org.glassfish.grizzly.utils
Class LinkedTransferQueue<E>

java.lang.Object
  extended by java.util.AbstractCollection<E>
      extended by java.util.AbstractQueue<E>
          extended by org.glassfish.grizzly.utils.LinkedTransferQueue<E>
Type Parameters:
E - the type of elements held in this collection
All Implemented Interfaces:
Serializable, Iterable<E>, Collection<E>, BlockingQueue<E>, Queue<E>, TransferQueue<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.

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.
version 1.17 Tue Mar 31 15:17:19 2009 UTC ( gustav trede copied from jsr166 CVS )

Since:
1.7
Author:
Doug Lea
See Also:
Serialized Form

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.
 
Method Summary
 boolean add(E e)
           
 int drainTo(Collection<? super E> c)
           
 int drainTo(Collection<? super E> c, int maxElements)
           
 int getWaitingConsumerCount()
          Returns an estimate of the number of consumers waiting to dequeue elements via take or poll.
 boolean hasWaitingConsumer()
          Returns true if there is at least one consumer waiting to dequeue an element via take or poll.
 boolean isEmpty()
           
 Iterator<E> iterator()
           
 boolean offer(E e)
           
 boolean offer(E e, long timeout, TimeUnit unit)
           
 E peek()
           
 E poll()
           
 E poll(long timeout, TimeUnit unit)
           
 void put(E e)
           
 int remainingCapacity()
           
 boolean remove(Object o)
           
 int size()
          Returns the number of elements in this queue.
 E take()
           
 void transfer(E e)
          Inserts the specified element into this queue, waiting if necessary for space to become available and the element to be dequeued by a consumer invoking take or poll.
 boolean tryTransfer(E e)
          Transfers the specified element if there exists a consumer already waiting to receive it, otherwise returning false without enqueuing the element.
 boolean tryTransfer(E e, long timeout, TimeUnit unit)
          Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available and the element to be dequeued by a consumer invoking take or poll.
 
Methods inherited from class java.util.AbstractQueue
addAll, clear, element, remove
 
Methods inherited from class java.util.AbstractCollection
contains, containsAll, removeAll, retainAll, toArray, toArray, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.concurrent.BlockingQueue
contains
 
Methods inherited from interface java.util.Queue
element, remove
 
Methods inherited from interface java.util.Collection
addAll, clear, containsAll, equals, hashCode, removeAll, retainAll, toArray, toArray
 

Constructor Detail

LinkedTransferQueue

public LinkedTransferQueue()
Creates an initially empty LinkedTransferQueue.


LinkedTransferQueue

public 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.

Parameters:
c - the collection of elements to initially contain
Throws:
NullPointerException - if the specified collection or any of its elements are null
Method Detail

put

public void put(E e)
         throws InterruptedException
Specified by:
put in interface BlockingQueue<E>
Throws:
InterruptedException

offer

public boolean offer(E e,
                     long timeout,
                     TimeUnit unit)
              throws InterruptedException
Specified by:
offer in interface BlockingQueue<E>
Throws:
InterruptedException

offer

public boolean offer(E e)
Specified by:
offer in interface BlockingQueue<E>
Specified by:
offer in interface Queue<E>

add

public boolean add(E e)
Specified by:
add in interface Collection<E>
Specified by:
add in interface BlockingQueue<E>
Specified by:
add in interface Queue<E>
Overrides:
add in class AbstractQueue<E>

transfer

public void transfer(E e)
              throws InterruptedException
Description copied from interface: TransferQueue
Inserts the specified element into this queue, waiting if necessary for space to become available and the element to be dequeued by a consumer invoking take or poll.

Specified by:
transfer in interface TransferQueue<E>
Parameters:
e - the element to transfer
Throws:
InterruptedException - if interrupted while waiting, in which case the element is not enqueued.

tryTransfer

public boolean tryTransfer(E e,
                           long timeout,
                           TimeUnit unit)
                    throws InterruptedException
Description copied from interface: TransferQueue
Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available and the element to be dequeued by a consumer invoking take or poll.

Specified by:
tryTransfer in interface TransferQueue<E>
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 enqueued.
Throws:
InterruptedException - if interrupted while waiting, in which case the element is not enqueued.

tryTransfer

public boolean tryTransfer(E e)
Description copied from interface: TransferQueue
Transfers the specified element if there exists a consumer already waiting to receive it, otherwise returning false without enqueuing the element.

Specified by:
tryTransfer in interface TransferQueue<E>
Parameters:
e - the element to transfer
Returns:
true if the element was transferred, else false

take

public E take()
       throws InterruptedException
Specified by:
take in interface BlockingQueue<E>
Throws:
InterruptedException

poll

public E poll(long timeout,
              TimeUnit unit)
       throws InterruptedException
Specified by:
poll in interface BlockingQueue<E>
Throws:
InterruptedException

poll

public E poll()
Specified by:
poll in interface Queue<E>

drainTo

public int drainTo(Collection<? super E> c)
Specified by:
drainTo in interface BlockingQueue<E>

drainTo

public int drainTo(Collection<? super E> c,
                   int maxElements)
Specified by:
drainTo in interface BlockingQueue<E>

iterator

public Iterator<E> iterator()
Specified by:
iterator in interface Iterable<E>
Specified by:
iterator in interface Collection<E>
Specified by:
iterator in class AbstractCollection<E>

peek

public E peek()
Specified by:
peek in interface Queue<E>

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in interface Collection<E>
Overrides:
isEmpty in class AbstractCollection<E>

hasWaitingConsumer

public boolean hasWaitingConsumer()
Description copied from interface: TransferQueue
Returns true if there is at least one consumer waiting to dequeue an element via take or poll. The return value represents a momentary state of affairs.

Specified by:
hasWaitingConsumer in interface TransferQueue<E>
Returns:
true if there is at least one waiting consumer

size

public int size()
Returns the number of elements in this queue. If this queue contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Beware that, unlike in most collections, this method is NOT a constant-time operation. Because of the asynchronous nature of these queues, determining the current number of elements requires an O(n) traversal.

Specified by:
size in interface Collection<E>
Specified by:
size in class AbstractCollection<E>
Returns:
the number of elements in this queue

getWaitingConsumerCount

public int getWaitingConsumerCount()
Description copied from interface: TransferQueue
Returns an estimate of the number of consumers waiting to dequeue elements via take or 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 TransferQueue.hasWaitingConsumer().

Specified by:
getWaitingConsumerCount in interface TransferQueue<E>
Returns:
the number of consumers waiting to dequeue elements

remainingCapacity

public int remainingCapacity()
Specified by:
remainingCapacity in interface BlockingQueue<E>

remove

public boolean remove(Object o)
Specified by:
remove in interface Collection<E>
Specified by:
remove in interface BlockingQueue<E>
Overrides:
remove in class AbstractCollection<E>


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