org.apache.commons.collections.set
Class MapBackedSet

java.lang.Object
  |
  +--org.apache.commons.collections.set.MapBackedSet

All Implemented Interfaces:

java.util.Collection, java.io.Serializable, java.util.Set

public final class MapBackedSet

extends java.lang.Object

implements java.util.Set, java.io.Serializable

Decorates a Map to obtain Set behaviour.

This class is used to create a Set with the same properties as the key set of any map. Thus, a ReferenceSet can be created by wrapping a ReferenceMap in an instance of this class.

Most map implementation can be used to create a set by passing in dummy values. Exceptions include BidiMap implementations, as they require unique values.

Since:

Commons Collections 3.1

Version:

$Revision: 1.2 $ $Date: 2004/06/02 22:00:47 $

Author:

Stephen Colebourne

See Also:

Serialized Form

Method Summary

boolean	add(java.lang.Object obj)
boolean	addAll(java.util.Collection coll)
void	clear()
boolean	contains(java.lang.Object obj)
boolean	containsAll(java.util.Collection coll)
static java.util.Set	decorate(java.util.Map map) Factory method to create a set from a map.
static java.util.Set	decorate(java.util.Map map, java.lang.Object dummyValue) Factory method to create a set from a map.
boolean	equals(java.lang.Object obj)
int	hashCode()
boolean	isEmpty()
java.util.Iterator	iterator()
boolean	remove(java.lang.Object obj)
boolean	removeAll(java.util.Collection coll)
boolean	retainAll(java.util.Collection coll)
int	size()
java.lang.Object[]	toArray()
java.lang.Object[]	toArray(java.lang.Object[] array)

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Method Detail

decorate

public static java.util.Set decorate(java.util.Map map)

Factory method to create a set from a map.

Parameters:

map - the map to decorate, must not be null

Throws:

java.lang.IllegalArgumentException - if set is null

decorate

public static java.util.Set decorate(java.util.Map map,
                                     java.lang.Object dummyValue)

Factory method to create a set from a map.

Parameters:

map - the map to decorate, must not be null

dummyValue - the dummy value to use

Throws:

java.lang.IllegalArgumentException - if map is null

size

public int size()

Specified by:

size in interface java.util.Set

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Set

iterator

public java.util.Iterator iterator()

Specified by:

iterator in interface java.util.Set

contains

public boolean contains(java.lang.Object obj)

Specified by:

contains in interface java.util.Set

containsAll

public boolean containsAll(java.util.Collection coll)

Specified by:

containsAll in interface java.util.Set

add

public boolean add(java.lang.Object obj)

Specified by:

add in interface java.util.Set

addAll

public boolean addAll(java.util.Collection coll)

Specified by:

addAll in interface java.util.Set

remove

public boolean remove(java.lang.Object obj)

Specified by:

remove in interface java.util.Set

removeAll

public boolean removeAll(java.util.Collection coll)

Specified by:

removeAll in interface java.util.Set

retainAll

public boolean retainAll(java.util.Collection coll)

Specified by:

retainAll in interface java.util.Set

clear

public void clear()

Specified by:

clear in interface java.util.Set

toArray

public java.lang.Object[] toArray()

Specified by:

toArray in interface java.util.Set

toArray

public java.lang.Object[] toArray(java.lang.Object[] array)

Specified by:

toArray in interface java.util.Set

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Set

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Set

Overrides:

hashCode in class java.lang.Object