1 /*
2 * Copyright (c) 1998, 2017, 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 id="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 /**
99 * A border without focus.
100 */
101 protected static Border noFocusBorder = DEFAULT_NO_FOCUS_BORDER;
102
103 // We need a place to store the color the JLabel should be returned
104 // to after its foreground and background colors have been set
105 // to the selection background color.
106 // These ivars will be made protected when their names are finalized.
107 private Color unselectedForeground;
108 private Color unselectedBackground;
109
110 /**
111 * Creates a default table cell renderer.
112 */
113 public DefaultTableCellRenderer() {
114 super();
115 setOpaque(true);
116 setBorder(getNoFocusBorder());
117 setName("Table.cellRenderer");
118 }
119
120 private Border getNoFocusBorder() {
121 Border border = DefaultLookup.getBorder(this, ui, "Table.cellNoFocusBorder");
122 if (System.getSecurityManager() != null) {
123 if (border != null) return border;
124 return SAFE_NO_FOCUS_BORDER;
125 } else if (border != null) {
126 if (noFocusBorder == null || noFocusBorder == DEFAULT_NO_FOCUS_BORDER) {
127 return border;
128 }
129 }
130 return noFocusBorder;
131 }
132
133 /**
134 * Overrides <code>JComponent.setForeground</code> to assign
135 * the unselected-foreground color to the specified color.
136 *
137 * @param c set the foreground color to this value
138 */
139 public void setForeground(Color c) {
140 super.setForeground(c);
141 unselectedForeground = c;
142 }
143
144 /**
145 * Overrides <code>JComponent.setBackground</code> to assign
146 * the unselected-background color to the specified color.
147 *
148 * @param c set the background color to this value
149 */
150 public void setBackground(Color c) {
151 super.setBackground(c);
152 unselectedBackground = c;
153 }
154
155 /**
156 * Notification from the <code>UIManager</code> that the look and feel
157 * [L&F] has changed.
158 * Replaces the current UI object with the latest version from the
159 * <code>UIManager</code>.
160 *
161 * @see JComponent#updateUI
162 */
163 public void updateUI() {
164 super.updateUI();
165 setForeground(null);
166 setBackground(null);
167 }
168
169 // implements javax.swing.table.TableCellRenderer
170 /**
171 *
172 * Returns the default table cell renderer.
173 * <p>
174 * During a printing operation, this method will be called with
175 * <code>isSelected</code> and <code>hasFocus</code> values of
176 * <code>false</code> to prevent selection and focus from appearing
177 * in the printed output. To do other customization based on whether
178 * or not the table is being printed, check the return value from
179 * {@link javax.swing.JComponent#isPaintingForPrint()}.
180 *
181 * @param table the <code>JTable</code>
182 * @param value the value to assign to the cell at
183 * <code>[row, column]</code>
184 * @param isSelected true if cell is selected
185 * @param hasFocus true if cell has focus
186 * @param row the row of the cell to render
187 * @param column the column of the cell to render
188 * @return the default table cell renderer
189 * @see javax.swing.JComponent#isPaintingForPrint()
190 */
191 public Component getTableCellRendererComponent(JTable table, Object value,
192 boolean isSelected, boolean hasFocus, int row, int column) {
193 if (table == null) {
194 return this;
195 }
196
197 Color fg = null;
198 Color bg = null;
199
200 JTable.DropLocation dropLocation = table.getDropLocation();
201 if (dropLocation != null
202 && !dropLocation.isInsertRow()
203 && !dropLocation.isInsertColumn()
204 && dropLocation.getRow() == row
205 && dropLocation.getColumn() == column) {
206
207 fg = DefaultLookup.getColor(this, ui, "Table.dropCellForeground");
208 bg = DefaultLookup.getColor(this, ui, "Table.dropCellBackground");
209
210 isSelected = true;
211 }
212
213 if (isSelected) {
214 super.setForeground(fg == null ? table.getSelectionForeground()
215 : fg);
216 super.setBackground(bg == null ? table.getSelectionBackground()
217 : bg);
218 } else {
219 Color background = unselectedBackground != null
220 ? unselectedBackground
221 : table.getBackground();
222 if (background == null || background instanceof javax.swing.plaf.UIResource) {
223 Color alternateColor = DefaultLookup.getColor(this, ui, "Table.alternateRowColor");
224 if (alternateColor != null && row % 2 != 0) {
225 background = alternateColor;
226 }
227 }
228 super.setForeground(unselectedForeground != null
229 ? unselectedForeground
230 : table.getForeground());
231 super.setBackground(background);
232 }
233
234 setFont(table.getFont());
235
236 if (hasFocus) {
237 Border border = null;
238 if (isSelected) {
239 border = DefaultLookup.getBorder(this, ui, "Table.focusSelectedCellHighlightBorder");
240 }
241 if (border == null) {
242 border = DefaultLookup.getBorder(this, ui, "Table.focusCellHighlightBorder");
243 }
244 setBorder(border);
245
246 if (!isSelected && table.isCellEditable(row, column)) {
247 Color col;
248 col = DefaultLookup.getColor(this, ui, "Table.focusCellForeground");
249 if (col != null) {
250 super.setForeground(col);
251 }
252 col = DefaultLookup.getColor(this, ui, "Table.focusCellBackground");
253 if (col != null) {
254 super.setBackground(col);
255 }
256 }
257 } else {
258 setBorder(getNoFocusBorder());
259 }
260
261 setValue(value);
262
263 return this;
264 }
265
266 /*
267 * The following methods are overridden as a performance measure to
268 * to prune code-paths are often called in the case of renders
269 * but which we know are unnecessary. Great care should be taken
270 * when writing your own renderer to weigh the benefits and
271 * drawbacks of overriding methods like these.
