org.apache.hadoop.mapreduce
Class JobID

java.lang.Object
  org.apache.hadoop.mapreduce.ID
      org.apache.hadoop.mapred.ID
          org.apache.hadoop.mapreduce.JobID

All Implemented Interfaces:

Comparable<ID>, Writable, WritableComparable<ID>

Direct Known Subclasses:

JobID

@InterfaceAudience.Public
@InterfaceStability.Stable
public class JobID
extends ID
implements Comparable<ID>

JobID represents the immutable and unique identifier for the job. JobID consists of two parts. First part represents the jobtracker identifier, so that jobID to jobtracker map is defined. For cluster setup this string is the jobtracker start time, for local setting, it is "local" and a random number. Second part of the JobID is the job number.
An example JobID is : job_200707121733_0003 , which represents the third job running at the jobtracker started at 200707121733.

Applications should never construct or parse JobID strings, but rather use appropriate constructors or forName(String) method.

See Also:

TaskID, TaskAttemptID

Field Summary

protected static NumberFormat	idFormat
protected static String	JOB
static String	JOBID_REGEX

Fields inherited from class org.apache.hadoop.mapreduce.ID

id, SEPARATOR

Constructor Summary

JobID()

JobID(String jtIdentifier, int id)
Constructs a JobID object

Method Summary

StringBuilder	appendTo(StringBuilder builder) Add the stuff after the "job" prefix to the given builder.
int	compareTo(ID o) Compare JobIds by first jtIdentifiers, then by job numbers
boolean	equals(Object o)
static JobID	forName(String str) Construct a JobId object from given string
String	getJtIdentifier()
int	hashCode()
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.mapreduce.ID

getId

Methods inherited from class java.lang.Object

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

Field Detail

JOB

protected static final String JOB

See Also:

Constant Field Values

JOBID_REGEX

public static final String JOBID_REGEX

See Also:

Constant Field Values

idFormat

protected static final NumberFormat idFormat

Constructor Detail

JobID

public JobID(String jtIdentifier,
             int id)

Constructs a JobID object

Parameters:

jtIdentifier - jobTracker identifier

id - job number

JobID

public JobID()

Method Detail

getJtIdentifier

public String getJtIdentifier()

equals

public boolean equals(Object o)

Overrides:

equals in class ID

compareTo

public int compareTo(ID o)

Compare JobIds by first jtIdentifiers, then by job numbers

Specified by:

compareTo in interface Comparable<ID>

Overrides:

compareTo in class ID

appendTo

public StringBuilder appendTo(StringBuilder builder)

Add the stuff after the "job" prefix to the given builder. This is useful, because the sub-ids use this substring at the start of their string.

Parameters:

builder - the builder to append to

Returns:

the builder that was passed in

hashCode

public int hashCode()

Overrides:

hashCode in class ID

toString

public String toString()

Overrides:

toString in class ID

readFields

public void readFields(DataInput in)
                throws IOException

Description copied from interface: Writable

Deserialize the fields of this object from in.

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

Specified by:

readFields in interface Writable

Overrides:

readFields in class ID

Parameters:

in - DataInput to deseriablize this object from.

Throws:

IOException

write

public void write(DataOutput out)
           throws IOException

Description copied from interface: Writable

Serialize the fields of this object to out.

Specified by:

write in interface Writable

Overrides:

write in class ID

Parameters:

out - DataOuput to serialize this object into.

Throws:

IOException

forName

public static JobID forName(String str)
                     throws IllegalArgumentException

Construct a JobId object from given string

Returns:

constructed JobId object or null if the given String is null

Throws:

IllegalArgumentException - if the given string is malformed