1 /* 2 * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.awt.event; 27 28 import java.util.EventListener; 29 30 /** 31 * The listener interface for receiving hierarchy changed events. 32 * The class that is interested in processing a hierarchy changed event 33 * should implement this interface. 34 * The listener object created from that class is then registered with a 35 * Component using the Component's <code>addHierarchyListener</code> 36 * method. When the hierarchy to which the Component belongs changes, the 37 * <code>hierarchyChanged</code> method in the listener object is invoked, 38 * and the <code>HierarchyEvent</code> is passed to it. 39 * <p> 40 * Hierarchy events are provided for notification purposes ONLY; 41 * The AWT will automatically handle changes to the hierarchy internally so 42 * that GUI layout, displayability, and visibility work properly regardless 43 * of whether a program registers a <code>HierarchyListener</code> or not. 44 * 45 * @author David Mendenhall 46 * @see HierarchyEvent 47 * @since 1.3 48 */ 49 public interface HierarchyListener extends EventListener { 50 /** 51 * Called when the hierarchy has been changed. To discern the actual 52 * type of change, call <code>HierarchyEvent.getChangeFlags()</code>. 53 * 54 * @see HierarchyEvent#getChangeFlags() 55 */ 56 public void hierarchyChanged(HierarchyEvent e); 57 }