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 import java.text.NumberFormat;
025 import java.util.EnumMap;
026 import java.util.HashMap;
027 import java.util.Map;
028
029 import org.apache.hadoop.classification.InterfaceAudience;
030 import org.apache.hadoop.classification.InterfaceStability;
031 import org.apache.hadoop.io.WritableUtils;
032
033
034 /**
035 * TaskID represents the immutable and unique identifier for
036 * a Map or Reduce Task. Each TaskID encompasses multiple attempts made to
037 * execute the Map or Reduce Task, each of which are uniquely indentified by
038 * their TaskAttemptID.
039 *
040 * TaskID consists of 3 parts. First part is the {@link JobID}, that this
041 * TaskInProgress belongs to. Second part of the TaskID is either 'm' or 'r'
042 * representing whether the task is a map task or a reduce task.
043 * And the third part is the task number. <br>
044 * An example TaskID is :
045 * <code>task_200707121733_0003_m_000005</code> , which represents the
046 * fifth map task in the third job running at the jobtracker
047 * started at <code>200707121733</code>.
048 * <p>
049 * Applications should never construct or parse TaskID strings
050 * , but rather use appropriate constructors or {@link #forName(String)}
051 * method.
052 *
053 * @see JobID
054 * @see TaskAttemptID
055 */
056 @InterfaceAudience.Public
057 @InterfaceStability.Stable
058 public class TaskID extends org.apache.hadoop.mapred.ID {
059 protected static final String TASK = "task";
060 protected static final NumberFormat idFormat = NumberFormat.getInstance();
061 static {
062 idFormat.setGroupingUsed(false);
063 idFormat.setMinimumIntegerDigits(6);
064 }
065
066 private JobID jobId;
067 private TaskType type;
068
069 /**
070 * Constructs a TaskID object from given {@link JobID}.
071 * @param jobId JobID that this tip belongs to
072 * @param type the {@link TaskType} of the task
073 * @param id the tip number
074 */
075 public TaskID(JobID jobId, TaskType type, int id) {
076 super(id);
077 if(jobId == null) {
078 throw new IllegalArgumentException("jobId cannot be null");
079 }
080 this.jobId = jobId;
081 this.type = type;
082 }
083
084 /**
085 * Constructs a TaskInProgressId object from given parts.
086 * @param jtIdentifier jobTracker identifier
087 * @param jobId job number
088 * @param type the TaskType
089 * @param id the tip number
090 */
091 public TaskID(String jtIdentifier, int jobId, TaskType type, int id) {
092 this(new JobID(jtIdentifier, jobId), type, id);
093 }
094
095 /**
096 * Constructs a TaskID object from given {@link JobID}.
097 * @param jobId JobID that this tip belongs to
098 * @param isMap whether the tip is a map
099 * @param id the tip number
100 */
101 @Deprecated
102 public TaskID(JobID jobId, boolean isMap, int id) {
103 this(jobId, isMap ? TaskType.MAP : TaskType.REDUCE, id);
104 }
105
106 /**
107 * Constructs a TaskInProgressId object from given parts.
108 * @param jtIdentifier jobTracker identifier
109 * @param jobId job number
110 * @param isMap whether the tip is a map
111 * @param id the tip number
112 */
113 @Deprecated
114 public TaskID(String jtIdentifier, int jobId, boolean isMap, int id) {
115 this(new JobID(jtIdentifier, jobId), isMap, id);
116 }
117
118 public TaskID() {
119 jobId = new JobID();
120 }
121
122 /** Returns the {@link JobID} object that this tip belongs to */
123 public JobID getJobID() {
124 return jobId;
125 }
126
127 /**Returns whether this TaskID is a map ID */
128 @Deprecated
129 public boolean isMap() {
130 return type == TaskType.MAP;
131 }
132
133 /**
134 * Get the type of the task
135 */
136 public TaskType getTaskType() {
137 return type;
138 }
139
140 @Override
141 public boolean equals(Object o) {
142 if (!super.equals(o))
143 return false;
144
145 TaskID that = (TaskID)o;
146 return this.type == that.type && this.jobId.equals(that.jobId);
147 }
148
149 /**Compare TaskInProgressIds by first jobIds, then by tip numbers. Reduces are
150 * defined as greater then maps.*/
151 @Override
152 public int compareTo(ID o) {
153 TaskID that = (TaskID)o;
154 int jobComp = this.jobId.compareTo(that.jobId);
155 if(jobComp == 0) {
156 if(this.type == that.type) {
157 return this.id - that.id;
158 }
159 else {
160 return this.type.compareTo(that.type);
161 }
162 }
163 else return jobComp;
164 }
165 @Override
166 public String toString() {
167 return appendTo(new StringBuilder(TASK)).toString();
168 }
169
170 /**
171 * Add the unique string to the given builder.
