1 /*
2 * Copyright (c) 1998, 2010, 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 javax.swing.table;
27
28 import javax.swing.*;
29 import javax.swing.border.*;
30
31 import java.awt.Component;
32 import java.awt.Color;
33 import java.awt.Rectangle;
34
35 import java.io.Serializable;
36 import sun.swing.DefaultLookup;
37
38
39 /**
40 * The standard class for rendering (displaying) individual cells
41 * in a <code>JTable</code>.
42 * <p>
43 *
44 * <strong><a name="override">Implementation Note:</a></strong>
45 * This class inherits from <code>JLabel</code>, a standard component class.
46 * However <code>JTable</code> employs a unique mechanism for rendering
47 * its cells and therefore requires some slightly modified behavior
48 * from its cell renderer.
49 * The table class defines a single cell renderer and uses it as a
50 * as a rubber-stamp for rendering all cells in the table;
51 * it renders the first cell,
52 * changes the contents of that cell renderer,
53 * shifts the origin to the new location, re-draws it, and so on.
54 * The standard <code>JLabel</code> component was not
55 * designed to be used this way and we want to avoid
56 * triggering a <code>revalidate</code> each time the
57 * cell is drawn. This would greatly decrease performance because the
58 * <code>revalidate</code> message would be
59 * passed up the hierarchy of the container to determine whether any other
60 * components would be affected.
61 * As the renderer is only parented for the lifetime of a painting operation
62 * we similarly want to avoid the overhead associated with walking the
63 * hierarchy for painting operations.
64 * So this class
65 * overrides the <code>validate</code>, <code>invalidate</code>,
66 * <code>revalidate</code>, <code>repaint</code>, and
67 * <code>firePropertyChange</code> methods to be
68 * no-ops and override the <code>isOpaque</code> method solely to improve
69 * performance. If you write your own renderer,
70 * please keep this performance consideration in mind.
71 * <p>
72 *
73 * <strong>Warning:</strong>
74 * Serialized objects of this class will not be compatible with
75 * future Swing releases. The current serialization support is
76 * appropriate for short term storage or RMI between applications running
77 * the same version of Swing. As of 1.4, support for long term storage
78 * of all JavaBeans™
79 * has been added to the <code>java.beans</code> package.
80 * Please see {@link java.beans.XMLEncoder}.
81 *
82 * @author Philip Milne
83 * @see JTable
84 */
85 public class DefaultTableCellRenderer extends JLabel
86 implements TableCellRenderer, Serializable
87 {
88
89 /**
90 * An empty <code>Border</code>. This field might not be used. To change the
91 * <code>Border</code> used by this renderer override the
92 * <code>getTableCellRendererComponent</code> method and set the border
93 * of the returned component directly.
94 */
95 private static final Border SAFE_NO_FOCUS_BORDER = new EmptyBorder(1, 1, 1, 1);
96 private static final Border DEFAULT_NO_FOCUS_BORDER = new EmptyBorder(1, 1, 1, 1);
97 protected static Border noFocusBorder = DEFAULT_NO_FOCUS_BORDER;
98
99 // We need a place to store the color the JLabel should be returned
100 // to after its foreground and background colors have been set
101 // to the selection background color.
102 // These ivars will be made protected when their names are finalized.
103 private Color unselectedForeground;
104 private Color unselectedBackground;
105
106 /**
107 * Creates a default table cell renderer.
108 */
109 public DefaultTableCellRenderer() {
110 super();
111 setOpaque(true);
112 setBorder(getNoFocusBorder());
113 setName("Table.cellRenderer");
114 }
115
116 private Border getNoFocusBorder() {
117 Border border = DefaultLookup.getBorder(this, ui, "Table.cellNoFocusBorder");
118 if (System.getSecurityManager() != null) {
119 if (border != null) return border;
120 return SAFE_NO_FOCUS_BORDER;
121 } else if (border != null) {
122 if (noFocusBorder == null || noFocusBorder == DEFAULT_NO_FOCUS_BORDER) {
123 return border;
124 }
125 }
126 return noFocusBorder;
127 }
128
129 /**
130 * Overrides <code>JComponent.setForeground</code> to assign
131 * the unselected-foreground color to the specified color.
