/*
* Copyright 1999,2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.modeler;
import java.util.ArrayList;
import java.util.Iterator;
import javax.management.ListenerNotFoundException;
import javax.management.MBeanNotificationInfo;
import javax.management.Notification;
import javax.management.NotificationBroadcaster;
import javax.management.NotificationFilter;
import javax.management.NotificationListener;
/**
* <p>Implementation of <code>NotificationBroadcaster</code> for attribute
* change notifications. This class is used by <code>BaseModelMBean</code> to
* handle notifications of attribute change events to interested listeners.
*</p>
*
* @author Craig R. McClanahan
* @author Costin Manolache
*/
public class BaseNotificationBroadcaster implements NotificationBroadcaster {
// ----------------------------------------------------------- Constructors
// ----------------------------------------------------- Instance Variables
/**
* The set of registered <code>BaseNotificationBroadcasterEntry</code>
* entries.
*/
protected ArrayList entries = new ArrayList();
// --------------------------------------------------------- Public Methods
/**
* Add a notification event listener to this MBean.
*
* @param listener Listener that will receive event notifications
* @param filter Filter object used to filter event notifications
* actually delivered, or <code>null</code> for no filtering
* @param handback Handback object to be sent along with event
* notifications
*
* @exception IllegalArgumentException if the listener parameter is null
*/
public void addNotificationListener(NotificationListener listener,
NotificationFilter filter,
Object handback)
throws IllegalArgumentException {
synchronized (entries) {
// Optimization to coalesce attribute name filters
if (filter instanceof BaseAttributeFilter) {
BaseAttributeFilter newFilter = (BaseAttributeFilter) filter;
Iterator items = entries.iterator();
while (items.hasNext()) {
BaseNotificationBroadcasterEntry item =
(BaseNotificationBroadcasterEntry) items.next();
if ((item.listener == listener) &&
(item.filter != null) &&
(item.filter instanceof BaseAttributeFilter) &&
(item.handback == handback)) {
BaseAttributeFilter oldFilter =
(BaseAttributeFilter) item.filter;
String newNames[] = newFilter.getNames();
String oldNames[] = oldFilter.getNames();
if (newNames.length == 0) {
oldFilter.clear();
} else {
if (oldNames.length != 0) {
for (int i = 0; i < newNames.length; i++)
oldFilter.addAttribute(newNames[i]);
}
}
return;
}
}
}
// General purpose addition of a new entry
entries.add(new BaseNotificationBroadcasterEntry
(listener, filter, handback));
}
}
/**
* Return an <code>MBeanNotificationInfo</code> object describing the
* notifications sent by this MBean.
*/
public MBeanNotificationInfo[] getNotificationInfo() {
return (new MBeanNotificationInfo[0]);
}
/**
* Remove a notification event listener from this MBean.
*
* @param listener The listener to be removed (any and all registrations
* for this listener will be eliminated)
*
* @exception ListenerNotFoundException if this listener is not
* registered in the MBean
*/
public void removeNotificationListener(NotificationListener listener)
throws ListenerNotFoundException {
synchronized (entries) {
Iterator items = entries.iterator();
while (items.hasNext()) {
BaseNotificationBroadcasterEntry item =
(BaseNotificationBroadcasterEntry) items.next();
if (item.listener == listener)
items.remove();
}
}
}
/**
* Remove a notification event listener from this MBean.
*
* @param listener The listener to be removed (any and all registrations
* for this listener will be eliminated)
* @param handback Handback object to be sent along with event
* notifications
*
* @exception ListenerNotFoundException if this listener is not
* registered in the MBean
*/
public void removeNotificationListener(NotificationListener listener,
Object handback)
throws ListenerNotFoundException {
removeNotificationListener(listener);
}
/**
* Remove a notification event listener from this MBean.
*
* @param listener The listener to be removed (any and all registrations
* for this listener will be eliminated)
* @param filter Filter object used to filter event notifications
* actually delivered, or <code>null</code> for no filtering
* @param handback Handback object to be sent along with event
* notifications
*
* @exception ListenerNotFoundException if this listener is not
* registered in the MBean
*/
public void removeNotificationListener(NotificationListener listener,
NotificationFilter filter,
Object handback)
throws ListenerNotFoundException {
removeNotificationListener(listener);
}
/**
* Send the specified notification to all interested listeners.
*
* @param notification The notification to be sent
*/
public void sendNotification(Notification notification) {
synchronized (entries) {
Iterator items = entries.iterator();
while (items.hasNext()) {
BaseNotificationBroadcasterEntry item =
(BaseNotificationBroadcasterEntry) items.next();
if ((item.filter != null) &&
(!item.filter.isNotificationEnabled(notification)))
continue;
item.listener.handleNotification(notification, item.handback);
}
}
}
// -------------------- Internal Extensions --------------------
// Fast access. First index is the hook type
// ( FixedNotificationFilter.getType() ).
NotificationListener hooks[][]=new NotificationListener[20][];
int hookCount[]=new int[20];
private synchronized void registerNotifications( FixedNotificationFilter filter ) {
String names[]=filter.getNames();
Registry reg=Registry.getRegistry();
for( int i=0; i<names.length; i++ ) {
int code=reg.getId(null, names[i]);
if( hooks.length < code ) {
// XXX reallocate
throw new RuntimeException( "Too many hooks " + code );
}
NotificationListener listeners[]=hooks[code];
if( listeners== null ) {
}
}
}
}
/**
* Utility class representing a particular registered listener entry.
*/
class BaseNotificationBroadcasterEntry {
public BaseNotificationBroadcasterEntry(NotificationListener listener,
NotificationFilter filter,
Object handback) {
this.listener = listener;
this.filter = filter;
this.handback = handback;
}
public NotificationFilter filter = null;
public Object handback = null;
public NotificationListener listener = null;
}