org.apache.hadoop.mapred
Class TaskAttemptID

java.lang.Object
  extended by org.apache.hadoop.mapreduce.ID
      extended by org.apache.hadoop.mapred.ID
          extended by org.apache.hadoop.mapreduce.TaskAttemptID
              extended by org.apache.hadoop.mapred.TaskAttemptID
All Implemented Interfaces:
Comparable<ID>, Writable, WritableComparable<ID>

@InterfaceAudience.Public
@InterfaceStability.Stable
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)
          Deprecated. Use TaskAttemptID(String, int, TaskType, int, int).
TaskAttemptID(String jtIdentifier, int jobId, TaskType type, 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. 
static String getTaskAttemptIDsPattern(String jtIdentifier, Integer jobId, TaskType type, 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, getTaskType, 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

@Deprecated
public TaskAttemptID(String jtIdentifier,
                                int jobId,
                                boolean isMap,
                                int taskId,
                                int id)
Deprecated. Use TaskAttemptID(String, int, TaskType, int, int).

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(String jtIdentifier,
                     int jobId,
                     TaskType type,
                     int taskId,
                     int id)
Constructs a TaskId object from given parts.

Parameters:
jtIdentifier - jobTracker identifier
jobId - job number
type - the TaskType
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

getTaskAttemptIDsPattern

@Deprecated
public static String getTaskAttemptIDsPattern(String jtIdentifier,
                                                         Integer jobId,
                                                         TaskType type,
                                                         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, TaskType.MAP, 1, null);
 
which will return :
 "attempt_[^_]*_[0-9]*_m_000001_[0-9]*" 

Parameters:
jtIdentifier - jobTracker identifier, or null
jobId - job number, or null
type - the TaskType
taskId - taskId number, or null
attemptId - the task attempt number, or null
Returns:
a regex pattern matching TaskAttemptIDs


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