1 /*
2 * Copyright 1998-2007 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package javax.swing;
27
28 import javax.swing;
29 import javax.swing.event;
30 import javax.swing.border;
31
32 import java.awt.Component;
33 import java.awt.Color;
34 import java.awt.Rectangle;
35
36 import java.io.Serializable;
37
38
39 /**
40 * Renders an item in a list.
41 * <p>
42 * <strong><a name="override">Implementation Note:</a></strong>
43 * This class overrides
44 * <code>invalidate</code>,
45 * <code>validate</code>,
46 * <code>revalidate</code>,
47 * <code>repaint</code>,
48 * <code>isOpaque</code>,
49 * and
50 * <code>firePropertyChange</code>
51 * solely to improve performance.
52 * If not overridden, these frequently called methods would execute code paths
53 * that are unnecessary for the default list cell renderer.
54 * If you write your own renderer,
55 * take care to weigh the benefits and
56 * drawbacks of overriding these methods.
57 *
58 * <p>
59 *
60 * <strong>Warning:</strong>
61 * Serialized objects of this class will not be compatible with
62 * future Swing releases. The current serialization support is
63 * appropriate for short term storage or RMI between applications running
64 * the same version of Swing. As of 1.4, support for long term storage
65 * of all JavaBeans<sup><font size="-2">TM</font></sup>
66 * has been added to the <code>java.beans</code> package.
67 * Please see {@link java.beans.XMLEncoder}.
68 *
69 * @author Philip Milne
70 * @author Hans Muller
71 */
72 public class DefaultListCellRenderer extends JLabel
73 implements ListCellRenderer, Serializable
74 {
75
76 /**
77 * An empty <code>Border</code>. This field might not be used. To change the
78 * <code>Border</code> used by this renderer override the
79 * <code>getListCellRendererComponent</code> method and set the border
80 * of the returned component directly.
81 */
82 protected static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
83 private static final Border SAFE_NO_FOCUS_BORDER = new EmptyBorder(1, 1, 1, 1);
84
85 /**
86 * Constructs a default renderer object for an item
87 * in a list.
88 */
89 public DefaultListCellRenderer() {
90 super();
91 setOpaque(true);
92 setBorder(getNoFocusBorder());
93 }
94
95
96 private static Border getNoFocusBorder() {
97 if (System.getSecurityManager() != null) {
98 return SAFE_NO_FOCUS_BORDER;
99 } else {
100 return UIManager.getBorder("List.noFocusBorder");
101 }
102 }
103
104 public Component getListCellRendererComponent(
105 JList list,
106 Object value,
107 int index,
108 boolean isSelected,
109 boolean cellHasFocus)
110 {
111 setComponentOrientation(list.getComponentOrientation());
112
113 Color bg = null;
114 Color fg = null;
115
116 JList.DropLocation dropLocation = list.getDropLocation();
117 if (dropLocation != null
118 && !dropLocation.isInsert()
119 && dropLocation.getIndex() == index) {
120
121 bg = UIManager.getColor("List.dropCellBackground");
122 fg = UIManager.getColor("List.dropCellForeground");
123
124 isSelected = true;
125 }
126
127 if (isSelected) {
128 setBackground(bg == null ? list.getSelectionBackground() : bg);
129 setForeground(fg == null ? list.getSelectionForeground() : fg);
130 }
131 else {
132 setBackground(list.getBackground());
133 setForeground(list.getForeground());
134 }
135
136 if (value instanceof Icon) {
137 setIcon((Icon)value);
138 setText("");
139 }
140 else {
141 setIcon(null);
142 setText((value == null) ? "" : value.toString());
143 }
144
145 setEnabled(list.isEnabled());
146 setFont(list.getFont());
147
148 Border border = null;
149 if (cellHasFocus) {
150 if (isSelected) {
151 border = UIManager.getBorder("List.focusSelectedCellHighlightBorder");
152 }
153 if (border == null) {
154 border = UIManager.getBorder("List.focusCellHighlightBorder");
155 }
156 } else {
157 border = getNoFocusBorder();
158 }
159 setBorder(border);
160
161 return this;
162 }
163
164
165 /**
166 * Overridden for performance reasons.
167 * See the <a href="#override">Implementation Note</a>
168 * for more information.
169 *
170 * @since 1.5
171 * @return <code>true</code> if the background is completely opaque
172 * and differs from the JList's background;
173 * <code>false</code> otherwise
174 */
175 public boolean isOpaque() {
176 Color back = getBackground();
177 Component p = getParent();
178 if (p != null) {
179 p = p.getParent();
180 }
181 // p should now be the JList.
