EDU.oswego.cs.dl.util.concurrent

Class ObservableSync

public class ObservableSync extends Object implements Sync

The ObservableSync class performs no synchronization itself, but invokes event-style messages to other observer objects upon invocation of Sync methods. These observers typically perform monitoring, logging, or other bookkeeping operations surrounding the object being managed by this Sync object.

Because ObservableSync does not itself perform any synchronization control, the attempt operation always succeeds. This class is typically used (via LayeredSync) as a wrapper around those that do perform synchronization control.

This class is based around a standard Observer design pattern. It is not hard to convert this to instead use a Listener design (as seen in AWT and JavaBeans), by defining associated EventObjects and forwarding them.

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See Also:

Nested Class Summary
interface	ObservableSync.SyncObserver Interface for objects that observe ObservableSyncs.

Field Summary
protected Object	arg_
protected CopyOnWriteArraySet	observers_

Constructor Summary
	ObservableSync(Object notificationArgument) Create an ObservableSync that uses the supplied argument for all notifications.

Method Summary
void	acquire()
void	attach(ObservableSync.SyncObserver obs) Add obs to the set of observers *
boolean	attempt(long msecs)
void	detach(ObservableSync.SyncObserver obs) Remove obs from the set of observers.
Object	getNotificationArgument() Return the argument used for notifications
Iterator	observers() Return an iterator that can be used to traverse through current set of observers
void	release()
Object	setNotificationArgument(Object notificationArg) Set the argument used for notifications.

Returns: the previous value of this argument

Class ObservableSync

Field Detail

arg_

observers_

Constructor Detail

ObservableSync

Method Detail

acquire

attach

attempt

detach

getNotificationArgument

observers

release

setNotificationArgument