Package org.apache.hadoop.io

Class NullWritable

java.lang.Object

org.apache.hadoop.io.NullWritable

All Implemented Interfaces:

Comparable<NullWritable>, Writable, WritableComparable<NullWritable>

@Public
@Stable
public class NullWritable
extends Object
implements WritableComparable<NullWritable>

Singleton Writable with no data.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	org.apache.hadoop.io.NullWritable.Comparator	A Comparator "optimized" for NullWritable.

Method Summary

Modifier and Type	Method	Description
int	compareTo(NullWritable other)
boolean	equals(Object other)
static NullWritable	get()	Returns the single instance of this class.
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 java.lang.Object

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

Method Details

get

public static NullWritable get()

Returns the single instance of this class.

Returns:

the single instance of this class.

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

compareTo

public int compareTo(NullWritable other)

Specified by:

compareTo in interface Comparable<NullWritable>

equals

public boolean equals(Object other)

Overrides:

equals in class Object

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 - any other problem for readFields.

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 - any other problem for write.