Mercurial > hg > blitz_condensed
diff src/EDU/oswego/cs/dl/util/concurrent/WaitableRef.java @ 0:3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
author | Dan Creswell <dan.creswell@gmail.com> |
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date | Sat, 21 Mar 2009 11:00:06 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/EDU/oswego/cs/dl/util/concurrent/WaitableRef.java Sat Mar 21 11:00:06 2009 +0000 @@ -0,0 +1,102 @@ +/* + File: WaitableRef.java + + Originally written by Doug Lea and released into the public domain. + This may be used for any purposes whatsoever without acknowledgment. + Thanks for the assistance and support of Sun Microsystems Labs, + and everyone contributing, testing, and using this code. + + History: + Date Who What + 19Jun1998 dl Create public version +*/ + +package EDU.oswego.cs.dl.util.concurrent; + +/** + * A class useful for offloading synch for Object reference instance variables. + * + * <p>[<a href="http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html"> Introduction to this package. </a>] + **/ + +public class WaitableRef extends SynchronizedRef { + + /** + * Create a WaitableRef initially holding the given reference + * and using its own internal lock. + **/ + public WaitableRef(Object initialValue) { + super(initialValue); + } + + /** + * Make a new WaitableRef with the given initial value, + * and using the supplied lock. + **/ + public WaitableRef(Object initialValue, Object lock) { + super(initialValue, lock); + } + + public Object set(Object newValue) { + synchronized (lock_) { + lock_.notifyAll(); + return super.set(newValue); + } + } + + public boolean commit(Object assumedValue, Object newValue) { + synchronized (lock_) { + boolean success = super.commit(assumedValue, newValue); + if (success) lock_.notifyAll(); + return success; + } + } + + /** + * Wait until value is null, then run action if nonnull. + * The action is run with the synchronization lock held. + **/ + + public void whenNull(Runnable action) throws InterruptedException { + synchronized (lock_) { + while (value_ != null) lock_.wait(); + if (action != null) action.run(); + } + } + + /** + * wait until value is nonnull, then run action if nonnull. + * The action is run with the synchronization lock held. + **/ + public void whenNotNull(Runnable action) throws InterruptedException { + synchronized (lock_) { + while (value_ == null) lock_.wait(); + if (action != null) action.run(); + } + } + + /** + * Wait until value equals c, then run action if nonnull. + * The action is run with the synchronization lock held. + **/ + + public void whenEqual(Object c, Runnable action) throws InterruptedException { + synchronized (lock_) { + while (!(value_ == c)) lock_.wait(); + if (action != null) action.run(); + } + } + + /** + * wait until value not equal to c, then run action if nonnull. + * The action is run with the synchronization lock held. + **/ + public void whenNotEqual(Object c, Runnable action) throws InterruptedException { + synchronized (lock_) { + while (!(value_ != c)) lock_.wait(); + if (action != null) action.run(); + } + } + +} +