KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > eclipse > swt > widgets > Listener


1 /*******************************************************************************
2  * Copyright (c) 2000, 2005 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.swt.widgets;
12
13
14 /**
15  * Implementers of <code>Listener</code> provide a simple
16  * <code>handleEvent()</code> method that is used internally
17  * by SWT to dispatch events.
18  * <p>
19  * After creating an instance of a class that implements this interface
20  * it can be added to a widget using the
21  * <code>addListener(int eventType, Listener handler)</code> method and
22  * removed using the
23  * <code>removeListener (int eventType, Listener handler)</code> method.
24  * When the specified event occurs, <code>handleEvent(...)</code> will
25  * be sent to the instance.
26  * </p>
27  * <p>
28  * Classes which implement this interface are described within SWT as
29  * providing the <em>untyped listener</em> API. Typically, widgets will
30  * also provide a higher-level <em>typed listener</em> API, that is based
31  * on the standard <code>java.util.EventListener</code> pattern.
32  * </p>
33  * <p>
34  * Note that, since all internal SWT event dispatching is based on untyped
35  * listeners, it is simple to build subsets of SWT for use on memory
36  * constrained, small footprint devices, by removing the classes and
37  * methods which implement the typed listener API.
38  * </p>
39  *
40  * @see Widget#addListener
41  * @see java.util.EventListener
42  * @see org.eclipse.swt.events
43  */
44 public interface Listener {
45
46 /**
47  * Sent when an event that the receiver has registered for occurs.
48  *
49  * @param event the event which occurred
50  */
51 void handleEvent (Event event);
52 }
53
Popular Tags