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
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 package javax.swing;
26
27 import java.awt.*;
28 import java.awt.event.*;
29 import java.applet.Applet;
30 import java.beans.PropertyChangeListener;
31 import java.util.Locale;
32 import java.util.Vector;
33 import java.io.Serializable;
34 import javax.accessibility.*;
35
36 /**
37 * An extended version of <code>java.applet.Applet</code> that adds support for
38 * the JFC/Swing component architecture.
39 * You can find task-oriented documentation about using <code>JApplet</code>
40 * in <em>The Java Tutorial</em>,
41 * in the section
42 * <a
43 href="http://java.sun.com/docs/books/tutorial/uiswing/components/applet.html">How to Make Applets</a>.
44 * <p>
45 * The <code>JApplet</code> class is slightly incompatible with
46 * <code>java.applet.Applet</code>. <code>JApplet</code> contains a
47 * <code>JRootPane</code> as its only child. The <code>contentPane</code>
48 * should be the parent of any children of the <code>JApplet</code>.
49 * As a convenience <code>add</code> and its variants, <code>remove</code> and
50 * <code>setLayout</code> have been overridden to forward to the
51 * <code>contentPane</code> as necessary. This means you can write:
52 * <pre>
53 * applet.add(child);
54 * </pre>
55 *
56 * And the child will be added to the <code>contentPane</code>.
57 * The <code>contentPane</code> will always be non-<code>null</code>.
58 * Attempting to set it to <code>null</code> will cause the
59 * <code>JApplet</code> to throw an exception. The default
60 * <code>contentPane</code> will have a <code>BorderLayout</code>
61 * manager set on it.
62 * Refer to {@link javax.swing.RootPaneContainer}
63 * for details on adding, removing and setting the <code>LayoutManager</code>
64 * of a <code>JApplet</code>.
65 * <p>
66 * Please see the <code>JRootPane</code> documentation for a
67 * complete description of the <code>contentPane</code>, <code>glassPane</code>,
68 * and <code>layeredPane</code> properties.
69 * <p>
70 * <strong>Warning:</strong> Swing is not thread safe. For more
71 * information see <a
72 * href="package-summary.html#threading">Swing's Threading
73 * Policy</a>.
74 * <p>
75 * <strong>Warning:</strong>
76 * Serialized objects of this class will not be compatible with
77 * future Swing releases. The current serialization support is
78 * appropriate for short term storage or RMI between applications running
79 * the same version of Swing. As of 1.4, support for long term storage
80 * of all JavaBeans<sup><font size="-2">TM</font></sup>
81 * has been added to the <code>java.beans</code> package.
82 * Please see {@link java.beans.XMLEncoder}.
83 *
84 * @see javax.swing.RootPaneContainer
85 * @beaninfo
86 * attribute: isContainer true
87 * attribute: containerDelegate getContentPane
88 * description: Swing's Applet subclass.
89 *
90 * @author Arnaud Weber
91 */
92 public class JApplet extends Applet implements Accessible,
93 RootPaneContainer,
94 TransferHandler.HasGetTransferHandler
95 {
96 /**
97 * @see #getRootPane
98 * @see #setRootPane
99 */
100 protected JRootPane rootPane;
101
102 /**
103 * If true then calls to <code>add</code> and <code>setLayout</code>
104 * will be forwarded to the <code>contentPane</code>. This is initially
105 * false, but is set to true when the <code>JApplet</code> is constructed.
106 *
107 * @see #isRootPaneCheckingEnabled
108 * @see #setRootPaneCheckingEnabled
109 * @see javax.swing.RootPaneContainer
110 */
111 protected boolean rootPaneCheckingEnabled = false;
112
113 /**
114 * The <code>TransferHandler</code> for this applet.
115 */
116 private TransferHandler transferHandler;
117
118 /**
119 * Creates a swing applet instance.
120 * <p>
121 * This constructor sets the component's locale property to the value
122 * returned by <code>JComponent.getDefaultLocale</code>.
123 *
124 * @exception HeadlessException if GraphicsEnvironment.isHeadless()
125 * returns true.
126 * @see java.awt.GraphicsEnvironment#isHeadless
127 * @see JComponent#getDefaultLocale
128 */
129 public JApplet() throws HeadlessException {
130 super();
131 // Check the timerQ and restart if necessary.
132 TimerQueue q = TimerQueue.sharedInstance();
133 if(q != null) {
134 q.startIfNeeded();
135 }
136
137 /* Workaround for bug 4155072. The shared double buffer image
138 * may hang on to a reference to this applet; unfortunately
139 * Image.getGraphics() will continue to call JApplet.getForeground()
140 * and getBackground() even after this applet has been destroyed.
