java.lang.Object

org.apache.commons.collections.set.MapBackedSet

All Implemented Interfaces:: Serializable, Iterable, Collection, Set

public final class MapBackedSet extends Object implements Set, 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: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type

Field

Description

protected final Object

dummyValue

The dummyValue to use

protected final Map

map

The map being used as the backing store
Method Summary

Modifier and Type

Method

Description

boolean

add(Object obj)

boolean

addAll(Collection coll)

void

clear()

boolean

contains(Object obj)

boolean

containsAll(Collection coll)

static Set

decorate(Map map)

Factory method to create a set from a map.

static Set

decorate(Map map, Object dummyValue)

Factory method to create a set from a map.

boolean

equals(Object obj)

int

hashCode()

boolean

isEmpty()

Iterator

iterator()

boolean

remove(Object obj)

boolean

removeAll(Collection coll)

boolean

retainAll(Collection coll)

int

size()

Object[]

toArray()

Object[]

toArray(Object[] array)

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable
forEach

Methods inherited from interface java.util.Set
spliterator

Field Details
- map
  
  protected final Map map
  
  The map being used as the backing store
- dummyValue
  
  protected final Object dummyValue
  
  The dummyValue to use
Method Details
- decorate
  
  public static Set decorate(Map map)
  
  Factory method to create a set from a map.
  
  Parameters:
  
  map - the map to decorate, must not be null
  
  Throws:
  
  IllegalArgumentException - if set is null
- decorate
  
  public static Set decorate(Map map, 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:
  
  IllegalArgumentException - if map is null
- size
  
  public int size()
  
  Specified by:
  
  size in interface Collection
  
  Specified by:
  
  size in interface Set
- isEmpty
  
  public boolean isEmpty()
  
  Specified by:
  
  isEmpty in interface Collection
  
  Specified by:
  
  isEmpty in interface Set
- iterator
  
  public Iterator iterator()
  
  Specified by:
  
  iterator in interface Collection
  
  Specified by:
  
  iterator in interface Iterable
  
  Specified by:
  
  iterator in interface Set
- contains
  
  public boolean contains(Object obj)
  
  Specified by:
  
  contains in interface Collection
  
  Specified by:
  
  contains in interface Set
- containsAll
  
  public boolean containsAll(Collection coll)
  
  Specified by:
  
  containsAll in interface Collection
  
  Specified by:
  
  containsAll in interface Set
- add
  
  public boolean add(Object obj)
  
  Specified by:
  
  add in interface Collection
  
  Specified by:
  
  add in interface Set
- addAll
  
  public boolean addAll(Collection coll)
  
  Specified by:
  
  addAll in interface Collection
  
  Specified by:
  
  addAll in interface Set
- remove
  
  public boolean remove(Object obj)
  
  Specified by:
  
  remove in interface Collection
  
  Specified by:
  
  remove in interface Set
- removeAll
  
  public boolean removeAll(Collection coll)
  
  Specified by:
  
  removeAll in interface Collection
  
  Specified by:
  
  removeAll in interface Set
- retainAll
  
  public boolean retainAll(Collection coll)
  
  Specified by:
  
  retainAll in interface Collection
  
  Specified by:
  
  retainAll in interface Set
- clear
  
  public void clear()
  
  Specified by:
  
  clear in interface Collection
  
  Specified by:
  
  clear in interface Set
- toArray
  
  public Object[] toArray()
  
  Specified by:
  
  toArray in interface Collection
  
  Specified by:
  
  toArray in interface Set
- toArray
  
  public Object[] toArray(Object[] array)
  
  Specified by:
  
  toArray in interface Collection
  
  Specified by:
  
  toArray in interface Set
- equals
  
  public boolean equals(Object obj)
  
  Specified by:
  
  equals in interface Collection
  
  Specified by:
  
  equals in interface Set
  
  Overrides:
  
  equals in class Object
- hashCode
  
  public int hashCode()
  
  Specified by:
  
  hashCode in interface Collection
  
  Specified by:
  
  hashCode in interface Set
  
  Overrides:
  
  hashCode in class Object

Class MapBackedSet

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Methods inherited from interface java.util.Set

Field Details

map

dummyValue

Method Details

decorate

decorate

size

isEmpty

iterator

contains

containsAll

add

addAll

remove

removeAll

retainAll

clear

toArray

toArray

equals

hashCode