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:

  • 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>