1 /*
2 * Copyright (c) 1997, 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 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://docs.oracle.com/javase/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, the {@code add}, {@code remove}, and {@code setLayout}
50 * methods of this class are overridden, so that they delegate calls
51 * to the corresponding methods of the {@code ContentPane}.
52 * For example, you can add a child component to an applet as follows:
53 * <pre>
54 * applet.add(child);
55 * </pre>
56 *
57 * And the child will be added to the <code>contentPane</code>.
58 * The <code>contentPane</code> will always be non-<code>null</code>.
59 * Attempting to set it to <code>null</code> will cause the
60 * <code>JApplet</code> to throw an exception. The default
61 * <code>contentPane</code> will have a <code>BorderLayout</code>
62 * manager set on it.
63 * Refer to {@link javax.swing.RootPaneContainer}
64 * for details on adding, removing and setting the <code>LayoutManager</code>
65 * of a <code>JApplet</code>.
66 * <p>
67 * Please see the <code>JRootPane</code> documentation for a
68 * complete description of the <code>contentPane</code>, <code>glassPane</code>,
69 * and <code>layeredPane</code> properties.
70 * <p>
71 * <strong>Warning:</strong> Swing is not thread safe. For more
72 * information see <a
73 * href="package-summary.html#threading">Swing's Threading
74 * Policy</a>.
75 * <p>
76 * <strong>Warning:</strong>
77 * Serialized objects of this class will not be compatible with
78 * future Swing releases. The current serialization support is
79 * appropriate for short term storage or RMI between applications running
80 * the same version of Swing. As of 1.4, support for long term storage
81 * of all JavaBeans™
82 * has been added to the <code>java.beans</code> package.
83 * Please see {@link java.beans.XMLEncoder}.
84 *
85 * @see javax.swing.RootPaneContainer
86 * @beaninfo
87 * attribute: isContainer true
88 * attribute: containerDelegate getContentPane
89 * description: Swing's Applet subclass.
90 *
91 * @author Arnaud Weber
92 */
93 @SuppressWarnings("serial") // Same-version serialization only
94 public class JApplet extends Applet implements Accessible,
95 RootPaneContainer,
96 TransferHandler.HasGetTransferHandler
97 {
98 /**
99 * @see #getRootPane
100 * @see #setRootPane
101 */
102 protected JRootPane rootPane;
103
104 /**
105 * If true then calls to <code>add</code> and <code>setLayout</code>
106 * will be forwarded to the <code>contentPane</code>. This is initially
107 * false, but is set to true when the <code>JApplet</code> is constructed.
108 *
109 * @see #isRootPaneCheckingEnabled
110 * @see #setRootPaneCheckingEnabled
111 * @see javax.swing.RootPaneContainer
112 */
113 protected boolean rootPaneCheckingEnabled = false;
114
115 /**
116 * The <code>TransferHandler</code> for this applet.
117 */
118 private TransferHandler transferHandler;
119
120 /**
121 * Creates a swing applet instance.
122 * <p>
123 * This constructor sets the component's locale property to the value
124 * returned by <code>JComponent.getDefaultLocale</code>.
125 *
126 * @exception HeadlessException if GraphicsEnvironment.isHeadless()
127 * returns true.
128 * @see java.awt.GraphicsEnvironment#isHeadless
129 * @see JComponent#getDefaultLocale
130 */
131 public JApplet() throws HeadlessException {
132 super();
133 // Check the timerQ and restart if necessary.
134 TimerQueue q = TimerQueue.sharedInstance();
135 if(q != null) {
136 q.startIfNeeded();
137 }
138
139 /* Workaround for bug 4155072. The shared double buffer image
140 * may hang on to a reference to this applet; unfortunately
141 * Image.getGraphics() will continue to call JApplet.getForeground()
142 * and getBackground() even after this applet has been destroyed.
143 * So we ensure that these properties are non-null here.
144 */
145 setForeground(Color.black);
146 setBackground(Color.white);
147
148 setLocale( JComponent.getDefaultLocale() );
149 setLayout(new BorderLayout());
150 setRootPane(createRootPane());
151 setRootPaneCheckingEnabled(true);
152
153 setFocusTraversalPolicyProvider(true);
154 sun.awt.SunToolkit.checkAndSetPolicy(this);
155
156 enableEvents(AWTEvent.KEY_EVENT_MASK);
157 }
158
159
160 /** Called by the constructor methods to create the default rootPane. */
161 protected JRootPane createRootPane() {
162 JRootPane rp = new JRootPane();
163 // NOTE: this uses setOpaque vs LookAndFeel.installProperty as there
164 // is NO reason for the RootPane not to be opaque. For painting to
165 // work the contentPane must be opaque, therefor the RootPane can
166 // also be opaque.
