LinkedTransferQueue

public class LinkedTransferQueue 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.

Public Constructor Summary

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.

Public Method Summary

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, int maxElements)
Removes at most the given number of available elements from this queue and adds them to the given collection.
int
drainTo(Collection<? super E> c)
Removes all 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 take() or timed poll.
boolean
hasWaitingConsumer()
Returns true if there is at least one consumer waiting to receive an element via 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, long timeout, TimeUnit unit)
Inserts the specified element at the tail of this queue.
boolean
offer(E e)
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(long timeout, TimeUnit unit)
Retrieves and removes the head of this queue, waiting up to the specified wait time if necessary for an element to become available.
E
poll()
Retrieves and removes the head of this queue, or returns null if this queue is empty.
void
put(E e)
Inserts the specified element at the tail of this queue.
int
remainingCapacity()
Always returns Integer.MAX_VALUE because a LinkedTransferQueue is not capacity constrained.
boolean
remove(Object o)
Removes a single instance of the specified element from this queue, if it is present.
int
size()
Returns the number of elements in this queue.
Spliterator<E>
spliterator()
Returns a Spliterator over the elements in this queue.
E
take()
Retrieves and removes the head of this queue, waiting if necessary until an element becomes available.
Object[]
toArray()
Returns an array containing all of the elements in this queue, in proper sequence.
<T> T[]
toArray(T[] a)
Returns an array containing all of the elements in this queue, in proper sequence; the runtime type of the returned array is that of the specified array.
String
toString()
Returns a string representation of this collection.
void
transfer(E e)
Transfers the element to a consumer, waiting if necessary to do so.
boolean
tryTransfer(E e)
Transfers the element to a waiting consumer immediately, if possible.
boolean
tryTransfer(E e, long timeout, TimeUnit unit)
Transfers the element to a consumer if it is possible to do so before the timeout elapses.

Inherited Method Summary