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 gnu.java.lang.CPStringBuilder;
042
043 import java.awt.AWTEvent;
044 import java.awt.Component;
045 import java.awt.Container;
046
047 /**
048 * This class represents an event generated for an ancestor component which
049 * may affect this component. These events normally do not need to be handled
050 * by the application, since the AWT system automatically takes care of them.
051 *
052 * <p>There are two types of hierarchy events. The first type is handled by
053 * HierarchyListener, and includes addition or removal of an ancestor, or
054 * an ancestor changing its on-screen status (visible and/or displayble). The
055 * second type is handled by HierarchyBoundsListener, and includes resizing
056 * or moving of an ancestor.
057 *
058 * @author Bryce McKinlay
059 * @see HierarchyListener
060 * @see HierarchyBoundsAdapter
061 * @see HierarchyBoundsListener
062 * @since 1.3
063 * @status updated to 1.4
064 */
065 public class HierarchyEvent extends AWTEvent
066 {
067 /**
068 * Compatible with JDK 1.3+.
069 */
070 private static final long serialVersionUID = -5337576970038043990L;
071
072 /** This is the first id in the range of ids used by this class. */
073 public static final int HIERARCHY_FIRST = 1400;
074
075 /** This id indicates that the hierarchy tree changed. */
076 public static final int HIERARCHY_CHANGED = 1400;
077
078 /** This id indicates that an ancestor was moved. */
079 public static final int ANCESTOR_MOVED = 1401;
080
081 /** This id indicates that an ancestor was resized. */
082 public static final int ANCESTOR_RESIZED = 1402;
083
084 /** This is the last id in the range of ids used by this class. */
085 public static final int HIERARCHY_LAST = 1402;
086
087 /** This indicates that the HIERARCHY_CHANGED is a changed parent. */
088 public static final int PARENT_CHANGED = 1;
089
090 /**
091 * This indicates that the HIERARCHY_CHANGED is caused by a change in
092 * displayability.
093 *
094 * @see Component#isDisplayable()
095 * @see Component#addNotify()
096 * @see Component#removeNotify()
097 */
098 public static final int DISPLAYABILITY_CHANGED = 2;
099
100 /**
101 * This indicates that the HIERARCHY_CHANGED is a changed visibility.
102 *
103 * @see Component#isShowing()
104 * @see Component#addNotify()
105 * @see Component#removeNotify()
106 * @see Component#show()
107 * @see Component#hide()
108 */
109 public static final int SHOWING_CHANGED = 4;
110
111 /**
112 * The component at the top of the changed hierarchy.
113 *
114 * @serial the top component changed
115 */
116 private final Component changed;
117
118 /**
119 * The parent of this component, either before or after the change depending
120 * on the type of change.
121 *
122 * @serial the parent component changed
123 */
124 private final Container changedParent;
125
126 /**
127 * The bitmask of HIERARCHY_CHANGED event types.
128 *
129 * @serial the change flags
130 */
131 private final long changeFlags;
132
133 /**
134 * Initializes a new instance of <code>HierarchyEvent</code> with the
135 * specified parameters. Note that an invalid id leads to unspecified
136 * results.
137 *
138 * @param source the component whose hierarchy changed
139 * @param id the event id
140 * @param changed the top component in the tree of changed hierarchy
141 * @param changedParent the updated parent of this object
142 * @throws IllegalArgumentException if source is null
143 */
144 public HierarchyEvent(Component source, int id, Component changed,
145 Container changedParent)
146 {
147 this(source, id, changed, changedParent, 0);
148 }
149
150 /**
151 * Initializes a new instance of <code>HierarchyEvent</code> with the
152 * specified parameters. Note that an invalid id leads to unspecified
153 * results.
154 *
155 * @param source the component whose hierarchy changed
156 * @param id the event id
157 * @param changed the top component in the tree of changed hierarchy
158 * @param changedParent the updated parent of this object
159 * @param changeFlags the bitmask of specific HIERARCHY_CHANGED events
160 * @throws IllegalArgumentException if source is null
161 */
162 public HierarchyEvent(Component source, int id, Component changed,
163 Container changedParent, long changeFlags)
164 {
165 super(source, id);
166 this.changed = changed;
167 this.changedParent = changedParent;
168 this.changeFlags = changeFlags;
169 }
170
171 /**
172 * This method returns the event source as a <code>Component</code>. If the
173 * source has subsequently been modified to a non-Component, this returns
174 * null.
175 *
176 * @return the event source as a <code>Component</code>, or null
177 */
178 public Component getComponent()
179 {
180 return source instanceof Component ? (Component) source : null;
181 }
182
183 /**
184 * Returns the component at the top of the hierarchy which changed.
185 *
186 * @return the top changed component
187 */
188 public Component getChanged()
189 {
190 return changed;
191 }
192
193 /**
194 * Returns the parent of the component listed in <code>getChanged()</code>.
195 * If the cause of this event was <code>Container.add</code>, this is the
196 * new parent; if the cause was <code>Container.remove</code>, this is the
197 * old parent; otherwise it is the unchanged parent.
198 *
199 * @return the parent container of the changed component
200 */
201 public Container getChangedParent()
202 {
203 return changedParent;
204 }
205
206 /**
207 * If this is a HIERARCHY_CHANGED event, this returns a bitmask of the
208 * types of changes that took place.
209 *
210 * @return the bitwise or of hierarchy change types, or 0
211 * @see #PARENT_CHANGED
212 * @see #DISPLAYABILITY_CHANGED
213 * @see #SHOWING_CHANGED
214 */
215 public long getChangeFlags()
216 {
217 return changeFlags;
218 }
219
220 /**
221 * This method returns a string identifying this event. This is the field
222 * name of the id type, followed by a parenthesized listing of the changed
223 * component and its parent container. In addition, if the type is
224 * HIERARCHY_CHANGED, the flags preceed the changed component, in the
225 * order PARENT_CHANGED, DISPLAYABILITY_CHANGED, and SHOWING_CHANGED.
226 *
227 * @return a string identifying this event
228 */
229 public String paramString()
230 {
231 CPStringBuilder r = new CPStringBuilder();
232 switch (id)
233 {
234 case HIERARCHY_CHANGED:
235 r.append("HIERARCHY_CHANGED (");
236 if ((changeFlags & PARENT_CHANGED) != 0)
237 r.append("PARENT_CHANGED,");
238 if ((changeFlags & DISPLAYABILITY_CHANGED) != 0)
239 r.append("DISPLAYABILITY_CHANGED,");
240 if ((changeFlags & SHOWING_CHANGED) != 0)
241 r.append("SHOWING_CHANGED,");
242 break;
243 case ANCESTOR_MOVED:
244 r.append("ANCESTOR_MOVED (");
245 break;
246 case ANCESTOR_RESIZED:
247 r.append("ANCESTOR_RESIZED (");
248 break;
249 default:
250 return "unknown type";
251 }
252 r.append(changed).append(',').append(changedParent).append(')');
253 return r.toString();
254 }
255 } // class HierarchyEvent