1 /** 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 package org.apache.hadoop.mapreduce; 20 21 import java.io.DataInput; 22 import java.io.DataOutput; 23 import java.io.IOException; 24 25 import org.apache.hadoop.classification.InterfaceAudience; 26 import org.apache.hadoop.classification.InterfaceStability; 27 28 /** 29 * TaskAttemptID represents the immutable and unique identifier for 30 * a task attempt. Each task attempt is one particular instance of a Map or 31 * Reduce Task identified by its TaskID. 32 * 33 * TaskAttemptID consists of 2 parts. First part is the 34 * {@link TaskID}, that this TaskAttemptID belongs to. 35 * Second part is the task attempt number. <br> 36 * An example TaskAttemptID is : 37 * <code>attempt_200707121733_0003_m_000005_0</code> , which represents the 38 * zeroth task attempt for the fifth map task in the third job 39 * running at the jobtracker started at <code>200707121733</code>. 40 * <p> 41 * Applications should never construct or parse TaskAttemptID strings 42 * , but rather use appropriate constructors or {@link #forName(String)} 43 * method. 44 * 45 * @see JobID 46 * @see TaskID 47 */ 48 @InterfaceAudience.Public 49 @InterfaceStability.Stable 50 public class TaskAttemptID extends org.apache.hadoop.mapred.ID { 51 protected static final String ATTEMPT = "attempt"; 52 private TaskID taskId; 53 54 /** 55 * Constructs a TaskAttemptID object from given {@link TaskID}. 56 * @param taskId TaskID that this task belongs to 57 * @param id the task attempt number 58 */ TaskAttemptID(TaskID taskId, int id)59 public TaskAttemptID(TaskID taskId, int id) { 60 super(id); 61 if(taskId == null) { 62 throw new IllegalArgumentException("taskId cannot be null"); 63 } 64 this.taskId = taskId; 65 } 66 67 /** 68 * Constructs a TaskId object from given parts. 69 * @param jtIdentifier jobTracker identifier 70 * @param jobId job number 71 * @param type the TaskType 72 * @param taskId taskId number 73 * @param id the task attempt number 74 */ TaskAttemptID(String jtIdentifier, int jobId, TaskType type, int taskId, int id)75 public TaskAttemptID(String jtIdentifier, int jobId, TaskType type, 76 int taskId, int id) { 77 this(new TaskID(jtIdentifier, jobId, type, taskId), id); 78 } 79 80 /** 81 * Constructs a TaskId object from given parts. 82 * @param jtIdentifier jobTracker identifier 83 * @param jobId job number 84 * @param isMap whether the tip is a map 85 * @param taskId taskId number 86 * @param id the task attempt number 87 */ 88 @Deprecated TaskAttemptID(String jtIdentifier, int jobId, boolean isMap, int taskId, int id)89 public TaskAttemptID(String jtIdentifier, int jobId, boolean isMap, 90 int taskId, int id) { 91 this(new TaskID(jtIdentifier, jobId, isMap, taskId), id); 92 } 93 TaskAttemptID()94 public TaskAttemptID() { 95 taskId = new TaskID(); 96 } 97 98 /** Returns the {@link JobID} object that this task attempt belongs to */ getJobID()99 public JobID getJobID() { 100 return taskId.getJobID(); 101 } 102 103 /** Returns the {@link TaskID} object that this task attempt belongs to */ getTaskID()104 public TaskID getTaskID() { 105 return taskId; 106 } 107 108 /**Returns whether this TaskID is a map ID */ 109 @Deprecated isMap()110 public boolean isMap() { 111 return taskId.isMap(); 112 } 113 114 /**Returns the TaskType of the TaskAttemptID */ getTaskType()115 public TaskType getTaskType() { 116 return taskId.getTaskType(); 117 } 118 @Override equals(Object o)119 public boolean equals(Object o) { 120 if (!super.equals(o)) 121 return false; 122 123 TaskAttemptID that = (TaskAttemptID)o; 124 return this.taskId.equals(that.taskId); 125 } 126 127 /** 128 * Add the unique string to the StringBuilder 129 * @param builder the builder to append ot 130 * @return the builder that was passed in. 131 */ appendTo(StringBuilder builder)132 protected StringBuilder appendTo(StringBuilder builder) { 133 return taskId.appendTo(builder).append(SEPARATOR).append(id); 134 } 135 136 @Override readFields(DataInput in)137 public void readFields(DataInput in) throws IOException { 138 super.readFields(in); 139 taskId.readFields(in); 140 } 141 142 @Override write(DataOutput out)143 public void write(DataOutput out) throws IOException { 144 super.write(out); 145 taskId.write(out); 146 } 147 148 @Override hashCode()149 public int hashCode() { 150 return taskId.hashCode() * 5 + id; 151 } 152 153 /**Compare TaskIds by first tipIds, then by task numbers. */ 154 @Override compareTo(ID o)155 public int compareTo(ID o) { 156 TaskAttemptID that = (TaskAttemptID)o; 157 int tipComp = this.taskId.compareTo(that.taskId); 158 if(tipComp == 0) { 159 return this.id - that.id; 160 } 161 else return tipComp; 162 } 163 @Override toString()164 public String toString() { 165 return appendTo(new StringBuilder(ATTEMPT)).toString(); 166 } 167 168 /** Construct a TaskAttemptID object from given string 169 * @return constructed TaskAttemptID object or null if the given String is null 170 * @throws IllegalArgumentException if the given string is malformed 171 */ forName(String str )172 public static TaskAttemptID forName(String str 173 ) throws IllegalArgumentException { 174 if(str == null) 175 return null; 176 String exceptionMsg = null; 177 try { 178 String[] parts = str.split(Character.toString(SEPARATOR)); 179 if(parts.length == 6) { 180 if(parts[0].equals(ATTEMPT)) { 181 String type = parts[3]; 182 TaskType t = TaskID.getTaskType(type.charAt(0)); 183 if(t != null) { 184 return new org.apache.hadoop.mapred.TaskAttemptID 185 (parts[1], 186 Integer.parseInt(parts[2]), 187 t, Integer.parseInt(parts[4]), 188 Integer.parseInt(parts[5])); 189 } else 190 exceptionMsg = "Bad TaskType identifier. TaskAttemptId string : " 191 + str + " is not properly formed."; 192 } 193 } 194 } catch (Exception ex) { 195 //fall below 196 } 197 if (exceptionMsg == null) { 198 exceptionMsg = "TaskAttemptId string : " + str 199 + " is not properly formed"; 200 } 201 throw new IllegalArgumentException(exceptionMsg); 202 } 203 204 } 205