1 /*
2 * Copyright (c) 1997, 2006, 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
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20 *
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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 defails 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></h2>
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 correspoding 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 * <p>
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 */
151 public abstract class LookAndFeel
152 {
153
154 /**
155 * Convenience method for setting a component's foreground
156 * and background color properties with values from the
157 * defaults. The properties are only set if the current
158 * value is either {@code null} or a {@code UIResource}.
159 *
160 * @param c component to set the colors on
161 * @param defaultBgName key for the background
162 * @param defaultFgName key for the foreground
163 *
164 * @see #installColorsAndFont
165 * @see UIManager#getColor
166 * @throws NullPointerException as described in
167 * <a href="#exceptions">exceptions</a>
168 */
169 public static void installColors(JComponent c,
170 String defaultBgName,
171 String defaultFgName)
172 {
173 Color bg = c.getBackground();
174 if (bg == null || bg instanceof UIResource) {
175 c.setBackground(UIManager.getColor(defaultBgName));
176 }
177
178 Color fg = c.getForeground();
179 if (fg == null || fg instanceof UIResource) {
180 c.setForeground(UIManager.getColor(defaultFgName));
181 }
182 }
183
184
185 /**
186 * Convenience method for setting a component's foreground,
187 * background and font properties with values from the
188 * defaults. The properties are only set if the current
189 * value is either {@code null} or a {@code UIResource}.
190 *
191 * @param c component set to the colors and font on
192 * @param defaultBgName key for the background
193 * @param defaultFgName key for the foreground
194 * @param defaultFontName key for the font
195 * @throws NullPointerException as described in
196 * <a href="#exceptions">exceptions</a>
197 *
198 * @see #installColors
199 * @see UIManager#getColor
200 * @see UIManager#getFont
201 */
202 public static void installColorsAndFont(JComponent c,
203 String defaultBgName,
204 String defaultFgName,
205 String defaultFontName) {
206 Font f = c.getFont();
207 if (f == null || f instanceof UIResource) {
208 c.setFont(UIManager.getFont(defaultFontName));
209 }
210
211 installColors(c, defaultBgName, defaultFgName);
212 }
213
214
215 /**
216 * Convenience method for setting a component's border property with
217 * a value from the defaults. The border is only set if the border is
218 * {@code null} or an instance of {@code UIResource}.
219 *
220 * @param c component to set the border on
221 * @param defaultBorderName key specifying the border
222 * @throws NullPointerException as described in
223 * <a href="#exceptions">exceptions</a>
224 */
225 public static void installBorder(JComponent c, String defaultBorderName) {
226 Border b = c.getBorder();
227 if (b == null || b instanceof UIResource) {
228 c.setBorder(UIManager.getBorder(defaultBorderName));
229 }
230 }
231
232
233 /**
234 * Convenience method for uninstalling a border. If the border of
235 * the component is a {@code UIResource}, it is set to {@code
236 * null}.
237 *
238 * @param c component to uninstall the border on
239 * @throws NullPointerException if {@code c} is {@code null}
240 */
241 public static void uninstallBorder(JComponent c) {
242 if (c.getBorder() instanceof UIResource) {
243 c.setBorder(null);
244 }
245 }
246
247 /**
248 * Convenience method for installing a property with the specified name
249 * and value on a component if that property has not already been set
250 * by the developer. This method is intended to be used by
251 * ui delegate instances that need to specify a default value for a
252 * property of primitive type (boolean, int, ..), but do not wish
253 * to override a value set by the client. Since primitive property
254 * values cannot be wrapped with the {@code UIResource} marker, this method
255 * uses private state to determine whether the property has been set
256 * by the client.
257 *
258 * @throws IllegalArgumentException if the specified property is not
259 * one which can be set using this method
260 * @throws ClassCastException if the property value has not been set
261 * by the developer and the type does not match the property's type
262 * @throws NullPointerException if {@code c} is {@code null}, or the
263 * named property has not been set by the developer and
264 * {@code propertyValue} is {@code null}
265 * @param c target component to set the property on
266 * @param propertyName name of the property to set
267 * @param propertyValue value of the property
268 * @since 1.5
269 */
270 public static void installProperty(JComponent c,
271 String propertyName, Object propertyValue) {
272 // this is a special case because the JPasswordField's ancestor heirarchy
273 // includes a class outside of javax.swing, thus we cannot call setUIProperty
274 // directly.
