1 /*
2 * Copyright (c) 1997, 2013, 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;
27
28 import java.awt.Font;
29 import java.awt.event.InputEvent;
30 import java.awt.event.KeyEvent;
31 import java.awt.Color;
32 import java.awt.Component;
33 import java.awt.SystemColor;
34 import java.awt.Toolkit;
35 import sun.awt.SunToolkit;
36
37 import javax.swing.text.*;
38 import javax.swing.border.*;
39 import javax.swing.plaf.*;
40
41 import java.net.URL;
42 import sun.swing.SwingUtilities2;
43 import sun.swing.DefaultLayoutStyle;
44 import sun.swing.ImageIconUIResource;
45
46 import java.util.StringTokenizer;
47
48
49 /**
50 * {@code LookAndFeel}, as the name implies, encapsulates a look and
51 * feel. Beyond installing a look and feel most developers never need to
52 * interact directly with {@code LookAndFeel}. In general only developers
53 * creating a custom look and feel need to concern themselves with this class.
54 * <p>
55 * Swing is built upon the foundation that each {@code JComponent}
56 * subclass has an implementation of a specific {@code ComponentUI}
57 * subclass. The {@code ComponentUI} is often referred to as "the ui",
58 * "component ui", or "look and feel delegate". The {@code ComponentUI}
59 * subclass is responsible for providing the look and feel specific
60 * functionality of the component. For example, {@code JTree} requires
61 * an implementation of the {@code ComponentUI} subclass {@code
62 * TreeUI}. The implementation of the specific {@code
63 * ComponentUI} subclass is provided by the {@code LookAndFeel}. Each
64 * {@code JComponent} subclass identifies the {@code ComponentUI}
65 * subclass it requires by way of the {@code JComponent} method {@code
66 * getUIClassID}.
67 * <p>
68 * Each {@code LookAndFeel} implementation must provide
69 * an implementation of the appropriate {@code ComponentUI} subclass by
70 * specifying a value for each of Swing's ui class ids in the {@code
71 * UIDefaults} object returned from {@code getDefaults}. For example,
72 * {@code BasicLookAndFeel} uses {@code BasicTreeUI} as the concrete
73 * implementation for {@code TreeUI}. This is accomplished by {@code
74 * BasicLookAndFeel} providing the key-value pair {@code
75 * "TreeUI"-"javax.swing.plaf.basic.BasicTreeUI"}, in the
76 * {@code UIDefaults} returned from {@code getDefaults}. Refer to
77 * {@link UIDefaults#getUI(JComponent)} for details on how the implementation
78 * of the {@code ComponentUI} subclass is obtained.
79 * <p>
80 * When a {@code LookAndFeel} is installed the {@code UIManager} does
81 * not check that an entry exists for all ui class ids. As such,
82 * random exceptions will occur if the current look and feel has not
83 * provided a value for a particular ui class id and an instance of
84 * the {@code JComponent} subclass is created.
85 *
86 * <h2>Recommendations for Look and Feels</h2>
87 *
88 * As noted in {@code UIManager} each {@code LookAndFeel} has the opportunity
89 * to provide a set of defaults that are layered in with developer and
90 * system defaults. Some of Swing's components require the look and feel
91 * to provide a specific set of defaults. These are documented in the
92 * classes that require the specific default.
93 *
94 * <h3><a name="defaultRecommendation">ComponentUIs and defaults</a></h3>
95 *
96 * All {@code ComponentUIs} typically need to set various properties
97 * on the {@code JComponent} the {@code ComponentUI} is providing the
98 * look and feel for. This is typically done when the {@code
99 * ComponentUI} is installed on the {@code JComponent}. Setting a
100 * property should only be done if the developer has not set the
101 * property. For non-primitive values it is recommended that the
102 * {@code ComponentUI} only change the property on the {@code
103 * JComponent} if the current value is {@code null} or implements
104 * {@code UIResource}. If the current value is {@code null} or
105 * implements {@code UIResource} it indicates the property has not
106 * been set by the developer, and the ui is free to change it. For
107 * example, {@code BasicButtonUI.installDefaults} only changes the
108 * font on the {@code JButton} if the return value from {@code
109 * button.getFont()} is {@code null} or implements {@code
110 * UIResource}. On the other hand if {@code button.getFont()} returned
111 * a {@code non-null} value that did not implement {@code UIResource}
112 * then {@code BasicButtonUI.installDefaults} would not change the
113 * {@code JButton}'s font.
