org.apache.commons.collections4.set

Class CompositeSet<E>

java.lang.Object

org.apache.commons.collections4.set.CompositeSet<E>

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.Set<E>

public class CompositeSet<E>
extends java.lang.Object
implements java.util.Set<E>, java.io.Serializable

Decorates a set of other sets to provide a single unified view.

Changes made to this set will actually be made on the decorated set. Add operations require the use of a pluggable strategy. If no strategy is provided then add is unsupported.

From version 4.0, this class does not extend CompositeCollection anymore due to its input restrictions (only accepts Sets). See COLLECTIONS-424 for more details.

Since:

3.0

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	CompositeSet.SetMutator<E> Define callbacks for mutation operations.

Constructor Summary

Constructors

Constructor and Description
CompositeSet() Create an empty CompositeSet.
CompositeSet(java.util.Set<E>... sets) Create a composite set with sets as the initial set of composited Sets.
CompositeSet(java.util.Set<E> set) Create a CompositeSet with just set composited.

Method Summary

Modifier and Type	Method and Description
boolean	add(E obj) Adds an object to the collection, throwing UnsupportedOperationException unless a SetMutator strategy is specified.
boolean	addAll(java.util.Collection<? extends E> coll) Adds a collection of elements to this composite, throwing UnsupportedOperationException unless a SetMutator strategy is specified.
void	addComposited(java.util.Set<E>... sets) Add these Sets to the list of sets in this composite
void	addComposited(java.util.Set<E> set) Add a Set to this composite.
void	addComposited(java.util.Set<E> set1, java.util.Set<E> set2) Add these Sets to the list of sets in this composite.
void	clear() Removes all of the elements from this composite set.
boolean	contains(java.lang.Object obj) Checks whether this composite set contains the object.
boolean	containsAll(java.util.Collection<?> coll) Checks whether this composite contains all the elements in the specified collection.
boolean	equals(java.lang.Object obj)
java.util.List<java.util.Set<E>>	getSets() Gets the sets being decorated.
int	hashCode()
boolean	isEmpty() Checks whether this composite set is empty.
java.util.Iterator<E>	iterator() Gets an iterator over all the sets in this composite.
boolean	remove(java.lang.Object obj) If a CollectionMutator is defined for this CompositeSet then this method will be called anyway.
boolean	removeAll(java.util.Collection<?> coll) Removes the elements in the specified collection from this composite set.
void	removeComposited(java.util.Set<E> set) Removes a set from those being decorated in this composite.
boolean	retainAll(java.util.Collection<?> coll) Retains all the elements in the specified collection in this composite set, removing all others.
void	setMutator(CompositeSet.SetMutator<E> mutator) Specify a SetMutator strategy instance to handle changes.
int	size() Gets the size of this composite set.
java.lang.Object[]	toArray() Returns an array containing all of the elements in this composite.
<T> T[]	toArray(T[] array) Returns an object array, populating the supplied array if possible.
java.util.Set<E>	toSet() Returns a new Set containing all of the elements.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Set

spliterator

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

CompositeSet

public CompositeSet()

Create an empty CompositeSet.

CompositeSet

public CompositeSet(java.util.Set<E> set)

Create a CompositeSet with just set composited.

Parameters:

set - the initial set in the composite

CompositeSet

public CompositeSet(java.util.Set<E>... sets)

Create a composite set with sets as the initial set of composited Sets.

Parameters:

sets - the initial sets in the composite

Method Detail

size

public int size()

Gets the size of this composite set.

This implementation calls size() on each set.

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in interface java.util.Set<E>

Returns:

total number of elements in all contained containers

isEmpty

public boolean isEmpty()

Checks whether this composite set is empty.

This implementation calls isEmpty() on each set.

Specified by:

isEmpty in interface java.util.Collection<E>

Specified by:

isEmpty in interface java.util.Set<E>

Returns:

true if all of the contained sets are empty

contains

public boolean contains(java.lang.Object obj)

Checks whether this composite set contains the object.

This implementation calls contains() on each set.

Specified by:

contains in interface java.util.Collection<E>

Specified by:

contains in interface java.util.Set<E>

Parameters:

obj - the object to search for

Returns:

true if obj is contained in any of the contained sets

iterator

public java.util.Iterator<E> iterator()

Gets an iterator over all the sets in this composite.

This implementation uses an IteratorChain.

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in interface java.util.Set<E>

Returns:

an IteratorChain instance which supports remove(). Iteration occurs over contained collections in the order they were added, but this behavior should not be relied upon.

See Also:

IteratorChain

toArray

public java.lang.Object[] toArray()

Returns an array containing all of the elements in this composite.

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.Set<E>

Returns:

an object array of all the elements in the collection

toArray

public <T> T[] toArray(T[] array)

Returns an object array, populating the supplied array if possible. See Collection interface for full details.

