/*

  * 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.giraph.utils;

 import io.netty.channel.Channel;

 import io.netty.channel.ChannelHandler;

 import io.netty.channel.ChannelPipeline;

 import io.netty.util.concurrent.EventExecutorGroup;

 /**

  * Utility class for ChannelPipeline

  */

 public class PipelineUtils {

   /** Do not instantiate. */

   private PipelineUtils() { }

   /**

    * Add a handler to pipeline if it is not already added

    * and configure the handler to use an executor group based on equality

    * of compareTo and handlerName

    *

    * @param handlerName string name of the handler

    * @param handler channelhandler object

    * @param compareTo string name to compare to for executorgroup usage check

    * @param executor executorgroup instance

    * @param channel netty channel

    */

   public static void addLastWithExecutorCheck(String handlerName,

     ChannelHandler handler, String compareTo, EventExecutorGroup executor,

     Channel channel) {

     ChannelPipeline pipeline = channel.pipeline();

     if (channel.pipeline().get(handlerName) != null) {

       return;

     }

     if (compareTo.equals(handlerName)) {

       pipeline.addLast(executor, handlerName, handler);

     } else {

       pipeline.addLast(handlerName, handler);

     }

   }

 }