275 if (SunToolkit.isInstanceOf(c, "javax.swing.JPasswordField")) {
276 if (!((JPasswordField)c).customSetUIProperty(propertyName, propertyValue)) {
277 c.setUIProperty(propertyName, propertyValue);
278 }
279 } else {
280 c.setUIProperty(propertyName, propertyValue);
281 }
282 }
283
284 /**
285 * Convenience method for building an array of {@code
286 * KeyBindings}. While this method is not deprecated, developers
287 * should instead use {@code ActionMap} and {@code InputMap} for
288 * supplying key bindings.
289 * <p>
290 * This method returns an array of {@code KeyBindings}, one for each
291 * alternating {@code key-action} pair in {@code keyBindingList}.
292 * A {@code key} can either be a {@code String} in the format
293 * specified by the <code>KeyStroke.getKeyStroke</code> method, or
294 * a {@code KeyStroke}. The {@code action} part of the pair is a
295 * {@code String} that corresponds to the name of the {@code
296 * Action}.
297 * <p>
298 * The following example illustrates creating a {@code KeyBinding} array
299 * from six alternating {@code key-action} pairs:
300 * <pre>
301 * JTextComponent.KeyBinding[] multilineBindings = makeKeyBindings( new Object[] {
302 * "UP", DefaultEditorKit.upAction,
303 * "DOWN", DefaultEditorKit.downAction,
304 * "PAGE_UP", DefaultEditorKit.pageUpAction,
305 * "PAGE_DOWN", DefaultEditorKit.pageDownAction,
306 * "ENTER", DefaultEditorKit.insertBreakAction,
307 * "TAB", DefaultEditorKit.insertTabAction
308 * });
309 * </pre>
310 * If {@code keyBindingList's} length is odd, the last element is
311 * ignored.
312 * <p>
313 * Supplying a {@code null} value for either the {@code key} or
314 * {@code action} part of the {@code key-action} pair results in
315 * creating a {@code KeyBinding} with the corresponding value
316 * {@code null}. As other parts of Swing's expect {@code non-null} values
317 * in a {@code KeyBinding}, you should avoid supplying {@code null} as
318 * either the {@code key} or {@code action} part of the {@code key-action}
319 * pair.
320 *
321 * @param keyBindingList an array of {@code key-action} pairs
322 * @return an array of {@code KeyBindings}
323 * @throws NullPointerException if {@code keyBindingList} is {@code null}
324 * @throws ClassCastException if the {@code key} part of the pair is
325 * not a {@code KeyStroke} or {@code String}, or the
326 * {@code action} part of the pair is not a {@code String}
327 * @see ActionMap
328 * @see InputMap
329 * @see KeyStroke#getKeyStroke
330 */
331 public static JTextComponent.KeyBinding[] makeKeyBindings(Object[] keyBindingList)
332 {
333 JTextComponent.KeyBinding[] rv = new JTextComponent.KeyBinding[keyBindingList.length / 2];
334
335 for(int i = 0; i < rv.length; i ++) {
336 Object o = keyBindingList[2 * i];
337 KeyStroke keystroke = (o instanceof KeyStroke)
338 ? (KeyStroke) o
339 : KeyStroke.getKeyStroke((String) o);
340 String action = (String) keyBindingList[2 * i + 1];
341 rv[i] = new JTextComponent.KeyBinding(keystroke, action);
342 }
343
344 return rv;
345 }
346
347 /**
348 * Creates a {@code InputMapUIResource} from <code>keys</code>. This is
349 * a convenience method for creating a new {@code InputMapUIResource},
350 * invoking {@code loadKeyBindings(map, keys)}, and returning the
351 * {@code InputMapUIResource}.
352 *
353 * @param keys alternating pairs of {@code keystroke-action key}
354 * pairs as described in {@link #loadKeyBindings}
355 * @return newly created and populated {@code InputMapUIResource}
356 * @see #loadKeyBindings
357 *
358 * @since 1.3
359 */
360 public static InputMap makeInputMap(Object[] keys) {
361 InputMap retMap = new InputMapUIResource();
362 loadKeyBindings(retMap, keys);
363 return retMap;
364 }
365
366 /**
367 * Creates a {@code ComponentInputMapUIResource} from
368 * <code>keys</code>. This is a convenience method for creating a
369 * new {@code ComponentInputMapUIResource}, invoking {@code
370 * loadKeyBindings(map, keys)}, and returning the {@code
371 * ComponentInputMapUIResource}.
