/*
* Copyright (c) 1999, 2011, Oracle and/or its affiliates. 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package com.sun.jndi.ldap;
import java.util.Vector;
import java.util.EventObject;
import javax.naming.event.NamingEvent;
import javax.naming.event.NamingExceptionEvent;
import javax.naming.event.NamingListener;
import javax.naming.ldap.UnsolicitedNotificationEvent;
import javax.naming.ldap.UnsolicitedNotificationListener;
/**
* Package private class used by EventSupport to dispatch events.
* This class implements an event queue, and a dispatcher thread that
* dequeues and dispatches events from the queue.
*
* Pieces stolen from sun.misc.Queue.
*
* @author Bill Shannon (from javax.mail.event)
* @author Rosanna Lee (modified for JNDI-related events)
*/
final class EventQueue implements Runnable {
final static private boolean debug = false;
private static class QueueElement {
QueueElement next = null;
QueueElement prev = null;
EventObject event = null;
Vector<NamingListener> vector = null;
QueueElement(EventObject event, Vector<NamingListener> vector) {
this.event = event;
this.vector = vector;
}
}
private QueueElement head = null;
private QueueElement tail = null;
private Thread qThread;
// package private
EventQueue() {
qThread = Obj.helper.createThread(this);
qThread.setDaemon(true); // not a user thread
qThread.start();
}
// package private;
/**
* Enqueue an event.
* @param event Either a <tt>NamingExceptionEvent</tt> or a subclass
* of <tt>NamingEvent</tt> or
* <tt>UnsolicitedNotificatoniEvent</tt>.
* If it is a subclass of <tt>NamingEvent</tt>, all listeners must implement
* the corresponding subinterface of <tt>NamingListener</tt>.
* For example, for a <tt>ObjectAddedEvent</tt>, all listeners <em>must</em>
* implement the <tt>ObjectAddedListener</tt> interface.
* <em>The current implementation does not check this before dispatching
* the event.</em>
* If the event is a <tt>NamingExceptionEvent</tt>, then all listeners
* are notified.
* @param vector List of NamingListeners that will be notified of event.
*/
synchronized void enqueue(EventObject event, Vector<NamingListener> vector) {
QueueElement newElt = new QueueElement(event, vector);
if (head == null) {
head = newElt;
tail = newElt;
} else {
newElt.next = head;
head.prev = newElt;
head = newElt;
}
notify();
}
/**
* Dequeue the oldest object on the queue.
* Used only by the run() method.
*
* @return the oldest object on the queue.
* @exception java.lang.InterruptedException if any thread has
* interrupted this thread.
*/
private synchronized QueueElement dequeue()
throws InterruptedException {
while (tail == null)
wait();
QueueElement elt = tail;
tail = elt.prev;
if (tail == null) {
head = null;
} else {
tail.next = null;
}
elt.prev = elt.next = null;
return elt;
}
/**
* Pull events off the queue and dispatch them.
*/
public void run() {
QueueElement qe;
try {
while ((qe = dequeue()) != null) {
EventObject e = qe.event;
Vector<NamingListener> v = qe.vector;
for (int i = 0; i < v.size(); i++) {
// Dispatch to corresponding NamingListener
// The listener should only be getting the event that
// it is interested in. (No need to check mask or
// instanceof subinterfaces.)
// It is the responsibility of the enqueuer to
// only enqueue events with listseners of the correct type.
if (e instanceof NamingEvent) {
((NamingEvent)e).dispatch(v.elementAt(i));
// An exception occurred: if notify all naming listeners
} else if (e instanceof NamingExceptionEvent) {
((NamingExceptionEvent)e).dispatch(v.elementAt(i));
} else if (e instanceof UnsolicitedNotificationEvent) {
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