org.eclipse.swt.widgets.Listener Maven / Gradle / Ivy

/*******************************************************************************
 * Copyright (c) 2000, 2005, 2012 IBM Corporation, Gerhardt Informatics Kft. and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Gerhardt Informatics Kft. - GEFGWT port
 *******************************************************************************/
package org.eclipse.swt.widgets;

/**
 * Implementers of Listener provide a simple
 * handleEvent() method that is used internally by SWT to dispatch
 * events.
 * 
 * After creating an instance of a class that implements this interface it can
 * be added to a widget using the
 * addListener(int eventType, Listener handler) method and removed
 * using the removeListener (int eventType, Listener handler)
 * method. When the specified event occurs, handleEvent(...) will
 * be sent to the instance.
 * 
 * 
 * Classes which implement this interface are described within SWT as providing
 * the untyped listener API. Typically, widgets will also provide a
 * higher-level typed listener API, that is based on the standard
 * java.util.EventListener pattern.
 * 
 * 
 * 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.
 * 
 * 
 * @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);
}