org.apache.hadoop.mapred

类 TaskAttemptID

java.lang.Object

org.apache.hadoop.mapreduce.ID

org.apache.hadoop.mapred.ID

org.apache.hadoop.mapreduce.TaskAttemptID

org.apache.hadoop.mapred.TaskAttemptID

所有已实现的接口:

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.

另请参阅:

JobID, TaskID

字段概要

从类继承的字段 org.apache.hadoop.mapreduce.TaskAttemptID

ATTEMPT

从类继承的字段 org.apache.hadoop.mapreduce.ID

id, SEPARATOR

构造器概要

构造器

构造器和说明
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.

方法概要

方法

限定符和类型	方法和说明
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) 已过时。
TaskID	getTaskID() Returns the TaskID object that this task attempt belongs to
static TaskAttemptID	read(DataInput in) 已过时。

从类继承的方法 org.apache.hadoop.mapreduce.TaskAttemptID

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

从类继承的方法 org.apache.hadoop.mapreduce.ID

getId

从类继承的方法 java.lang.Object

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

构造器详细资料

TaskAttemptID

public TaskAttemptID(TaskID taskId,
             int id)

Constructs a TaskAttemptID object from given TaskID.

参数:

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.

参数:

jtIdentifier - jobTracker identifier

jobId - job number

isMap - whether the tip is a map

taskId - taskId number

id - the task attempt number

TaskAttemptID

public TaskAttemptID()

方法详细资料

downgrade

public static TaskAttemptID downgrade(TaskAttemptID old)

Downgrade a new TaskAttemptID to an old one

参数:

old - the new id

返回:

either old or a new TaskAttemptID constructed to match old

getTaskID

public TaskID getTaskID()

从类复制的说明: TaskAttemptID

Returns the TaskID object that this task attempt belongs to

覆盖:

getTaskID 在类中 TaskAttemptID

getJobID

public JobID getJobID()

从类复制的说明: TaskAttemptID

Returns the JobID object that this task attempt belongs to

覆盖:

getJobID 在类中 TaskAttemptID

read

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

已过时。

抛出:

IOException

forName

public static TaskAttemptID forName(String str)
                             throws IllegalArgumentException

Construct a TaskAttemptID object from given string

返回:

constructed TaskAttemptID object or null if the given String is null

抛出:

IllegalArgumentException - if the given string is malformed

getTaskAttemptIDsPattern

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

已过时。

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]*" 

参数:

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

返回:

a regex pattern matching TaskAttemptIDs