpRequestWrapper extends RequestWrapper {
  
      private static NiciraNvpRequestWrapper instance;
  
      static {
          instance = new NiciraNvpRequestWrapper();
      }
  
      Reflections baseWrappers = new Reflections("com.cloud.network.resource.wrapper");
      @SuppressWarnings("rawtypes")
      Set<Class<? extends CommandWrapper>> baseSet = baseWrappers.getSubTypesOf(CommandWrapper.class);
  
      private NiciraNvpRequestWrapper() {
          init();
      }
  
      @SuppressWarnings("rawtypes")
      private void init() {
          // NiciraNvpResource commands
          final Hashtable<Class<? extends Command>, CommandWrapper> niciraCommands = processAnnotations(baseSet);
  
          resources.put(NiciraNvpResource.class, niciraCommands);
      }
  
      public static NiciraNvpRequestWrapper getInstance() {
          return instance;
      }
  
      @SuppressWarnings({"rawtypes" })
      @Override
      public Answer execute(final Command command, final ServerResource serverResource) {
          final Class<? extends ServerResource> resourceClass = serverResource.getClass();
  
          final Hashtable<Class<? extends Command>, CommandWrapper> resourceCommands = retrieveResource(command, resourceClass);
  
          CommandWrapper<Command, Answer, ServerResource> commandWrapper = retrieveCommands(command.getClass(), resourceCommands);
  
          while (commandWrapper == null) {
              //Could not find the command in the given resource, will traverse the family tree.
              commandWrapper = retryWhenAllFails(command, resourceClass, resourceCommands);
          }
  
          return commandWrapper.execute(command, serverResource);
      }
  }
  