1 /*
2 * Copyright (c) 1997, 2015, 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.applet.Applet;
28 import java.awt.AWTEvent;
29 import java.awt.BorderLayout;
30 import java.awt.Color;
31 import java.awt.Component;
32 import java.awt.Container;
33 import java.awt.Graphics;
34 import java.awt.HeadlessException;
35 import java.awt.LayoutManager;
36 import java.beans.BeanProperty;
37 import java.beans.JavaBean;
38
39 import javax.accessibility.Accessible;
40 import javax.accessibility.AccessibleContext;
41
42 /**
43 * An extended version of <code>java.applet.Applet</code> that adds support for
44 * the JFC/Swing component architecture.
45 * You can find task-oriented documentation about using <code>JApplet</code>
46 * in <em>The Java Tutorial</em>,
47 * in the section
48 * <a
49 href="http://docs.oracle.com/javase/tutorial/uiswing/components/applet.html">How to Make Applets</a>.
50 * <p>
51 * The <code>JApplet</code> class is slightly incompatible with
52 * <code>java.applet.Applet</code>. <code>JApplet</code> contains a
53 * <code>JRootPane</code> as its only child. The <code>contentPane</code>
54 * should be the parent of any children of the <code>JApplet</code>.
55 * As a convenience, the {@code add}, {@code remove}, and {@code setLayout}
56 * methods of this class are overridden, so that they delegate calls
57 * to the corresponding methods of the {@code ContentPane}.
58 * For example, you can add a child component to an applet as follows:
59 * <pre>
60 * applet.add(child);
61 * </pre>
62 *
63 * And the child will be added to the <code>contentPane</code>.
64 * The <code>contentPane</code> will always be non-<code>null</code>.
65 * Attempting to set it to <code>null</code> will cause the
66 * <code>JApplet</code> to throw an exception. The default
67 * <code>contentPane</code> will have a <code>BorderLayout</code>
68 * manager set on it.
69 * Refer to {@link javax.swing.RootPaneContainer}
70 * for details on adding, removing and setting the <code>LayoutManager</code>
71 * of a <code>JApplet</code>.
72 * <p>
73 * Please see the <code>JRootPane</code> documentation for a
74 * complete description of the <code>contentPane</code>, <code>glassPane</code>,
75 * and <code>layeredPane</code> properties.
76 * <p>
77 * <strong>Warning:</strong> Swing is not thread safe. For more
78 * information see <a
79 * href="package-summary.html#threading">Swing's Threading
80 * Policy</a>.
81 * <p>
82 * <strong>Warning:</strong>
83 * Serialized objects of this class will not be compatible with
84 * future Swing releases. The current serialization support is
85 * appropriate for short term storage or RMI between applications running
86 * the same version of Swing. As of 1.4, support for long term storage
87 * of all JavaBeans™
88 * has been added to the <code>java.beans</code> package.
89 * Please see {@link java.beans.XMLEncoder}.
90 *
91 * @see javax.swing.RootPaneContainer
92 *
93 * @author Arnaud Weber
94 * @since 1.2
95 */
96 @JavaBean(defaultProperty = "JMenuBar", description = "Swing's Applet subclass.")
97 @SwingContainer(delegate = "getContentPane")
98 @SuppressWarnings("serial") // Same-version serialization only
99 public class JApplet extends Applet implements Accessible,
100 RootPaneContainer,
101 TransferHandler.HasGetTransferHandler
102 {
103 /**
104 * @see #getRootPane
105 * @see #setRootPane
106 */
107 protected JRootPane rootPane;
108
109 /**
110 * If true then calls to <code>add</code> and <code>setLayout</code>
111 * will be forwarded to the <code>contentPane</code>. This is initially
112 * false, but is set to true when the <code>JApplet</code> is constructed.
113 *
114 * @see #isRootPaneCheckingEnabled
115 * @see #setRootPaneCheckingEnabled
116 * @see javax.swing.RootPaneContainer
117 */
118 protected boolean rootPaneCheckingEnabled = false;
119
120 /**
121 * The <code>TransferHandler</code> for this applet.
122 */
123 private TransferHandler transferHandler;
124
125 /**
126 * Creates a swing applet instance.
127 * <p>
128 * This constructor sets the component's locale property to the value
129 * returned by <code>JComponent.getDefaultLocale</code>.
