/*
* eXist Open Source Native XML Database
* Copyright (C) 2005-2010 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* $Id$
*/
package org.exist.storage;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.exist.dom.persistent.DocumentImpl;
import org.exist.numbering.NodeId;
import java.util.IdentityHashMap;
import org.exist.dom.persistent.IStoredNode;
/**
* Global notification service for document updates. Other classes
* can subscribe to this service to be notified of document modifications,
* removals or additions.
*
* @author wolf
*
*/
public class NotificationService extends IdentityHashMap<UpdateListener, Object> implements BrokerPoolService {
private static final long serialVersionUID = -3629584664969740903L;
private final static Logger LOG = LogManager.getLogger(NotificationService.class);
public NotificationService() {
super();
}
/**
* Subscribe an {@link UpdateListener} to receive notifications.
*
* @param listener
*/
public synchronized void subscribe(UpdateListener listener) {
put(listener, new Object());
}
/**
* Unsubscribe an {@link UpdateListener}.
*
* @param listener
*/
public synchronized void unsubscribe(UpdateListener listener) {
final Object i = remove(listener);
if (i == null)
{throw new RuntimeException(hashCode() + " listener not found: " + listener.hashCode());}
listener.unsubscribe();
}
/**
* Notify all subscribers that a document has been updated/removed or
* a new document has been added.
*
* @param document
* @param event
*/
public synchronized void notifyUpdate(DocumentImpl document, int event) {
for (final UpdateListener listener : keySet()) {
listener.documentUpdated(document, event);
}
}
/**
* Notify all subscribers that a node has been moved. Nodes may be moved during a
* defragmentation run.
*/
public synchronized void notifyMove(NodeId oldNodeId, IStoredNode newNode) {
for (final UpdateListener listener : keySet()) {
listener.nodeMoved(oldNodeId, newNode);
}
}
public void debug() {
LOG.debug("Registered UpdateListeners:");
for (final UpdateListener listener : keySet()) {
listener.debug();
}
}
}