1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | |
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19 | package org.apache.hadoop.mapreduce; |
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20 | |
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21 | import java.io.DataInput; |
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22 | import java.io.DataOutput; |
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23 | import java.io.IOException; |
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24 | |
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25 | /** |
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26 | * TaskAttemptID represents the immutable and unique identifier for |
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27 | * a task attempt. Each task attempt is one particular instance of a Map or |
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28 | * Reduce Task identified by its TaskID. |
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29 | * |
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30 | * TaskAttemptID consists of 2 parts. First part is the |
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31 | * {@link TaskID}, that this TaskAttemptID belongs to. |
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32 | * Second part is the task attempt number. <br> |
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33 | * An example TaskAttemptID is : |
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34 | * <code>attempt_200707121733_0003_m_000005_0</code> , which represents the |
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35 | * zeroth task attempt for the fifth map task in the third job |
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36 | * running at the jobtracker started at <code>200707121733</code>. |
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37 | * <p> |
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38 | * Applications should never construct or parse TaskAttemptID strings |
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39 | * , but rather use appropriate constructors or {@link #forName(String)} |
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40 | * method. |
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41 | * |
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42 | * @see JobID |
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43 | * @see TaskID |
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44 | */ |
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45 | public class TaskAttemptID extends org.apache.hadoop.mapred.ID { |
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46 | protected static final String ATTEMPT = "attempt"; |
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47 | private TaskID taskId; |
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48 | |
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49 | /** |
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50 | * Constructs a TaskAttemptID object from given {@link TaskID}. |
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51 | * @param taskId TaskID that this task belongs to |
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52 | * @param id the task attempt number |
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53 | */ |
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54 | public TaskAttemptID(TaskID taskId, int id) { |
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55 | super(id); |
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56 | if(taskId == null) { |
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57 | throw new IllegalArgumentException("taskId cannot be null"); |
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58 | } |
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59 | this.taskId = taskId; |
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60 | } |
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61 | |
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62 | /** |
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63 | * Constructs a TaskId object from given parts. |
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64 | * @param jtIdentifier jobTracker identifier |
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65 | * @param jobId job number |
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66 | * @param isMap whether the tip is a map |
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67 | * @param taskId taskId number |
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68 | * @param id the task attempt number |
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69 | */ |
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70 | public TaskAttemptID(String jtIdentifier, int jobId, boolean isMap, |
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71 | int taskId, int id) { |
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72 | this(new TaskID(jtIdentifier, jobId, isMap, taskId), id); |
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73 | } |
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74 | |
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75 | public TaskAttemptID() { |
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76 | taskId = new TaskID(); |
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77 | } |
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78 | |
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79 | /** Returns the {@link JobID} object that this task attempt belongs to */ |
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80 | public JobID getJobID() { |
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81 | return taskId.getJobID(); |
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82 | } |
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83 | |
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84 | /** Returns the {@link TaskID} object that this task attempt belongs to */ |
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85 | public TaskID getTaskID() { |
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86 | return taskId; |
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87 | } |
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88 | |
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89 | /**Returns whether this TaskAttemptID is a map ID */ |
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90 | public boolean isMap() { |
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91 | return taskId.isMap(); |
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92 | } |
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93 | |
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94 | @Override |
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95 | public boolean equals(Object o) { |
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96 | if (!super.equals(o)) |
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97 | return false; |
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98 | |
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99 | TaskAttemptID that = (TaskAttemptID)o; |
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100 | return this.taskId.equals(that.taskId); |
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101 | } |
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102 | |
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103 | /** |
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104 | * Add the unique string to the StringBuilder |
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105 | * @param builder the builder to append ot |
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106 | * @return the builder that was passed in. |
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107 | */ |
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108 | protected StringBuilder appendTo(StringBuilder builder) { |
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109 | return taskId.appendTo(builder).append(SEPARATOR).append(id); |
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110 | } |
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111 | |
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112 | @Override |
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113 | public void readFields(DataInput in) throws IOException { |
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114 | super.readFields(in); |
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115 | taskId.readFields(in); |
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116 | } |
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117 | |
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118 | @Override |
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119 | public void write(DataOutput out) throws IOException { |
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120 | super.write(out); |
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121 | taskId.write(out); |
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122 | } |
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123 | |
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124 | @Override |
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125 | public int hashCode() { |
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126 | return taskId.hashCode() * 5 + id; |
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127 | } |
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128 | |
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129 | /**Compare TaskIds by first tipIds, then by task numbers. */ |
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130 | @Override |
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131 | public int compareTo(ID o) { |
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132 | TaskAttemptID that = (TaskAttemptID)o; |
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133 | int tipComp = this.taskId.compareTo(that.taskId); |
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134 | if(tipComp == 0) { |
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135 | return this.id - that.id; |
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136 | } |
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137 | else return tipComp; |
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138 | } |
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139 | @Override |
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140 | public String toString() { |
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141 | return appendTo(new StringBuilder(ATTEMPT)).toString(); |
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142 | } |
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143 | |
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144 | /** Construct a TaskAttemptID object from given string |
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145 | * @return constructed TaskAttemptID object or null if the given String is null |
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146 | * @throws IllegalArgumentException if the given string is malformed |
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147 | */ |
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148 | public static TaskAttemptID forName(String str |
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149 | ) throws IllegalArgumentException { |
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150 | if(str == null) |
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151 | return null; |
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152 | try { |
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153 | String[] parts = str.split(Character.toString(SEPARATOR)); |
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154 | if(parts.length == 6) { |
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155 | if(parts[0].equals(ATTEMPT)) { |
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156 | boolean isMap = false; |
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157 | if(parts[3].equals("m")) isMap = true; |
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158 | else if(parts[3].equals("r")) isMap = false; |
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159 | else throw new Exception(); |
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160 | return new org.apache.hadoop.mapred.TaskAttemptID |
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161 | (parts[1], |
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162 | Integer.parseInt(parts[2]), |
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163 | isMap, Integer.parseInt(parts[4]), |
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164 | Integer.parseInt(parts[5])); |
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165 | } |
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166 | } |
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167 | } catch (Exception ex) { |
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168 | //fall below |
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169 | } |
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170 | throw new IllegalArgumentException("TaskAttemptId string : " + str |
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171 | + " is not properly formed"); |
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172 | } |
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173 | |
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174 | } |
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