272 */
273
274 /**
275 * Overridden for performance reasons.
276 * See the <a href="#override">Implementation Note</a>
277 * for more information.
278 */
279 public boolean isOpaque() {
280 Color back = getBackground();
281 Component p = getParent();
282 if (p != null) {
283 p = p.getParent();
284 }
285
286 // p should now be the JTable.
287 boolean colorMatch = (back != null) && (p != null) &&
288 back.equals(p.getBackground()) &&
289 p.isOpaque();
290 return !colorMatch && super.isOpaque();
291 }
292
293 /**
294 * Overridden for performance reasons.
295 * See the <a href="#override">Implementation Note</a>
296 * for more information.
297 *
298 * @since 1.5
299 */
300 public void invalidate() {}
301
302 /**
303 * Overridden for performance reasons.
304 * See the <a href="#override">Implementation Note</a>
305 * for more information.
306 */
307 public void validate() {}
308
309 /**
310 * Overridden for performance reasons.
311 * See the <a href="#override">Implementation Note</a>
312 * for more information.
313 */
314 public void revalidate() {}
315
316 /**
317 * Overridden for performance reasons.
318 * See the <a href="#override">Implementation Note</a>
319 * for more information.
320 */
321 public void repaint(long tm, int x, int y, int width, int height) {}
322
323 /**
324 * Overridden for performance reasons.
325 * See the <a href="#override">Implementation Note</a>
326 * for more information.
327 */
328 public void repaint(Rectangle r) { }
329
330 /**
331 * Overridden for performance reasons.
332 * See the <a href="#override">Implementation Note</a>
333 * for more information.
334 *
335 * @since 1.5
336 */
337 public void repaint() {
338 }
339
340 /**
341 * Overridden for performance reasons.
342 * See the <a href="#override">Implementation Note</a>
343 * for more information.
344 */
345 protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) {
346 // Strings get interned...
347 if (propertyName=="text"
348 || propertyName == "labelFor"
349 || propertyName == "displayedMnemonic"
350 || ((propertyName == "font" || propertyName == "foreground")
351 && oldValue != newValue
352 && getClientProperty(javax.swing.plaf.basic.BasicHTML.propertyKey) != null)) {
353
354 super.firePropertyChange(propertyName, oldValue, newValue);
355 }
356 }
357
358 /**
359 * Overridden for performance reasons.
360 * See the <a href="#override">Implementation Note</a>
361 * for more information.
362 */
363 public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) { }
364
365
366 /**
367 * Sets the <code>String</code> object for the cell being rendered to
368 * <code>value</code>.
369 *
370 * @param value the string value for this cell; if value is
371 * <code>null</code> it sets the text value to an empty string
372 * @see JLabel#setText
373 *
374 */
375 protected void setValue(Object value) {
376 setText((value == null) ? "" : value.toString());
377 }
378
379
380 /**
381 * A subclass of <code>DefaultTableCellRenderer</code> that
382 * implements <code>UIResource</code>.
383 * <code>DefaultTableCellRenderer</code> doesn't implement
384 * <code>UIResource</code>
385 * directly so that applications can safely override the
386 * <code>cellRenderer</code> property with
387 * <code>DefaultTableCellRenderer</code> subclasses.
388 * <p>
389 * <strong>Warning:</strong>
390 * Serialized objects of this class will not be compatible with
391 * future Swing releases. The current serialization support is
392 * appropriate for short term storage or RMI between applications running
393 * the same version of Swing. As of 1.4, support for long term storage
394 * of all JavaBeans™
395 * has been added to the <code>java.beans</code> package.
396 * Please see {@link java.beans.XMLEncoder}.
397 */
398 @SuppressWarnings("serial") // Same-version serialization only
399 public static class UIResource extends DefaultTableCellRenderer
400 implements javax.swing.plaf.UIResource
401 {
402 }
403
404 }