CLOUDSTACK-8590 - Refactoring NiciraNVP resource

- Adding the NiciraNvpWrapper
  - This class will keep track of all Wrappers of the Nicira NVP Plugin

Signed-off-by: wilderrodrigues <wrodrigues@schubergphilis.com>

plugins/network-elements/nicira-nvp/src/com/cloud/network/resource/NiciraNvpRequestWrapper.java

@@ -0,0 +1,76 @@
+//
+// 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> libvirtCommands = processAnnotations(baseSet);
+
+        resources.put(NiciraNvpResource.class, libvirtCommands);
+    }
+
+    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);
+    }
+}