java.lang.Object
- org.apache.commons.collections.collection.CompositeCollection

All Implemented Interfaces:

Iterable, Collection

Direct Known Subclasses:

CompositeSet
```
public class CompositeCollection
extends Object
implements Collection
```
Decorates a collection of other collections to provide a single unified view.
Changes made to this collection will actually be made on the decorated collection. Add and remove operations require the use of a pluggable strategy. If no strategy is provided then add and remove are unsupported.

Since:

Commons Collections 3.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Brian McCallister, Stephen Colebourne, Phil Steitz

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static interface CompositeCollection.CollectionMutator
Pluggable strategy to handle changes to the composite.

Field Summary

Fields
Modifier and Type	Field	Description
`protected Collection[]`	`all`	Collections in the composite
`protected CompositeCollection.CollectionMutator`	`mutator`	CollectionMutator to handle changes to the collection

Constructor Summary

Constructors
Constructor	Description
`CompositeCollection()`	Create an empty CompositeCollection.
`CompositeCollection(Collection coll)`	Create a Composite Collection with only coll composited.
`CompositeCollection(Collection[] colls)`	Create a CompositeCollection with colls as the initial list of composited collections.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`add(Object obj)`	Adds an object to the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
`boolean`	`addAll(Collection coll)`	Adds a collection of elements to this collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
`void`	`addComposited(Collection c)`	Add an additional collection to this composite.
`void`	`addComposited(Collection[] comps)`	Add these Collections to the list of collections in this composite
`void`	`addComposited(Collection c, Collection d)`	Add two additional collections to this composite.
`void`	`clear()`	Removes all of the elements from this collection .
`boolean`	`contains(Object obj)`	Checks whether this composite collection contains the object.
`boolean`	`containsAll(Collection coll)`	Checks whether this composite contains all the elements in the specified collection.
`Collection`	`getCollections()`	Gets the collections being decorated.
`boolean`	`isEmpty()`	Checks whether this composite collection is empty.
`Iterator`	`iterator()`	Gets an iterator over all the collections in this composite.
`boolean`	`remove(Object obj)`	Removes an object from the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
`boolean`	`removeAll(Collection coll)`	Removes the elements in the specified collection from this composite collection.
`void`	`removeComposited(Collection coll)`	Removes a collection from the those being decorated in this composite.
`boolean`	`retainAll(Collection coll)`	Retains all the elements in the specified collection in this composite collection, removing all others.
`void`	`setMutator(CompositeCollection.CollectionMutator mutator)`	Specify a CollectionMutator strategy instance to handle changes.
`int`	`size()`	Gets the size of this composite collection.
`Object[]`	`toArray()`	Returns an array containing all of the elements in this composite.
`Object[]`	`toArray(Object[] array)`	Returns an object array, populating the supplied array if possible.
`Collection`	`toCollection()`	Returns a new collection containing all of the elements

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

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

Methods inherited from interface java.lang.Iterable
forEach

- Field Detail
  - mutator
```
protected CompositeCollection.CollectionMutator mutator
```
    CollectionMutator to handle changes to the collection
  - all
```
protected Collection[] all
```
    Collections in the composite
- Constructor Detail
  - CompositeCollection
```
public CompositeCollection()
```
    Create an empty CompositeCollection.
  - CompositeCollection
```
public CompositeCollection(Collection coll)
```
    Create a Composite Collection with only coll composited.
    
    Parameters:
    
    coll - a collection to decorate
  - CompositeCollection
```
public CompositeCollection(Collection[] colls)
```
    Create a CompositeCollection with colls as the initial list of composited collections.
    
    Parameters:
    
    colls - an array of collections to decorate
- Method Detail
  - size
```
public int size()
```
    Gets the size of this composite collection.
    This implementation calls size() on each collection.
    
    Specified by:
    
    size in interface Collection
    
    Returns:
    
    total number of elements in all contained containers
  - isEmpty
```
public boolean isEmpty()
```
    Checks whether this composite collection is empty.
    This implementation calls isEmpty() on each collection.
    
    Specified by:
    
    isEmpty in interface Collection
    
    Returns:
    
    true if all of the contained collections are empty
  - contains
```
public boolean contains(Object obj)
```
    Checks whether this composite collection contains the object.
    This implementation calls contains() on each collection.
    
    Specified by:
    
    contains in interface Collection
    
    Parameters:
    
    obj - the object to search for
    
    Returns:
    
    true if obj is contained in any of the contained collections
  - iterator
```
public Iterator iterator()
```
    Gets an iterator over all the collections in this composite.
    This implementation uses an IteratorChain.
    