114 * <p>
115 * For primitive values, such as {@code opaque}, the method {@code
116 * installProperty} should be invoked. {@code installProperty} only changes
117 * the corresponding property if the value has not been changed by the
118 * developer.
119 * <p>
120 * {@code ComponentUI} implementations should use the various install methods
121 * provided by this class as they handle the necessary checking and install
122 * the property using the recommended guidelines.
123 *
124 * <h3><a name="exceptions"></a>Exceptions</h3>
125 *
126 * All of the install methods provided by {@code LookAndFeel} need to
127 * access the defaults if the value of the property being changed is
128 * {@code null} or a {@code UIResource}. For example, installing the
129 * font does the following:
130 * <pre>
131 * JComponent c;
132 * Font font = c.getFont();
133 * if (font == null || (font instanceof UIResource)) {
134 * c.setFont(UIManager.getFont("fontKey"));
135 * }
136 * </pre>
137 * If the font is {@code null} or a {@code UIResource}, the
138 * defaults table is queried with the key {@code fontKey}. All of
139 * {@code UIDefault's} get methods throw a {@code
140 * NullPointerException} if passed in {@code null}. As such, unless
141 * otherwise noted each of the various install methods of {@code
142 * LookAndFeel} throw a {@code NullPointerException} if the current
143 * value is {@code null} or a {@code UIResource} and the supplied
144 * defaults key is {@code null}. In addition, unless otherwise specified
145 * all of the {@code install} methods throw a {@code NullPointerException} if
146 * a {@code null} component is passed in.
147 *
148 * @author Tom Ball
149 * @author Hans Muller
150 * @since 1.2
151 */
152 public abstract class LookAndFeel
153 {
154
155 /**
156 * Convenience method for setting a component's foreground
157 * and background color properties with values from the
158 * defaults. The properties are only set if the current
159 * value is either {@code null} or a {@code UIResource}.
160 *
161 * @param c component to set the colors on
162 * @param defaultBgName key for the background
163 * @param defaultFgName key for the foreground
164 *
165 * @see #installColorsAndFont
166 * @see UIManager#getColor
167 * @throws NullPointerException as described in
168 * <a href="#exceptions">exceptions</a>
169 */
170 public static void installColors(JComponent c,
171 String defaultBgName,
172 String defaultFgName)
173 {
174 Color bg = c.getBackground();
175 if (bg == null || bg instanceof UIResource) {
176 c.setBackground(UIManager.getColor(defaultBgName));
177 }
178
179 Color fg = c.getForeground();
180 if (fg == null || fg instanceof UIResource) {
181 c.setForeground(UIManager.getColor(defaultFgName));
182 }
183 }
184
185
186 /**
187 * Convenience method for setting a component's foreground,
188 * background and font properties with values from the
189 * defaults. The properties are only set if the current
190 * value is either {@code null} or a {@code UIResource}.
191 *
192 * @param c component set to the colors and font on
193 * @param defaultBgName key for the background
194 * @param defaultFgName key for the foreground
195 * @param defaultFontName key for the font
196 * @throws NullPointerException as described in
197 * <a href="#exceptions">exceptions</a>
198 *
199 * @see #installColors
200 * @see UIManager#getColor
201 * @see UIManager#getFont
202 */
203 public static void installColorsAndFont(JComponent c,
204 String defaultBgName,
205 String defaultFgName,
206 String defaultFontName) {
207 Font f = c.getFont();
208 if (f == null || f instanceof UIResource) {
209 c.setFont(UIManager.getFont(defaultFontName));
210 }
211
212 installColors(c, defaultBgName, defaultFgName);
213 }
214
215
216 /**
217 * Convenience method for setting a component's border property with
218 * a value from the defaults. The border is only set if the border is
219 * {@code null} or an instance of {@code UIResource}.
