diff -r fd16c54261b3 -r 90ce3da70b43 jdk/src/share/classes/sun/misc/ConditionLock.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/jdk/src/share/classes/sun/misc/ConditionLock.java Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,82 @@ +/* + * Copyright 1994-2005 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. Sun designates this + * particular file as subject to the "Classpath" exception as provided + * by Sun in the LICENSE file that accompanied this code. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + */ + +package sun.misc; + +/** + * ConditionLock is a Lock with a built in state variable. This class + * provides the ability to wait for the state variable to be set to a + * desired value and then acquire the lock.

+ * + * The lockWhen() and unlockWith() methods can be safely intermixed + * with the lock() and unlock() methods. However if there is a thread + * waiting for the state variable to become a particular value and you + * simply call Unlock(), that thread will not be able to acquire the + * lock until the state variable equals its desired value.

+ * + * @author Peter King + */ +public final +class ConditionLock extends Lock { + private int state = 0; + + /** + * Creates a ConditionLock. + */ + public ConditionLock () { + } + + /** + * Creates a ConditionLock in an initialState. + */ + public ConditionLock (int initialState) { + state = initialState; + } + + /** + * Acquires the lock when the state variable equals the desired state. + * + * @param desiredState the desired state + * @exception java.lang.InterruptedException if any thread has + * interrupted this thread. + */ + public synchronized void lockWhen(int desiredState) + throws InterruptedException + { + while (state != desiredState) { + wait(); + } + lock(); + } + + /** + * Releases the lock, and sets the state to a new value. + * @param newState the new state + */ + public synchronized void unlockWith(int newState) { + state = newState; + unlock(); + } +}