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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/licenses/publicdomain
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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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}
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