132 *
133 * @param c set the foreground color to this value
134 */
135 public void setForeground(Color c) {
136 super.setForeground(c);
137 unselectedForeground = c;
138 }
139
140 /**
141 * Overrides <code>JComponent.setBackground</code> to assign
142 * the unselected-background color to the specified color.
143 *
144 * @param c set the background color to this value
145 */
146 public void setBackground(Color c) {
147 super.setBackground(c);
148 unselectedBackground = c;
149 }
150
151 /**
152 * Notification from the <code>UIManager</code> that the look and feel
153 * [L&F] has changed.
154 * Replaces the current UI object with the latest version from the
155 * <code>UIManager</code>.
156 *
157 * @see JComponent#updateUI
158 */
159 public void updateUI() {
160 super.updateUI();
161 setForeground(null);
162 setBackground(null);
163 }
164
165 // implements javax.swing.table.TableCellRenderer
166 /**
167 *
168 * Returns the default table cell renderer.
169 * <p>
170 * During a printing operation, this method will be called with
171 * <code>isSelected</code> and <code>hasFocus</code> values of
172 * <code>false</code> to prevent selection and focus from appearing
173 * in the printed output. To do other customization based on whether
174 * or not the table is being printed, check the return value from
175 * {@link javax.swing.JComponent#isPaintingForPrint()}.
176 *
177 * @param table the <code>JTable</code>
178 * @param value the value to assign to the cell at
179 * <code>[row, column]</code>
180 * @param isSelected true if cell is selected
181 * @param hasFocus true if cell has focus
182 * @param row the row of the cell to render
183 * @param column the column of the cell to render
184 * @return the default table cell renderer
185 * @see javax.swing.JComponent#isPaintingForPrint()
186 */
187 public Component getTableCellRendererComponent(JTable table, Object value,
188 boolean isSelected, boolean hasFocus, int row, int column) {
189 if (table == null) {
190 return this;
191 }
192
193 Color fg = null;
194 Color bg = null;
195
196 JTable.DropLocation dropLocation = table.getDropLocation();
197 if (dropLocation != null
198 && !dropLocation.isInsertRow()
199 && !dropLocation.isInsertColumn()
200 && dropLocation.getRow() == row
201 && dropLocation.getColumn() == column) {
202
203 fg = DefaultLookup.getColor(this, ui, "Table.dropCellForeground");
204 bg = DefaultLookup.getColor(this, ui, "Table.dropCellBackground");
205
206 isSelected = true;
207 }
208
209 if (isSelected) {
210 super.setForeground(fg == null ? table.getSelectionForeground()
211 : fg);
212 super.setBackground(bg == null ? table.getSelectionBackground()
213 : bg);
214 } else {
215 Color background = unselectedBackground != null
216 ? unselectedBackground
217 : table.getBackground();
218 if (background == null || background instanceof javax.swing.plaf.UIResource) {
219 Color alternateColor = DefaultLookup.getColor(this, ui, "Table.alternateRowColor");
220 if (alternateColor != null && row % 2 != 0) {
221 background = alternateColor;
222 }
223 }
224 super.setForeground(unselectedForeground != null
225 ? unselectedForeground
226 : table.getForeground());
227 super.setBackground(background);
228 }
229
230 setFont(table.getFont());
231
232 if (hasFocus) {
233 Border border = null;
234 if (isSelected) {
235 border = DefaultLookup.getBorder(this, ui, "Table.focusSelectedCellHighlightBorder");
236 }
237 if (border == null) {
238 border = DefaultLookup.getBorder(this, ui, "Table.focusCellHighlightBorder");
239 }
240 setBorder(border);
241
242 if (!isSelected && table.isCellEditable(row, column)) {
243 Color col;
244 col = DefaultLookup.getColor(this, ui, "Table.focusCellForeground");
245 if (col != null) {
246 super.setForeground(col);
247 }
248 col = DefaultLookup.getColor(this, ui, "Table.focusCellBackground");
249 if (col != null) {
250 super.setBackground(col);
251 }
252 }
253 } else {
254 setBorder(getNoFocusBorder());
255 }
256
257 setValue(value);
258
259 return this;
260 }
261
262 /*
263 * The following methods are overridden as a performance measure to
264 * to prune code-paths are often called in the case of renders
265 * but which we know are unnecessary. Great care should be taken
266 * when writing your own renderer to weigh the benefits and
267 * drawbacks of overriding methods like these.
