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PipelineUtils xref
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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.giraph.utils;
20  
21  import io.netty.channel.Channel;
22  import io.netty.channel.ChannelHandler;
23  import io.netty.channel.ChannelPipeline;
24  import io.netty.util.concurrent.EventExecutorGroup;
25  
26  /**
27   * Utility class for ChannelPipeline
28   */
29  public class PipelineUtils {
30    /** Do not instantiate. */
31    private PipelineUtils() { }
32  
33    /**
34     * Add a handler to pipeline if it is not already added
35     * and configure the handler to use an executor group based on equality
36     * of compareTo and handlerName
37     *
38     * @param handlerName string name of the handler
39     * @param handler channelhandler object
40     * @param compareTo string name to compare to for executorgroup usage check
41     * @param executor executorgroup instance
42     * @param channel netty channel
43     */
44    public static void addLastWithExecutorCheck(String handlerName,
45      ChannelHandler handler, String compareTo, EventExecutorGroup executor,
46      Channel channel) {
47      ChannelPipeline pipeline = channel.pipeline();
48      if (channel.pipeline().get(handlerName) != null) {
49        return;
50      }
51      if (compareTo.equals(handlerName)) {
52        pipeline.addLast(executor, handlerName, handler);
53      } else {
54        pipeline.addLast(handlerName, handler);
55      }
56    }
57  }