hadoop-mapreduce/hadoop-mr-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapred/ReduceTaskAttemptImpl.java

/**
* 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,
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* See the License for the specific language governing permissions and
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package org.apache.hadoop.mapred;

import java.util.Collection;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.MRJobConfig;
import org.apache.hadoop.mapreduce.OutputCommitter;
import org.apache.hadoop.mapreduce.TypeConverter;
import org.apache.hadoop.mapreduce.security.token.JobTokenIdentifier;
import org.apache.hadoop.mapreduce.v2.api.records.TaskId;
import org.apache.hadoop.mapreduce.v2.app.TaskAttemptListener;
import org.apache.hadoop.mapreduce.v2.app.job.impl.TaskAttemptImpl;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.security.token.TokenIdentifier;
import org.apache.hadoop.yarn.Clock;
import org.apache.hadoop.yarn.event.EventHandler;


public class ReduceTaskAttemptImpl extends TaskAttemptImpl {

  private final int numMapTasks;

  public ReduceTaskAttemptImpl(TaskId id, int attempt,
      EventHandler eventHandler, Path jobFile, int partition,
      int numMapTasks, Configuration conf,
      TaskAttemptListener taskAttemptListener, OutputCommitter committer,
      Token<JobTokenIdentifier> jobToken,
      Collection<Token<? extends TokenIdentifier>> fsTokens, Clock clock) {
    super(id, attempt, eventHandler, taskAttemptListener, jobFile, partition,
        conf, new String[] {}, committer, jobToken, fsTokens, clock);
    this.numMapTasks = numMapTasks;
  }

  @Override
  public Task createRemoteTask() {
  //job file name is set in TaskAttempt, setting it null here
    ReduceTask reduceTask =
      new ReduceTask("", TypeConverter.fromYarn(getID()), partition,
          numMapTasks, 1); // YARN doesn't have the concept of slots per task, set it as 1.
  reduceTask.setUser(conf.get(MRJobConfig.USER_NAME));
  reduceTask.setConf(conf);
    return reduceTask;
  }

}