com.oracle.common.base

Class SingleWaiterMultiNotifier

java.lang.Object

com.oracle.common.base.SingleWaiterMultiNotifier

All Implemented Interfaces:

Notifier

Direct Known Subclasses:

SingleWaiterCooperativeNotifier

public class SingleWaiterMultiNotifier
extends Object
implements Notifier

A Condition-like object, used by a single thread to block for a notification, and optimized for many concurrent notifications by other threads. Basically, this is a blocking queue without any state to actually enqueue: the await() method is analogous to an imaginary "take all" variant of the BlockingQueue.take() method, and the signal() method is analogous to BlockingQueue.put().

Note that no synchronization is needed to use this class; i.e. clients must not synchronize on this class prior to calling await() or signal(), nor should the use any of the primitive wait() or notify() methods.

Author:

cp/mf 2010-06-15

Field Summary

Fields

Modifier and Type	Field and Description
protected Object	m_oState The signaling state, null for unsignaled, this for signaled, or a thread for the single awaiting thread

Constructor Summary

Constructors

Constructor and Description
SingleWaiterMultiNotifier()

Method Summary

Modifier and Type	Method and Description
void	await() Wait for a notification (which may have already occurred).
void	await(long cMillis) Wait for a notification (which may have already occurred).
protected void	consumeSignal() Consume the signal.
Thread	getWaitingThread() Return the thread which is waiting on this notifier.
void	signal() Notifies the waiting thread(s), waking them up if awaiting, or preventing the next thread from going to sleep on the next await attempt.
protected Thread	signalInternal() Signal the notifier returning any thread which needs to be unparked.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

m_oState

protected volatile Object m_oState

The signaling state, null for unsignaled, this for signaled, or a thread for the single awaiting thread

Constructor Detail

SingleWaiterMultiNotifier

public SingleWaiterMultiNotifier()

Method Detail

await

public void await()
           throws InterruptedException

Description copied from interface: Notifier

Wait for a notification (which may have already occurred). Note that spurious wake-ups are possible.

Specified by:

await in interface Notifier

Throws:

InterruptedException - if the calling thread is interrupted while it is waiting

await

public void await(long cMillis)
           throws InterruptedException

Description copied from interface: Notifier

Wait for a notification (which may have already occurred). Note that spurious wake-ups are possible.

Specified by:

await in interface Notifier

Parameters:

cMillis - the maximum wait time in milliseconds, or zero for indefinite

Throws:

InterruptedException - if the calling thread is interrupted while it is waiting

signal

public void signal()

Description copied from interface: Notifier

Notifies the waiting thread(s), waking them up if awaiting, or preventing the next thread from going to sleep on the next await attempt.

Specified by:

signal in interface Notifier

toString

public String toString()

Overrides:

toString in class Object

getWaitingThread

public Thread getWaitingThread()

Return the thread which is waiting on this notifier.

Returns:

the waiting thread or null

signalInternal

protected Thread signalInternal()

Signal the notifier returning any thread which needs to be unparked.

Returns:

a the thread if any which needs to be unparked.

consumeSignal

protected void consumeSignal()

Consume the signal.