268 */
269
270 /**
271 * Overridden for performance reasons.
272 * See the <a href="#override">Implementation Note</a>
273 * for more information.
274 */
275 public boolean isOpaque() {
276 Color back = getBackground();
277 Component p = getParent();
278 if (p != null) {
279 p = p.getParent();
280 }
281
282 // p should now be the JTable.
283 boolean colorMatch = (back != null) && (p != null) &&
284 back.equals(p.getBackground()) &&
285 p.isOpaque();
286 return !colorMatch && super.isOpaque();
287 }
288
289 /**
290 * Overridden for performance reasons.
291 * See the <a href="#override">Implementation Note</a>
292 * for more information.
293 *
294 * @since 1.5
295 */
296 public void invalidate() {}
297
298 /**
299 * Overridden for performance reasons.
300 * See the <a href="#override">Implementation Note</a>
301 * for more information.
302 */
303 public void validate() {}
304
305 /**
306 * Overridden for performance reasons.
307 * See the <a href="#override">Implementation Note</a>
308 * for more information.
309 */
310 public void revalidate() {}
311
312 /**
313 * Overridden for performance reasons.
314 * See the <a href="#override">Implementation Note</a>
315 * for more information.
316 */
317 public void repaint(long tm, int x, int y, int width, int height) {}
318
319 /**
320 * Overridden for performance reasons.
321 * See the <a href="#override">Implementation Note</a>
322 * for more information.
323 */
324 public void repaint(Rectangle r) { }
325
326 /**
327 * Overridden for performance reasons.
328 * See the <a href="#override">Implementation Note</a>
329 * for more information.
330 *
331 * @since 1.5
332 */
333 public void repaint() {
334 }
335
336 /**
337 * Overridden for performance reasons.
338 * See the <a href="#override">Implementation Note</a>
339 * for more information.
340 */
341 protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) {
342 // Strings get interned...
343 if (propertyName=="text"
344 || propertyName == "labelFor"
345 || propertyName == "displayedMnemonic"
346 || ((propertyName == "font" || propertyName == "foreground")
347 && oldValue != newValue
348 && getClientProperty(javax.swing.plaf.basic.BasicHTML.propertyKey) != null)) {
349
350 super.firePropertyChange(propertyName, oldValue, newValue);
351 }
352 }
353
354 /**
355 * Overridden for performance reasons.
356 * See the <a href="#override">Implementation Note</a>
357 * for more information.
358 */
359 public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) { }
360
361
362 /**
363 * Sets the <code>String</code> object for the cell being rendered to
364 * <code>value</code>.
365 *
366 * @param value the string value for this cell; if value is
367 * <code>null</code> it sets the text value to an empty string
368 * @see JLabel#setText
369 *
370 */
371 protected void setValue(Object value) {
372 setText((value == null) ? "" : value.toString());
373 }
374
375
376 /**
377 * A subclass of <code>DefaultTableCellRenderer</code> that
378 * implements <code>UIResource</code>.
379 * <code>DefaultTableCellRenderer</code> doesn't implement
380 * <code>UIResource</code>
381 * directly so that applications can safely override the
382 * <code>cellRenderer</code> property with
383 * <code>DefaultTableCellRenderer</code> subclasses.
384 * <p>
385 * <strong>Warning:</strong>
386 * Serialized objects of this class will not be compatible with
387 * future Swing releases. The current serialization support is
388 * appropriate for short term storage or RMI between applications running
389 * the same version of Swing. As of 1.4, support for long term storage
390 * of all JavaBeans™
391 * has been added to the <code>java.beans</code> package.
392 * Please see {@link java.beans.XMLEncoder}.
393 */
394 public static class UIResource extends DefaultTableCellRenderer
395 implements javax.swing.plaf.UIResource
396 {
397 }
398
399 }