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
26 package javax.swing;
27
28 import java.awt.Component;
29 import java.awt.Dimension;
30 import java.awt.Graphics;
31 import java.awt.Insets;
32 import java.awt.Point;
33 import java.awt.Rectangle;
34 import java.awt.event.*;
35 import java.beans.Transient;
36 import java.util.Vector;
37 import java.util.Enumeration;
38
39 import java.io.Serializable;
40 import java.io.ObjectOutputStream;
41 import java.io.ObjectInputStream;
42 import java.io.IOException;
43
44 import javax.swing.event.*;
45 import javax.swing.border.Border;
46 import javax.swing.plaf.*;
47 import javax.accessibility.*;
48
49 /**
50 * An implementation of a menu bar. You add <code>JMenu</code> objects to the
51 * menu bar to construct a menu. When the user selects a <code>JMenu</code>
52 * object, its associated <code>JPopupMenu</code> is displayed, allowing the
53 * user to select one of the <code>JMenuItems</code> on it.
54 * <p>
55 * For information and examples of using menu bars see
56 * <a
57 href="http://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
58 * a section in <em>The Java Tutorial.</em>
59 * <p>
60 * <strong>Warning:</strong> Swing is not thread safe. For more
61 * information see <a
62 * href="package-summary.html#threading">Swing's Threading
63 * Policy</a>.
64 * <p>
65 * <strong>Warning:</strong>
66 * Serialized objects of this class will not be compatible with
67 * future Swing releases. The current serialization support is
68 * appropriate for short term storage or RMI between applications running
69 * the same version of Swing. As of 1.4, support for long term storage
70 * of all JavaBeans™
71 * has been added to the <code>java.beans</code> package.
72 * Please see {@link java.beans.XMLEncoder}.
73 * <p>
74 * <strong>Warning:</strong>
75 * By default, pressing the Tab key does not transfer focus from a <code>
76 * JMenuBar</code> which is added to a container together with other Swing
77 * components, because the <code>focusTraversalKeysEnabled</code> property
78 * of <code>JMenuBar</code> is set to <code>false</code>. To resolve this,
79 * you should call the <code>JMenuBar.setFocusTraversalKeysEnabled(true)</code>
80 * method.
81 * @beaninfo
82 * attribute: isContainer true
83 * description: A container for holding and displaying menus.
84 *
85 * @author Georges Saab
86 * @author David Karlton
87 * @author Arnaud Weber
88 * @see JMenu
89 * @see JPopupMenu
90 * @see JMenuItem
91 * @since 1.2
92 */
93 @SuppressWarnings("serial")
94 public class JMenuBar extends JComponent implements Accessible,MenuElement
95 {
96 /**
97 * @see #getUIClassID
98 * @see #readObject
99 */
100 private static final String uiClassID = "MenuBarUI";
101
102 /*
103 * Model for the selected subcontrol.
104 */
105 private transient SingleSelectionModel selectionModel;
106
107 private boolean paintBorder = true;
108 private Insets margin = null;
109
110 /* diagnostic aids -- should be false for production builds. */
111 private static final boolean TRACE = false; // trace creates and disposes
112 private static final boolean VERBOSE = false; // show reuse hits/misses
113 private static final boolean DEBUG = false; // show bad params, misc.
114
115 /**
116 * Creates a new menu bar.
117 */
118 public JMenuBar() {
119 super();
120 setFocusTraversalKeysEnabled(false);
121 setSelectionModel(new DefaultSingleSelectionModel());
122 updateUI();
123 }
124
125 /**
126 * Returns the menubar's current UI.
127 *
128 * @return a {@code MenuBarUI} which is the menubar's current L&F object
129 * @see #setUI
130 */
131 public MenuBarUI getUI() {
132 return (MenuBarUI)ui;
133 }
134
135 /**
136 * Sets the L&F object that renders this component.
