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:

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

public class TransformedQueue<E>
extends TransformedCollection<E>
implements 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

Field Summary

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

transformer

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	TransformedQueue(Queue<E> queue, Transformer<? super E,? extends E> transformer)	Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method	Description
E	element()
protected Queue<E>	getQueue()	Gets the decorated queue.
boolean	offer(E obj)
E	peek()
E	poll()
E	remove()
static <E> TransformedQueue<E>	transformedQueue(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(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, transform, transform, transformedCollection, transformingCollection

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

clear, contains, containsAll, decorated, 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

TransformedQueue

protected TransformedQueue(Queue<E> queue,
 Transformer<? super E,? extends E> transformer)

Constructor that wraps (not copies).

If there are any elements already in the queue being decorated, they are NOT transformed.

Parameters:

queue - the queue to decorate, must not be null

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

Throws:

NullPointerException - if queue or transformer is null

Method Details

transformedQueue

public static <E> TransformedQueue<E> transformedQueue(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:

NullPointerException - if queue or transformer is null

Since:

4.0

transformingQueue

public static <E> TransformedQueue<E> transformingQueue(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:

NullPointerException - if queue or transformer is null

element

public E element()

Specified by:

element in interface Queue<E>

getQueue

protected Queue<E> getQueue()

Gets the decorated queue.

Returns:

the decorated queue

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>