1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
5 *
6 * The contents of this file are subject to the terms of either the GNU
7 * General Public License Version 2 only ("GPL") or the Common Development
8 * and Distribution License("CDDL") (collectively, the "License"). You
9 * may not use this file except in compliance with the License. You can obtain
10 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
11 * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
12 * language governing permissions and limitations under the License.
13 *
14 * When distributing the software, include this License Header Notice in each
15 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
16 * Sun designates this particular file as subject to the "Classpath" exception
17 * as provided by Sun in the GPL Version 2 section of the License file that
18 * accompanied this code. If applicable, add the following below the License
19 * Header, with the fields enclosed by brackets [] replaced by your own
20 * identifying information: "Portions Copyrighted [year]
21 * [name of copyright owner]"
22 *
23 * Contributor(s):
24 *
25 * If you wish your version of this file to be governed by only the CDDL or
26 * only the GPL Version 2, indicate your decision by adding "[Contributor]
27 * elects to include this software in this distribution under the [CDDL or GPL
28 * Version 2] license." If you don't indicate a single choice of license, a
29 * recipient has the option to distribute your version of this file under
30 * either the CDDL, the GPL Version 2 or to extend the choice of license to
31 * its licensees as provided above. However, if you add GPL Version 2 code
32 * and therefore, elected the GPL Version 2 license, then the option applies
33 * only if the new code is made subject to such option by the copyright
34 * holder.
35 */
36
37 /*
38 * @(#)EventQueue.java 1.11 07/05/04
39 */
40
41 package javax.mail;
42
43 import java.io;
44 import java.util.Vector;
45 import javax.mail.event.MailEvent;
46
47 /**
48 * Package private class used by Store & Folder to dispatch events.
49 * This class implements an event queue, and a dispatcher thread that
50 * dequeues and dispatches events from the queue.
51 *
52 * Pieces stolen from sun.misc.Queue.
53 *
54 * @author Bill Shannon
55 */
56 class EventQueue implements Runnable {
57
58 static class QueueElement {
59 QueueElement next = null;
60 QueueElement prev = null;
61 MailEvent event = null;
62 Vector vector = null;
63
64 QueueElement(MailEvent event, Vector vector) {
65 this.event = event;
66 this.vector = vector;
67 }
68 }
69
70 private QueueElement head = null;
71 private QueueElement tail = null;
72 private Thread qThread;
73
74 public EventQueue() {
75 qThread = new Thread(this, "JavaMail-EventQueue");
76 qThread.setDaemon(true); // not a user thread
77 qThread.start();
78 }
79
80 /**
81 * Enqueue an event.
82 */
83 public synchronized void enqueue(MailEvent event, Vector vector) {
84 QueueElement newElt = new QueueElement(event, vector);
85
86 if (head == null) {
87 head = newElt;
88 tail = newElt;
89 } else {
90 newElt.next = head;
91 head.prev = newElt;
92 head = newElt;
93 }
94 notifyAll();
95 }
96
97 /**
98 * Dequeue the oldest object on the queue.
99 * Used only by the run() method.
100 *
101 * @return the oldest object on the queue.
102 * @exception java.lang.InterruptedException if another thread has
103 * interrupted this thread.
104 */
105 private synchronized QueueElement dequeue()
106 throws InterruptedException {
107 while (tail == null)
108 wait();
109 QueueElement elt = tail;
110 tail = elt.prev;
111 if (tail == null) {
112 head = null;
113 } else {
114 tail.next = null;
115 }
116 elt.prev = elt.next = null;
117 return elt;
118 }
119
120 /**
121 * Pull events off the queue and dispatch them.
122 */
123 public void run() {
124 QueueElement qe;
125
126 try {
127 loop:
128 while ((qe = dequeue()) != null) {
129 MailEvent e = qe.event;
130 Vector v = qe.vector;
131
132 for (int i = 0; i < v.size(); i++)
133 try {
134 e.dispatch(v.elementAt(i));
135 } catch (Throwable t) {
136 if (t instanceof InterruptedException)
137 break loop;
138 // ignore anything else thrown by the listener
139 }
140
141 qe = null; e = null; v = null;
142 }
143 } catch (InterruptedException e) {
144 // just die
145 }
146 }
147
148 /**
149 * Stop the dispatcher so we can be destroyed.
150 */
151 void stop() {
152 if (qThread != null) {
153 qThread.interrupt(); // kill our thread
154 qThread = null;
155 }
156 }
157 }
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