AbstractOwnableSynchronizer

AI-generated Key Takeaways

• AbstractOwnableSynchronizer is a base class for creating synchronizers with an ownership concept, allowing subclasses to manage and monitor access.

• It provides methods to get and set the thread that exclusively owns the synchronizer.

• Subclasses like AbstractQueuedSynchronizer and AbstractQueuedLongSynchronizer utilize this framework to build locks and other synchronization primitives.

• Although AbstractOwnableSynchronizer itself doesn't manage the ownership information, it enables tools and subclasses to control and diagnose access.

• It offers a protected empty constructor for subclass instantiation and protected methods for exclusive owner thread management.

public abstract class AbstractOwnableSynchronizer extends Object
implements Serializable

Known Direct Subclasses AbstractQueuedLongSynchronizer, AbstractQueuedSynchronizer AbstractQueuedLongSynchronizer A version of AbstractQueuedSynchronizer in which synchronization state is maintained as a long.  AbstractQueuedSynchronizer Provides a framework for implementing blocking locks and related synchronizers (semaphores, events, etc) that rely on first-in-first-out (FIFO) wait queues.

A synchronizer that may be exclusively owned by a thread. This class provides a basis for creating locks and related synchronizers that may entail a notion of ownership. The AbstractOwnableSynchronizer class itself does not manage or use this information. However, subclasses and tools may use appropriately maintained values to help control and monitor access and provide diagnostics.

Protected Constructor Summary

AbstractOwnableSynchronizer() Empty constructor for use by subclasses.

Protected Method Summary

final Thread	getExclusiveOwnerThread() Returns the thread last set by setExclusiveOwnerThread, or null if never set.
final void	setExclusiveOwnerThread(Thread thread) Sets the thread that currently owns exclusive access.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Protected Constructors

protected AbstractOwnableSynchronizer ()

Empty constructor for use by subclasses.

Protected Methods

protected final Thread getExclusiveOwnerThread ()

Returns the thread last set by setExclusiveOwnerThread, or null if never set. This method does not otherwise impose any synchronization or volatile field accesses.

Returns

• the owner thread

protected final void setExclusiveOwnerThread (Thread thread)

Sets the thread that currently owns exclusive access. A null argument indicates that no thread owns access. This method does not otherwise impose any synchronization or volatile field accesses.

Parameters

thread	the owner thread