J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package com.sun.jndi.ldap; |
| 27 | |
| 28 | import java.io.*; |
| 29 | import java.util.Vector; |
| 30 | import java.util.EventObject; |
| 31 | |
| 32 | import javax.naming.event.NamingEvent; |
| 33 | import javax.naming.event.NamingExceptionEvent; |
| 34 | import javax.naming.event.NamingListener; |
| 35 | import javax.naming.ldap.UnsolicitedNotificationEvent; |
| 36 | import javax.naming.ldap.UnsolicitedNotificationListener; |
| 37 | |
| 38 | /** |
| 39 | * Package private class used by EventSupport to dispatch events. |
| 40 | * This class implements an event queue, and a dispatcher thread that |
| 41 | * dequeues and dispatches events from the queue. |
| 42 | * |
| 43 | * Pieces stolen from sun.misc.Queue. |
| 44 | * |
| 45 | * @author Bill Shannon (from javax.mail.event) |
| 46 | * @author Rosanna Lee (modified for JNDI-related events) |
| 47 | */ |
| 48 | final class EventQueue implements Runnable { |
| 49 | final static private boolean debug = false; |
| 50 | |
| 51 | private static class QueueElement { |
| 52 | QueueElement next = null; |
| 53 | QueueElement prev = null; |
| 54 | EventObject event = null; |
| 55 | Vector vector = null; |
| 56 | |
| 57 | QueueElement(EventObject event, Vector vector) { |
| 58 | this.event = event; |
| 59 | this.vector = vector; |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | private QueueElement head = null; |
| 64 | private QueueElement tail = null; |
| 65 | private Thread qThread; |
| 66 | |
| 67 | // package private |
| 68 | EventQueue() { |
| 69 | qThread = Obj.helper.createThread(this); |
| 70 | qThread.setDaemon(true); // not a user thread |
| 71 | qThread.start(); |
| 72 | } |
| 73 | |
| 74 | // package private; |
| 75 | /** |
| 76 | * Enqueue an event. |
| 77 | * @param event Either a <tt>NamingExceptionEvent</tt> or a subclass |
| 78 | * of <tt>NamingEvent</tt> or |
| 79 | * <tt>UnsolicitedNotificatoniEvent</tt>. |
| 80 | * If it is a subclass of <tt>NamingEvent</tt>, all listeners must implement |
| 81 | * the corresponding subinterface of <tt>NamingListener</tt>. |
| 82 | * For example, for a <tt>ObjectAddedEvent</tt>, all listeners <em>must</em> |
| 83 | * implement the <tt>ObjectAddedListener</tt> interface. |
| 84 | * <em>The current implementation does not check this before dispatching |
| 85 | * the event.</em> |
| 86 | * If the event is a <tt>NamingExceptionEvent</tt>, then all listeners |
| 87 | * are notified. |
| 88 | * @param vector List of NamingListeners that will be notified of event. |
| 89 | */ |
| 90 | synchronized void enqueue(EventObject event, Vector vector) { |
| 91 | QueueElement newElt = new QueueElement(event, vector); |
| 92 | |
| 93 | if (head == null) { |
| 94 | head = newElt; |
| 95 | tail = newElt; |
| 96 | } else { |
| 97 | newElt.next = head; |
| 98 | head.prev = newElt; |
| 99 | head = newElt; |
| 100 | } |
| 101 | notify(); |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Dequeue the oldest object on the queue. |
| 106 | * Used only by the run() method. |
| 107 | * |
| 108 | * @return the oldest object on the queue. |
| 109 | * @exception java.lang.InterruptedException if any thread has |
| 110 | * interrupted this thread. |
| 111 | */ |
| 112 | private synchronized QueueElement dequeue() |
| 113 | throws InterruptedException { |
| 114 | while (tail == null) |
| 115 | wait(); |
| 116 | QueueElement elt = tail; |
| 117 | tail = elt.prev; |
| 118 | if (tail == null) { |
| 119 | head = null; |
| 120 | } else { |
| 121 | tail.next = null; |
| 122 | } |
| 123 | elt.prev = elt.next = null; |
| 124 | return elt; |
| 125 | } |
| 126 | |
| 127 | /** |
| 128 | * Pull events off the queue and dispatch them. |
| 129 | */ |
| 130 | public void run() { |
| 131 | QueueElement qe; |
| 132 | |
| 133 | try { |
| 134 | while ((qe = dequeue()) != null) { |
| 135 | EventObject e = qe.event; |
| 136 | Vector v = qe.vector; |
| 137 | |
| 138 | for (int i = 0; i < v.size(); i++) { |
| 139 | |
| 140 | // Dispatch to corresponding NamingListener |
| 141 | // The listener should only be getting the event that |
| 142 | // it is interested in. (No need to check mask or |
| 143 | // instanceof subinterfaces.) |
| 144 | // It is the responsibility of the enqueuer to |
| 145 | // only enqueue events with listseners of the correct type. |
| 146 | |
| 147 | if (e instanceof NamingEvent) { |
| 148 | ((NamingEvent)e).dispatch((NamingListener)v.elementAt(i)); |
| 149 | |
| 150 | // An exception occurred: if notify all naming listeners |
| 151 | } else if (e instanceof NamingExceptionEvent) { |
| 152 | ((NamingExceptionEvent)e).dispatch( |
| 153 | (NamingListener)v.elementAt(i)); |
| 154 | } else if (e instanceof UnsolicitedNotificationEvent) { |
| 155 | ((UnsolicitedNotificationEvent)e).dispatch( |
| 156 | (UnsolicitedNotificationListener)v.elementAt(i)); |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | qe = null; e = null; v = null; |
| 161 | } |
| 162 | } catch (InterruptedException e) { |
| 163 | // just die |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | // package private; used by EventSupport; |
| 168 | /** |
| 169 | * Stop the dispatcher so we can be destroyed. |
| 170 | */ |
| 171 | void stop() { |
| 172 | if (debug) System.err.println("EventQueue stopping"); |
| 173 | if (qThread != null) { |
| 174 | qThread.interrupt(); // kill our thread |
| 175 | qThread = null; |
| 176 | } |
| 177 | } |
| 178 | } |