org.apache.hadoop.mapreduce

类 TaskAttemptID

java.lang.Object

org.apache.hadoop.mapreduce.ID

org.apache.hadoop.mapred.ID

org.apache.hadoop.mapreduce.TaskAttemptID

所有已实现的接口:

Comparable<ID>, Writable, WritableComparable<ID>

直接已知子类:

TaskAttemptID

public class TaskAttemptID
extends ID

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

字段

限定符和类型	字段和说明
protected static String	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
protected StringBuilder	appendTo(StringBuilder builder) Add the unique string to the StringBuilder
int	compareTo(ID o) Compare TaskIds by first tipIds, then by task numbers.
boolean	equals(Object o)
static TaskAttemptID	forName(String str) Construct a TaskAttemptID object from given string
JobID	getJobID() Returns the JobID object that this task attempt belongs to
TaskID	getTaskID() Returns the TaskID object that this task attempt belongs to
int	hashCode()
boolean	isMap() Returns whether this TaskAttemptID is a map ID
void	readFields(DataInput in) Deserialize the fields of this object from in.
String	toString()
void	write(DataOutput out) Serialize the fields of this object to out.

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

字段详细资料

ATTEMPT

protected static final String ATTEMPT

另请参阅:

常量字段值

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

getJobID

public JobID getJobID()

Returns the JobID object that this task attempt belongs to

getTaskID

public TaskID getTaskID()

Returns the TaskID object that this task attempt belongs to

isMap

public boolean isMap()

Returns whether this TaskAttemptID is a map ID

equals

public boolean equals(Object o)

覆盖:

equals 在类中 ID

appendTo

protected StringBuilder appendTo(StringBuilder builder)

Add the unique string to the StringBuilder

参数:

builder - the builder to append ot

返回:

the builder that was passed in.

readFields

public void readFields(DataInput in)
                throws IOException

从接口复制的说明: Writable

Deserialize the fields of this object from in.

For efficiency, implementations should attempt to re-use storage in the existing object where possible.

指定者:

readFields 在接口中 Writable

覆盖:

readFields 在类中 ID

参数:

in - DataInput to deseriablize this object from.

抛出:

IOException

write

public void write(DataOutput out)
           throws IOException

从接口复制的说明: Writable

Serialize the fields of this object to out.

指定者:

write 在接口中 Writable

覆盖:

write 在类中 ID

参数:

out - DataOuput to serialize this object into.

抛出:

IOException

hashCode

public int hashCode()

覆盖:

hashCode 在类中 ID

compareTo

public int compareTo(ID o)

Compare TaskIds by first tipIds, then by task numbers.

指定者:

compareTo 在接口中 Comparable<ID>

覆盖:

compareTo 在类中 ID

toString

public String toString()

覆盖:

toString 在类中 ID

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