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java.lang.Objectorg.apache.hadoop.mapreduce.ID
org.apache.hadoop.mapred.ID
org.apache.hadoop.mapreduce.TaskID
public class TaskID
TaskID represents the immutable and unique identifier for
a Map or Reduce Task. Each TaskID encompasses multiple attempts made to
execute the Map or Reduce Task, each of which are uniquely indentified by
their TaskAttemptID.
TaskID consists of 3 parts. First part is the JobID
, that this
TaskInProgress belongs to. Second part of the TaskID is either 'm' or 'r'
representing whether the task is a map task or a reduce task.
And the third part is the task number.
An example TaskID is :
task_200707121733_0003_m_000005
, which represents the
fifth map task in the third job running at the jobtracker
started at 200707121733
.
Applications should never construct or parse TaskID strings
, but rather use appropriate constructors or forName(String)
method.
JobID
,
TaskAttemptID
Field Summary | |
---|---|
protected static java.text.NumberFormat |
idFormat
|
protected static java.lang.String |
TASK
|
Fields inherited from class org.apache.hadoop.mapreduce.ID |
---|
id, SEPARATOR |
Constructor Summary | |
---|---|
TaskID()
|
|
TaskID(JobID jobId,
boolean isMap,
int id)
Constructs a TaskID object from given JobID . |
|
TaskID(java.lang.String jtIdentifier,
int jobId,
boolean isMap,
int id)
Constructs a TaskInProgressId object from given parts. |
Method Summary | |
---|---|
protected java.lang.StringBuilder |
appendTo(java.lang.StringBuilder builder)
Add the unique string to the given builder. |
int |
compareTo(ID o)
Compare TaskInProgressIds by first jobIds, then by tip numbers. |
boolean |
equals(java.lang.Object o)
|
static TaskID |
forName(java.lang.String str)
Construct a TaskID object from given string |
JobID |
getJobID()
Returns the JobID object that this tip belongs to |
int |
hashCode()
|
boolean |
isMap()
Returns whether this TaskID is a map ID |
void |
readFields(java.io.DataInput in)
Deserialize the fields of this object from in . |
java.lang.String |
toString()
|
void |
write(java.io.DataOutput out)
Serialize the fields of this object to out . |
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 |
Field Detail |
---|
protected static final java.lang.String TASK
protected static final java.text.NumberFormat idFormat
Constructor Detail |
---|
public TaskID(JobID jobId, boolean isMap, int id)
JobID
.
jobId
- JobID that this tip belongs toisMap
- whether the tip is a mapid
- the tip numberpublic TaskID(java.lang.String jtIdentifier, int jobId, boolean isMap, int id)
jtIdentifier
- jobTracker identifierjobId
- job numberisMap
- whether the tip is a mapid
- the tip numberpublic TaskID()
Method Detail |
---|
public JobID getJobID()
JobID
object that this tip belongs to
public boolean isMap()
public boolean equals(java.lang.Object o)
equals
in class ID
public int compareTo(ID o)
compareTo
in interface java.lang.Comparable<ID>
compareTo
in class ID
public java.lang.String toString()
toString
in class ID
protected java.lang.StringBuilder appendTo(java.lang.StringBuilder builder)
builder
- the builder to append to
public int hashCode()
hashCode
in class ID
public void readFields(java.io.DataInput in) throws java.io.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.
java.io.IOException
public void write(java.io.DataOutput out) throws java.io.IOException
Writable
out
.
write
in interface Writable
write
in class ID
out
- DataOuput
to serialize this object into.
java.io.IOException
public static TaskID forName(java.lang.String str) throws java.lang.IllegalArgumentException
java.lang.IllegalArgumentException
- if the given string is malformed
|
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