1 /*
2 * Copyright (c) 1998, 2014, 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 @SuppressWarnings("serial") // Same-version serialization only
86 public class DefaultTableCellRenderer extends JLabel
87 implements TableCellRenderer, Serializable
88 {
89
90 /**
91 * An empty <code>Border</code>. This field might not be used. To change the
92 * <code>Border</code> used by this renderer override the
93 * <code>getTableCellRendererComponent</code> method and set the border
94 * of the returned component directly.
95 */
96 private static final Border SAFE_NO_FOCUS_BORDER = new EmptyBorder(1, 1, 1, 1);
97 private static final Border DEFAULT_NO_FOCUS_BORDER = new EmptyBorder(1, 1, 1, 1);
98 protected static Border noFocusBorder = DEFAULT_NO_FOCUS_BORDER;
99
100 // We need a place to store the color the JLabel should be returned
101 // to after its foreground and background colors have been set
102 // to the selection background color.
103 // These ivars will be made protected when their names are finalized.
104 private Color unselectedForeground;
105 private Color unselectedBackground;
106
107 /**
108 * Creates a default table cell renderer.
109 */
110 public DefaultTableCellRenderer() {
111 super();
112 setOpaque(true);
113 setBorder(getNoFocusBorder());
114 setName("Table.cellRenderer");
115 }
116
117 private Border getNoFocusBorder() {
118 Border border = DefaultLookup.getBorder(this, ui, "Table.cellNoFocusBorder");
119 if (System.getSecurityManager() != null) {
120 if (border != null) return border;
121 return SAFE_NO_FOCUS_BORDER;
122 } else if (border != null) {
123 if (noFocusBorder == null || noFocusBorder == DEFAULT_NO_FOCUS_BORDER) {
124 return border;
125 }
126 }
127 return noFocusBorder;
128 }
129
130 /**
131 * Overrides <code>JComponent.setForeground</code> to assign
132 * the unselected-foreground color to the specified color.
133 *
134 * @param c set the foreground color to this value
135 */
136 public void setForeground(Color c) {
137 super.setForeground(c);
138 unselectedForeground = c;
139 }
140
141 /**
142 * Overrides <code>JComponent.setBackground</code> to assign
143 * the unselected-background color to the specified color.
144 *
145 * @param c set the background color to this value
146 */
147 public void setBackground(Color c) {
148 super.setBackground(c);
149 unselectedBackground = c;
150 }
151
152 /**
153 * Notification from the <code>UIManager</code> that the look and feel
154 * [L&F] has changed.
155 * Replaces the current UI object with the latest version from the
156 * <code>UIManager</code>.
157 *
158 * @see JComponent#updateUI
159 */
160 public void updateUI() {
161 super.updateUI();
162 setForeground(null);
163 setBackground(null);
164 }
165
166 // implements javax.swing.table.TableCellRenderer
167 /**
168 *
169 * Returns the default table cell renderer.
170 * <p>
171 * During a printing operation, this method will be called with
172 * <code>isSelected</code> and <code>hasFocus</code> values of
173 * <code>false</code> to prevent selection and focus from appearing
174 * in the printed output. To do other customization based on whether
175 * or not the table is being printed, check the return value from
176 * {@link javax.swing.JComponent#isPaintingForPrint()}.
177 *
178 * @param table the <code>JTable</code>
179 * @param value the value to assign to the cell at
180 * <code>[row, column]</code>
181 * @param isSelected true if cell is selected
182 * @param hasFocus true if cell has focus
183 * @param row the row of the cell to render
184 * @param column the column of the cell to render
185 * @return the default table cell renderer
186 * @see javax.swing.JComponent#isPaintingForPrint()
187 */
188 public Component getTableCellRendererComponent(JTable table, Object value,
189 boolean isSelected, boolean hasFocus, int row, int column) {
190 if (table == null) {
191 return this;
192 }
193
194 Color fg = null;
195 Color bg = null;
196
197 JTable.DropLocation dropLocation = table.getDropLocation();
198 if (dropLocation != null
199 && !dropLocation.isInsertRow()
200 && !dropLocation.isInsertColumn()
201 && dropLocation.getRow() == row
202 && dropLocation.getColumn() == column) {
203
204 fg = DefaultLookup.getColor(this, ui, "Table.dropCellForeground");
205 bg = DefaultLookup.getColor(this, ui, "Table.dropCellBackground");
206
207 isSelected = true;
208 }
209
210 if (isSelected) {
211 super.setForeground(fg == null ? table.getSelectionForeground()
212 : fg);
213 super.setBackground(bg == null ? table.getSelectionBackground()
214 : bg);
215 } else {
216 Color background = unselectedBackground != null
217 ? unselectedBackground
218 : table.getBackground();
219 if (background == null || background instanceof javax.swing.plaf.UIResource) {
220 Color alternateColor = DefaultLookup.getColor(this, ui, "Table.alternateRowColor");
221 if (alternateColor != null && row % 2 != 0) {
222 background = alternateColor;
223 }
224 }
225 super.setForeground(unselectedForeground != null
226 ? unselectedForeground
227 : table.getForeground());
228 super.setBackground(background);
229 }
230
231 setFont(table.getFont());
232
233 if (hasFocus) {
234 Border border = null;
235 if (isSelected) {
236 border = DefaultLookup.getBorder(this, ui, "Table.focusSelectedCellHighlightBorder");
237 }
238 if (border == null) {
239 border = DefaultLookup.getBorder(this, ui, "Table.focusCellHighlightBorder");
240 }
241 setBorder(border);
242
243 if (!isSelected && table.isCellEditable(row, column)) {
244 Color col;
245 col = DefaultLookup.getColor(this, ui, "Table.focusCellForeground");
246 if (col != null) {
247 super.setForeground(col);
248 }
249 col = DefaultLookup.getColor(this, ui, "Table.focusCellBackground");
250 if (col != null) {
251 super.setBackground(col);
252 }
253 }
254 } else {
255 setBorder(getNoFocusBorder());
256 }
257
258 setValue(value);
259
260 return this;
261 }
262
263 /*
264 * The following methods are overridden as a performance measure to
265 * to prune code-paths are often called in the case of renders
266 * but which we know are unnecessary. Great care should be taken
267 * when writing your own renderer to weigh the benefits and
268 * drawbacks of overriding methods like these.
