TaskID.java
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.mapred;
import java.io.DataInput;
import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.mapreduce.TaskType;
/**
* TaskID represents the immutable and unique identifier for
* a Map or Reduce Task. Each TaskID encompasses multiple attempts made to
* execute the Map or Reduce Task, each of which are uniquely indentified by
* their TaskAttemptID.
*
* TaskID consists of 3 parts. First part is the {@link JobID}, that this
* TaskInProgress belongs to. Second part of the TaskID is either 'm' or 'r'
* representing whether the task is a map task or a reduce task.
* And the third part is the task number. <br>
* An example TaskID is :
* <code>task_200707121733_0003_m_000005</code> , which represents the
* fifth map task in the third job running at the jobtracker
* started at <code>200707121733</code>.
* <p>
* Applications should never construct or parse TaskID strings
* , but rather use appropriate constructors or {@link #forName(String)}
* method.
*
* @see JobID
* @see TaskAttemptID
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class TaskID extends org.apache.hadoop.mapreduce.TaskID {
/**
* Constructs a TaskID object from given {@link JobID}.
* @param jobId JobID that this tip belongs to
* @param isMap whether the tip is a map
* @param id the tip number
* @deprecated Use {@link #TaskID(String, int, TaskType, int)}
*/
@Deprecated
public TaskID(org.apache.hadoop.mapreduce.JobID jobId, boolean isMap,int id) {
this(jobId, isMap ? TaskType.MAP : TaskType.REDUCE, id);
}
/**
* Constructs a TaskInProgressId object from given parts.
* @param jtIdentifier jobTracker identifier
* @param jobId job number
* @param isMap whether the tip is a map
* @param id the tip number
* @deprecated Use {@link #TaskID(org.apache.hadoop.mapreduce.JobID, TaskType,
* int)}
*/
@Deprecated
public TaskID(String jtIdentifier, int jobId, boolean isMap, int id) {
this(jtIdentifier, jobId, isMap ? TaskType.MAP : TaskType.REDUCE, id);
}
/**
* Constructs a TaskID object from given {@link JobID}.
* @param jobId JobID that this tip belongs to
* @param type the {@link TaskType}
* @param id the tip number
*/
public TaskID(org.apache.hadoop.mapreduce.JobID jobId, TaskType type,int id) {
super(jobId, type, id);
}
/**
* Constructs a TaskInProgressId object from given parts.
* @param jtIdentifier jobTracker identifier
* @param jobId job number
* @param type the {@link TaskType}
* @param id the tip number
*/
public TaskID(String jtIdentifier, int jobId, TaskType type, int id) {
this(new JobID(jtIdentifier, jobId), type, id);
}
public TaskID() {
super(new JobID(), TaskType.REDUCE, 0);
}
/**
* Downgrade a new TaskID to an old one
* @param old a new or old TaskID
* @return either old or a new TaskID build to match old
*/
public static TaskID downgrade(org.apache.hadoop.mapreduce.TaskID old) {
if (old instanceof TaskID) {
return (TaskID) old;
} else {
return new TaskID(JobID.downgrade(old.getJobID()), old.getTaskType(),
old.getId());
}
}
@Deprecated
public static TaskID read(DataInput in) throws IOException {
TaskID tipId = new TaskID();
tipId.readFields(in);
return tipId;
}
public JobID getJobID() {
return (JobID) super.getJobID();
}
/**
* Returns a regex pattern which matches task IDs. Arguments can
* be given null, in which case that part of the regex will be generic.
* For example to obtain a regex matching <i>the first map task</i>
* of <i>any jobtracker</i>, of <i>any job</i>, we would use :
* <pre>
* TaskID.getTaskIDsPattern(null, null, true, 1);
* </pre>
* which will return :
* <pre> "task_[^_]*_[0-9]*_m_000001*" </pre>
* @param jtIdentifier jobTracker identifier, or null
* @param jobId job number, or null
* @param isMap whether the tip is a map, or null
* @param taskId taskId number, or null
* @return a regex pattern matching TaskIDs
* @deprecated Use {@link TaskID#getTaskIDsPattern(String, Integer, TaskType,
* Integer)}
*/
@Deprecated
public static String getTaskIDsPattern(String jtIdentifier, Integer jobId
, Boolean isMap, Integer taskId) {
return getTaskIDsPattern(jtIdentifier, jobId,
isMap ? TaskType.MAP : TaskType.REDUCE, taskId);
}
/**
* Returns a regex pattern which matches task IDs. Arguments can
* be given null, in which case that part of the regex will be generic.
* For example to obtain a regex matching <i>the first map task</i>
* of <i>any jobtracker</i>, of <i>any job</i>, we would use :
* <pre>
* TaskID.getTaskIDsPattern(null, null, true, 1);
* </pre>
* which will return :
* <pre> "task_[^_]*_[0-9]*_m_000001*" </pre>
* @param jtIdentifier jobTracker identifier, or null
* @param jobId job number, or null
* @param type the {@link TaskType}, or null
* @param taskId taskId number, or null
* @return a regex pattern matching TaskIDs
*/
@Deprecated
public static String getTaskIDsPattern(String jtIdentifier, Integer jobId
, TaskType type, Integer taskId) {
StringBuilder builder = new StringBuilder(TASK).append(SEPARATOR)
.append(getTaskIDsPatternWOPrefix(jtIdentifier, jobId, type, taskId));
return builder.toString();
}
@Deprecated
static StringBuilder getTaskIDsPatternWOPrefix(String jtIdentifier
, Integer jobId, TaskType type, Integer taskId) {
StringBuilder builder = new StringBuilder();
builder.append(JobID.getJobIDsPatternWOPrefix(jtIdentifier, jobId))
.append(SEPARATOR)
.append(type != null ?
(org.apache.hadoop.mapreduce.TaskID.getRepresentingCharacter(type)) :
org.apache.hadoop.mapreduce.TaskID.getAllTaskTypes()).
append(SEPARATOR)
.append(taskId != null ? idFormat.format(taskId) : "[0-9]*");
return builder;
}
public static TaskID forName(String str
) throws IllegalArgumentException {
return (TaskID) org.apache.hadoop.mapreduce.TaskID.forName(str);
}
}