rt/emul/compact/src/main/java/java/util/concurrent/locks/AbstractOwnableSynchronizer.java
author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
Sat, 19 Mar 2016 10:46:31 +0100
branchjdk7-b147
changeset 1890 212417b74b72
permissions -rw-r--r--
Bringing in all concurrent package from JDK7-b147
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/*
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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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/*
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 * This file is available under and governed by the GNU General Public
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 * License version 2 only, as published by the Free Software Foundation.
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 * However, the following notice accompanied the original version of this
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 * file:
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 *
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 * Written by Doug Lea with assistance from members of JCP JSR-166
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 * Expert Group and released to the public domain, as explained at
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 * http://creativecommons.org/publicdomain/zero/1.0/
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 */
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package java.util.concurrent.locks;
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/**
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 * A synchronizer that may be exclusively owned by a thread.  This
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 * class provides a basis for creating locks and related synchronizers
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 * that may entail a notion of ownership.  The
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 * <tt>AbstractOwnableSynchronizer</tt> class itself does not manage or
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 * use this information. However, subclasses and tools may use
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 * appropriately maintained values to help control and monitor access
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 * and provide diagnostics.
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 *
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 * @since 1.6
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 * @author Doug Lea
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 */
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public abstract class AbstractOwnableSynchronizer
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    implements java.io.Serializable {
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    /** Use serial ID even though all fields transient. */
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    private static final long serialVersionUID = 3737899427754241961L;
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    /**
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     * Empty constructor for use by subclasses.
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     */
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    protected AbstractOwnableSynchronizer() { }
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    /**
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     * The current owner of exclusive mode synchronization.
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     */
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    private transient Thread exclusiveOwnerThread;
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    /**
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     * Sets the thread that currently owns exclusive access. A
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     * <tt>null</tt> argument indicates that no thread owns access.
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     * This method does not otherwise impose any synchronization or
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     * <tt>volatile</tt> field accesses.
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     */
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    protected final void setExclusiveOwnerThread(Thread t) {
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        exclusiveOwnerThread = t;
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    }
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    /**
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     * Returns the thread last set by
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     * <tt>setExclusiveOwnerThread</tt>, or <tt>null</tt> if never
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     * set.  This method does not otherwise impose any synchronization
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     * or <tt>volatile</tt> field accesses.
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     * @return the owner thread
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     */
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    protected final Thread getExclusiveOwnerThread() {
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        return exclusiveOwnerThread;
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    }
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}