83 lines
2.7 KiB
Java
83 lines
2.7 KiB
Java
/*
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* Copyright (c) 1994, 2005, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.misc;
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/**
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* ConditionLock is a Lock with a built in state variable. This class
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* provides the ability to wait for the state variable to be set to a
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* desired value and then acquire the lock.<p>
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*
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* The lockWhen() and unlockWith() methods can be safely intermixed
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* with the lock() and unlock() methods. However if there is a thread
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* waiting for the state variable to become a particular value and you
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* simply call Unlock(), that thread will not be able to acquire the
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* lock until the state variable equals its desired value. <p>
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*
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* @author Peter King
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*/
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public final
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class ConditionLock extends Lock {
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private int state = 0;
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/**
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* Creates a ConditionLock.
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*/
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public ConditionLock () {
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}
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/**
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* Creates a ConditionLock in an initialState.
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*/
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public ConditionLock (int initialState) {
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state = initialState;
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}
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/**
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* Acquires the lock when the state variable equals the desired state.
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*
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* @param desiredState the desired state
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* @exception java.lang.InterruptedException if any thread has
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* interrupted this thread.
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*/
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public synchronized void lockWhen(int desiredState)
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throws InterruptedException
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{
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while (state != desiredState) {
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wait();
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}
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lock();
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}
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/**
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* Releases the lock, and sets the state to a new value.
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* @param newState the new state
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*/
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public synchronized void unlockWith(int newState) {
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state = newState;
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unlock();
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}
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}
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