org.apache.hadoop.mapred
Class ID

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

All Implemented Interfaces:

Comparable<ID>, Writable, WritableComparable<ID>

Direct Known Subclasses:

JobID, TaskAttemptID, TaskID

public class ID
extends Object
implements WritableComparable<ID>

A general identifier, which internally stores the id as an integer. This is the super class of JobID, TaskID and TaskAttemptID.

See Also:

JobID, TaskID, TaskAttemptID

Field Summary

protected int

id

Constructor Summary

protected	ID()
	ID(int id) constructs an ID object from the given int

Method Summary

int	compareTo(ID that) Compare IDs by associated numbers
boolean	equals(Object o)
static ID	forName(String str) Construct an ID object from given string
int	getId() returns the int which represents the identifier
int	hashCode()
static ID	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 java.lang.Object

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

Field Detail

id

protected int id

Constructor Detail

ID

public ID(int id)

constructs an ID object from the given int

ID

protected ID()

Method Detail

getId

public int getId()

returns the int which represents the identifier

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

compareTo

public int compareTo(ID that)

Compare IDs by associated numbers

Specified by:

compareTo in interface Comparable<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

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

Parameters:

out - DataOuput to serialize this object into.

Throws:

IOException

read

public static ID read(DataInput in)
               throws IOException

Throws:

IOException

forName

public static ID forName(String str)
                  throws IllegalArgumentException

Construct an ID object from given string

Returns:

constructed Id object or null if the given String is null

Throws:

IllegalArgumentException - if the given string is malformed