141 * So we ensure that these properties are non-null here.
142 */
143 setForeground(Color.black);
144 setBackground(Color.white);
145
146 setLocale( JComponent.getDefaultLocale() );
147 setLayout(new BorderLayout());
148 setRootPane(createRootPane());
149 setRootPaneCheckingEnabled(true);
150
151 setFocusTraversalPolicyProvider(true);
152 sun.awt.SunToolkit.checkAndSetPolicy(this);
153
154 enableEvents(AWTEvent.KEY_EVENT_MASK);
155 }
156
157
158 /** Called by the constructor methods to create the default rootPane. */
159 protected JRootPane createRootPane() {
160 JRootPane rp = new JRootPane();
161 // NOTE: this uses setOpaque vs LookAndFeel.installProperty as there
162 // is NO reason for the RootPane not to be opaque. For painting to
163 // work the contentPane must be opaque, therefor the RootPane can
164 // also be opaque.
165 rp.setOpaque(true);
166 return rp;
167 }
168
169 /**
170 * Sets the {@code transferHandler} property, which is a mechanism to
171 * support transfer of data into this component. Use {@code null}
172 * if the component does not support data transfer operations.
173 * <p>
174 * If the system property {@code suppressSwingDropSupport} is {@code false}
175 * (the default) and the current drop target on this component is either
176 * {@code null} or not a user-set drop target, this method will change the
177 * drop target as follows: If {@code newHandler} is {@code null} it will
178 * clear the drop target. If not {@code null} it will install a new
179 * {@code DropTarget}.
180 * <p>
181 * Note: When used with {@code JApplet}, {@code TransferHandler} only
182 * provides data import capability, as the data export related methods
183 * are currently typed to {@code JComponent}.
184 * <p>
185 * Please see
186 * <a href="http://java.sun.com/docs/books/tutorial/uiswing/misc/dnd.html">
187 * How to Use Drag and Drop and Data Transfer</a>, a section in
188 * <em>The Java Tutorial</em>, for more information.
189 *
190 * @param newHandler the new {@code TransferHandler}
191 *
192 * @see TransferHandler
193 * @see #getTransferHandler
194 * @see java.awt.Component#setDropTarget
195 * @since 1.6
196 *
197 * @beaninfo
198 * bound: true
199 * hidden: true
200 * description: Mechanism for transfer of data into the component
201 */
202 public void setTransferHandler(TransferHandler newHandler) {
203 TransferHandler oldHandler = transferHandler;
204 transferHandler = newHandler;
205 SwingUtilities.installSwingDropTargetAsNecessary(this, transferHandler);
206 firePropertyChange("transferHandler", oldHandler, newHandler);
207 }
208
209 /**
210 * Gets the <code>transferHandler</code> property.
211 *
212 * @return the value of the <code>transferHandler</code> property
213 *
214 * @see TransferHandler
215 * @see #setTransferHandler
216 * @since 1.6
217 */
218 public TransferHandler getTransferHandler() {
219 return transferHandler;
220 }
221
222 /**
223 * Just calls <code>paint(g)</code>. This method was overridden to
224 * prevent an unnecessary call to clear the background.
225 */
226 public void update(Graphics g) {
227 paint(g);
228 }
229
230 /**
231 * Sets the menubar for this applet.
232 * @param menuBar the menubar being placed in the applet
233 *
234 * @see #getJMenuBar
235 *
236 * @beaninfo
237 * hidden: true
238 * description: The menubar for accessing pulldown menus from this applet.
239 */
240 public void setJMenuBar(JMenuBar menuBar) {
241 getRootPane().setMenuBar(menuBar);
242 }
243
244 /**
245 * Returns the menubar set on this applet.
246 *
247 * @see #setJMenuBar
248 */
249 public JMenuBar getJMenuBar() {
250 return getRootPane().getMenuBar();
251 }
252
253
254 /**
255 * Returns whether calls to <code>add</code> and
256 * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
257 *
258 * @return true if <code>add</code> and <code>setLayout</code>
259 * are fowarded; false otherwise
260 *
261 * @see #addImpl
262 * @see #setLayout
263 * @see #setRootPaneCheckingEnabled
264 * @see javax.swing.RootPaneContainer
265 */
266 protected boolean isRootPaneCheckingEnabled() {
267 return rootPaneCheckingEnabled;
268 }
269
270
271 /**
272 * Sets whether calls to <code>add</code> and
273 * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
274 *
275 * @param enabled true if <code>add</code> and <code>setLayout</code>
276 * are forwarded, false if they should operate directly on the
277 * <code>JApplet</code>.