137 *
138 * @param ui the new MenuBarUI L&F object
139 * @see UIDefaults#getUI
140 * @beaninfo
141 * bound: true
142 * hidden: true
143 * attribute: visualUpdate true
144 * description: The UI object that implements the Component's LookAndFeel.
145 */
146 public void setUI(MenuBarUI ui) {
147 super.setUI(ui);
148 }
149
150 /**
151 * Resets the UI property with a value from the current look and feel.
152 *
153 * @see JComponent#updateUI
154 */
155 public void updateUI() {
156 setUI((MenuBarUI)UIManager.getUI(this));
157 }
158
159
160 /**
161 * Returns the name of the L&F class that renders this component.
162 *
163 * @return the string "MenuBarUI"
164 * @see JComponent#getUIClassID
165 * @see UIDefaults#getUI
166 */
167 public String getUIClassID() {
168 return uiClassID;
169 }
170
171
172 /**
173 * Returns the model object that handles single selections.
174 *
175 * @return the <code>SingleSelectionModel</code> property
176 * @see SingleSelectionModel
177 */
178 public SingleSelectionModel getSelectionModel() {
179 return selectionModel;
180 }
181
182 /**
183 * Sets the model object to handle single selections.
184 *
185 * @param model the <code>SingleSelectionModel</code> to use
186 * @see SingleSelectionModel
187 * @beaninfo
188 * bound: true
189 * description: The selection model, recording which child is selected.
190 */
191 public void setSelectionModel(SingleSelectionModel model) {
192 SingleSelectionModel oldValue = selectionModel;
193 this.selectionModel = model;
194 firePropertyChange("selectionModel", oldValue, selectionModel);
195 }
196
197
198 /**
199 * Appends the specified menu to the end of the menu bar.
200 *
201 * @param c the <code>JMenu</code> component to add
202 * @return the menu component
203 */
204 public JMenu add(JMenu c) {
205 super.add(c);
206 return c;
207 }
208
209 /**
210 * Returns the menu at the specified position in the menu bar.
211 *
212 * @param index an integer giving the position in the menu bar, where
213 * 0 is the first position
214 * @return the <code>JMenu</code> at that position, or <code>null</code> if
215 * if there is no <code>JMenu</code> at that position (ie. if
216 * it is a <code>JMenuItem</code>)
217 */
218 public JMenu getMenu(int index) {
219 Component c = getComponentAtIndex(index);
220 if (c instanceof JMenu)
221 return (JMenu) c;
222 return null;
223 }
224
225 /**
226 * Returns the number of items in the menu bar.
227 *
228 * @return the number of items in the menu bar
229 */
230 public int getMenuCount() {
231 return getComponentCount();
232 }
233
234 /**
235 * Sets the help menu that appears when the user selects the
236 * "help" option in the menu bar. This method is not yet implemented
237 * and will throw an exception.
238 *
239 * @param menu the JMenu that delivers help to the user
240 */
241 public void setHelpMenu(JMenu menu) {
242 throw new Error("setHelpMenu() not yet implemented.");
243 }
244
245 /**
246 * Gets the help menu for the menu bar. This method is not yet
247 * implemented and will throw an exception.
248 *
249 * @return the <code>JMenu</code> that delivers help to the user
250 */
251 @Transient
252 public JMenu getHelpMenu() {
253 throw new Error("getHelpMenu() not yet implemented.");
254 }
255
256 /**
257 * Returns the component at the specified index.
258 *
259 * @param i an integer specifying the position, where 0 is first
260 * @return the <code>Component</code> at the position,
261 * or <code>null</code> for an invalid index
262 * @deprecated replaced by <code>getComponent(int i)</code>
263 */
264 @Deprecated
265 public Component getComponentAtIndex(int i) {
266 if(i < 0 || i >= getComponentCount()) {
267 return null;
268 }
269 return getComponent(i);
270 }
271
272 /**
273 * Returns the index of the specified component.