172 * @param builder the builder to append to
173 * @return the builder that was passed in
174 */
175 protected StringBuilder appendTo(StringBuilder builder) {
176 return jobId.appendTo(builder).
177 append(SEPARATOR).
178 append(CharTaskTypeMaps.getRepresentingCharacter(type)).
179 append(SEPARATOR).
180 append(idFormat.format(id));
181 }
182
183 @Override
184 public int hashCode() {
185 return jobId.hashCode() * 524287 + id;
186 }
187
188 @Override
189 public void readFields(DataInput in) throws IOException {
190 super.readFields(in);
191 jobId.readFields(in);
192 type = WritableUtils.readEnum(in, TaskType.class);
193 }
194
195 @Override
196 public void write(DataOutput out) throws IOException {
197 super.write(out);
198 jobId.write(out);
199 WritableUtils.writeEnum(out, type);
200 }
201
202 /** Construct a TaskID object from given string
203 * @return constructed TaskID object or null if the given String is null
204 * @throws IllegalArgumentException if the given string is malformed
205 */
206 public static TaskID forName(String str)
207 throws IllegalArgumentException {
208 if(str == null)
209 return null;
210 String exceptionMsg = null;
211 try {
212 String[] parts = str.split("_");
213 if(parts.length == 5) {
214 if(parts[0].equals(TASK)) {
215 String type = parts[3];
216 TaskType t = CharTaskTypeMaps.getTaskType(type.charAt(0));
217 if(t != null) {
218
219 return new org.apache.hadoop.mapred.TaskID(parts[1],
220 Integer.parseInt(parts[2]),
221 t,
222 Integer.parseInt(parts[4]));
223 } else
224 exceptionMsg = "Bad TaskType identifier. TaskId string : " + str
225 + " is not properly formed.";
226 }
227 }
228 }catch (Exception ex) {//fall below
229 }
230 if (exceptionMsg == null) {
231 exceptionMsg = "TaskId string : " + str + " is not properly formed";
232 }
233 throw new IllegalArgumentException(exceptionMsg);
234 }
235 /**
236 * Gets the character representing the {@link TaskType}
237 * @param type the TaskType
238 * @return the character
239 */
240 public static char getRepresentingCharacter(TaskType type) {
241 return CharTaskTypeMaps.getRepresentingCharacter(type);
242 }
243 /**
244 * Gets the {@link TaskType} corresponding to the character
245 * @param c the character
246 * @return the TaskType
247 */
248 public static TaskType getTaskType(char c) {
249 return CharTaskTypeMaps.getTaskType(c);
250 }
251
252 public static String getAllTaskTypes() {
253 return CharTaskTypeMaps.allTaskTypes;
254 }
255
256 /**
257 * Maintains the mapping from the character representation of a task type to
258 * the enum class TaskType constants
259 */
260 static class CharTaskTypeMaps {
261 private static EnumMap<TaskType, Character> typeToCharMap =
262 new EnumMap<TaskType,Character>(TaskType.class);
263 private static Map<Character, TaskType> charToTypeMap =
264 new HashMap<Character, TaskType>();
265 static String allTaskTypes = "(m|r|s|c|t)";
266 static {
267 setupTaskTypeToCharMapping();
268 setupCharToTaskTypeMapping();
269 }
270
271 private static void setupTaskTypeToCharMapping() {
272 typeToCharMap.put(TaskType.MAP, 'm');
273 typeToCharMap.put(TaskType.REDUCE, 'r');
274 typeToCharMap.put(TaskType.JOB_SETUP, 's');
275 typeToCharMap.put(TaskType.JOB_CLEANUP, 'c');
276 typeToCharMap.put(TaskType.TASK_CLEANUP, 't');
277 }
278
279 private static void setupCharToTaskTypeMapping() {
280 charToTypeMap.put('m', TaskType.MAP);
281 charToTypeMap.put('r', TaskType.REDUCE);
282 charToTypeMap.put('s', TaskType.JOB_SETUP);
283 charToTypeMap.put('c', TaskType.JOB_CLEANUP);
284 charToTypeMap.put('t', TaskType.TASK_CLEANUP);
285 }
286
287 static char getRepresentingCharacter(TaskType type) {
288 return typeToCharMap.get(type);
289 }
290 static TaskType getTaskType(char c) {
291 return charToTypeMap.get(c);
292 }
293 }
294
295 }