278 *
279 * @see #addImpl
280 * @see #setLayout
281 * @see #isRootPaneCheckingEnabled
282 * @see javax.swing.RootPaneContainer
283 * @beaninfo
284 * hidden: true
285 * description: Whether the add and setLayout methods are forwarded
286 */
287 protected void setRootPaneCheckingEnabled(boolean enabled) {
288 rootPaneCheckingEnabled = enabled;
289 }
290
291
292 /**
293 * Adds the specified child <code>Component</code>.
294 * This method is overridden to conditionally forward calls to the
295 * <code>contentPane</code>.
296 * By default, children are added to the <code>contentPane</code> instead
297 * of the frame, refer to {@link javax.swing.RootPaneContainer} for
298 * details.
299 *
300 * @param comp the component to be enhanced
301 * @param constraints the constraints to be respected
302 * @param index the index
303 * @exception IllegalArgumentException if <code>index</code> is invalid
304 * @exception IllegalArgumentException if adding the container's parent
305 * to itself
306 * @exception IllegalArgumentException if adding a window to a container
307 *
308 * @see #setRootPaneCheckingEnabled
309 * @see javax.swing.RootPaneContainer
310 */
311 protected void addImpl(Component comp, Object constraints, int index)
312 {
313 if(isRootPaneCheckingEnabled()) {
314 getContentPane().add(comp, constraints, index);
315 }
316 else {
317 super.addImpl(comp, constraints, index);
318 }
319 }
320
321 /**
322 * Removes the specified component from the container. If
323 * <code>comp</code> is not the <code>rootPane</code>, this will forward
324 * the call to the <code>contentPane</code>. This will do nothing if
325 * <code>comp</code> is not a child of the <code>JFrame</code> or
326 * <code>contentPane</code>.
327 *
328 * @param comp the component to be removed
329 * @throws NullPointerException if <code>comp</code> is null
330 * @see #add
331 * @see javax.swing.RootPaneContainer
332 */
333 public void remove(Component comp) {
334 if (comp == rootPane) {
335 super.remove(comp);
336 } else {
337 getContentPane().remove(comp);
338 }
339 }
340
341
342 /**
343 * Sets the <code>LayoutManager</code>.
344 * Overridden to conditionally forward the call to the
345 * <code>contentPane</code>.
346 * Refer to {@link javax.swing.RootPaneContainer} for
347 * more information.
348 *
349 * @param manager the <code>LayoutManager</code>
350 * @see #setRootPaneCheckingEnabled
351 * @see javax.swing.RootPaneContainer
352 */
353 public void setLayout(LayoutManager manager) {
354 if(isRootPaneCheckingEnabled()) {
355 getContentPane().setLayout(manager);
356 }
357 else {
358 super.setLayout(manager);
359 }
360 }
361
362
363 /**
364 * Returns the rootPane object for this applet.
365 *
366 * @see #setRootPane
367 * @see RootPaneContainer#getRootPane
368 */
369 public JRootPane getRootPane() {
370 return rootPane;
371 }
372
373
374 /**
375 * Sets the rootPane property. This method is called by the constructor.
376 * @param root the rootPane object for this applet
377 *
378 * @see #getRootPane
379 *
380 * @beaninfo
381 * hidden: true
382 * description: the RootPane object for this applet.
383 */
384 protected void setRootPane(JRootPane root) {
385 if(rootPane != null) {
386 remove(rootPane);
387 }
388 rootPane = root;
389 if(rootPane != null) {
390 boolean checkingEnabled = isRootPaneCheckingEnabled();
391 try {
392 setRootPaneCheckingEnabled(false);
393 add(rootPane, BorderLayout.CENTER);
394 }
395 finally {
396 setRootPaneCheckingEnabled(checkingEnabled);
397 }
398 }
399 }
400
401
402 /**
403 * Returns the contentPane object for this applet.
404 *
405 * @see #setContentPane
406 * @see RootPaneContainer#getContentPane
407 */
408 public Container getContentPane() {
409 return getRootPane().getContentPane();
410 }
411
412 /**
413 * Sets the contentPane property. This method is called by the constructor.
414 * @param contentPane the contentPane object for this applet
415 *
416 * @exception java.awt.IllegalComponentStateException (a runtime
417 * exception) if the content pane parameter is null
418 * @see #getContentPane
419 * @see RootPaneContainer#setContentPane
420 *
421 * @beaninfo
422 * hidden: true
423 * description: The client area of the applet where child
424 * components are normally inserted.
