Type Parameters:

E - the type of elements held in this collection

All Superinterfaces:

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

All Known Implementing Classes:

LinkedTransferQueue

public interface TransferQueue<E>
extends BlockingQueue<E>

Since:

1.7

• Method Summary

  Methods

  Modifier and Type	Method and Description
  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.
  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.

  • Methods inherited from interface java.util.concurrent.BlockingQueue

    add, contains, drainTo, drainTo, offer, offer, poll, put, remainingCapacity, remove, take

  • Methods inherited from interface java.util.Queue

    element, peek, poll, remove

  • Methods inherited from interface java.util.Collection

    addAll, clear, containsAll, equals, hashCode, isEmpty, iterator, removeAll, retainAll, size, toArray, toArray

• Method Detail

  • tryTransfer

    boolean tryTransfer(E e)

    Transfers the element to a waiting consumer immediately, if possible.

    More precisely, transfers the specified element immediately if there exists a consumer already waiting to receive it (in BlockingQueue.take() or timed poll), otherwise returning false without enqueuing the element.

    Parameters:

    e - the element to transfer

    Returns:

    true if the element was transferred, else false

    Throws:

    ClassCastException - if the class of the specified element prevents it from being added to this queue

    NullPointerException - if the specified element is null

    IllegalArgumentException - if some property of the specified element prevents it from being added to this queue

  • transfer

    void transfer(E e)
     throws InterruptedException 

    Transfers the element to a consumer, waiting if necessary to do so.

    More precisely, transfers the specified element immediately if there exists a consumer already waiting to receive it (in BlockingQueue.take() or timed poll), else waits until the element is received by a consumer.

    Parameters:

    e - the element to transfer

    Throws:

    InterruptedException - if interrupted while waiting, in which case the element is not left enqueued

    ClassCastException - if the class of the specified element prevents it from being added to this queue

    NullPointerException - if the specified element is null

    IllegalArgumentException - if some property of the specified element prevents it from being added to this queue

  • tryTransfer

    boolean tryTransfer(E e,
     long timeout,
     TimeUnit unit)
     throws InterruptedException 

    Transfers the element to a consumer if it is possible to do so before the timeout elapses.

    More precisely, transfers the specified element immediately if there exists a consumer already waiting to receive it (in BlockingQueue.take() or timed poll), else waits until the element is received by a consumer, returning false if the specified wait time elapses before the element can be transferred.

    Parameters:

    e - the element to transfer

    timeout - how long to wait before giving up, in units of unit

    unit - a TimeUnit determining how to interpret the timeout parameter

    Returns:

    true if successful, or false if the specified waiting time elapses before completion, in which case the element is not left enqueued

    Throws:

    InterruptedException - if interrupted while waiting, in which case the element is not left enqueued

    ClassCastException - if the class of the specified element prevents it from being added to this queue

    NullPointerException - if the specified element is null

    IllegalArgumentException - if some property of the specified element prevents it from being added to this queue

  • hasWaitingConsumer

    boolean hasWaitingConsumer()

    Returns true if there is at least one consumer waiting to receive an element via BlockingQueue.take() or timed poll. The return value represents a momentary state of affairs.

    Returns:

    true if there is at least one waiting consumer

  • getWaitingConsumerCount

    int getWaitingConsumerCount()

    Returns an estimate of the number of consumers waiting to receive elements via BlockingQueue.take() or timed poll. The return value is an approximation of a momentary state of affairs, that may be inaccurate if consumers have completed or given up waiting. The value may be useful for monitoring and heuristics, but not for synchronization control. Implementations of this method are likely to be noticeably slower than those for hasWaitingConsumer().

    Returns:

    the number of consumers waiting to receive elements