Package org.apache.commons.collections4.queue

Class AbstractQueueDecorator<E>

java.lang.Object

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

org.apache.commons.collections4.queue.AbstractQueueDecorator<E>

Type Parameters:

E - the type of the elements in the queue

All Implemented Interfaces:

Serializable, Iterable<E>, Collection<E>, Queue<E>

Direct Known Subclasses:

UnmodifiableQueue

public abstract class AbstractQueueDecorator<E>
extends AbstractCollectionDecorator<E>
implements Queue<E>

Decorates another Queue to provide additional behavior.

Methods are forwarded directly to the decorated queue.

This implementation does not forward the hashCode and equals methods through to the backing object, but relies on Object's implementation. This is necessary as some Queue implementations, e.g. LinkedList, have a custom equals implementation for which symmetry can not be preserved. See class Javadoc of AbstractCollectionDecorator for more information.

Since:

4.0

See Also:

• Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractQueueDecorator()	Constructor only used in deserialization, do not use otherwise.
protected	AbstractQueueDecorator(Queue<E> queue)	Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method	Description
protected Queue<E>	decorated()	Gets the queue being decorated.
E	element()
boolean	offer(E obj)
E	peek()
E	poll()
E	remove()

Methods inherited from class org.apache.commons.collections4.collection.AbstractCollectionDecorator

add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, removeIf, retainAll, setCollection, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, remove, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Queue

add

Constructor Details

AbstractQueueDecorator

protected AbstractQueueDecorator()

Constructor only used in deserialization, do not use otherwise.

AbstractQueueDecorator

protected AbstractQueueDecorator(Queue<E> queue)

Constructor that wraps (not copies).

Parameters:

queue - the queue to decorate, must not be null

Throws:

NullPointerException - if queue is null

Method Details

decorated

protected Queue<E> decorated()

Gets the queue being decorated.

Overrides:

decorated in class AbstractCollectionDecorator<E>

Returns:

the decorated queue

element

public E element()

Specified by:

element in interface Queue<E>

offer

public boolean offer(E obj)

Specified by:

offer in interface Queue<E>

peek

public E peek()

Specified by:

peek in interface Queue<E>

poll

public E poll()

Specified by:

poll in interface Queue<E>

remove

public E remove()

Specified by:

remove in interface Queue<E>