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.mapred;
020    
021    import java.io.DataInput;
022    import java.io.IOException;
023    
024    import org.apache.hadoop.classification.InterfaceAudience;
025    import org.apache.hadoop.classification.InterfaceStability;
026    import org.apache.hadoop.mapreduce.TaskType;
027    
028    /**
029     * TaskID represents the immutable and unique identifier for 
030     * a Map or Reduce Task. Each TaskID encompasses multiple attempts made to
031     * execute the Map or Reduce Task, each of which are uniquely indentified by
032     * their TaskAttemptID.
033     * 
034     * TaskID consists of 3 parts. First part is the {@link JobID}, that this 
035     * TaskInProgress belongs to. Second part of the TaskID is either 'm' or 'r' 
036     * representing whether the task is a map task or a reduce task. 
037     * And the third part is the task number. <br> 
038     * An example TaskID is : 
039     * <code>task_200707121733_0003_m_000005</code> , which represents the
040     * fifth map task in the third job running at the jobtracker 
041     * started at <code>200707121733</code>. 
042     * <p>
043     * Applications should never construct or parse TaskID strings
044     * , but rather use appropriate constructors or {@link #forName(String)} 
045     * method. 
046     * 
047     * @see JobID
048     * @see TaskAttemptID
049     */
050    @InterfaceAudience.Public
051    @InterfaceStability.Stable
052    public class TaskID extends org.apache.hadoop.mapreduce.TaskID {
053    
054      /**
055       * Constructs a TaskID object from given {@link JobID}.  
056       * @param jobId JobID that this tip belongs to 
057       * @param isMap whether the tip is a map 
058       * @param id the tip number
059       * @deprecated Use {@link #TaskID(String, int, TaskType, int)}
060       */
061      @Deprecated
062      public TaskID(org.apache.hadoop.mapreduce.JobID jobId, boolean isMap,int id) {
063        this(jobId, isMap ? TaskType.MAP : TaskType.REDUCE, id);
064      }
065       
066      /**
067       * Constructs a TaskInProgressId object from given parts.
068       * @param jtIdentifier jobTracker identifier
069       * @param jobId job number 
070       * @param isMap whether the tip is a map 
071       * @param id the tip number
072       * @deprecated Use {@link #TaskID(org.apache.hadoop.mapreduce.JobID, TaskType,
073       * int)}
074       */
075      @Deprecated
076      public TaskID(String jtIdentifier, int jobId, boolean isMap, int id) {
077        this(jtIdentifier, jobId, isMap ? TaskType.MAP : TaskType.REDUCE, id);
078      }
079        
080      /**
081       * Constructs a TaskID object from given {@link JobID}.  
082       * @param jobId JobID that this tip belongs to 
083       * @param type the {@link TaskType} 
084       * @param id the tip number
085       */
086      public TaskID(org.apache.hadoop.mapreduce.JobID jobId, TaskType type,int id) {
087        super(jobId, type, id);
088      }
089      
090      /**
091       * Constructs a TaskInProgressId object from given parts.
092       * @param jtIdentifier jobTracker identifier
093       * @param jobId job number 
094       * @param type the {@link TaskType} 
095       * @param id the tip number
096       */
097      public TaskID(String jtIdentifier, int jobId, TaskType type, int id) {
098        this(new JobID(jtIdentifier, jobId), type, id);
099      }
100      
101      public TaskID() {
102        super(new JobID(), TaskType.REDUCE, 0);
103      }
104      
105      /**
106       * Downgrade a new TaskID to an old one
107       * @param old a new or old TaskID
108       * @return either old or a new TaskID build to match old
109       */
110      public static TaskID downgrade(org.apache.hadoop.mapreduce.TaskID old) {
111        if (old instanceof TaskID) {
112          return (TaskID) old;
113        } else {
114          return new TaskID(JobID.downgrade(old.getJobID()), old.getTaskType(), 
115                            old.getId());
116        }
117      }
118    
119      @Deprecated
120      public static TaskID read(DataInput in) throws IOException {
121        TaskID tipId = new TaskID();
122        tipId.readFields(in);
123        return tipId;
124      }
125      
126      public JobID getJobID() {
127        return (JobID) super.getJobID();
128      }
129    
130      /** 
131       * Returns a regex pattern which matches task IDs. Arguments can 
132       * be given null, in which case that part of the regex will be generic.  
133       * For example to obtain a regex matching <i>the first map task</i> 
134       * of <i>any jobtracker</i>, of <i>any job</i>, we would use :
135       * <pre> 
136       * TaskID.getTaskIDsPattern(null, null, true, 1);
137       * </pre>
138       * which will return :
139       * <pre> "task_[^_]*_[0-9]*_m_000001*" </pre> 
140       * @param jtIdentifier jobTracker identifier, or null
141       * @param jobId job number, or null
142       * @param isMap whether the tip is a map, or null 
143       * @param taskId taskId number, or null
144       * @return a regex pattern matching TaskIDs
145       * @deprecated Use {@link TaskID#getTaskIDsPattern(String, Integer, TaskType,
146       * Integer)}
147       */
148      @Deprecated
149      public static String getTaskIDsPattern(String jtIdentifier, Integer jobId
150          , Boolean isMap, Integer taskId) {
151        return getTaskIDsPattern(jtIdentifier, jobId,
152            isMap ? TaskType.MAP : TaskType.REDUCE, taskId);
153      }
154      
155      /** 
156       * Returns a regex pattern which matches task IDs. Arguments can 
157       * be given null, in which case that part of the regex will be generic.  
158       * For example to obtain a regex matching <i>the first map task</i> 
159       * of <i>any jobtracker</i>, of <i>any job</i>, we would use :
160       * <pre> 
161       * TaskID.getTaskIDsPattern(null, null, true, 1);
162       * </pre>
163       * which will return :
164       * <pre> "task_[^_]*_[0-9]*_m_000001*" </pre> 
165       * @param jtIdentifier jobTracker identifier, or null
166       * @param jobId job number, or null
167       * @param type the {@link TaskType}, or null 
168       * @param taskId taskId number, or null
169       * @return a regex pattern matching TaskIDs
170       */
171      @Deprecated
172      public static String getTaskIDsPattern(String jtIdentifier, Integer jobId
173          , TaskType type, Integer taskId) {
174        StringBuilder builder = new StringBuilder(TASK).append(SEPARATOR)
175          .append(getTaskIDsPatternWOPrefix(jtIdentifier, jobId, type, taskId));
176        return builder.toString();
177      }
178      
179      @Deprecated
180      static StringBuilder getTaskIDsPatternWOPrefix(String jtIdentifier
181          , Integer jobId, TaskType type, Integer taskId) {
182        StringBuilder builder = new StringBuilder();
183        builder.append(JobID.getJobIDsPatternWOPrefix(jtIdentifier, jobId))
184          .append(SEPARATOR)
185          .append(type != null ? 
186              (org.apache.hadoop.mapreduce.TaskID.getRepresentingCharacter(type)) : 
187                org.apache.hadoop.mapreduce.TaskID.getAllTaskTypes()).
188                append(SEPARATOR)
189          .append(taskId != null ? idFormat.format(taskId) : "[0-9]*");
190        return builder;
191      }
192    
193      public static TaskID forName(String str
194                                   ) throws IllegalArgumentException {
195        return (TaskID) org.apache.hadoop.mapreduce.TaskID.forName(str);
196      }
197    
198    }