130 *
131 * @exception HeadlessException if GraphicsEnvironment.isHeadless()
132 * returns true.
133 * @see java.awt.GraphicsEnvironment#isHeadless
134 * @see JComponent#getDefaultLocale
135 */
136 public JApplet() throws HeadlessException {
137 super();
138 // Check the timerQ and restart if necessary.
139 TimerQueue q = TimerQueue.sharedInstance();
140 if(q != null) {
141 q.startIfNeeded();
142 }
143
144 /* Workaround for bug 4155072. The shared double buffer image
145 * may hang on to a reference to this applet; unfortunately
146 * Image.getGraphics() will continue to call JApplet.getForeground()
147 * and getBackground() even after this applet has been destroyed.
148 * So we ensure that these properties are non-null here.
149 */
150 setForeground(Color.black);
151 setBackground(Color.white);
152
153 setLocale( JComponent.getDefaultLocale() );
154 setLayout(new BorderLayout());
155 setRootPane(createRootPane());
156 setRootPaneCheckingEnabled(true);
157
158 setFocusTraversalPolicyProvider(true);
159 sun.awt.SunToolkit.checkAndSetPolicy(this);
160
161 enableEvents(AWTEvent.KEY_EVENT_MASK);
162 }
163
164 /**
165 * Called by the constructor methods to create the default rootPane.
166 *
167 * @return a new {@code JRootPane}
168 */
169 protected JRootPane createRootPane() {
170 JRootPane rp = new JRootPane();
171 // NOTE: this uses setOpaque vs LookAndFeel.installProperty as there
172 // is NO reason for the RootPane not to be opaque. For painting to
173 // work the contentPane must be opaque, therefor the RootPane can
174 // also be opaque.
175 rp.setOpaque(true);
176 return rp;
177 }
178
179 /**
180 * Sets the {@code transferHandler} property, which is a mechanism to
181 * support transfer of data into this component. Use {@code null}
182 * if the component does not support data transfer operations.
183 * <p>
184 * If the system property {@code suppressSwingDropSupport} is {@code false}
185 * (the default) and the current drop target on this component is either
186 * {@code null} or not a user-set drop target, this method will change the
187 * drop target as follows: If {@code newHandler} is {@code null} it will
188 * clear the drop target. If not {@code null} it will install a new
189 * {@code DropTarget}.
190 * <p>
191 * Note: When used with {@code JApplet}, {@code TransferHandler} only
192 * provides data import capability, as the data export related methods
193 * are currently typed to {@code JComponent}.
194 * <p>
195 * Please see
196 * <a href="http://docs.oracle.com/javase/tutorial/uiswing/dnd/index.html">
197 * How to Use Drag and Drop and Data Transfer</a>, a section in
198 * <em>The Java Tutorial</em>, for more information.
199 *
200 * @param newHandler the new {@code TransferHandler}
201 *
202 * @see TransferHandler
203 * @see #getTransferHandler
204 * @see java.awt.Component#setDropTarget
205 * @since 1.6
206 */
207 @BeanProperty(hidden = true, description
208 = "Mechanism for transfer of data into the component")
209 public void setTransferHandler(TransferHandler newHandler) {
210 TransferHandler oldHandler = transferHandler;
211 transferHandler = newHandler;
212 SwingUtilities.installSwingDropTargetAsNecessary(this, transferHandler);
213 firePropertyChange("transferHandler", oldHandler, newHandler);
214 }
215
216 /**
217 * Gets the <code>transferHandler</code> property.
218 *
219 * @return the value of the <code>transferHandler</code> property
220 *
221 * @see TransferHandler
222 * @see #setTransferHandler
223 * @since 1.6
224 */
225 public TransferHandler getTransferHandler() {
226 return transferHandler;
227 }
228
229 /**
230 * Just calls <code>paint(g)</code>. This method was overridden to
231 * prevent an unnecessary call to clear the background.
232 */
233 public void update(Graphics g) {
234 paint(g);
235 }
236
237 /**
238 * Sets the menubar for this applet.
239 * @param menuBar the menubar being placed in the applet
240 *
241 * @see #getJMenuBar
242 */
243 @BeanProperty(bound = false, hidden = true, description
244 = "The menubar for accessing pulldown menus from this applet.")