167 rp.setOpaque(true);
168 return rp;
169 }
170
171 /**
172 * Sets the {@code transferHandler} property, which is a mechanism to
173 * support transfer of data into this component. Use {@code null}
174 * if the component does not support data transfer operations.
175 * <p>
176 * If the system property {@code suppressSwingDropSupport} is {@code false}
177 * (the default) and the current drop target on this component is either
178 * {@code null} or not a user-set drop target, this method will change the
179 * drop target as follows: If {@code newHandler} is {@code null} it will
180 * clear the drop target. If not {@code null} it will install a new
181 * {@code DropTarget}.
182 * <p>
183 * Note: When used with {@code JApplet}, {@code TransferHandler} only
184 * provides data import capability, as the data export related methods
185 * are currently typed to {@code JComponent}.
186 * <p>
187 * Please see
188 * <a href="http://docs.oracle.com/javase/tutorial/uiswing/dnd/index.html">
189 * How to Use Drag and Drop and Data Transfer</a>, a section in
190 * <em>The Java Tutorial</em>, for more information.
191 *
192 * @param newHandler the new {@code TransferHandler}
193 *
194 * @see TransferHandler
195 * @see #getTransferHandler
196 * @see java.awt.Component#setDropTarget
197 * @since 1.6
198 *
199 * @beaninfo
200 * bound: true
201 * hidden: true
202 * description: Mechanism for transfer of data into the component
203 */
204 public void setTransferHandler(TransferHandler newHandler) {
205 TransferHandler oldHandler = transferHandler;
206 transferHandler = newHandler;
207 SwingUtilities.installSwingDropTargetAsNecessary(this, transferHandler);
208 firePropertyChange("transferHandler", oldHandler, newHandler);
209 }
210
211 /**
212 * Gets the <code>transferHandler</code> property.
213 *
214 * @return the value of the <code>transferHandler</code> property
215 *
216 * @see TransferHandler
217 * @see #setTransferHandler
218 * @since 1.6
219 */
220 public TransferHandler getTransferHandler() {
221 return transferHandler;
222 }
223
224 /**
225 * Just calls <code>paint(g)</code>. This method was overridden to
226 * prevent an unnecessary call to clear the background.
227 */
228 public void update(Graphics g) {
229 paint(g);
230 }
231
232 /**
233 * Sets the menubar for this applet.
234 * @param menuBar the menubar being placed in the applet
235 *
236 * @see #getJMenuBar
237 *
238 * @beaninfo
239 * hidden: true
240 * description: The menubar for accessing pulldown menus from this applet.
241 */
242 public void setJMenuBar(JMenuBar menuBar) {
243 getRootPane().setMenuBar(menuBar);
244 }
245
246 /**
247 * Returns the menubar set on this applet.
248 *
249 * @see #setJMenuBar
250 */
251 public JMenuBar getJMenuBar() {
252 return getRootPane().getMenuBar();
253 }
254
255
256 /**
257 * Returns whether calls to <code>add</code> and
258 * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
259 *
260 * @return true if <code>add</code> and <code>setLayout</code>
261 * are forwarded; false otherwise
262 *
263 * @see #addImpl
264 * @see #setLayout
265 * @see #setRootPaneCheckingEnabled
266 * @see javax.swing.RootPaneContainer
267 */
268 protected boolean isRootPaneCheckingEnabled() {
269 return rootPaneCheckingEnabled;
270 }
271
272
273 /**
274 * Sets whether calls to <code>add</code> and
275 * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
276 *
277 * @param enabled true if <code>add</code> and <code>setLayout</code>
278 * are forwarded, false if they should operate directly on the
279 * <code>JApplet</code>.
