001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019 package org.apache.hadoop.mapreduce; 020 021 import java.io.DataInput; 022 import java.io.DataOutput; 023 import java.io.IOException; 024 025 import org.apache.hadoop.classification.InterfaceAudience; 026 import org.apache.hadoop.classification.InterfaceStability; 027 028 /** 029 * TaskAttemptID represents the immutable and unique identifier for 030 * a task attempt. Each task attempt is one particular instance of a Map or 031 * Reduce Task identified by its TaskID. 032 * 033 * TaskAttemptID consists of 2 parts. First part is the 034 * {@link TaskID}, that this TaskAttemptID belongs to. 035 * Second part is the task attempt number. <br> 036 * An example TaskAttemptID is : 037 * <code>attempt_200707121733_0003_m_000005_0</code> , which represents the 038 * zeroth task attempt for the fifth map task in the third job 039 * running at the jobtracker started at <code>200707121733</code>. 040 * <p> 041 * Applications should never construct or parse TaskAttemptID strings 042 * , but rather use appropriate constructors or {@link #forName(String)} 043 * method. 044 * 045 * @see JobID 046 * @see TaskID 047 */ 048 @InterfaceAudience.Public 049 @InterfaceStability.Stable 050 public class TaskAttemptID extends org.apache.hadoop.mapred.ID { 051 protected static final String ATTEMPT = "attempt"; 052 private TaskID taskId; 053 054 /** 055 * Constructs a TaskAttemptID object from given {@link TaskID}. 056 * @param taskId TaskID that this task belongs to 057 * @param id the task attempt number 058 */ 059 public TaskAttemptID(TaskID taskId, int id) { 060 super(id); 061 if(taskId == null) { 062 throw new IllegalArgumentException("taskId cannot be null"); 063 } 064 this.taskId = taskId; 065 } 066 067 /** 068 * Constructs a TaskId object from given parts. 069 * @param jtIdentifier jobTracker identifier 070 * @param jobId job number 071 * @param type the TaskType 072 * @param taskId taskId number 073 * @param id the task attempt number 074 */ 075 public TaskAttemptID(String jtIdentifier, int jobId, TaskType type, 076 int taskId, int id) { 077 this(new TaskID(jtIdentifier, jobId, type, taskId), id); 078 } 079 080 public TaskAttemptID() { 081 taskId = new TaskID(); 082 } 083 084 /** Returns the {@link JobID} object that this task attempt belongs to */ 085 public JobID getJobID() { 086 return taskId.getJobID(); 087 } 088 089 /** Returns the {@link TaskID} object that this task attempt belongs to */ 090 public TaskID getTaskID() { 091 return taskId; 092 } 093 094 /**Returns the TaskType of the TaskAttemptID */ 095 public TaskType getTaskType() { 096 return taskId.getTaskType(); 097 } 098 @Override 099 public boolean equals(Object o) { 100 if (!super.equals(o)) 101 return false; 102 103 TaskAttemptID that = (TaskAttemptID)o; 104 return this.taskId.equals(that.taskId); 105 } 106 107 /** 108 * Add the unique string to the StringBuilder 109 * @param builder the builder to append ot 110 * @return the builder that was passed in. 111 */ 112 protected StringBuilder appendTo(StringBuilder builder) { 113 return taskId.appendTo(builder).append(SEPARATOR).append(id); 114 } 115 116 @Override 117 public void readFields(DataInput in) throws IOException { 118 super.readFields(in); 119 taskId.readFields(in); 120 } 121 122 @Override 123 public void write(DataOutput out) throws IOException { 124 super.write(out); 125 taskId.write(out); 126 } 127 128 @Override 129 public int hashCode() { 130 return taskId.hashCode() * 5 + id; 131 } 132 133 /**Compare TaskIds by first tipIds, then by task numbers. */ 134 @Override 135 public int compareTo(ID o) { 136 TaskAttemptID that = (TaskAttemptID)o; 137 int tipComp = this.taskId.compareTo(that.taskId); 138 if(tipComp == 0) { 139 return this.id - that.id; 140 } 141 else return tipComp; 142 } 143 @Override 144 public String toString() { 145 return appendTo(new StringBuilder(ATTEMPT)).toString(); 146 } 147 148 /** Construct a TaskAttemptID object from given string 149 * @return constructed TaskAttemptID object or null if the given String is null 150 * @throws IllegalArgumentException if the given string is malformed 151 */ 152 public static TaskAttemptID forName(String str 153 ) throws IllegalArgumentException { 154 if(str == null) 155 return null; 156 try { 157 String[] parts = str.split(Character.toString(SEPARATOR)); 158 if(parts.length == 6) { 159 if(parts[0].equals(ATTEMPT)) { 160 String type = parts[3]; 161 TaskType t = TaskID.getTaskType(type.charAt(0)); 162 if(t != null) { 163 return new org.apache.hadoop.mapred.TaskAttemptID 164 (parts[1], 165 Integer.parseInt(parts[2]), 166 t, Integer.parseInt(parts[4]), 167 Integer.parseInt(parts[5])); 168 } else throw new Exception(); 169 } 170 } 171 } catch (Exception ex) { 172 //fall below 173 } 174 throw new IllegalArgumentException("TaskAttemptId string : " + str 175 + " is not properly formed"); 176 } 177 178 }