245 public void setJMenuBar(final JMenuBar menuBar) {
246 getRootPane().setJMenuBar(menuBar);
247 }
248
249 /**
250 * Returns the menubar set on this applet.
251 *
252 * @return the menubar set on this applet
253 * @see #setJMenuBar
254 */
255 public JMenuBar getJMenuBar() {
256 return getRootPane().getJMenuBar();
257 }
258
259
260 /**
261 * Returns whether calls to <code>add</code> and
262 * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
263 *
264 * @return true if <code>add</code> and <code>setLayout</code>
265 * are forwarded; false otherwise
266 *
267 * @see #addImpl
268 * @see #setLayout
269 * @see #setRootPaneCheckingEnabled
270 * @see javax.swing.RootPaneContainer
271 */
272 protected boolean isRootPaneCheckingEnabled() {
273 return rootPaneCheckingEnabled;
274 }
275
276
277 /**
278 * Sets whether calls to <code>add</code> and
279 * <code>setLayout</code> are forwarded to the <code>contentPane</code>.
280 *
281 * @param enabled true if <code>add</code> and <code>setLayout</code>
282 * are forwarded, false if they should operate directly on the
283 * <code>JApplet</code>.
284 *
285 * @see #addImpl
286 * @see #setLayout
287 * @see #isRootPaneCheckingEnabled
288 * @see javax.swing.RootPaneContainer
289 */
290 @BeanProperty(hidden = true, description
291 = "Whether the add and setLayout methods are forwarded")
292 protected void setRootPaneCheckingEnabled(boolean enabled) {
293 rootPaneCheckingEnabled = enabled;
294 }
295
296
297 /**
298 * Adds the specified child <code>Component</code>.
299 * This method is overridden to conditionally forward calls to the
300 * <code>contentPane</code>.
301 * By default, children are added to the <code>contentPane</code> instead
302 * of the frame, refer to {@link javax.swing.RootPaneContainer} for
303 * details.
304 *
305 * @param comp the component to be enhanced
306 * @param constraints the constraints to be respected
307 * @param index the index
308 * @exception IllegalArgumentException if <code>index</code> is invalid
309 * @exception IllegalArgumentException if adding the container's parent
310 * to itself
311 * @exception IllegalArgumentException if adding a window to a container
312 *
313 * @see #setRootPaneCheckingEnabled
314 * @see javax.swing.RootPaneContainer
315 */
316 protected void addImpl(Component comp, Object constraints, int index)
317 {
318 if(isRootPaneCheckingEnabled()) {
319 getContentPane().add(comp, constraints, index);
320 }
321 else {
322 super.addImpl(comp, constraints, index);
323 }
324 }
325
326 /**
327 * Removes the specified component from the container. If
328 * <code>comp</code> is not the <code>rootPane</code>, this will forward
329 * the call to the <code>contentPane</code>. This will do nothing if
330 * <code>comp</code> is not a child of the <code>JFrame</code> or
331 * <code>contentPane</code>.
332 *
333 * @param comp the component to be removed
334 * @throws NullPointerException if <code>comp</code> is null
335 * @see #add
336 * @see javax.swing.RootPaneContainer
337 */
338 public void remove(Component comp) {
339 if (comp == rootPane) {
340 super.remove(comp);
341 } else {
342 getContentPane().remove(comp);
343 }
344 }
345
346
347 /**
348 * Sets the <code>LayoutManager</code>.
349 * Overridden to conditionally forward the call to the
350 * <code>contentPane</code>.
351 * Refer to {@link javax.swing.RootPaneContainer} for
352 * more information.
353 *
354 * @param manager the <code>LayoutManager</code>
355 * @see #setRootPaneCheckingEnabled
356 * @see javax.swing.RootPaneContainer
357 */
358 public void setLayout(LayoutManager manager) {
359 if(isRootPaneCheckingEnabled()) {
360 getContentPane().setLayout(manager);
361 }
362 else {
363 super.setLayout(manager);
364 }
365 }
366
367
368 /**
369 * Returns the rootPane object for this applet.
370 *
371 * @see #setRootPane
372 * @see RootPaneContainer#getRootPane
373 */
374 @BeanProperty(bound = false, hidden = true, description
375 = "the RootPane object for this applet.")