372 *
373 * @param c component to create the {@code ComponentInputMapUIResource}
374 * with
375 * @param keys alternating pairs of {@code keystroke-action key}
376 * pairs as described in {@link #loadKeyBindings}
377 * @return newly created and populated {@code InputMapUIResource}
378 * @throws IllegalArgumentException if {@code c} is {@code null}
379 *
380 * @see #loadKeyBindings
381 * @see ComponentInputMapUIResource
382 *
383 * @since 1.3
384 */
385 public static ComponentInputMap makeComponentInputMap(JComponent c,
386 Object[] keys) {
387 ComponentInputMap retMap = new ComponentInputMapUIResource(c);
388 loadKeyBindings(retMap, keys);
389 return retMap;
390 }
391
392
393 /**
394 * Populates an {@code InputMap} with the specified bindings.
395 * The bindings are supplied as a list of alternating
396 * {@code keystroke-action key} pairs. The {@code keystroke} is either
397 * an instance of {@code KeyStroke}, or a {@code String}
398 * that identifies the {@code KeyStroke} for the binding. Refer
399 * to {@code KeyStroke.getKeyStroke(String)} for the specific
400 * format. The {@code action key} part of the pair is the key
401 * registered in the {@code InputMap} for the {@code KeyStroke}.
402 * <p>
403 * The following illustrates loading an {@code InputMap} with two
404 * {@code key-action} pairs:
405 * <pre>
406 * LookAndFeel.loadKeyBindings(inputMap, new Object[] {
407 * "control X", "cut",
408 * "control V", "paste"
409 * });
410 * </pre>
411 * <p>
412 * Supplying a {@code null} list of bindings ({@code keys}) does not
413 * change {@code retMap} in any way.
414 * <p>
415 * Specifying a {@code null} {@code action key} results in
416 * removing the {@code keystroke's} entry from the {@code InputMap}.
417 * A {@code null} {@code keystroke} is ignored.
418 *
419 * @param retMap {@code InputMap} to add the {@code key-action}
420 * pairs to
421 * @param keys bindings to add to {@code retMap}
422 * @throws NullPointerException if {@code keys} is
423 * {@code non-null}, not empty, and {@code retMap} is
424 * {@code null}
425 *
426 * @see KeyStroke#getKeyStroke(String)
427 * @see InputMap
428 *
429 * @since 1.3
430 */
431 public static void loadKeyBindings(InputMap retMap, Object[] keys) {
432 if (keys != null) {
433 for (int counter = 0, maxCounter = keys.length;
434 counter < maxCounter; counter++) {
435 Object keyStrokeO = keys[counter++];
436 KeyStroke ks = (keyStrokeO instanceof KeyStroke) ?
437 (KeyStroke)keyStrokeO :
438 KeyStroke.getKeyStroke((String)keyStrokeO);
439 retMap.put(ks, keys[counter]);
440 }
441 }
442 }
443
444 /**
445 * Creates and returns a {@code UIDefault.LazyValue} that loads an
446 * image. The returned value is an implementation of {@code
447 * UIDefaults.LazyValue}. When {@code createValue} is invoked on
448 * the returned object, the image is loaded. If the image is {@code
449 * non-null}, it is then wrapped in an {@code Icon} that implements {@code
450 * UIResource}. The image is loaded using {@code
451 * Class.getResourceAsStream(gifFile)}.
452 * <p>
453 * This method does not check the arguments in any way. It is
454 * strongly recommended that {@code non-null} values are supplied else
455 * exceptions may occur when {@code createValue} is invoked on the
456 * returned object.
457 *
458 * @param baseClass {@code Class} used to load the resource
459 * @param gifFile path to the image to load
460 * @return a {@code UIDefaults.LazyValue}; when resolved the
461 * {@code LazyValue} loads the specified image
462 * @see UIDefaults.LazyValue
463 * @see Icon
464 * @see Class#getResourceAsStream(String)
465 */
466 public static Object makeIcon(final Class<?> baseClass, final String gifFile) {
467 return SwingUtilities2.makeIcon(baseClass, baseClass, gifFile);
468 }
469
470 /**
471 * Returns the <code>LayoutStyle</code> for this look
472 * and feel. This never returns {@code null}.
473 * <p>
474 * You generally don't use the <code>LayoutStyle</code> from
475 * the look and feel, instead use the <code>LayoutStyle</code>
476 * method <code>getInstance</code>.
