Jake Slack | 03928ae | 2014-05-13 18:41:56 -0700 | [diff] [blame] | 1 | // |
| 2 | // ======================================================================== |
| 3 | // Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd. |
| 4 | // ------------------------------------------------------------------------ |
| 5 | // All rights reserved. This program and the accompanying materials |
| 6 | // are made available under the terms of the Eclipse Public License v1.0 |
| 7 | // and Apache License v2.0 which accompanies this distribution. |
| 8 | // |
| 9 | // The Eclipse Public License is available at |
| 10 | // http://www.eclipse.org/legal/epl-v10.html |
| 11 | // |
| 12 | // The Apache License v2.0 is available at |
| 13 | // http://www.opensource.org/licenses/apache2.0.php |
| 14 | // |
| 15 | // You may elect to redistribute this code under either of these licenses. |
| 16 | // ======================================================================== |
| 17 | // |
| 18 | |
| 19 | package org.eclipse.jetty.util.thread; |
| 20 | |
| 21 | import java.util.Arrays; |
| 22 | import java.util.List; |
| 23 | import java.util.concurrent.CopyOnWriteArrayList; |
| 24 | |
| 25 | import org.eclipse.jetty.util.component.Destroyable; |
| 26 | import org.eclipse.jetty.util.component.LifeCycle; |
| 27 | import org.eclipse.jetty.util.log.Log; |
| 28 | import org.eclipse.jetty.util.log.Logger; |
| 29 | |
| 30 | |
| 31 | /* ------------------------------------------------------------ */ |
| 32 | /** |
| 33 | * ShutdownThread is a shutdown hook thread implemented as |
| 34 | * singleton that maintains a list of lifecycle instances |
| 35 | * that are registered with it and provides ability to stop |
| 36 | * these lifecycles upon shutdown of the Java Virtual Machine |
| 37 | */ |
| 38 | public class ShutdownThread extends Thread |
| 39 | { |
| 40 | private static final Logger LOG = Log.getLogger(ShutdownThread.class); |
| 41 | private static final ShutdownThread _thread = new ShutdownThread(); |
| 42 | |
| 43 | private boolean _hooked; |
| 44 | private final List<LifeCycle> _lifeCycles = new CopyOnWriteArrayList<LifeCycle>(); |
| 45 | |
| 46 | /* ------------------------------------------------------------ */ |
| 47 | /** |
| 48 | * Default constructor for the singleton |
| 49 | * |
| 50 | * Registers the instance as shutdown hook with the Java Runtime |
| 51 | */ |
| 52 | private ShutdownThread() |
| 53 | { |
| 54 | } |
| 55 | |
| 56 | /* ------------------------------------------------------------ */ |
| 57 | private synchronized void hook() |
| 58 | { |
| 59 | try |
| 60 | { |
| 61 | if (!_hooked) |
| 62 | Runtime.getRuntime().addShutdownHook(this); |
| 63 | _hooked=true; |
| 64 | } |
| 65 | catch(Exception e) |
| 66 | { |
| 67 | LOG.ignore(e); |
| 68 | LOG.info("shutdown already commenced"); |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | /* ------------------------------------------------------------ */ |
| 73 | private synchronized void unhook() |
| 74 | { |
| 75 | try |
| 76 | { |
| 77 | _hooked=false; |
| 78 | Runtime.getRuntime().removeShutdownHook(this); |
| 79 | } |
| 80 | catch(Exception e) |
| 81 | { |
| 82 | LOG.ignore(e); |
| 83 | LOG.debug("shutdown already commenced"); |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | /* ------------------------------------------------------------ */ |
| 88 | /** |
| 89 | * Returns the instance of the singleton |
| 90 | * |
| 91 | * @return the singleton instance of the {@link ShutdownThread} |
| 92 | */ |
| 93 | public static ShutdownThread getInstance() |
| 94 | { |
| 95 | return _thread; |
| 96 | } |
| 97 | |
| 98 | /* ------------------------------------------------------------ */ |
| 99 | public static synchronized void register(LifeCycle... lifeCycles) |
| 100 | { |
| 101 | _thread._lifeCycles.addAll(Arrays.asList(lifeCycles)); |
| 102 | if (_thread._lifeCycles.size()>0) |
| 103 | _thread.hook(); |
| 104 | } |
| 105 | |
| 106 | /* ------------------------------------------------------------ */ |
| 107 | public static synchronized void register(int index, LifeCycle... lifeCycles) |
| 108 | { |
| 109 | _thread._lifeCycles.addAll(index,Arrays.asList(lifeCycles)); |
| 110 | if (_thread._lifeCycles.size()>0) |
| 111 | _thread.hook(); |
| 112 | } |
| 113 | |
| 114 | /* ------------------------------------------------------------ */ |
| 115 | public static synchronized void deregister(LifeCycle lifeCycle) |
| 116 | { |
| 117 | _thread._lifeCycles.remove(lifeCycle); |
| 118 | if (_thread._lifeCycles.size()==0) |
| 119 | _thread.unhook(); |
| 120 | } |
| 121 | |
| 122 | /* ------------------------------------------------------------ */ |
| 123 | @Override |
| 124 | public void run() |
| 125 | { |
| 126 | for (LifeCycle lifeCycle : _thread._lifeCycles) |
| 127 | { |
| 128 | try |
| 129 | { |
| 130 | if (lifeCycle.isStarted()) |
| 131 | { |
| 132 | lifeCycle.stop(); |
| 133 | LOG.debug("Stopped {}",lifeCycle); |
| 134 | } |
| 135 | |
| 136 | if (lifeCycle instanceof Destroyable) |
| 137 | { |
| 138 | ((Destroyable)lifeCycle).destroy(); |
| 139 | LOG.debug("Destroyed {}",lifeCycle); |
| 140 | } |
| 141 | } |
| 142 | catch (Exception ex) |
| 143 | { |
| 144 | LOG.debug(ex); |
| 145 | } |
| 146 | } |
| 147 | } |
| 148 | } |