/*
* Copyright (c) 1994, 2005, Oracle and/or its affiliates. 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
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.<p>
*
* 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. <p>
*
* @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();
}
}