Package org.apache.hadoop.io

Class MapWritable

java.lang.Object

org.apache.hadoop.io.AbstractMapWritable

org.apache.hadoop.io.MapWritable

All Implemented Interfaces:

java.util.Map<Writable,Writable>, Configurable, Writable

@Public
@Stable
public class MapWritable
extends AbstractMapWritable
implements java.util.Map<Writable,Writable>

A Writable Map.

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K extends java.lang.Object,V extends java.lang.Object>

Constructor Summary

Constructors

Constructor	Description
MapWritable()	Default constructor.
MapWritable(MapWritable other)	Copy constructor.

Method Summary

Modifier and Type	Method	Description
void	clear()
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
java.util.Set<java.util.Map.Entry<Writable,Writable>>	entrySet()
boolean	equals(java.lang.Object obj)
Writable	get(java.lang.Object key)
int	hashCode()
boolean	isEmpty()
java.util.Set<Writable>	keySet()
Writable	put(Writable key, Writable value)
void	putAll(java.util.Map<? extends Writable,? extends Writable> t)
void	readFields(java.io.DataInput in)	Deserialize the fields of this object from in.
Writable	remove(java.lang.Object key)
int	size()
java.lang.String	toString()
java.util.Collection<Writable>	values()
void	write(java.io.DataOutput out)	Serialize the fields of this object to out.

Methods inherited from class org.apache.hadoop.io.AbstractMapWritable

addToMap, copy, getClass, getConf, getId, setConf

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

MapWritable

public MapWritable()

Default constructor.

MapWritable

public MapWritable(MapWritable other)

Copy constructor.

Parameters:

other - the map to copy from

Method Detail

clear

public void clear()

Specified by:

clear in interface java.util.Map<Writable,Writable>

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<Writable,Writable>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<Writable,Writable>

entrySet

public java.util.Set<java.util.Map.Entry<Writable,Writable>> entrySet()

Specified by:

entrySet in interface java.util.Map<Writable,Writable>

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Map<Writable,Writable>

Overrides:

equals in class java.lang.Object

get

public Writable get(java.lang.Object key)

Specified by:

get in interface java.util.Map<Writable,Writable>

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Map<Writable,Writable>

Overrides:

hashCode in class java.lang.Object

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<Writable,Writable>

keySet

public java.util.Set<Writable> keySet()

Specified by:

keySet in interface java.util.Map<Writable,Writable>

put

public Writable put(Writable key,
                    Writable value)

Specified by:

put in interface java.util.Map<Writable,Writable>

putAll

public void putAll(java.util.Map<? extends Writable,? extends Writable> t)

Specified by:

putAll in interface java.util.Map<Writable,Writable>

remove

public Writable remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<Writable,Writable>

size

public int size()

Specified by:

size in interface java.util.Map<Writable,Writable>

values

public java.util.Collection<Writable> values()

Specified by:

values in interface java.util.Map<Writable,Writable>

write

public void write(java.io.DataOutput out)
           throws java.io.IOException

Description copied from interface: Writable

Serialize the fields of this object to out.

Specified by:

write in interface Writable

Overrides:

write in class AbstractMapWritable

Parameters:

out - DataOuput to serialize this object into.

Throws:

java.io.IOException - any other problem for write.

readFields

public void readFields(java.io.DataInput in)
                throws java.io.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 AbstractMapWritable

Parameters:

in - DataInput to deseriablize this object from.

Throws:

java.io.IOException - any other problem for readFields.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object