hadoop DownwardProtocol 源码

  • 2022-10-20
  • 浏览 (131)

haddop DownwardProtocol 代码

文件路径:/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/pipes/DownwardProtocol.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,
 * 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.hadoop.mapred.pipes;

import java.io.IOException;

import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.JobConf;

/**
 * The abstract description of the downward (from Java to C++) Pipes protocol.
 * All of these calls are asynchronous and return before the message has been 
 * processed.
 */
interface DownwardProtocol<K extends WritableComparable, V extends Writable> {
  /**
   * request authentication
   * @throws IOException
   */
  void authenticate(String digest, String challenge) throws IOException;
  
  /**
   * Start communication
   * @throws IOException
   */
  void start() throws IOException;
  
  /**
   * Set the JobConf for the task.
   * @param conf
   * @throws IOException
   */
  void setJobConf(JobConf conf) throws IOException;
  
  /**
   * Set the input types for Maps.
   * @param keyType the name of the key's type
   * @param valueType the name of the value's type
   * @throws IOException
   */
  void setInputTypes(String keyType, String valueType) throws IOException;
  
  /**
   * Run a map task in the child.
   * @param split The input split for this map.
   * @param numReduces The number of reduces for this job.
   * @param pipedInput Is the input coming from Java?
   * @throws IOException
   */
  void runMap(InputSplit split, int numReduces, 
              boolean pipedInput) throws IOException;
  
  /**
   * For maps with pipedInput, the key/value pairs are sent via this messaage.
   * @param key The record's key
   * @param value The record's value
   * @throws IOException
   */
  void mapItem(K key, V value) throws IOException;
  
  /**
   * Run a reduce task in the child
   * @param reduce the index of the reduce (0 .. numReduces - 1)
   * @param pipedOutput is the output being sent to Java?
   * @throws IOException
   */
  void runReduce(int reduce, boolean pipedOutput) throws IOException;
  
  /**
   * The reduce should be given a new key
   * @param key the new key
   * @throws IOException
   */
  void reduceKey(K key) throws IOException;
  
  /**
   * The reduce should be given a new value
   * @param value the new value
   * @throws IOException
   */
  void reduceValue(V value) throws IOException;
  
  /**
   * The task has no more input coming, but it should finish processing it's 
   * input.
   * @throws IOException
   */
  void endOfInput() throws IOException;
  
  /**
   * The task should stop as soon as possible, because something has gone wrong.
   * @throws IOException
   */
  void abort() throws IOException;
  
  /**
   * Flush the data through any buffers.
   */
  void flush() throws IOException;
  
  /**
   * Close the connection.
   */
  void close() throws IOException, InterruptedException;
}

相关信息

hadoop 源码目录

相关文章

hadoop Application 源码

hadoop BinaryProtocol 源码

hadoop OutputHandler 源码

hadoop PipesMapRunner 源码

hadoop PipesNonJavaInputFormat 源码

hadoop PipesPartitioner 源码

hadoop PipesReducer 源码

hadoop Submitter 源码

hadoop UpwardProtocol 源码

0  赞