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 whether this TaskID is a map ID */
095 @Deprecated
096 public boolean isMap() {
097 return taskId.isMap();
098 }
099
100 /**Returns the TaskType of the TaskAttemptID */
101 public TaskType getTaskType() {
102 return taskId.getTaskType();
103 }
104 @Override
105 public boolean equals(Object o) {
106 if (!super.equals(o))
107 return false;
108
109 TaskAttemptID that = (TaskAttemptID)o;
110 return this.taskId.equals(that.taskId);
111 }
112
113 /**
114 * Add the unique string to the StringBuilder
115 * @param builder the builder to append ot
116 * @return the builder that was passed in.
117 */
118 protected StringBuilder appendTo(StringBuilder builder) {
119 return taskId.appendTo(builder).append(SEPARATOR).append(id);
120 }
121
122 @Override
123 public void readFields(DataInput in) throws IOException {
124 super.readFields(in);
125 taskId.readFields(in);
126 }
127
128 @Override
129 public void write(DataOutput out) throws IOException {
130 super.write(out);
131 taskId.write(out);
132 }
133
134 @Override
135 public int hashCode() {
136 return taskId.hashCode() * 5 + id;
137 }
138
139 /**Compare TaskIds by first tipIds, then by task numbers. */
140 @Override
141 public int compareTo(ID o) {
142 TaskAttemptID that = (TaskAttemptID)o;
143 int tipComp = this.taskId.compareTo(that.taskId);
144 if(tipComp == 0) {
145 return this.id - that.id;
146 }
147 else return tipComp;
148 }
149 @Override
150 public String toString() {
151 return appendTo(new StringBuilder(ATTEMPT)).toString();
152 }
153
154 /** Construct a TaskAttemptID object from given string
155 * @return constructed TaskAttemptID object or null if the given String is null
156 * @throws IllegalArgumentException if the given string is malformed
157 */
158 public static TaskAttemptID forName(String str
159 ) throws IllegalArgumentException {
160 if(str == null)
161 return null;
162 String exceptionMsg = null;
163 try {
164 String[] parts = str.split(Character.toString(SEPARATOR));
165 if(parts.length == 6) {
166 if(parts[0].equals(ATTEMPT)) {
167 String type = parts[3];
168 TaskType t = TaskID.getTaskType(type.charAt(0));
169 if(t != null) {
170 return new org.apache.hadoop.mapred.TaskAttemptID
171 (parts[1],
172 Integer.parseInt(parts[2]),
173 t, Integer.parseInt(parts[4]),
174 Integer.parseInt(parts[5]));
175 } else
176 exceptionMsg = "Bad TaskType identifier. TaskAttemptId string : "
177 + str + " is not properly formed.";
178 }
179 }
180 } catch (Exception ex) {
181 //fall below
182 }
183 if (exceptionMsg == null) {
184 exceptionMsg = "TaskAttemptId string : " + str
185 + " is not properly formed";
186 }
187 throw new IllegalArgumentException(exceptionMsg);
188 }
189
190 }