477 *
478 * @see LayoutStyle#getInstance
479 * @return the <code>LayoutStyle</code> for this look and feel
480 * @since 1.6
481 */
482 public LayoutStyle getLayoutStyle() {
483 return DefaultLayoutStyle.getInstance();
484 }
485
486 /**
487 * Invoked when the user attempts an invalid operation,
488 * such as pasting into an uneditable <code>JTextField</code>
489 * that has focus. The default implementation beeps. Subclasses
490 * that wish different behavior should override this and provide
491 * the additional feedback.
492 *
493 * @param component the <code>Component</code> the error occurred in,
494 * may be <code>null</code>
495 * indicating the error condition is not directly
496 * associated with a <code>Component</code>
497 * @since 1.4
498 */
499 public void provideErrorFeedback(Component component) {
500 Toolkit toolkit = null;
501 if (component != null) {
502 toolkit = component.getToolkit();
503 } else {
504 toolkit = Toolkit.getDefaultToolkit();
505 }
506 toolkit.beep();
507 } // provideErrorFeedback()
508
509 /**
510 * Returns the value of the specified system desktop property by
511 * invoking <code>Toolkit.getDefaultToolkit().getDesktopProperty()</code>.
512 * If the value of the specified property is {@code null},
513 * {@code fallbackValue} is returned.
514 *
515 * @param systemPropertyName the name of the system desktop property being queried
516 * @param fallbackValue the object to be returned as the value if the system value is null
517 * @return the current value of the desktop property
518 *
519 * @see java.awt.Toolkit#getDesktopProperty
520 *
521 * @since 1.4
522 */
523 public static Object getDesktopPropertyValue(String systemPropertyName, Object fallbackValue) {
524 Object value = Toolkit.getDefaultToolkit().getDesktopProperty(systemPropertyName);
525 if (value == null) {
526 return fallbackValue;
527 } else if (value instanceof Color) {
528 return new ColorUIResource((Color)value);
529 } else if (value instanceof Font) {
530 return new FontUIResource((Font)value);
531 }
532 return value;
533 }
534
535 /**
536 * Returns an <code>Icon</code> with a disabled appearance.
537 * This method is used to generate a disabled <code>Icon</code> when
538 * one has not been specified. For example, if you create a
539 * <code>JButton</code> and only specify an <code>Icon</code> via
540 * <code>setIcon</code> this method will be called to generate the
541 * disabled <code>Icon</code>. If {@code null} is passed as
542 * <code>icon</code> this method returns {@code null}.
543 * <p>
544 * Some look and feels might not render the disabled {@code Icon}, in which
545 * case they will ignore this.
546 *
547 * @param component {@code JComponent} that will display the {@code Icon},
548 * may be {@code null}
549 * @param icon {@code Icon} to generate the disabled icon from
550 * @return disabled {@code Icon}, or {@code null} if a suitable
551 * {@code Icon} can not be generated
552 * @since 1.5
553 */
554 public Icon getDisabledIcon(JComponent component, Icon icon) {
555 if (icon instanceof ImageIcon) {
556 return new ImageIconUIResource(GrayFilter.
557 createDisabledImage(((ImageIcon)icon).getImage()));
558 }
559 return null;
560 }
561
562 /**
563 * Returns an <code>Icon</code> for use by disabled
564 * components that are also selected. This method is used to generate an
565 * <code>Icon</code> for components that are in both the disabled and
566 * selected states but do not have a specific <code>Icon</code> for this
567 * state. For example, if you create a <code>JButton</code> and only
568 * specify an <code>Icon</code> via <code>setIcon</code> this method
569 * will be called to generate the disabled and selected
570 * <code>Icon</code>. If {@code null} is passed as <code>icon</code> this
571 * methods returns {@code null}.
572 * <p>
573 * Some look and feels might not render the disabled and selected
574 * {@code Icon}, in which case they will ignore this.
575 *
576 * @param component {@code JComponent} that will display the {@code Icon},
577 * may be {@code null}
578 * @param icon {@code Icon} to generate disabled and selected icon from
579 * @return disabled and selected icon, or {@code null} if a suitable
580 * {@code Icon} can not be generated.
581 * @since 1.5
582 */
583 public Icon getDisabledSelectedIcon(JComponent component, Icon icon) {
584 return getDisabledIcon(component, icon);
585 }
586
587 /**
588 * Return a short string that identifies this look and feel, e.g.
589 * "CDE/Motif". This string should be appropriate for a menu item.
590 * Distinct look and feels should have different names, e.g.