269 */
270
271 /**
272 * Overridden for performance reasons.
273 * See the <a href="#override">Implementation Note</a>
274 * for more information.
275 */
276 public boolean isOpaque() {
277 Color back = getBackground();
278 Component p = getParent();
279 if (p != null) {
280 p = p.getParent();
281 }
282
283 // p should now be the JTable.
284 boolean colorMatch = (back != null) && (p != null) &&
285 back.equals(p.getBackground()) &&
286 p.isOpaque();
287 return !colorMatch && super.isOpaque();
288 }
289
290 /**
291 * Overridden for performance reasons.
292 * See the <a href="#override">Implementation Note</a>
293 * for more information.
294 *
295 * @since 1.5
296 */
297 public void invalidate() {}
298
299 /**
300 * Overridden for performance reasons.
301 * See the <a href="#override">Implementation Note</a>
302 * for more information.
303 */
304 public void validate() {}
305
306 /**
307 * Overridden for performance reasons.
308 * See the <a href="#override">Implementation Note</a>
309 * for more information.
310 */
311 public void revalidate() {}
312
313 /**
314 * Overridden for performance reasons.
315 * See the <a href="#override">Implementation Note</a>
316 * for more information.
317 */
318 public void repaint(long tm, int x, int y, int width, int height) {}
319
320 /**
321 * Overridden for performance reasons.
322 * See the <a href="#override">Implementation Note</a>
323 * for more information.
324 */
325 public void repaint(Rectangle r) { }
326
327 /**
328 * Overridden for performance reasons.
329 * See the <a href="#override">Implementation Note</a>
330 * for more information.
331 *
332 * @since 1.5
333 */
334 public void repaint() {
335 }
336
337 /**
338 * Overridden for performance reasons.
339 * See the <a href="#override">Implementation Note</a>
340 * for more information.
341 */
342 protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) {
343 // Strings get interned...
344 if (propertyName=="text"
345 || propertyName == "labelFor"
346 || propertyName == "displayedMnemonic"
347 || ((propertyName == "font" || propertyName == "foreground")
348 && oldValue != newValue
349 && getClientProperty(javax.swing.plaf.basic.BasicHTML.propertyKey) != null)) {
350
351 super.firePropertyChange(propertyName, oldValue, newValue);
352 }
353 }
354
355 /**
356 * Overridden for performance reasons.
357 * See the <a href="#override">Implementation Note</a>
358 * for more information.
359 */
360 public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) { }
361
362
363 /**
364 * Sets the <code>String</code> object for the cell being rendered to
365 * <code>value</code>.
366 *
367 * @param value the string value for this cell; if value is
368 * <code>null</code> it sets the text value to an empty string
369 * @see JLabel#setText
370 *
371 */
372 protected void setValue(Object value) {
373 setText((value == null) ? "" : value.toString());
374 }
375
376
377 /**
378 * A subclass of <code>DefaultTableCellRenderer</code> that
379 * implements <code>UIResource</code>.
380 * <code>DefaultTableCellRenderer</code> doesn't implement
381 * <code>UIResource</code>
382 * directly so that applications can safely override the
383 * <code>cellRenderer</code> property with
384 * <code>DefaultTableCellRenderer</code> subclasses.
385 * <p>
386 * <strong>Warning:</strong>
387 * Serialized objects of this class will not be compatible with
388 * future Swing releases. The current serialization support is
389 * appropriate for short term storage or RMI between applications running
390 * the same version of Swing. As of 1.4, support for long term storage
391 * of all JavaBeans™
392 * has been added to the <code>java.beans</code> package.
393 * Please see {@link java.beans.XMLEncoder}.
394 */
395 @SuppressWarnings("serial") // Same-version serialization only
396 public static class UIResource extends DefaultTableCellRenderer
397 implements javax.swing.plaf.UIResource
398 {
399 }
400
401 }