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.Set<E>

Type Parameters:

T - the type of the elements in the collection

Parameters:

array - the array to use, populating if possible

Returns:

an array of all the elements in the collection

add

public boolean add(E obj)

Adds an object to the collection, throwing UnsupportedOperationException unless a SetMutator strategy is specified.

Specified by:

add in interface java.util.Collection<E>

Specified by:

add in interface java.util.Set<E>

Parameters:

obj - the object to add

Returns:

true if the collection was modified

Throws:

java.lang.UnsupportedOperationException - if SetMutator hasn't been set or add is unsupported

java.lang.ClassCastException - if the object cannot be added due to its type

java.lang.NullPointerException - if the object cannot be added because its null

java.lang.IllegalArgumentException - if the object cannot be added

remove

public boolean remove(java.lang.Object obj)

If a CollectionMutator is defined for this CompositeSet then this method will be called anyway.

Specified by:

remove in interface java.util.Collection<E>

Specified by:

remove in interface java.util.Set<E>

Parameters:

obj - object to be removed

Returns:

true if the object is removed, false otherwise

containsAll

public boolean containsAll(java.util.Collection<?> coll)

Checks whether this composite contains all the elements in the specified collection.

This implementation calls contains() for each element in the specified collection.

Specified by:

containsAll in interface java.util.Collection<E>

Specified by:

containsAll in interface java.util.Set<E>

Parameters:

coll - the collection to check for

Returns:

true if all elements contained

addAll

public boolean addAll(java.util.Collection<? extends E> coll)

Adds a collection of elements to this composite, throwing UnsupportedOperationException unless a SetMutator strategy is specified.

Specified by:

addAll in interface java.util.Collection<E>

Specified by:

addAll in interface java.util.Set<E>

Parameters:

coll - the collection to add

Returns:

true if the composite was modified

Throws:

java.lang.UnsupportedOperationException - if SetMutator hasn't been set or add is unsupported

java.lang.ClassCastException - if the object cannot be added due to its type

java.lang.NullPointerException - if the object cannot be added because its null

java.lang.IllegalArgumentException - if the object cannot be added

removeAll

public boolean removeAll(java.util.Collection<?> coll)

Removes the elements in the specified collection from this composite set.

This implementation calls removeAll on each collection.

Specified by:

removeAll in interface java.util.Collection<E>

Specified by:

removeAll in interface java.util.Set<E>

Parameters:

coll - the collection to remove

Returns:

true if the composite was modified

Throws:

java.lang.UnsupportedOperationException - if removeAll is unsupported

retainAll

public boolean retainAll(java.util.Collection<?> coll)

Retains all the elements in the specified collection in this composite set, removing all others.

This implementation calls retainAll() on each collection.

Specified by:

retainAll in interface java.util.Collection<E>

Specified by:

retainAll in interface java.util.Set<E>

Parameters:

coll - the collection to remove

Returns:

true if the composite was modified

Throws:

java.lang.UnsupportedOperationException - if retainAll is unsupported

clear

public void clear()

Removes all of the elements from this composite set.

This implementation calls clear() on each set.

Specified by:

clear in interface java.util.Collection<E>

Specified by:

clear in interface java.util.Set<E>

Throws:

java.lang.UnsupportedOperationException - if clear is unsupported

setMutator

public void setMutator(CompositeSet.SetMutator<E> mutator)

Specify a SetMutator strategy instance to handle changes.

Parameters:

mutator - the mutator to use

addComposited

public void addComposited(java.util.Set<E> set)

Add a Set to this composite.

Parameters:

set - the set to add

Throws:

java.lang.IllegalArgumentException - if a SetMutator is set, but fails to resolve a collision

java.lang.UnsupportedOperationException - if there is no SetMutator set

java.lang.NullPointerException - if set is null

See Also:

CompositeSet.SetMutator

addComposited

public void addComposited(java.util.Set<E> set1,
                          java.util.Set<E> set2)

Add these Sets to the list of sets in this composite.

Parameters:

set1 - the first Set to be appended to the composite

set2 - the second Set to be appended to the composite

addComposited

public void addComposited(java.util.Set<E>... sets)

Add these Sets to the list of sets in this composite

Parameters:

sets - the Sets to be appended to the composite

removeComposited

public void removeComposited(java.util.Set<E> set)

Removes a set from those being decorated in this composite.

Parameters:

set - set to be removed

toSet

public java.util.Set<E> toSet()

Returns a new Set containing all of the elements.

Returns:

A new HashSet containing all of the elements in this composite. The new collection is not backed by this composite.

getSets

public java.util.List<java.util.Set<E>> getSets()

Gets the sets being decorated.

Returns:

Unmodifiable list of all sets in this composite.

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Collection<E>

Specified by:

equals in interface java.util.Set<E>

Overrides:

equals in class java.lang.Object

See Also:

Set.equals(java.lang.Object)

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Collection<E>

Specified by:

hashCode in interface java.util.Set<E>

Overrides:

hashCode in class java.lang.Object

See Also:

Set.hashCode()