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 /**
081 * Constructs a TaskId object from given parts.
082 * @param jtIdentifier jobTracker identifier
083 * @param jobId job number
084 * @param isMap whether the tip is a map
085 * @param taskId taskId number
086 * @param id the task attempt number
087 */
088 @Deprecated
089 public TaskAttemptID(String jtIdentifier, int jobId, boolean isMap,
090 int taskId, int id) {
091 this(new TaskID(jtIdentifier, jobId, isMap, taskId), id);
092 }
093
094 public TaskAttemptID() {
095 taskId = new TaskID();
096 }
097
098 /** Returns the {@link JobID} object that this task attempt belongs to */
099 public JobID getJobID() {
100 return taskId.getJobID();
101 }
102
103 /** Returns the {@link TaskID} object that this task attempt belongs to */
104 public TaskID getTaskID() {
105 return taskId;
106 }
107
108 /**Returns whether this TaskID is a map ID */
109 @Deprecated
110 public boolean isMap() {
111 return taskId.isMap();
112 }
113
114 /**Returns the TaskType of the TaskAttemptID */
115 public TaskType getTaskType() {
116 return taskId.getTaskType();
117 }
118 @Override
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 */
132 protected StringBuilder appendTo(StringBuilder builder) {
133 return taskId.appendTo(builder).append(SEPARATOR).append(id);
134 }
135
136 @Override
137 public void readFields(DataInput in) throws IOException {
138 super.readFields(in);
139 taskId.readFields(in);
140 }
141
142 @Override
143 public void write(DataOutput out) throws IOException {
144 super.write(out);
145 taskId.write(out);
146 }
147
148 @Override
149 public int hashCode() {
150 return taskId.hashCode() * 5 + id;
151 }
152
153 /**Compare TaskIds by first tipIds, then by task numbers. */
154 @Override
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
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 */
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 }