425 */
426 public void setContentPane(Container contentPane) {
427 getRootPane().setContentPane(contentPane);
428 }
429
430 /**
431 * Returns the layeredPane object for this applet.
432 *
433 * @exception java.awt.IllegalComponentStateException (a runtime
434 * exception) if the layered pane parameter is null
435 * @see #setLayeredPane
436 * @see RootPaneContainer#getLayeredPane
437 */
438 public JLayeredPane getLayeredPane() {
439 return getRootPane().getLayeredPane();
440 }
441
442 /**
443 * Sets the layeredPane property. This method is called by the constructor.
444 * @param layeredPane the layeredPane object for this applet
445 *
446 * @see #getLayeredPane
447 * @see RootPaneContainer#setLayeredPane
448 *
449 * @beaninfo
450 * hidden: true
451 * description: The pane which holds the various applet layers.
452 */
453 public void setLayeredPane(JLayeredPane layeredPane) {
454 getRootPane().setLayeredPane(layeredPane);
455 }
456
457 /**
458 * Returns the glassPane object for this applet.
459 *
460 * @see #setGlassPane
461 * @see RootPaneContainer#getGlassPane
462 */
463 public Component getGlassPane() {
464 return getRootPane().getGlassPane();
465 }
466
467 /**
468 * Sets the glassPane property.
469 * This method is called by the constructor.
470 * @param glassPane the glassPane object for this applet
471 *
472 * @see #getGlassPane
473 * @see RootPaneContainer#setGlassPane
474 *
475 * @beaninfo
476 * hidden: true
477 * description: A transparent pane used for menu rendering.
478 */
479 public void setGlassPane(Component glassPane) {
480 getRootPane().setGlassPane(glassPane);
481 }
482
483 /**
484 * {@inheritDoc}
485 *
486 * @since 1.6
487 */
488 public Graphics getGraphics() {
489 JComponent.getGraphicsInvoked(this);
490 return super.getGraphics();
491 }
492
493 /**
494 * Repaints the specified rectangle of this component within
495 * <code>time</code> milliseconds. Refer to <code>RepaintManager</code>
496 * for details on how the repaint is handled.
497 *
498 * @param time maximum time in milliseconds before update
499 * @param x the <i>x</i> coordinate
500 * @param y the <i>y</i> coordinate
501 * @param width the width
502 * @param height the height
503 * @see RepaintManager
504 * @since 1.6
505 */
506 public void repaint(long time, int x, int y, int width, int height) {
507 if (RepaintManager.HANDLE_TOP_LEVEL_PAINT) {
508 RepaintManager.currentManager(this).addDirtyRegion(
509 this, x, y, width, height);
510 }
511 else {
512 super.repaint(time, x, y, width, height);
513 }
514 }
515
516 /**
517 * Returns a string representation of this JApplet. This method
518 * is intended to be used only for debugging purposes, and the
519 * content and format of the returned string may vary between
520 * implementations. The returned string may be empty but may not
521 * be <code>null</code>.
522 *
523 * @return a string representation of this JApplet.
524 */
525 protected String paramString() {
526 String rootPaneString = (rootPane != null ?
527 rootPane.toString() : "");
528 String rootPaneCheckingEnabledString = (rootPaneCheckingEnabled ?
529 "true" : "false");
530
531 return super.paramString() +
532 ",rootPane=" + rootPaneString +
533 ",rootPaneCheckingEnabled=" + rootPaneCheckingEnabledString;
534 }
535
536
537
538 /////////////////
539 // Accessibility support
540 ////////////////
541
542 protected AccessibleContext accessibleContext = null;
543
544 /**
545 * Gets the AccessibleContext associated with this JApplet.
546 * For JApplets, the AccessibleContext takes the form of an
547 * AccessibleJApplet.
548 * A new AccessibleJApplet instance is created if necessary.
549 *
550 * @return an AccessibleJApplet that serves as the
551 * AccessibleContext of this JApplet
552 */
553 public AccessibleContext getAccessibleContext() {
554 if (accessibleContext == null) {
555 accessibleContext = new AccessibleJApplet();
556 }
557 return accessibleContext;
558 }
559
560 /**
561 * This class implements accessibility support for the
562 * <code>JApplet</code> class.
563 */
564 protected class AccessibleJApplet extends AccessibleApplet {
565 // everything moved to new parent, AccessibleApplet
566 }
567 }