280 *
281 * @see #addImpl
282 * @see #setLayout
283 * @see #isRootPaneCheckingEnabled
284 * @see javax.swing.RootPaneContainer
285 * @beaninfo
286 * hidden: true
287 * description: Whether the add and setLayout methods are forwarded
288 */
289 protected void setRootPaneCheckingEnabled(boolean enabled) {
290 rootPaneCheckingEnabled = enabled;
291 }
292
293
294 /**
295 * Adds the specified child <code>Component</code>.
296 * This method is overridden to conditionally forward calls to the
297 * <code>contentPane</code>.
298 * By default, children are added to the <code>contentPane</code> instead
299 * of the frame, refer to {@link javax.swing.RootPaneContainer} for
300 * details.
301 *
302 * @param comp the component to be enhanced
303 * @param constraints the constraints to be respected
304 * @param index the index
305 * @exception IllegalArgumentException if <code>index</code> is invalid
306 * @exception IllegalArgumentException if adding the container's parent
307 * to itself
308 * @exception IllegalArgumentException if adding a window to a container
309 *
310 * @see #setRootPaneCheckingEnabled
311 * @see javax.swing.RootPaneContainer
312 */
313 protected void addImpl(Component comp, Object constraints, int index)
314 {
315 if(isRootPaneCheckingEnabled()) {
316 getContentPane().add(comp, constraints, index);
317 }
318 else {
319 super.addImpl(comp, constraints, index);
320 }
321 }
322
323 /**
324 * Removes the specified component from the container. If
325 * <code>comp</code> is not the <code>rootPane</code>, this will forward
326 * the call to the <code>contentPane</code>. This will do nothing if
327 * <code>comp</code> is not a child of the <code>JFrame</code> or
328 * <code>contentPane</code>.
329 *
330 * @param comp the component to be removed
331 * @throws NullPointerException if <code>comp</code> is null
332 * @see #add
333 * @see javax.swing.RootPaneContainer
334 */
335 public void remove(Component comp) {
336 if (comp == rootPane) {
337 super.remove(comp);
338 } else {
339 getContentPane().remove(comp);
340 }
341 }
342
343
344 /**
345 * Sets the <code>LayoutManager</code>.
346 * Overridden to conditionally forward the call to the
347 * <code>contentPane</code>.
348 * Refer to {@link javax.swing.RootPaneContainer} for
349 * more information.
350 *
351 * @param manager the <code>LayoutManager</code>
352 * @see #setRootPaneCheckingEnabled
353 * @see javax.swing.RootPaneContainer
354 */
355 public void setLayout(LayoutManager manager) {
356 if(isRootPaneCheckingEnabled()) {
357 getContentPane().setLayout(manager);
358 }
359 else {
360 super.setLayout(manager);
361 }
362 }
363
364
365 /**
366 * Returns the rootPane object for this applet.
367 *
368 * @see #setRootPane
369 * @see RootPaneContainer#getRootPane
370 */
371 public JRootPane getRootPane() {
372 return rootPane;
373 }
374
375
376 /**
377 * Sets the rootPane property. This method is called by the constructor.
378 * @param root the rootPane object for this applet
379 *
380 * @see #getRootPane
381 *
382 * @beaninfo
383 * hidden: true
384 * description: the RootPane object for this applet.
385 */
386 protected void setRootPane(JRootPane root) {
387 if(rootPane != null) {
388 remove(rootPane);
389 }
390 rootPane = root;
391 if(rootPane != null) {
392 boolean checkingEnabled = isRootPaneCheckingEnabled();
393 try {
394 setRootPaneCheckingEnabled(false);
395 add(rootPane, BorderLayout.CENTER);
396 }
397 finally {
398 setRootPaneCheckingEnabled(checkingEnabled);
399 }
400 }
401 }
402
403
404 /**
405 * Returns the contentPane object for this applet.
406 *
407 * @see #setContentPane
408 * @see RootPaneContainer#getContentPane
409 */
410 public Container getContentPane() {
411 return getRootPane().getContentPane();
412 }
413
414 /**
415 * Sets the contentPane property. This method is called by the constructor.
416 * @param contentPane the contentPane object for this applet
417 *
418 * @exception java.awt.IllegalComponentStateException (a runtime
419 * exception) if the content pane parameter is null
420 * @see #getContentPane
421 * @see RootPaneContainer#setContentPane
422 *
423 * @beaninfo
424 * hidden: true
425 * description: The client area of the applet where child
426 * components are normally inserted.
