| /* |
| * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| package java.lang; |
| |
| import java.util.*; |
| |
| /* |
| * Class to track and run user level shutdown hooks registered through |
| * <tt>{@link Runtime#addShutdownHook Runtime.addShutdownHook}</tt>. |
| * |
| * @see java.lang.Runtime#addShutdownHook |
| * @see java.lang.Runtime#removeShutdownHook |
| */ |
| |
| class ApplicationShutdownHooks implements Runnable { |
| private static ApplicationShutdownHooks instance = null; |
| |
| /* The set of registered hooks */ |
| private static IdentityHashMap<Thread, Thread> hooks = new IdentityHashMap<Thread, Thread>(); |
| |
| static synchronized ApplicationShutdownHooks hook() { |
| if (instance == null) |
| instance = new ApplicationShutdownHooks(); |
| |
| return instance; |
| } |
| |
| private ApplicationShutdownHooks() {} |
| |
| /* Add a new shutdown hook. Checks the shutdown state and the hook itself, |
| * but does not do any security checks. |
| */ |
| static synchronized void add(Thread hook) { |
| if(hooks == null) |
| throw new IllegalStateException("Shutdown in progress"); |
| |
| if (hook.isAlive()) |
| throw new IllegalArgumentException("Hook already running"); |
| |
| if (hooks.containsKey(hook)) |
| throw new IllegalArgumentException("Hook previously registered"); |
| |
| hooks.put(hook, hook); |
| } |
| |
| /* Remove a previously-registered hook. Like the add method, this method |
| * does not do any security checks. |
| */ |
| static synchronized boolean remove(Thread hook) { |
| if(hooks == null) |
| throw new IllegalStateException("Shutdown in progress"); |
| |
| if (hook == null) |
| throw new NullPointerException(); |
| |
| return hooks.remove(hook) != null; |
| } |
| |
| /* Iterates over all application hooks creating a new thread for each |
| * to run in. Hooks are run concurrently and this method waits for |
| * them to finish. |
| */ |
| public void run() { |
| Collection<Thread> threads; |
| synchronized(ApplicationShutdownHooks.class) { |
| threads = hooks.keySet(); |
| hooks = null; |
| } |
| |
| for (Thread hook : threads) { |
| hook.start(); |
| } |
| for (Thread hook : threads) { |
| try { |
| hook.join(); |
| } catch (InterruptedException x) { } |
| } |
| } |
| } |