hadoop-mapreduce/hadoop-mr-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/ReduceTaskImpl.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.mapreduce.v2.app.job.impl;

import java.util.Collection;
import java.util.Set;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapred.ReduceTaskAttemptImpl;
import org.apache.hadoop.mapreduce.MRJobConfig;
import org.apache.hadoop.mapreduce.OutputCommitter;
import org.apache.hadoop.mapreduce.security.token.JobTokenIdentifier;
import org.apache.hadoop.mapreduce.v2.api.records.JobId;
import org.apache.hadoop.mapreduce.v2.api.records.TaskId;
import org.apache.hadoop.mapreduce.v2.api.records.TaskType;
import org.apache.hadoop.mapreduce.v2.app.metrics.MRAppMetrics;
import org.apache.hadoop.mapreduce.v2.app.TaskAttemptListener;
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 ReduceTaskImpl extends TaskImpl {
  
  private final int numMapTasks;

  public ReduceTaskImpl(JobId jobId, int partition,
      EventHandler eventHandler, Path jobFile, Configuration conf,
      int numMapTasks, TaskAttemptListener taskAttemptListener,
      OutputCommitter committer, Token<JobTokenIdentifier> jobToken,
      Collection<Token<? extends TokenIdentifier>> fsTokens, Clock clock, 
      Set<TaskId> completedTasksFromPreviousRun, int startCount,
      MRAppMetrics metrics) {
    super(jobId, TaskType.REDUCE, partition, eventHandler, jobFile, conf,
        taskAttemptListener, committer, jobToken, fsTokens, clock,
        completedTasksFromPreviousRun, startCount, metrics);
    this.numMapTasks = numMapTasks;
  }

  @Override
  protected int getMaxAttempts() {
    return conf.getInt(MRJobConfig.REDUCE_MAX_ATTEMPTS, 4);
  }

  @Override
  protected TaskAttemptImpl createAttempt() {
    return new ReduceTaskAttemptImpl(getID(), nextAttemptNumber,
        eventHandler, jobFile,
        partition, numMapTasks, conf, taskAttemptListener,
        committer, jobToken, fsTokens, clock);
  }

  @Override
  public TaskType getType() {
    return TaskType.REDUCE;
  }

}