1 /* ContainerEvent.java -- components added/removed from a container 2 Copyright (C) 1999, 2002, 2005 Free Software Foundation, Inc. 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 39 package java.awt.event; 40 41 import java.awt.Component; 42 import java.awt.Container; 43 44 /** 45 * This event is generated when a component is added or removed from a 46 * container. Applications do not ordinarily need to handle these events 47 * since the AWT system handles them internally. 48 * 49 * @author Aaron M. Renn (arenn@urbanophile.com) 50 * @see ContainerAdapter 51 * @see ContainerListener 52 * @since 1.1 53 * @status updated to 1.4 54 */ 55 public class ContainerEvent extends ComponentEvent 56 { 57 /** 58 * Compatible with JDK 1.1+. 59 */ 60 private static final long serialVersionUID = -4114942250539772041L; 61 62 /** This is the first id in the id range used by this class. */ 63 public static final int CONTAINER_FIRST = 300; 64 65 /** This is the last id in the id range used by this class. */ 66 public static final int CONTAINER_LAST = 301; 67 68 /** This id indicates a component was added to the container. */ 69 public static final int COMPONENT_ADDED = 300; 70 71 /** This id indicates a component was removed from the container. */ 72 public static final int COMPONENT_REMOVED = 301; 73 74 /** 75 * The non-null child component that was added or removed. 76 * 77 * @serial the child component that changed 78 */ 79 private final Component child; 80 81 /** 82 * Initializes a new instance of <code>ContainerEvent</code> with the 83 * specified source and id. Additionally, the affected child component 84 * is also passed as a parameter. Note that an invalid id leads to 85 * unspecified results. 86 * 87 * @param source the source container of the event 88 * @param id the event id 89 * @param child the child component affected by this event 90 * @throws IllegalArgumentException if source is null 91 */ ContainerEvent(Component source, int id, Component child)92 public ContainerEvent(Component source, int id, Component child) 93 { 94 super(source, id); 95 this.child = child; 96 } 97 98 /** 99 * Returns the source of this event as a <code>Container</code>. 100 * 101 * @return the source of the event 102 * @throws ClassCastException if the source is changed to a non-Container 103 */ getContainer()104 public Container getContainer() 105 { 106 return (Container) source; 107 } 108 109 /** 110 * This method returns the child object that was added or removed from 111 * the container. 112 * 113 * @return the child object added or removed 114 */ getChild()115 public Component getChild() 116 { 117 return child; 118 } 119 120 /** 121 * This method returns a string identifying this event. It is formatted as: 122 * <code>(getID() == COMPONENT_ADDED ? "COMPONENT_ADDED" 123 * : "COMPONENT_REMOVED") + ",child=" + getChild().getName()</code>. 124 * 125 * @return a string identifying this event 126 */ paramString()127 public String paramString() 128 { 129 // Unlike Sun, we don't throw NullPointerException if child is illegally 130 // null. 131 return (id == COMPONENT_ADDED ? "COMPONENT_ADDED,child=" 132 : id == COMPONENT_REMOVED ? "COMPONENT_REMOVED,child=" 133 : "unknown type,child=") + (child == null ? "" : child.getName()); 134 } 135 } // class ContainerEvent 136