376 public JRootPane getRootPane() {
377 return rootPane;
378 }
379
380
381 /**
382 * Sets the rootPane property. This method is called by the constructor.
383 * @param root the rootPane object for this applet
384 *
385 * @see #getRootPane
386 */
387 protected void setRootPane(JRootPane root) {
388 if(rootPane != null) {
389 remove(rootPane);
390 }
391 rootPane = root;
392 if(rootPane != null) {
393 boolean checkingEnabled = isRootPaneCheckingEnabled();
394 try {
395 setRootPaneCheckingEnabled(false);
396 add(rootPane, BorderLayout.CENTER);
397 }
398 finally {
399 setRootPaneCheckingEnabled(checkingEnabled);
400 }
401 }
402 }
403
404
405 /**
406 * Returns the contentPane object for this applet.
407 *
408 * @see #setContentPane
409 * @see RootPaneContainer#getContentPane
410 */
411 public Container getContentPane() {
412 return getRootPane().getContentPane();
413 }
414
415 /**
416 * Sets the contentPane property. This method is called by the constructor.
417 * @param contentPane the contentPane object for this applet
418 *
419 * @exception java.awt.IllegalComponentStateException (a runtime
420 * exception) if the content pane parameter is null
421 * @see #getContentPane
422 * @see RootPaneContainer#setContentPane
423 */
424 @BeanProperty(bound = false, hidden = true, description
425 = "The client area of the applet where child components are normally inserted.")
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 @BeanProperty(bound = false, hidden = true, description
450 = "The pane which holds the various applet layers.")
451 public void setLayeredPane(JLayeredPane layeredPane) {
452 getRootPane().setLayeredPane(layeredPane);
453 }
454
455 /**
456 * Returns the glassPane object for this applet.
457 *
458 * @see #setGlassPane
459 * @see RootPaneContainer#getGlassPane
460 */
461 public Component getGlassPane() {
462 return getRootPane().getGlassPane();
463 }
464
465 /**
466 * Sets the glassPane property.
467 * This method is called by the constructor.
468 * @param glassPane the glassPane object for this applet
469 *
470 * @see #getGlassPane
471 * @see RootPaneContainer#setGlassPane
472 */
473 @BeanProperty(bound = false, hidden = true, description
474 = "A transparent pane used for menu rendering.")
475 public void setGlassPane(Component glassPane) {
476 getRootPane().setGlassPane(glassPane);
477 }
478
479 /**
480 * {@inheritDoc}
481 *
482 * @since 1.6
483 */
484 @BeanProperty(bound = false)
485 public Graphics getGraphics() {
486 JComponent.getGraphicsInvoked(this);
487 return super.getGraphics();
488 }
489
490 /**
491 * Repaints the specified rectangle of this component within
492 * <code>time</code> milliseconds. Refer to <code>RepaintManager</code>
493 * for details on how the repaint is handled.
494 *
495 * @param time maximum time in milliseconds before update
496 * @param x the <i>x</i> coordinate
497 * @param y the <i>y</i> coordinate
498 * @param width the width
499 * @param height the height
500 * @see RepaintManager
501 * @since 1.6
502 */
503 public void repaint(long time, int x, int y, int width, int height) {
504 if (RepaintManager.HANDLE_TOP_LEVEL_PAINT) {
505 RepaintManager.currentManager(this).addDirtyRegion(
506 this, x, y, width, height);
507 }
508 else {
509 super.repaint(time, x, y, width, height);
510 }
511 }
512
513 /**
514 * Returns a string representation of this JApplet. This method
515 * is intended to be used only for debugging purposes, and the
516 * content and format of the returned string may vary between
517 * implementations. The returned string may be empty but may not
518 * be <code>null</code>.
519 *
520 * @return a string representation of this JApplet.
521 */
522 protected String paramString() {
523 String rootPaneString = (rootPane != null ?
524 rootPane.toString() : "");
525 String rootPaneCheckingEnabledString = (rootPaneCheckingEnabled ?
526 "true" : "false");
527
528 return super.paramString() +
529 ",rootPane=" + rootPaneString +
530 ",rootPaneCheckingEnabled=" + rootPaneCheckingEnabledString;
531 }
532
533
534
535 /////////////////
536 // Accessibility support
537 ////////////////
538
539 /**
540 * {@code AccessibleContext} associated with this {@code JApplet}
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 }