    Specified by:
    
    iterator in interface Collection
    
    Specified by:
    
    iterator in interface Iterable
    
    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 Object[] toArray()
```
    Returns an array containing all of the elements in this composite.
    
    Specified by:
    
    toArray in interface Collection
    
    Returns:
    
    an object array of all the elements in the collection
  - toArray
```
public Object[] toArray(Object[] array)
```
    Returns an object array, populating the supplied array if possible. See Collection interface for full details.
    
    Specified by:
    
    toArray in interface Collection
    
    Parameters:
    
    array - the array to use, populating if possible
    
    Returns:
    
    an array of all the elements in the collection
  - add
```
public boolean add(Object obj)
```
    Adds an object to the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
    
    Specified by:
    
    add in interface Collection
    
    Parameters:
    
    obj - the object to add
    
    Returns:
    
    true if the collection was modified
    
    Throws:
    
    UnsupportedOperationException - if CollectionMutator hasn't been set
    
    UnsupportedOperationException - if add is unsupported
    
    ClassCastException - if the object cannot be added due to its type
    
    NullPointerException - if the object cannot be added because its null
    
    IllegalArgumentException - if the object cannot be added
  - remove
```
public boolean remove(Object obj)
```
    Removes an object from the collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
    
    Specified by:
    
    remove in interface Collection
    
    Parameters:
    
    obj - the object being removed
    
    Returns:
    
    true if the collection is changed
    
    Throws:
    
    UnsupportedOperationException - if removed is unsupported
    
    ClassCastException - if the object cannot be removed due to its type
    
    NullPointerException - if the object cannot be removed because its null
    
    IllegalArgumentException - if the object cannot be removed
  - containsAll
```
public boolean containsAll(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 Collection
    
    Parameters:
    
    coll - the collection to check for
    
    Returns:
    
    true if all elements contained
  - addAll
```
public boolean addAll(Collection coll)
```
    Adds a collection of elements to this collection, throwing UnsupportedOperationException unless a CollectionMutator strategy is specified.
    
    Specified by:
    
    addAll in interface Collection
    
    Parameters:
    
    coll - the collection to add
    
    Returns:
    
    true if the collection was modified
    
    Throws:
    
    UnsupportedOperationException - if CollectionMutator hasn't been set
    
    UnsupportedOperationException - if add is unsupported
    
    ClassCastException - if the object cannot be added due to its type
    
    NullPointerException - if the object cannot be added because its null
    
    IllegalArgumentException - if the object cannot be added
  - removeAll
```
public boolean removeAll(Collection coll)
```
    Removes the elements in the specified collection from this composite collection.
    This implementation calls removeAll on each collection.
    
    Specified by:
    
    removeAll in interface Collection
    
    Parameters:
    
    coll - the collection to remove
    
    Returns:
    
    true if the collection was modified
    
    Throws:
    
    UnsupportedOperationException - if removeAll is unsupported
  - retainAll
```
public boolean retainAll(Collection coll)
```
    Retains all the elements in the specified collection in this composite collection, removing all others.
    This implementation calls retainAll() on each collection.
    
    Specified by:
    
    retainAll in interface Collection
    
    Parameters:
    
    coll - the collection to remove
    
    Returns:
    
    true if the collection was modified
    
    Throws:
    
    UnsupportedOperationException - if retainAll is unsupported
  - clear
```
public void clear()
```
    Removes all of the elements from this collection .
    This implementation calls clear() on each collection.
    
    Specified by:
    
    clear in interface Collection
    
    Throws:
    
    UnsupportedOperationException - if clear is unsupported
  - setMutator
```
public void setMutator(CompositeCollection.CollectionMutator mutator)
```
    Specify a CollectionMutator strategy instance to handle changes.
    
    Parameters:
    
    mutator - the mutator to use
  - addComposited
```
public void addComposited(Collection[] comps)
```
    Add these Collections to the list of collections in this composite
    
    Parameters:
    
    comps - Collections to be appended to the composite
  - addComposited
```
public void addComposited(Collection c)
```
    Add an additional collection to this composite.
    
    Parameters:
    
    c - the collection to add
  - addComposited
```
public void addComposited(Collection c,
                          Collection d)
```
    Add two additional collections to this composite.
    
    Parameters:
    
    c - the first collection to add
    
    d - the second collection to add
  - removeComposited
```
public void removeComposited(Collection coll)
```
    Removes a collection from the those being decorated in this composite.
    
    Parameters:
    
    coll - collection to be removed
  - toCollection
```
public Collection toCollection()
```
    Returns a new collection containing all of the elements
    
    Returns:
    
    A new ArrayList containing all of the elements in this composite. The new collection is not backed by this composite.
  - getCollections
```
public Collection getCollections()
```
    Gets the collections being decorated.
    
    Returns:
    
    Unmodifiable collection of all collections in this composite.

Class CompositeCollection

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Field Detail

mutator

all

Constructor Detail

CompositeCollection

CompositeCollection

CompositeCollection

Method Detail

size

isEmpty

contains

iterator

toArray

toArray

add

remove

containsAll

addAll

removeAll

retainAll

clear

setMutator

addComposited

addComposited

addComposited

removeComposited

toCollection

getCollections