274 *
275 * @param c the <code>Component</code> to find
276 * @return an integer giving the component's position, where 0 is first;
277 * or -1 if it can't be found
278 */
279 public int getComponentIndex(Component c) {
280 int ncomponents = this.getComponentCount();
281 Component[] component = this.getComponents();
282 for (int i = 0 ; i < ncomponents ; i++) {
283 Component comp = component[i];
284 if (comp == c)
285 return i;
286 }
287 return -1;
288 }
289
290 /**
291 * Sets the currently selected component, producing a
292 * a change to the selection model.
293 *
294 * @param sel the <code>Component</code> to select
295 */
296 public void setSelected(Component sel) {
297 SingleSelectionModel model = getSelectionModel();
298 int index = getComponentIndex(sel);
299 model.setSelectedIndex(index);
300 }
301
302 /**
303 * Returns true if the menu bar currently has a component selected.
304 *
305 * @return true if a selection has been made, else false
306 */
307 public boolean isSelected() {
308 return selectionModel.isSelected();
309 }
310
311 /**
312 * Returns true if the menu bars border should be painted.
313 *
314 * @return true if the border should be painted, else false
315 */
316 public boolean isBorderPainted() {
317 return paintBorder;
318 }
319
320 /**
321 * Sets whether the border should be painted.
322 *
323 * @param b if true and border property is not <code>null</code>,
324 * the border is painted.
325 * @see #isBorderPainted
326 * @beaninfo
327 * bound: true
328 * attribute: visualUpdate true
329 * description: Whether the border should be painted.
330 */
331 public void setBorderPainted(boolean b) {
332 boolean oldValue = paintBorder;
333 paintBorder = b;
334 firePropertyChange("borderPainted", oldValue, paintBorder);
335 if (b != oldValue) {
336 revalidate();
337 repaint();
338 }
339 }
340
341 /**
342 * Paints the menubar's border if <code>BorderPainted</code>
343 * property is true.
344 *
345 * @param g the <code>Graphics</code> context to use for painting
346 * @see JComponent#paint
347 * @see JComponent#setBorder
348 */
349 protected void paintBorder(Graphics g) {
350 if (isBorderPainted()) {
351 super.paintBorder(g);
352 }
353 }
354
355 /**
356 * Sets the margin between the menubar's border and
357 * its menus. Setting to <code>null</code> will cause the menubar to
358 * use the default margins.
359 *
360 * @param m an Insets object containing the margin values
361 * @see Insets
362 * @beaninfo
363 * bound: true
364 * attribute: visualUpdate true
365 * description: The space between the menubar's border and its contents
366 */
367 public void setMargin(Insets m) {
368 Insets old = margin;
369 this.margin = m;
370 firePropertyChange("margin", old, m);
371 if (old == null || !old.equals(m)) {
372 revalidate();
373 repaint();
374 }
375 }
376
377 /**
378 * Returns the margin between the menubar's border and
379 * its menus. If there is no previous margin, it will create
380 * a default margin with zero size.
381 *
382 * @return an <code>Insets</code> object containing the margin values
383 * @see Insets
384 */
385 public Insets getMargin() {
386 if(margin == null) {
387 return new Insets(0,0,0,0);
388 } else {
389 return margin;
390 }
391 }
392
393
394 /**
395 * Implemented to be a <code>MenuElement</code> -- does nothing.
396 *
397 * @see #getSubElements
398 */
399 public void processMouseEvent(MouseEvent event,MenuElement path[],MenuSelectionManager manager) {
400 }
401
402 /**
403 * Implemented to be a <code>MenuElement</code> -- does nothing.
404 *
405 * @see #getSubElements
406 */
407 public void processKeyEvent(KeyEvent e,MenuElement path[],MenuSelectionManager manager) {
408 }
409
410 /**
411 * Implemented to be a <code>MenuElement</code> -- does nothing.
