/******************************************************************************* * Copyright (c) 2000, 2003 IBM Corporation and others. * All rights reserved. This program and the accompanying materials  * are made available under the terms of the Common Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/cpl-v10.html *  * Contributors: *     IBM Corporation - initial API and implementation *******************************************************************************/package org.eclipse.swt.widgets;/** * Implementers of <code>Listener</code> provide a simple  * <code>handleEvent()</code> method that is used internally  * by SWT to dispatch events. * <p> * After creating an instance of a class that implements this interface * it can be added to a widget using the  * <code>addListener(int eventType, Listener handler)</code> method and * removed using the  * <code>removeListener (int eventType, Listener handler)</code> method.  * When the specified event occurs, <code>handleEvent(...)</code> will * will be sent to the instance. * </p> * <p> * Classes which implement this interface are described within SWT as * providing the <em>untyped listener</em> API. Typically, widgets will * also provide a higher-level <em>typed listener</em> API, that is based * on the standard <code>java.util.EventListener</code> pattern. * </p>  * <p> * Note that, since all internal SWT event dispatching is based on untyped * listeners, it is simple to build subsets of SWT for use on memory  * constrained, small footprint devices, by removing the classes and * methods which implement the typed listener API. * </p> * * @see Widget#addListener * @see java.util.EventListener * @see org.eclipse.swt.events */public interface Listener {/** * Sent when an event that the receiver has registered for occurs. * * @param event the event which occurred */void handleEvent (Event event);}