jdk/src/java.base/share/classes/sun/misc/ConditionLock.java
author chegar
Sun, 17 Aug 2014 15:54:13 +0100
changeset 25859 3317bb8137f4
parent 5506 jdk/src/share/classes/sun/misc/ConditionLock.java@202f599c92aa
child 30655 d83f50188ca9
permissions -rw-r--r--
8054834: Modular Source Code Reviewed-by: alanb, chegar, ihse, mduigou Contributed-by: alan.bateman@oracle.com, alex.buckley@oracle.com, chris.hegarty@oracle.com, erik.joelsson@oracle.com, jonathan.gibbons@oracle.com, karen.kinnear@oracle.com, magnus.ihse.bursie@oracle.com, mandy.chung@oracle.com, mark.reinhold@oracle.com, paul.sandoz@oracle.com
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/*
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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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}