220 *
221 * @param c component to set the border on
222 * @param defaultBorderName key specifying the border
223 * @throws NullPointerException as described in
224 * <a href="#exceptions">exceptions</a>
225 */
226 public static void installBorder(JComponent c, String defaultBorderName) {
227 Border b = c.getBorder();
228 if (b == null || b instanceof UIResource) {
229 c.setBorder(UIManager.getBorder(defaultBorderName));
230 }
231 }
232
233
234 /**
235 * Convenience method for uninstalling a border. If the border of
236 * the component is a {@code UIResource}, it is set to {@code
237 * null}.
238 *
239 * @param c component to uninstall the border on
240 * @throws NullPointerException if {@code c} is {@code null}
241 */
242 public static void uninstallBorder(JComponent c) {
243 if (c.getBorder() instanceof UIResource) {
244 c.setBorder(null);
245 }
246 }
247
248 /**
249 * Convenience method for installing a property with the specified name
250 * and value on a component if that property has not already been set
251 * by the developer. This method is intended to be used by
252 * ui delegate instances that need to specify a default value for a
253 * property of primitive type (boolean, int, ..), but do not wish
254 * to override a value set by the client. Since primitive property
255 * values cannot be wrapped with the {@code UIResource} marker, this method
256 * uses private state to determine whether the property has been set
257 * by the client.
258 *
259 * @throws IllegalArgumentException if the specified property is not
260 * one which can be set using this method
261 * @throws ClassCastException if the property value has not been set
262 * by the developer and the type does not match the property's type
263 * @throws NullPointerException if {@code c} is {@code null}, or the
264 * named property has not been set by the developer and
265 * {@code propertyValue} is {@code null}
266 * @param c target component to set the property on
267 * @param propertyName name of the property to set
268 * @param propertyValue value of the property
269 * @since 1.5
270 */
271 public static void installProperty(JComponent c,
272 String propertyName, Object propertyValue) {
273 // this is a special case because the JPasswordField's ancestor hierarchy
274 // includes a class outside of javax.swing, thus we cannot call setUIProperty
275 // directly.
276 if (SunToolkit.isInstanceOf(c, "javax.swing.JPasswordField")) {
277 if (!((JPasswordField)c).customSetUIProperty(propertyName, propertyValue)) {
278 c.setUIProperty(propertyName, propertyValue);
279 }
280 } else {
281 c.setUIProperty(propertyName, propertyValue);
282 }
283 }
284
285 /**
286 * Convenience method for building an array of {@code
287 * KeyBindings}. While this method is not deprecated, developers
288 * should instead use {@code ActionMap} and {@code InputMap} for
289 * supplying key bindings.
290 * <p>
291 * This method returns an array of {@code KeyBindings}, one for each
292 * alternating {@code key-action} pair in {@code keyBindingList}.
293 * A {@code key} can either be a {@code String} in the format
294 * specified by the <code>KeyStroke.getKeyStroke</code> method, or
295 * a {@code KeyStroke}. The {@code action} part of the pair is a
296 * {@code String} that corresponds to the name of the {@code
297 * Action}.
298 * <p>
299 * The following example illustrates creating a {@code KeyBinding} array
300 * from six alternating {@code key-action} pairs:
301 * <pre>
302 * JTextComponent.KeyBinding[] multilineBindings = makeKeyBindings( new Object[] {
303 * "UP", DefaultEditorKit.upAction,
304 * "DOWN", DefaultEditorKit.downAction,
305 * "PAGE_UP", DefaultEditorKit.pageUpAction,
306 * "PAGE_DOWN", DefaultEditorKit.pageDownAction,
307 * "ENTER", DefaultEditorKit.insertBreakAction,
308 * "TAB", DefaultEditorKit.insertTabAction
309 * });
310 * </pre>
311 * If {@code keyBindingList's} length is odd, the last element is
312 * ignored.
