com.google.common.collect
Class ForwardingQueue<E>

java.lang.Object
  com.google.common.collect.ForwardingObject
      com.google.common.collect.ForwardingCollection<E>
          com.google.common.collect.ForwardingQueue<E>

All Implemented Interfaces:

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

Direct Known Subclasses:

ForwardingBlockingQueue

public abstract class ForwardingQueue<E>
extends ForwardingCollection<E>
implements Queue<E>

A queue which forwards all its method calls to another queue. Subclasses should override one or more methods to modify the behavior of the backing queue as desired per the decorator pattern.

Since:

2 (imported from Google Collections Library)

Author:

Mike Bostock

ForwardingQueue

protected ForwardingQueue()

Constructor for use by subclasses.

delegate

protected abstract Queue<E> delegate()

Description copied from class: ForwardingObject

Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.

Specified by:

delegate in class ForwardingCollection<E>

offer

public boolean offer(E o)

Description copied from interface: java.util.Queue

Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions. When using a capacity-restricted queue, this method is generally preferable to Queue.add(E), which can fail to insert an element only by throwing an exception.

Specified by:

offer in interface Queue<E>

Parameters:

o - the element to add

Returns:

true if the element was added to this queue, else false

poll

public E poll()

Description copied from interface: java.util.Queue

Retrieves and removes the head of this queue, or returns null if this queue is empty.

Specified by:

poll in interface Queue<E>

Returns:

the head of this queue, or null if this queue is empty

remove

public E remove()

Description copied from interface: java.util.Queue

Retrieves and removes the head of this queue. This method differs from poll only in that it throws an exception if this queue is empty.

Specified by:

remove in interface Queue<E>

Returns:

the head of this queue

peek

public E peek()

Description copied from interface: java.util.Queue

Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty.

Specified by:

peek in interface Queue<E>

Returns:

the head of this queue, or null if this queue is empty

element

public E element()

Description copied from interface: java.util.Queue

Retrieves, but does not remove, the head of this queue. This method differs from peek only in that it throws an exception if this queue is empty.

Specified by:

element in interface Queue<E>

Returns:

the head of this queue