427 */
428 public void setContentPane(Container contentPane) {
429 getRootPane().setContentPane(contentPane);
430 }
431
432 /**
433 * Returns the layeredPane object for this applet.
434 *
435 * @exception java.awt.IllegalComponentStateException (a runtime
436 * exception) if the layered pane parameter is null
437 * @see #setLayeredPane
438 * @see RootPaneContainer#getLayeredPane
439 */
440 public JLayeredPane getLayeredPane() {
441 return getRootPane().getLayeredPane();
442 }
443
444 /**
445 * Sets the layeredPane property. This method is called by the constructor.
446 * @param layeredPane the layeredPane object for this applet
447 *
448 * @see #getLayeredPane
449 * @see RootPaneContainer#setLayeredPane
450 *
451 * @beaninfo
452 * hidden: true
453 * description: The pane which holds the various applet layers.
454 */
455 public void setLayeredPane(JLayeredPane layeredPane) {
456 getRootPane().setLayeredPane(layeredPane);
457 }
458
459 /**
460 * Returns the glassPane object for this applet.
461 *
462 * @see #setGlassPane
463 * @see RootPaneContainer#getGlassPane
464 */
465 public Component getGlassPane() {
466 return getRootPane().getGlassPane();
467 }
468
469 /**
470 * Sets the glassPane property.
471 * This method is called by the constructor.
472 * @param glassPane the glassPane object for this applet
473 *
474 * @see #getGlassPane
475 * @see RootPaneContainer#setGlassPane
476 *
477 * @beaninfo
478 * hidden: true
479 * description: A transparent pane used for menu rendering.
480 */
481 public void setGlassPane(Component glassPane) {
482 getRootPane().setGlassPane(glassPane);
483 }
484
485 /**
486 * {@inheritDoc}
487 *
488 * @since 1.6
489 */
490 public Graphics getGraphics() {
491 JComponent.getGraphicsInvoked(this);
492 return super.getGraphics();
493 }
494
495 /**
496 * Repaints the specified rectangle of this component within
497 * <code>time</code> milliseconds. Refer to <code>RepaintManager</code>
498 * for details on how the repaint is handled.
499 *
500 * @param time maximum time in milliseconds before update
501 * @param x the <i>x</i> coordinate
502 * @param y the <i>y</i> coordinate
503 * @param width the width
504 * @param height the height
505 * @see RepaintManager
506 * @since 1.6
507 */
508 public void repaint(long time, int x, int y, int width, int height) {
509 if (RepaintManager.HANDLE_TOP_LEVEL_PAINT) {
510 RepaintManager.currentManager(this).addDirtyRegion(
511 this, x, y, width, height);
512 }
513 else {
514 super.repaint(time, x, y, width, height);
515 }
516 }
517
518 /**
519 * Returns a string representation of this JApplet. This method
520 * is intended to be used only for debugging purposes, and the
521 * content and format of the returned string may vary between
522 * implementations. The returned string may be empty but may not
523 * be <code>null</code>.
524 *
525 * @return a string representation of this JApplet.
526 */
527 protected String paramString() {
528 String rootPaneString = (rootPane != null ?
529 rootPane.toString() : "");
530 String rootPaneCheckingEnabledString = (rootPaneCheckingEnabled ?
531 "true" : "false");
532
533 return super.paramString() +
534 ",rootPane=" + rootPaneString +
535 ",rootPaneCheckingEnabled=" + rootPaneCheckingEnabledString;
536 }
537
538
539
540 /////////////////
541 // Accessibility support
542 ////////////////
543
544 protected AccessibleContext accessibleContext = null;
545
546 /**
547 * Gets the AccessibleContext associated with this JApplet.
548 * For JApplets, the AccessibleContext takes the form of an
549 * AccessibleJApplet.
550 * A new AccessibleJApplet instance is created if necessary.
551 *
552 * @return an AccessibleJApplet that serves as the
553 * AccessibleContext of this JApplet
554 */
555 public AccessibleContext getAccessibleContext() {
556 if (accessibleContext == null) {
557 accessibleContext = new AccessibleJApplet();
558 }
559 return accessibleContext;
560 }
561
562 /**
563 * This class implements accessibility support for the
564 * <code>JApplet</code> class.
565 */
566 protected class AccessibleJApplet extends AccessibleApplet {
567 // everything moved to new parent, AccessibleApplet
568 }
569 }