org.apache.commons.collections4.collection

Class AbstractCollectionDecorator<E>

java.lang.Object

org.apache.commons.collections4.collection.AbstractCollectionDecorator<E>

Type Parameters:

E - the type of the elements in the collection

All Implemented Interfaces:

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

Direct Known Subclasses:

AbstractBagDecorator, AbstractDualBidiMap.View, AbstractListDecorator, AbstractQueueDecorator, AbstractSetDecorator, IndexedCollection, PredicatedCollection, TransformedCollection, UnmodifiableBoundedCollection, UnmodifiableCollection

public abstract class AbstractCollectionDecorator<E>
extends java.lang.Object
implements java.util.Collection<E>, java.io.Serializable

Decorates another Collection to provide additional behaviour.

Each method call made on this Collection is forwarded to the decorated Collection. This class is used as a framework on which to build to extensions such as synchronized and unmodifiable behaviour. The main advantage of decoration is that one decorator can wrap any implementation of Collection, whereas sub-classing requires a new class to be written for each implementation.

This implementation does not perform any special processing with iterator(). Instead it simply returns the value from the wrapped collection. This may be undesirable, for example if you are trying to write an unmodifiable implementation it might provide a loophole.

Since:

3.0

Version:

$Id: AbstractCollectionDecorator.java 1494280 2013-06-18 20:07:04Z tn $

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Collection<E>	collection The collection being decorated
private static long	serialVersionUID Serialization version

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractCollectionDecorator() Constructor only used in deserialization, do not use otherwise.
protected	AbstractCollectionDecorator(java.util.Collection<E> coll) Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method and Description
boolean	add(E object)
boolean	addAll(java.util.Collection<? extends E> coll)
void	clear()
boolean	contains(java.lang.Object object)
boolean	containsAll(java.util.Collection<?> coll)
protected java.util.Collection<E>	decorated() Gets the collection being decorated.
boolean	equals(java.lang.Object object)
int	hashCode()
boolean	isEmpty()
java.util.Iterator<E>	iterator()
boolean	remove(java.lang.Object object)
boolean	removeAll(java.util.Collection<?> coll)
boolean	retainAll(java.util.Collection<?> coll)
protected void	setCollection(java.util.Collection<E> coll) Sets the collection being decorated.
int	size()
java.lang.Object[]	toArray()
<T> T[]	toArray(T[] object)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

serialVersionUID

private static final long serialVersionUID

Serialization version

See Also:

Constant Field Values

collection

private java.util.Collection<E> collection

The collection being decorated

Constructor Detail

AbstractCollectionDecorator

protected AbstractCollectionDecorator()

Constructor only used in deserialization, do not use otherwise.

Since:

3.1

AbstractCollectionDecorator

protected AbstractCollectionDecorator(java.util.Collection<E> coll)

Constructor that wraps (not copies).

Parameters:

coll - the collection to decorate, must not be null

Throws:

java.lang.IllegalArgumentException - if the collection is null

Method Detail

decorated

protected java.util.Collection<E> decorated()

Gets the collection being decorated. All access to the decorated collection goes via this method.

Returns:

the decorated collection

setCollection

protected void setCollection(java.util.Collection<E> coll)

Sets the collection being decorated.

NOTE: this method should only be used during deserialization

Parameters:

coll - the decorated collection

add

public boolean add(E object)

Specified by:

add in interface java.util.Collection<E>

addAll

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

Specified by:

addAll in interface java.util.Collection<E>

clear

public void clear()

Specified by:

clear in interface java.util.Collection<E>

contains

public boolean contains(java.lang.Object object)

Specified by:

contains in interface java.util.Collection<E>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Collection<E>

iterator

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

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

remove

public boolean remove(java.lang.Object object)

Specified by:

remove in interface java.util.Collection<E>

size

public int size()

Specified by:

size in interface java.util.Collection<E>

toArray

public java.lang.Object[] toArray()

Specified by:

toArray in interface java.util.Collection<E>

toArray

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

Specified by:

toArray in interface java.util.Collection<E>

containsAll

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

Specified by:

containsAll in interface java.util.Collection<E>

removeAll

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

Specified by:

removeAll in interface java.util.Collection<E>

retainAll

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

Specified by:

retainAll in interface java.util.Collection<E>

equals

public boolean equals(java.lang.Object object)

Specified by:

equals in interface java.util.Collection<E>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Collection<E>

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object