313 * <p>
314 * Supplying a {@code null} value for either the {@code key} or
315 * {@code action} part of the {@code key-action} pair results in
316 * creating a {@code KeyBinding} with the corresponding value
317 * {@code null}. As other parts of Swing's expect {@code non-null} values
318 * in a {@code KeyBinding}, you should avoid supplying {@code null} as
319 * either the {@code key} or {@code action} part of the {@code key-action}
320 * pair.
321 *
322 * @param keyBindingList an array of {@code key-action} pairs
323 * @return an array of {@code KeyBindings}
324 * @throws NullPointerException if {@code keyBindingList} is {@code null}
325 * @throws ClassCastException if the {@code key} part of the pair is
326 * not a {@code KeyStroke} or {@code String}, or the
327 * {@code action} part of the pair is not a {@code String}
328 * @see ActionMap
329 * @see InputMap
330 * @see KeyStroke#getKeyStroke
331 */
332 public static JTextComponent.KeyBinding[] makeKeyBindings(Object[] keyBindingList)
333 {
334 JTextComponent.KeyBinding[] rv = new JTextComponent.KeyBinding[keyBindingList.length / 2];
335
336 for(int i = 0; i < rv.length; i ++) {
337 Object o = keyBindingList[2 * i];
338 KeyStroke keystroke = (o instanceof KeyStroke)
339 ? (KeyStroke) o
340 : KeyStroke.getKeyStroke((String) o);
341 String action = (String) keyBindingList[2 * i + 1];
342 rv[i] = new JTextComponent.KeyBinding(keystroke, action);
343 }
344
345 return rv;
346 }
347
348 /**
349 * Creates a {@code InputMapUIResource} from <code>keys</code>. This is
350 * a convenience method for creating a new {@code InputMapUIResource},
351 * invoking {@code loadKeyBindings(map, keys)}, and returning the
352 * {@code InputMapUIResource}.
353 *
354 * @param keys alternating pairs of {@code keystroke-action key}
355 * pairs as described in {@link #loadKeyBindings}
356 * @return newly created and populated {@code InputMapUIResource}
357 * @see #loadKeyBindings
358 *
359 * @since 1.3
360 */
361 public static InputMap makeInputMap(Object[] keys) {
362 InputMap retMap = new InputMapUIResource();
363 loadKeyBindings(retMap, keys);
364 return retMap;
365 }
366
367 /**
368 * Creates a {@code ComponentInputMapUIResource} from
369 * <code>keys</code>. This is a convenience method for creating a
370 * new {@code ComponentInputMapUIResource}, invoking {@code
371 * loadKeyBindings(map, keys)}, and returning the {@code
372 * ComponentInputMapUIResource}.
373 *
374 * @param c component to create the {@code ComponentInputMapUIResource}
375 * with
376 * @param keys alternating pairs of {@code keystroke-action key}
377 * pairs as described in {@link #loadKeyBindings}
378 * @return newly created and populated {@code InputMapUIResource}
379 * @throws IllegalArgumentException if {@code c} is {@code null}
380 *
381 * @see #loadKeyBindings
382 * @see ComponentInputMapUIResource
383 *
384 * @since 1.3
385 */
386 public static ComponentInputMap makeComponentInputMap(JComponent c,
387 Object[] keys) {
388 ComponentInputMap retMap = new ComponentInputMapUIResource(c);
389 loadKeyBindings(retMap, keys);
390 return retMap;
391 }
392
393
394 /**
395 * Populates an {@code InputMap} with the specified bindings.
396 * The bindings are supplied as a list of alternating
397 * {@code keystroke-action key} pairs. The {@code keystroke} is either
398 * an instance of {@code KeyStroke}, or a {@code String}
399 * that identifies the {@code KeyStroke} for the binding. Refer
400 * to {@code KeyStroke.getKeyStroke(String)} for the specific
401 * format. The {@code action key} part of the pair is the key
402 * registered in the {@code InputMap} for the {@code KeyStroke}.
