115 lines
3.8 KiB
Java
115 lines
3.8 KiB
Java
/*
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* Copyright (c) 2005, 2010, 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 java.lang;
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import java.util.*;
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/*
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* Class to track and run user level shutdown hooks registered through
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* {@link Runtime#addShutdownHook Runtime.addShutdownHook}.
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*
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* @see java.lang.Runtime#addShutdownHook
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* @see java.lang.Runtime#removeShutdownHook
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*/
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class ApplicationShutdownHooks {
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/* The set of registered hooks */
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private static IdentityHashMap<Thread, Thread> hooks;
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static {
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try {
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Shutdown.add(1 /* shutdown hook invocation order */,
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false /* not registered if shutdown in progress */,
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new Runnable() {
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public void run() {
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runHooks();
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}
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}
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);
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hooks = new IdentityHashMap<>();
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} catch (IllegalStateException e) {
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// application shutdown hooks cannot be added if
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// shutdown is in progress.
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hooks = null;
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}
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}
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private ApplicationShutdownHooks() {}
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/* Add a new shutdown hook. Checks the shutdown state and the hook itself,
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* but does not do any security checks.
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*/
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static synchronized void add(Thread hook) {
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if(hooks == null)
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throw new IllegalStateException("Shutdown in progress");
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if (hook.isAlive())
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throw new IllegalArgumentException("Hook already running");
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if (hooks.containsKey(hook))
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throw new IllegalArgumentException("Hook previously registered");
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hooks.put(hook, hook);
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}
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/* Remove a previously-registered hook. Like the add method, this method
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* does not do any security checks.
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*/
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static synchronized boolean remove(Thread hook) {
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if(hooks == null)
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throw new IllegalStateException("Shutdown in progress");
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if (hook == null)
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throw new NullPointerException();
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return hooks.remove(hook) != null;
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}
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/* Iterates over all application hooks creating a new thread for each
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* to run in. Hooks are run concurrently and this method waits for
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* them to finish.
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*/
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static void runHooks() {
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Collection<Thread> threads;
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synchronized(ApplicationShutdownHooks.class) {
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threads = hooks.keySet();
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hooks = null;
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}
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for (Thread hook : threads) {
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hook.start();
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}
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for (Thread hook : threads) {
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while (true) {
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try {
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hook.join();
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break;
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} catch (InterruptedException ignored) {
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}
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}
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}
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}
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}
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