182 boolean colorMatch = (back != null) && (p != null) &&
183 back.equals(p.getBackground()) &&
184 p.isOpaque();
185 return !colorMatch && super.isOpaque();
186 }
187
188 /**
189 * Overridden for performance reasons.
190 * See the <a href="#override">Implementation Note</a>
191 * for more information.
192 */
193 public void validate() {}
194
195 /**
196 * Overridden for performance reasons.
197 * See the <a href="#override">Implementation Note</a>
198 * for more information.
199 *
200 * @since 1.5
201 */
202 public void invalidate() {}
203
204 /**
205 * Overridden for performance reasons.
206 * See the <a href="#override">Implementation Note</a>
207 * for more information.
208 *
209 * @since 1.5
210 */
211 public void repaint() {}
212
213 /**
214 * Overridden for performance reasons.
215 * See the <a href="#override">Implementation Note</a>
216 * for more information.
217 */
218 public void revalidate() {}
219 /**
220 * Overridden for performance reasons.
221 * See the <a href="#override">Implementation Note</a>
222 * for more information.
223 */
224 public void repaint(long tm, int x, int y, int width, int height) {}
225
226 /**
227 * Overridden for performance reasons.
228 * See the <a href="#override">Implementation Note</a>
229 * for more information.
230 */
231 public void repaint(Rectangle r) {}
232
233 /**
234 * Overridden for performance reasons.
235 * See the <a href="#override">Implementation Note</a>
236 * for more information.
237 */
238 protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) {
239 // Strings get interned...
240 if (propertyName == "text"
241 || ((propertyName == "font" || propertyName == "foreground")
242 && oldValue != newValue
243 && getClientProperty(javax.swing.plaf.basic.BasicHTML.propertyKey) != null)) {
244
245 super.firePropertyChange(propertyName, oldValue, newValue);
246 }
247 }
248
249 /**
250 * Overridden for performance reasons.
251 * See the <a href="#override">Implementation Note</a>
252 * for more information.
253 */
254 public void firePropertyChange(String propertyName, byte oldValue, byte newValue) {}
255
256 /**
257 * Overridden for performance reasons.
258 * See the <a href="#override">Implementation Note</a>
259 * for more information.
260 */
261 public void firePropertyChange(String propertyName, char oldValue, char newValue) {}
262
263 /**
264 * Overridden for performance reasons.
265 * See the <a href="#override">Implementation Note</a>
266 * for more information.
267 */
268 public void firePropertyChange(String propertyName, short oldValue, short newValue) {}
269
270 /**
271 * Overridden for performance reasons.
272 * See the <a href="#override">Implementation Note</a>
273 * for more information.
274 */
275 public void firePropertyChange(String propertyName, int oldValue, int newValue) {}
276
277 /**
278 * Overridden for performance reasons.
279 * See the <a href="#override">Implementation Note</a>
280 * for more information.
281 */
282 public void firePropertyChange(String propertyName, long oldValue, long newValue) {}
283
284 /**
285 * Overridden for performance reasons.
286 * See the <a href="#override">Implementation Note</a>
287 * for more information.
288 */
289 public void firePropertyChange(String propertyName, float oldValue, float newValue) {}
290
291 /**
292 * Overridden for performance reasons.
293 * See the <a href="#override">Implementation Note</a>
294 * for more information.
295 */
296 public void firePropertyChange(String propertyName, double oldValue, double newValue) {}
297
298 /**
299 * Overridden for performance reasons.
300 * See the <a href="#override">Implementation Note</a>
301 * for more information.
302 */
303 public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) {}
304
305 /**
306 * A subclass of DefaultListCellRenderer that implements UIResource.
307 * DefaultListCellRenderer doesn't implement UIResource
308 * directly so that applications can safely override the
309 * cellRenderer property with DefaultListCellRenderer subclasses.
310 * <p>
311 * <strong>Warning:</strong>
312 * Serialized objects of this class will not be compatible with
313 * future Swing releases. The current serialization support is
314 * appropriate for short term storage or RMI between applications running
315 * the same version of Swing. As of 1.4, support for long term storage
316 * of all JavaBeans<sup><font size="-2">TM</font></sup>
317 * has been added to the <code>java.beans</code> package.
318 * Please see {@link java.beans.XMLEncoder}.
319 */
320 public static class UIResource extends DefaultListCellRenderer
321 implements javax.swing.plaf.UIResource
322 {
323 }
324
325 }
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