403 * <p>
404 * The following illustrates loading an {@code InputMap} with two
405 * {@code key-action} pairs:
406 * <pre>
407 * LookAndFeel.loadKeyBindings(inputMap, new Object[] {
408 * "control X", "cut",
409 * "control V", "paste"
410 * });
411 * </pre>
412 * <p>
413 * Supplying a {@code null} list of bindings ({@code keys}) does not
414 * change {@code retMap} in any way.
415 * <p>
416 * Specifying a {@code null} {@code action key} results in
417 * removing the {@code keystroke's} entry from the {@code InputMap}.
418 * A {@code null} {@code keystroke} is ignored.
419 *
420 * @param retMap {@code InputMap} to add the {@code key-action}
421 * pairs to
422 * @param keys bindings to add to {@code retMap}
423 * @throws NullPointerException if {@code keys} is
424 * {@code non-null}, not empty, and {@code retMap} is
425 * {@code null}
426 *
427 * @see KeyStroke#getKeyStroke(String)
428 * @see InputMap
429 *
430 * @since 1.3
431 */
432 public static void loadKeyBindings(InputMap retMap, Object[] keys) {
433 if (keys != null) {
434 for (int counter = 0, maxCounter = keys.length;
435 counter < maxCounter; counter++) {
436 Object keyStrokeO = keys[counter++];
437 KeyStroke ks = (keyStrokeO instanceof KeyStroke) ?
438 (KeyStroke)keyStrokeO :
439 KeyStroke.getKeyStroke((String)keyStrokeO);
440 retMap.put(ks, keys[counter]);
441 }
442 }
443 }
444
445 /**
446 * Creates and returns a {@code UIDefault.LazyValue} that loads an
447 * image. The returned value is an implementation of {@code
448 * UIDefaults.LazyValue}. When {@code createValue} is invoked on
449 * the returned object, the image is loaded. If the image is {@code
450 * non-null}, it is then wrapped in an {@code Icon} that implements {@code
451 * UIResource}. The image is loaded using {@code
452 * Class.getResourceAsStream(gifFile)}.
453 * <p>
454 * This method does not check the arguments in any way. It is
455 * strongly recommended that {@code non-null} values are supplied else
456 * exceptions may occur when {@code createValue} is invoked on the
457 * returned object.
458 *
459 * @param baseClass {@code Class} used to load the resource
460 * @param gifFile path to the image to load
461 * @return a {@code UIDefaults.LazyValue}; when resolved the
462 * {@code LazyValue} loads the specified image
463 * @see UIDefaults.LazyValue
464 * @see Icon
465 * @see Class#getResourceAsStream(String)
466 */
467 public static Object makeIcon(final Class<?> baseClass, final String gifFile) {
468 return SwingUtilities2.makeIcon_Unprivileged(baseClass, baseClass, gifFile);
469 }
470
471 /**
472 * Returns the <code>LayoutStyle</code> for this look
473 * and feel. This never returns {@code null}.
474 * <p>
475 * You generally don't use the <code>LayoutStyle</code> from
476 * the look and feel, instead use the <code>LayoutStyle</code>
477 * method <code>getInstance</code>.
478 *
479 * @see LayoutStyle#getInstance
480 * @return the <code>LayoutStyle</code> for this look and feel
481 * @since 1.6
482 */
483 public LayoutStyle getLayoutStyle() {
484 return DefaultLayoutStyle.getInstance();
485 }
486
487 /**
488 * Invoked when the user attempts an invalid operation,
489 * such as pasting into an uneditable <code>JTextField</code>
490 * that has focus. The default implementation beeps. Subclasses
491 * that wish different behavior should override this and provide
492 * the additional feedback.
493 *
494 * @param component the <code>Component</code> the error occurred in,
495 * may be <code>null</code>
496 * indicating the error condition is not directly
497 * associated with a <code>Component</code>
498 * @since 1.4
499 */
500 public void provideErrorFeedback(Component component) {
501 Toolkit toolkit = null;
502 if (component != null) {
503 toolkit = component.getToolkit();
504 } else {
505 toolkit = Toolkit.getDefaultToolkit();
506 }
507 toolkit.beep();
508 } // provideErrorFeedback()
509
510 /**
511 * Returns the value of the specified system desktop property by
512 * invoking <code>Toolkit.getDefaultToolkit().getDesktopProperty()</code>.
