/** * $RCSfile$ * $Revision$ * $Date$ * * Copyright (C) 2004-2005 Jive Software. All rights reserved. * * This software is published under the terms of the GNU Public License (GPL), * a copy of which is included in this distribution. */ package org.jivesoftware.util; import org.jivesoftware.util.Log; import java.util.List; import java.util.Map; import java.util.concurrent.CopyOnWriteArrayList; /** * Dispatches property events. Each event has a {@link EventType type} * and optional parameters, as follows:<p> * * <table border="1"> * <tr><th>Event Type</th><th>Extra Params</th></tr> * <tr><td>{@link EventType#property_set property_set}</td><td>A param named <tt>value</tt> that * has the value of the property set.</td></tr> * <tr><td>{@link EventType#property_deleted property_deleted}</td><td><i>None</i></td></tr> * <tr><td>{@link EventType#xml_property_set xml_property_set}</td><td>A param named <tt>value</tt> that * has the value of the property set.</td></tr> * <tr><td>{@link EventType#xml_property_deleted xml_property_deleted}</td><td><i>None</i></td></tr> * </table> * * @author Matt Tucker */ public class PropertyEventDispatcher { private static List<PropertyEventListener> listeners = new CopyOnWriteArrayList<PropertyEventListener>(); private PropertyEventDispatcher() { // Not instantiable. } /** * Registers a listener to receive events. * * @param listener the listener. */ public static void addListener(PropertyEventListener listener) { if (listener == null) { throw new NullPointerException(); } listeners.add(listener); } /** * Unregisters a listener to receive events. * * @param listener the listener. */ public static void removeListener(PropertyEventListener listener) { listeners.remove(listener); } /** * Dispatches an event to all listeners. * * @param property the property. * @param eventType the event type. * @param params event parameters. */ public static void dispatchEvent(String property, EventType eventType, Map params) { for (PropertyEventListener listener : listeners) { try { switch (eventType) { case property_set: { listener.propertySet(property, params); break; } case property_deleted: { listener.propertyDeleted(property, params); break; } case xml_property_set: { listener.xmlPropertySet(property, params); break; } case xml_property_deleted: { listener.xmlPropertyDeleted(property, params); break; } default: break; } } catch (Exception e) { Log.error(e); } } } /** * Represents valid event types. */ public enum EventType { /** * A property was set. */ property_set, /** * A property was deleted. */ property_deleted, /** * An XML property was set. */ xml_property_set, /** * An XML property was deleted. */ xml_property_deleted; } }