org.apache.hadoop.mapred
Class TaskAttemptID

java.lang.Object
  org.apache.hadoop.mapreduce.ID
      org.apache.hadoop.mapred.ID
          org.apache.hadoop.mapreduce.TaskAttemptID
              org.apache.hadoop.mapred.TaskAttemptID

All Implemented Interfaces:

Comparable<ID>, Writable, WritableComparable<ID>

public class TaskAttemptID
extends TaskAttemptID

TaskAttemptID represents the immutable and unique identifier for a task attempt. Each task attempt is one particular instance of a Map or Reduce Task identified by its TaskID. TaskAttemptID consists of 2 parts. First part is the TaskID, that this TaskAttemptID belongs to. Second part is the task attempt number.
An example TaskAttemptID is : attempt_200707121733_0003_m_000005_0 , which represents the zeroth task attempt for the fifth map task in the third job running at the jobtracker started at 200707121733.

Applications should never construct or parse TaskAttemptID strings , but rather use appropriate constructors or forName(String) method.

See Also:

JobID, TaskID

Field Summary

Fields inherited from class org.apache.hadoop.mapreduce.TaskAttemptID

ATTEMPT

Fields inherited from class org.apache.hadoop.mapreduce.ID

id, SEPARATOR

Constructor Summary

TaskAttemptID()

TaskAttemptID(String jtIdentifier, int jobId, boolean isMap, int taskId, int id)
Constructs a TaskId object from given parts.

TaskAttemptID(TaskID taskId, int id)
Constructs a TaskAttemptID object from given TaskID.

Method Summary

static TaskAttemptID	downgrade(TaskAttemptID old) Downgrade a new TaskAttemptID to an old one
static TaskAttemptID	forName(String str) Construct a TaskAttemptID object from given string
JobID	getJobID() Returns the JobID object that this task attempt belongs to
static String	getTaskAttemptIDsPattern(String jtIdentifier, Integer jobId, Boolean isMap, Integer taskId, Integer attemptId) Deprecated.
TaskID	getTaskID() Returns the TaskID object that this task attempt belongs to
static TaskAttemptID	read(DataInput in) Deprecated.

Methods inherited from class org.apache.hadoop.mapreduce.TaskAttemptID

appendTo, compareTo, equals, hashCode, isMap, readFields, toString, write

Methods inherited from class org.apache.hadoop.mapreduce.ID

getId

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

TaskAttemptID

public TaskAttemptID(TaskID taskId,
                     int id)

Constructs a TaskAttemptID object from given TaskID.

Parameters:

taskId - TaskID that this task belongs to

id - the task attempt number

TaskAttemptID

public TaskAttemptID(String jtIdentifier,
                     int jobId,
                     boolean isMap,
                     int taskId,
                     int id)

Constructs a TaskId object from given parts.

Parameters:

jtIdentifier - jobTracker identifier

jobId - job number

isMap - whether the tip is a map

taskId - taskId number

id - the task attempt number

TaskAttemptID

public TaskAttemptID()

Method Detail

downgrade

public static TaskAttemptID downgrade(TaskAttemptID old)

Downgrade a new TaskAttemptID to an old one

Parameters:

old - the new id

Returns:

either old or a new TaskAttemptID constructed to match old

getTaskID

public TaskID getTaskID()

Description copied from class: TaskAttemptID

Returns the TaskID object that this task attempt belongs to

Overrides:

getTaskID in class TaskAttemptID

getJobID

public JobID getJobID()

Description copied from class: TaskAttemptID

Returns the JobID object that this task attempt belongs to

Overrides:

getJobID in class TaskAttemptID

read

@Deprecated
public static TaskAttemptID read(DataInput in)
                          throws IOException

Deprecated.

Throws:

IOException

forName

public static TaskAttemptID forName(String str)
                             throws IllegalArgumentException

Construct a TaskAttemptID object from given string

Returns:

constructed TaskAttemptID object or null if the given String is null

Throws:

IllegalArgumentException - if the given string is malformed

getTaskAttemptIDsPattern

@Deprecated
public static String getTaskAttemptIDsPattern(String jtIdentifier,
                                                         Integer jobId,
                                                         Boolean isMap,
                                                         Integer taskId,
                                                         Integer attemptId)

Deprecated.

Returns a regex pattern which matches task attempt IDs. Arguments can be given null, in which case that part of the regex will be generic. For example to obtain a regex matching all task attempt IDs of any jobtracker, in any job, of the first map task, we would use :

 
 TaskAttemptID.getTaskAttemptIDsPattern(null, null, true, 1, null);
 

which will return :

 "attempt_[^_]*_[0-9]*_m_000001_[0-9]*" 

Parameters:

jtIdentifier - jobTracker identifier, or null

jobId - job number, or null

isMap - whether the tip is a map, or null

taskId - taskId number, or null

attemptId - the task attempt number, or null

Returns:

a regex pattern matching TaskAttemptIDs