513 * If the value of the specified property is {@code null},
514 * {@code fallbackValue} is returned.
515 *
516 * @param systemPropertyName the name of the system desktop property being queried
517 * @param fallbackValue the object to be returned as the value if the system value is null
518 * @return the current value of the desktop property
519 *
520 * @see java.awt.Toolkit#getDesktopProperty
521 *
522 * @since 1.4
523 */
524 public static Object getDesktopPropertyValue(String systemPropertyName, Object fallbackValue) {
525 Object value = Toolkit.getDefaultToolkit().getDesktopProperty(systemPropertyName);
526 if (value == null) {
527 return fallbackValue;
528 } else if (value instanceof Color) {
529 return new ColorUIResource((Color)value);
530 } else if (value instanceof Font) {
531 return new FontUIResource((Font)value);
532 }
533 return value;
534 }
535
536 /**
537 * Returns an <code>Icon</code> with a disabled appearance.
538 * This method is used to generate a disabled <code>Icon</code> when
539 * one has not been specified. For example, if you create a
540 * <code>JButton</code> and only specify an <code>Icon</code> via
541 * <code>setIcon</code> this method will be called to generate the
542 * disabled <code>Icon</code>. If {@code null} is passed as
543 * <code>icon</code> this method returns {@code null}.
544 * <p>
545 * Some look and feels might not render the disabled {@code Icon}, in which
546 * case they will ignore this.
547 *
548 * @param component {@code JComponent} that will display the {@code Icon},
549 * may be {@code null}
550 * @param icon {@code Icon} to generate the disabled icon from
551 * @return disabled {@code Icon}, or {@code null} if a suitable
552 * {@code Icon} can not be generated
553 * @since 1.5
554 */
555 public Icon getDisabledIcon(JComponent component, Icon icon) {
556 if (icon instanceof ImageIcon) {
557 return new ImageIconUIResource(GrayFilter.
558 createDisabledImage(((ImageIcon)icon).getImage()));
559 }
560 return null;
561 }
562
563 /**
564 * Returns an <code>Icon</code> for use by disabled
565 * components that are also selected. This method is used to generate an
566 * <code>Icon</code> for components that are in both the disabled and
567 * selected states but do not have a specific <code>Icon</code> for this
568 * state. For example, if you create a <code>JButton</code> and only
569 * specify an <code>Icon</code> via <code>setIcon</code> this method
570 * will be called to generate the disabled and selected
571 * <code>Icon</code>. If {@code null} is passed as <code>icon</code> this
572 * methods returns {@code null}.
573 * <p>
574 * Some look and feels might not render the disabled and selected
575 * {@code Icon}, in which case they will ignore this.
576 *
577 * @param component {@code JComponent} that will display the {@code Icon},
578 * may be {@code null}
579 * @param icon {@code Icon} to generate disabled and selected icon from
580 * @return disabled and selected icon, or {@code null} if a suitable
581 * {@code Icon} can not be generated.
582 * @since 1.5
583 */
584 public Icon getDisabledSelectedIcon(JComponent component, Icon icon) {
585 return getDisabledIcon(component, icon);
586 }
587
588 /**
589 * Return a short string that identifies this look and feel, e.g.
590 * "CDE/Motif". This string should be appropriate for a menu item.
591 * Distinct look and feels should have different names, e.g.
592 * a subclass of MotifLookAndFeel that changes the way a few components
593 * are rendered should be called "CDE/Motif My Way"; something
594 * that would be useful to a user trying to select a L&F from a list
595 * of names.
596 *
597 * @return short identifier for the look and feel
598 */
599 public abstract String getName();
600
601
602 /**
603 * Return a string that identifies this look and feel. This string
604 * will be used by applications/services that want to recognize
605 * well known look and feel implementations. Presently
606 * the well known names are "Motif", "Windows", "Mac", "Metal". Note
607 * that a LookAndFeel derived from a well known superclass
608 * that doesn't make any fundamental changes to the look or feel
609 * shouldn't override this method.
