001 /* HierarchyEvent.java -- generated for a change in hierarchy 002 Copyright (C) 2000, 2002 Free Software Foundation 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package java.awt.event; 040 041 import java.awt.AWTEvent; 042 import java.awt.Component; 043 import java.awt.Container; 044 045 /** 046 * This class represents an event generated for an ancestor component which 047 * may affect this component. These events normally do not need to be handled 048 * by the application, since the AWT system automatically takes care of them. 049 * 050 * <p>There are two types of hierarchy events. The first type is handled by 051 * HierarchyListener, and includes addition or removal of an ancestor, or 052 * an ancestor changing its on-screen status (visible and/or displayble). The 053 * second type is handled by HierarchyBoundsListener, and includes resizing 054 * or moving of an ancestor. 055 * 056 * @author Bryce McKinlay 057 * @see HierarchyListener 058 * @see HierarchyBoundsAdapter 059 * @see HierarchyBoundsListener 060 * @since 1.3 061 * @status updated to 1.4 062 */ 063 public class HierarchyEvent extends AWTEvent 064 { 065 /** 066 * Compatible with JDK 1.3+. 067 */ 068 private static final long serialVersionUID = -5337576970038043990L; 069 070 /** This is the first id in the range of ids used by this class. */ 071 public static final int HIERARCHY_FIRST = 1400; 072 073 /** This id indicates that the hierarchy tree changed. */ 074 public static final int HIERARCHY_CHANGED = 1400; 075 076 /** This id indicates that an ancestor was moved. */ 077 public static final int ANCESTOR_MOVED = 1401; 078 079 /** This id indicates that an ancestor was resized. */ 080 public static final int ANCESTOR_RESIZED = 1402; 081 082 /** This is the last id in the range of ids used by this class. */ 083 public static final int HIERARCHY_LAST = 1402; 084 085 /** This indicates that the HIERARCHY_CHANGED is a changed parent. */ 086 public static final int PARENT_CHANGED = 1; 087 088 /** 089 * This indicates that the HIERARCHY_CHANGED is caused by a change in 090 * displayability. 091 * 092 * @see Component#isDisplayable() 093 * @see Component#addNotify() 094 * @see Component#removeNotify() 095 */ 096 public static final int DISPLAYABILITY_CHANGED = 2; 097 098 /** 099 * This indicates that the HIERARCHY_CHANGED is a changed visibility. 100 * 101 * @see Component#isShowing() 102 * @see Component#addNotify() 103 * @see Component#removeNotify() 104 * @see Component#show() 105 * @see Component#hide() 106 */ 107 public static final int SHOWING_CHANGED = 4; 108 109 /** 110 * The component at the top of the changed hierarchy. 111 * 112 * @serial the top component changed 113 */ 114 private final Component changed; 115 116 /** 117 * The parent of this component, either before or after the change depending 118 * on the type of change. 119 * 120 * @serial the parent component changed 121 */ 122 private final Container changedParent; 123 124 /** 125 * The bitmask of HIERARCHY_CHANGED event types. 126 * 127 * @serial the change flags 128 */ 129 private final long changeFlags; 130 131 /** 132 * Initializes a new instance of <code>HierarchyEvent</code> with the 133 * specified parameters. Note that an invalid id leads to unspecified 134 * results. 135 * 136 * @param source the component whose hierarchy changed 137 * @param id the event id 138 * @param changed the top component in the tree of changed hierarchy 139 * @param changedParent the updated parent of this object 140 * @throws IllegalArgumentException if source is null 141 */ 142 public HierarchyEvent(Component source, int id, Component changed, 143 Container changedParent) 144 { 145 this(source, id, changed, changedParent, 0); 146 } 147 148 /** 149 * Initializes a new instance of <code>HierarchyEvent</code> with the 150 * specified parameters. Note that an invalid id leads to unspecified 151 * results. 152 * 153 * @param source the component whose hierarchy changed 154 * @param id the event id 155 * @param changed the top component in the tree of changed hierarchy 156 * @param changedParent the updated parent of this object 157 * @param changeFlags the bitmask of specific HIERARCHY_CHANGED events 158 * @throws IllegalArgumentException if source is null 159 */ 160 public HierarchyEvent(Component source, int id, Component changed, 161 Container changedParent, long changeFlags) 162 { 163 super(source, id); 164 this.changed = changed; 165 this.changedParent = changedParent; 166 this.changeFlags = changeFlags; 167 } 168 169 /** 170 * This method returns the event source as a <code>Component</code>. If the 171 * source has subsequently been modified to a non-Component, this returns 172 * null. 173 * 174 * @return the event source as a <code>Component</code>, or null 175 */ 176 public Component getComponent() 177 { 178 return source instanceof Component ? (Component) source : null; 179 } 180 181 /** 182 * Returns the component at the top of the hierarchy which changed. 183 * 184 * @return the top changed component 185 */ 186 public Component getChanged() 187 { 188 return changed; 189 } 190 191 /** 192 * Returns the parent of the component listed in <code>getChanged()</code>. 193 * If the cause of this event was <code>Container.add</code>, this is the 194 * new parent; if the cause was <code>Container.remove</code>, this is the 195 * old parent; otherwise it is the unchanged parent. 196 * 197 * @return the parent container of the changed component 198 */ 199 public Container getChangedParent() 200 { 201 return changedParent; 202 } 203 204 /** 205 * If this is a HIERARCHY_CHANGED event, this returns a bitmask of the 206 * types of changes that took place. 207 * 208 * @return the bitwise or of hierarchy change types, or 0 209 * @see #PARENT_CHANGED 210 * @see #DISPLAYABILITY_CHANGED 211 * @see #SHOWING_CHANGED 212 */ 213 public long getChangeFlags() 214 { 215 return changeFlags; 216 } 217 218 /** 219 * This method returns a string identifying this event. This is the field 220 * name of the id type, followed by a parenthesized listing of the changed 221 * component and its parent container. In addition, if the type is 222 * HIERARCHY_CHANGED, the flags preceed the changed component, in the 223 * order PARENT_CHANGED, DISPLAYABILITY_CHANGED, and SHOWING_CHANGED. 224 * 225 * @return a string identifying this event 226 */ 227 public String paramString() 228 { 229 StringBuffer r = new StringBuffer(); 230 switch (id) 231 { 232 case HIERARCHY_CHANGED: 233 r.append("HIERARCHY_CHANGED ("); 234 if ((changeFlags & PARENT_CHANGED) != 0) 235 r.append("PARENT_CHANGED,"); 236 if ((changeFlags & DISPLAYABILITY_CHANGED) != 0) 237 r.append("DISPLAYABILITY_CHANGED,"); 238 if ((changeFlags & SHOWING_CHANGED) != 0) 239 r.append("SHOWING_CHANGED,"); 240 break; 241 case ANCESTOR_MOVED: 242 r.append("ANCESTOR_MOVED ("); 243 break; 244 case ANCESTOR_RESIZED: 245 r.append("ANCESTOR_RESIZED ("); 246 break; 247 default: 248 return "unknown type"; 249 } 250 r.append(changed).append(',').append(changedParent).append(')'); 251 return r.toString(); 252 } 253 } // class HierarchyEvent