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java.lang.Object org.apache.hadoop.mapred.ID org.apache.hadoop.mapred.TaskAttemptID
public class 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.
JobID
,
TaskID
Field Summary |
---|
Fields inherited from class org.apache.hadoop.mapred.ID |
---|
id |
Constructor Summary | |
---|---|
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 | |
---|---|
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 |
static String |
getTaskAttemptIDsPattern(String jtIdentifier,
Integer jobId,
Boolean isMap,
Integer taskId,
Integer attemptId)
Returns a regex pattern which matches task attempt IDs. |
TaskID |
getTaskID()
Returns the TaskID object that this task attempt belongs to |
int |
hashCode()
|
boolean |
isMap()
Returns whether this TaskAttemptID is a map ID |
static TaskAttemptID |
read(DataInput in)
|
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 . |
Methods inherited from class org.apache.hadoop.mapred.ID |
---|
getId |
Methods inherited from class java.lang.Object |
---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Constructor Detail |
---|
public TaskAttemptID(TaskID taskId, int id)
TaskID
.
taskId
- TaskID that this task belongs toid
- the task attempt numberpublic TaskAttemptID(String jtIdentifier, int jobId, boolean isMap, int taskId, int id)
jtIdentifier
- jobTracker identifierjobId
- job numberisMap
- whether the tip is a maptaskId
- taskId numberid
- the task attempt numberMethod Detail |
---|
public JobID getJobID()
JobID
object that this task attempt belongs to
public TaskID getTaskID()
TaskID
object that this task attempt belongs to
public boolean isMap()
public boolean equals(Object o)
equals
in class ID
public int compareTo(ID o)
compareTo
in interface Comparable<ID>
compareTo
in class ID
public String toString()
toString
in class ID
public int hashCode()
hashCode
in class ID
public void readFields(DataInput in) throws IOException
Writable
in
.
For efficiency, implementations should attempt to re-use storage in the existing object where possible.
readFields
in interface Writable
readFields
in class ID
in
- DataInput
to deseriablize this object from.
IOException
public void write(DataOutput out) throws IOException
Writable
out
.
write
in interface Writable
write
in class ID
out
- DataOuput
to serialize this object into.
IOException
public static TaskAttemptID read(DataInput in) throws IOException
IOException
public static TaskAttemptID forName(String str) throws IllegalArgumentException
IllegalArgumentException
- if the given string is malformedpublic static String getTaskAttemptIDsPattern(String jtIdentifier, Integer jobId, Boolean isMap, Integer taskId, Integer attemptId)
TaskAttemptID.getTaskAttemptIDsPattern(null, null, true, 1, null);which will return :
"attempt_[^_]*_[0-9]*_m_000001_[0-9]*"
jtIdentifier
- jobTracker identifier, or nulljobId
- job number, or nullisMap
- whether the tip is a map, or nulltaskId
- taskId number, or nullattemptId
- the task attempt number, or null
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