Package org.apache.commons.collections4.queue

Class TransformedQueue<E>

java.lang.Object

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

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

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

Type Parameters:

E - the type of elements held in this queue

All Implemented Interfaces:

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

public class TransformedQueue<E>
extends TransformedCollection<E>
implements java.util.Queue<E>

Decorates another Queue to transform objects that are added.

The add/offer methods are affected by this class. Thus objects must be removed or searched for using their transformed form. For example, if the transformation converts Strings to Integers, you must use the Integer form to remove objects.

Since:

4.0

See Also:

Serialized Form

Method Summary

Modifier and Type	Method	Description
E	element()
boolean	offer(E obj)
E	peek()
E	poll()
E	remove()
static <E> TransformedQueue<E>	transformedQueue(java.util.Queue<E> queue, Transformer<? super E,? extends E> transformer)	Factory method to create a transforming queue that will transform existing contents of the specified queue.
static <E> TransformedQueue<E>	transformingQueue(java.util.Queue<E> queue, Transformer<? super E,? extends E> transformer)	Factory method to create a transforming queue.

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

add, addAll, transformedCollection, transformingCollection

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

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

Methods inherited from class java.lang.Object

equals, 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, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Queue

add

Method Detail

transformingQueue

public static <E> TransformedQueue<E> transformingQueue(java.util.Queue<E> queue,
                                                        Transformer<? super E,? extends E> transformer)

Factory method to create a transforming queue.

If there are any elements already in the queue being decorated, they are NOT transformed. Contrast this with transformedQueue(Queue, Transformer).

Type Parameters:

E - the type of the elements in the queue

Parameters:

queue - the queue to decorate, must not be null

transformer - the transformer to use for conversion, must not be null

Returns:

a new transformed Queue

Throws:

java.lang.NullPointerException - if queue or transformer is null

transformedQueue

public static <E> TransformedQueue<E> transformedQueue(java.util.Queue<E> queue,
                                                       Transformer<? super E,? extends E> transformer)

Factory method to create a transforming queue that will transform existing contents of the specified queue.

If there are any elements already in the queue being decorated, they will be transformed by this method. Contrast this with transformingQueue(Queue, Transformer).

Type Parameters:

E - the type of the elements in the queue

Parameters:

queue - the queue to decorate, must not be null

transformer - the transformer to use for conversion, must not be null

Returns:

a new transformed Queue

Throws:

java.lang.NullPointerException - if queue or transformer is null

Since:

4.0

offer

public boolean offer(E obj)

Specified by:

offer in interface java.util.Queue<E>

poll

public E poll()

Specified by:

poll in interface java.util.Queue<E>

peek

public E peek()

Specified by:

peek in interface java.util.Queue<E>

element

public E element()

Specified by:

element in interface java.util.Queue<E>

remove

public E remove()

Specified by:

remove in interface java.util.Queue<E>