java.util.concurrent

Class LinkedTransferQueue<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<E>

java.util.concurrent.LinkedTransferQueue<E>

Type Parameters:

E - the type of elements held in this collection

All Implemented Interfaces:

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

public class LinkedTransferQueue<E>
extends AbstractQueue<E>
implements TransferQueue<E>, Serializable

An unbounded TransferQueue based on linked nodes. This queue orders elements FIFO (first-in-first-out) with respect to any given producer. The head of the queue is that element that has been on the queue the longest time for some producer. The tail of the queue is that element that has been on the queue the shortest time for some producer.

Beware that, unlike in most collections, the size method is NOT a constant-time operation. Because of the asynchronous nature of these queues, determining the current number of elements requires a traversal of the elements, and so may report inaccurate results if this collection is modified during traversal. Additionally, the bulk operations addAll, removeAll, retainAll, containsAll, equals, and toArray are not guaranteed to be performed atomically. For example, an iterator operating concurrently with an addAll operation might view only some of the added elements.

This class and its iterator implement all of the optional methods of the Collection and Iterator interfaces.

Memory consistency effects: As with other concurrent collections, actions in a thread prior to placing an object into a LinkedTransferQueue happen-before actions subsequent to the access or removal of that element from the LinkedTransferQueue in another thread.

This class is a member of the Java Collections Framework.

Since:

1.7

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
LinkedTransferQueue() Creates an initially empty LinkedTransferQueue.
LinkedTransferQueue(Collection<? extends E> c) Creates a LinkedTransferQueue initially containing the elements of the given collection, added in traversal order of the collection's iterator.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(E e) Inserts the specified element at the tail of this queue.
boolean	contains(Object o) Returns true if this queue contains the specified element.
int	drainTo(Collection<? super E> c) Removes all available elements from this queue and adds them to the given collection.
int	drainTo(Collection<? super E> c, int maxElements) Removes at most the given number of available elements from this queue and adds them to the given collection.
int	getWaitingConsumerCount() Returns an estimate of the number of consumers waiting to receive elements via BlockingQueue.take() or timed poll.
boolean	hasWaitingConsumer() Returns true if there is at least one consumer waiting to receive an element via BlockingQueue.take() or timed poll.
boolean	isEmpty() Returns true if this queue contains no elements.
Iterator<E>	iterator() Returns an iterator over the elements in this queue in proper sequence.
boolean	offer(E e) Inserts the specified element at the tail of this queue.
boolean	offer(E e, long timeout, TimeUnit unit) Inserts the specified element at the tail of this queue.
E	peek() Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty.
E	poll() Retrieves and removes the head of this queue, or returns null if this queue is empty.
E	poll(long timeout,