java.util.concurrent
Class SynchronousQueue.Node

java.lang.Object
  java.util.concurrent.locks.AbstractQueuedSynchronizer
      java.util.concurrent.SynchronousQueue.Node

All Implemented Interfaces:

Serializable

Enclosing class:

SynchronousQueue<E>

static final class SynchronousQueue.Node
extends AbstractQueuedSynchronizer

Nodes each maintain an item and handle waits and signals for getting and setting it. The class extends AbstractQueuedSynchronizer to manage blocking, using AQS state 0 for waiting, 1 for ack, -1 for cancelled.

Nested Class Summary

Nested classes/interfaces inherited from class java.util.concurrent.locks.AbstractQueuedSynchronizer

AbstractQueuedSynchronizer.ConditionObject

Field Summary

(package private) Object	item The item being transferred
(package private) SynchronousQueue.Node	next Next node in wait queue

Constructor Summary

SynchronousQueue.Node(Object x)
Creates a node with initial item

SynchronousQueue.Node(Object x, SynchronousQueue.Node n)
Creates a node with initial item and next

Method Summary

(package private) Object	getItem() Removes item from slot created by producer and signal producer to continue.
(package private) boolean	setItem(Object x) Fills in the slot created by the consumer and signal consumer to continue.
protected boolean	tryAcquire(int ignore) Implements AQS base acquire to succeed if not in WAITING state
protected boolean	tryRelease(int newState) Implements AQS base release to signal if state changed
(package private) Object	waitForPut() Waits for a producer to put item placed by consumer.
(package private) Object	waitForPut(long nanos) Waits for a producer to put item placed by consumer, or time out.
(package private) void	waitForTake() Waits for a consumer to take item placed by producer.
(package private) boolean	waitForTake(long nanos) Waits for a consumer to take item placed by producer or time out.

Methods inherited from class java.util.concurrent.locks.AbstractQueuedSynchronizer

acquire, acquireInterruptibly, acquireShared, acquireSharedInterruptibly, compareAndSetState, getExclusiveQueuedThreads, getFirstQueuedThread, getQueuedThreads, getQueueLength, getSharedQueuedThreads, getState, getWaitingThreads, getWaitQueueLength, hasContended, hasQueuedThreads, hasWaiters, isHeldExclusively, isQueued, owns, release, releaseShared, setState, toString, tryAcquireNanos, tryAcquireShared, tryAcquireSharedNanos, tryReleaseShared

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

item

Object item

The item being transferred

next

SynchronousQueue.Node next

Next node in wait queue

Constructor Detail

SynchronousQueue.Node

SynchronousQueue.Node(Object x)

Creates a node with initial item

SynchronousQueue.Node

SynchronousQueue.Node(Object x,
                      SynchronousQueue.Node n)

Creates a node with initial item and next

Method Detail

tryAcquire

protected boolean tryAcquire(int ignore)

Implements AQS base acquire to succeed if not in WAITING state

Overrides:

tryAcquire in class AbstractQueuedSynchronizer

Parameters:

ignore - the acquire argument. This value is always the one passed to an acquire method, or is the value saved on entry to a condition wait. The value is otherwise uninterpreted and can represent anything you like.

Returns:

true if successful. Upon success, this object has been acquired.

tryRelease

protected boolean tryRelease(int newState)

Implements AQS base release to signal if state changed

Overrides:

tryRelease in class AbstractQueuedSynchronizer

Parameters:

newState - the release argument. This value is always the one passed to a release method, or the current state value upon entry to a condition wait. The value is otherwise uninterpreted and can represent anything you like.

Returns:

true if this object is now in a fully released state, so that any waiting threads may attempt to acquire; and false otherwise.

setItem

boolean setItem(Object x)

Fills in the slot created by the consumer and signal consumer to continue.

getItem

Object getItem()

Removes item from slot created by producer and signal producer to continue.

waitForTake

void waitForTake()
           throws InterruptedException

Waits for a consumer to take item placed by producer.

Throws:

InterruptedException

waitForPut

Object waitForPut()
            throws InterruptedException

Waits for a producer to put item placed by consumer.

Throws:

InterruptedException

waitForTake

boolean waitForTake(long nanos)
              throws InterruptedException

Waits for a consumer to take item placed by producer or time out.

Throws:

InterruptedException

waitForPut

Object waitForPut(long nanos)
            throws InterruptedException

Waits for a producer to put item placed by consumer, or time out.

Throws:

InterruptedException