610 *
611 * @return identifier for the look and feel
612 */
613 public abstract String getID();
614
615
616 /**
617 * Return a one line description of this look and feel implementation,
618 * e.g. "The CDE/Motif Look and Feel". This string is intended for
619 * the user, e.g. in the title of a window or in a ToolTip message.
620 *
621 * @return short description for the look and feel
622 */
623 public abstract String getDescription();
624
625
626 /**
627 * Returns {@code true} if the <code>LookAndFeel</code> returned
628 * <code>RootPaneUI</code> instances support providing {@code Window}
629 * decorations in a <code>JRootPane</code>.
630 * <p>
631 * The default implementation returns {@code false}, subclasses that
632 * support {@code Window} decorations should override this and return
633 * {@code true}.
634 *
635 * @return {@code true} if the {@code RootPaneUI} instances created by
636 * this look and feel support client side decorations
637 * @see JDialog#setDefaultLookAndFeelDecorated
638 * @see JFrame#setDefaultLookAndFeelDecorated
639 * @see JRootPane#setWindowDecorationStyle
640 * @since 1.4
641 */
642 public boolean getSupportsWindowDecorations() {
643 return false;
644 }
645
646 /**
647 * If the underlying platform has a "native" look and feel, and
648 * this is an implementation of it, return {@code true}. For
649 * example, when the underlying platform is Solaris running CDE
650 * a CDE/Motif look and feel implementation would return {@code
651 * true}.
652 *
653 * @return {@code true} if this look and feel represents the underlying
654 * platform look and feel
655 */
656 public abstract boolean isNativeLookAndFeel();
657
658
659 /**
660 * Return {@code true} if the underlying platform supports and or permits
661 * this look and feel. This method returns {@code false} if the look
662 * and feel depends on special resources or legal agreements that
663 * aren't defined for the current platform.
664 *
665 *
666 * @return {@code true} if this is a supported look and feel
667 * @see UIManager#setLookAndFeel
668 */
669 public abstract boolean isSupportedLookAndFeel();
670
671
672 /**
673 * Initializes the look and feel. While this method is public,
674 * it should only be invoked by the {@code UIManager} when a
675 * look and feel is installed as the current look and feel. This
676 * method is invoked before the {@code UIManager} invokes
677 * {@code getDefaults}. This method is intended to perform any
678 * initialization for the look and feel. Subclasses
679 * should do any one-time setup they need here, rather than
680 * in a static initializer, because look and feel class objects
681 * may be loaded just to discover that {@code isSupportedLookAndFeel()}
682 * returns {@code false}.
683 *
684 * @see #uninitialize
685 * @see UIManager#setLookAndFeel
686 */
687 public void initialize() {
688 }
689
690
691 /**
692 * Uninitializes the look and feel. While this method is public,
693 * it should only be invoked by the {@code UIManager} when
694 * the look and feel is uninstalled. For example,
695 * {@code UIManager.setLookAndFeel} invokes this when the look and
696 * feel is changed.
697 * <p>
698 * Subclasses may choose to free up some resources here.
699 *
700 * @see #initialize
701 * @see UIManager#setLookAndFeel
702 */
703 public void uninitialize() {
704 }
705
706 /**
707 * Returns the look and feel defaults. While this method is public,
708 * it should only be invoked by the {@code UIManager} when the
709 * look and feel is set as the current look and feel and after
710 * {@code initialize} has been invoked.
711 *
712 * @return the look and feel defaults
713 * @see #initialize
714 * @see #uninitialize
715 * @see UIManager#setLookAndFeel
716 */
717 public UIDefaults getDefaults() {
718 return null;
719 }
720
721 /**
722 * Returns a string that displays and identifies this
723 * object's properties.
724 *
725 * @return a String representation of this object
726 */
727 public String toString() {
728 return "[" + getDescription() + " - " + getClass().getName() + "]";
729 }
730 }