591 * a subclass of MotifLookAndFeel that changes the way a few components
592 * are rendered should be called "CDE/Motif My Way"; something
593 * that would be useful to a user trying to select a L&F from a list
594 * of names.
595 *
596 * @return short identifier for the look and feel
597 */
598 public abstract String getName();
599
600
601 /**
602 * Return a string that identifies this look and feel. This string
603 * will be used by applications/services that want to recognize
604 * well known look and feel implementations. Presently
605 * the well known names are "Motif", "Windows", "Mac", "Metal". Note
606 * that a LookAndFeel derived from a well known superclass
607 * that doesn't make any fundamental changes to the look or feel
608 * shouldn't override this method.
609 *
610 * @return identifier for the look and feel
611 */
612 public abstract String getID();
613
614
615 /**
616 * Return a one line description of this look and feel implementation,
617 * e.g. "The CDE/Motif Look and Feel". This string is intended for
618 * the user, e.g. in the title of a window or in a ToolTip message.
619 *
620 * @return short description for the look and feel
621 */
622 public abstract String getDescription();
623
624
625 /**
626 * Returns {@code true} if the <code>LookAndFeel</code> returned
627 * <code>RootPaneUI</code> instances support providing {@code Window}
628 * decorations in a <code>JRootPane</code>.
629 * <p>
630 * The default implementation returns {@code false}, subclasses that
631 * support {@code Window} decorations should override this and return
632 * {@code true}.
633 *
634 * @return {@code true} if the {@code RootPaneUI} instances created by
635 * this look and feel support client side decorations
636 * @see JDialog#setDefaultLookAndFeelDecorated
637 * @see JFrame#setDefaultLookAndFeelDecorated
638 * @see JRootPane#setWindowDecorationStyle
639 * @since 1.4
640 */
641 public boolean getSupportsWindowDecorations() {
642 return false;
643 }
644
645 /**
646 * If the underlying platform has a "native" look and feel, and
647 * this is an implementation of it, return {@code true}. For
648 * example, when the underlying platform is Solaris running CDE
649 * a CDE/Motif look and feel implementation would return {@code
650 * true}.
651 *
652 * @return {@code true} if this look and feel represents the underlying
653 * platform look and feel
654 */
655 public abstract boolean isNativeLookAndFeel();
656
657
658 /**
659 * Return {@code true} if the underlying platform supports and or permits
660 * this look and feel. This method returns {@code false} if the look
661 * and feel depends on special resources or legal agreements that
662 * aren't defined for the current platform.
663 *
664 *
665 * @return {@code true} if this is a supported look and feel
666 * @see UIManager#setLookAndFeel
667 */
668 public abstract boolean isSupportedLookAndFeel();
669
670
671 /**
672 * Initializes the look and feel. While this method is public,
673 * it should only be invoked by the {@code UIManager} when a
674 * look and feel is installed as the current look and feel. This
675 * method is invoked before the {@code UIManager} invokes
676 * {@code getDefaults}. This method is intended to perform any
677 * initialization for the look and feel. Subclasses
678 * should do any one-time setup they need here, rather than
679 * in a static initializer, because look and feel class objects
680 * may be loaded just to discover that {@code isSupportedLookAndFeel()}
681 * returns {@code false}.
682 *
683 * @see #uninitialize
684 * @see UIManager#setLookAndFeel
685 */
686 public void initialize() {
687 }
688
689
690 /**
691 * Uninitializes the look and feel. While this method is public,
692 * it should only be invoked by the {@code UIManager} when
693 * the look and feel is uninstalled. For example,
694 * {@code UIManager.setLookAndFeel} invokes this when the look and
695 * feel is changed.
696 * <p>
697 * Subclasses may choose to free up some resources here.
698 *
699 * @see #initialize
700 * @see UIManager#setLookAndFeel
701 */
702 public void uninitialize() {
703 }
704
705 /**
706 * Returns the look and feel defaults. While this method is public,
707 * it should only be invoked by the {@code UIManager} when the
708 * look and feel is set as the current look and feel and after
709 * {@code initialize} has been invoked.
710 *
711 * @return the look and feel defaults
712 * @see #initialize
713 * @see #uninitialize
714 * @see UIManager#setLookAndFeel
715 */
716 public UIDefaults getDefaults() {
717 return null;
718 }
719
720 /**
721 * Returns a string that displays and identifies this
722 * object's properties.
723 *
724 * @return a String representation of this object
725 */
726 public String toString() {
727 return "[" + getDescription() + " - " + getClass().getName() + "]";
728 }
729 }