412 *
413 * @see #getSubElements
414 */
415 public void menuSelectionChanged(boolean isIncluded) {
416 }
417
418 /**
419 * Implemented to be a <code>MenuElement</code> -- returns the
420 * menus in this menu bar.
421 * This is the reason for implementing the <code>MenuElement</code>
422 * interface -- so that the menu bar can be treated the same as
423 * other menu elements.
424 * @return an array of menu items in the menu bar.
425 */
426 public MenuElement[] getSubElements() {
427 MenuElement result[];
428 Vector<MenuElement> tmp = new Vector<MenuElement>();
429 int c = getComponentCount();
430 int i;
431 Component m;
432
433 for(i=0 ; i < c ; i++) {
434 m = getComponent(i);
435 if(m instanceof MenuElement)
436 tmp.addElement((MenuElement) m);
437 }
438
439 result = new MenuElement[tmp.size()];
440 for(i=0,c=tmp.size() ; i < c ; i++)
441 result[i] = tmp.elementAt(i);
442 return result;
443 }
444
445 /**
446 * Implemented to be a <code>MenuElement</code>. Returns this object.
447 *
448 * @return the current <code>Component</code> (this)
449 * @see #getSubElements
450 */
451 public Component getComponent() {
452 return this;
453 }
454
455
456 /**
457 * Returns a string representation of this <code>JMenuBar</code>.
458 * This method
459 * is intended to be used only for debugging purposes, and the
460 * content and format of the returned string may vary between
461 * implementations. The returned string may be empty but may not
462 * be <code>null</code>.
463 *
464 * @return a string representation of this <code>JMenuBar</code>
465 */
466 protected String paramString() {
467 String paintBorderString = (paintBorder ?
468 "true" : "false");
469 String marginString = (margin != null ?
470 margin.toString() : "");
471
472 return super.paramString() +
473 ",margin=" + marginString +
474 ",paintBorder=" + paintBorderString;
475 }
476
477 /////////////////
478 // Accessibility support
479 ////////////////
480
481 /**
482 * Gets the AccessibleContext associated with this JMenuBar.
483 * For JMenuBars, the AccessibleContext takes the form of an
484 * AccessibleJMenuBar.
485 * A new AccessibleJMenuBar instance is created if necessary.
486 *
487 * @return an AccessibleJMenuBar that serves as the
488 * AccessibleContext of this JMenuBar
489 */
490 public AccessibleContext getAccessibleContext() {
491 if (accessibleContext == null) {
492 accessibleContext = new AccessibleJMenuBar();
493 }
494 return accessibleContext;
495 }
496
497 /**
498 * This class implements accessibility support for the
499 * <code>JMenuBar</code> class. It provides an implementation of the
500 * Java Accessibility API appropriate to menu bar user-interface
501 * elements.
502 * <p>
503 * <strong>Warning:</strong>
504 * Serialized objects of this class will not be compatible with
505 * future Swing releases. The current serialization support is
506 * appropriate for short term storage or RMI between applications running
507 * the same version of Swing. As of 1.4, support for long term storage
508 * of all JavaBeans™
509 * has been added to the <code>java.beans</code> package.
510 * Please see {@link java.beans.XMLEncoder}.
511 */
512 @SuppressWarnings("serial")
513 protected class AccessibleJMenuBar extends AccessibleJComponent
514 implements AccessibleSelection {
515
516 /**
517 * Get the accessible state set of this object.
518 *
519 * @return an instance of AccessibleState containing the current state
520 * of the object
521 */
522 public AccessibleStateSet getAccessibleStateSet() {
523 AccessibleStateSet states = super.getAccessibleStateSet();
524 return states;
525 }
526
527 /**
528 * Get the role of this object.
529 *
530 * @return an instance of AccessibleRole describing the role of the
531 * object
532 */
533 public AccessibleRole getAccessibleRole() {
534 return AccessibleRole.MENU_BAR;
535 }
536
537 /**
538 * Get the AccessibleSelection associated with this object. In the
539 * implementation of the Java Accessibility API for this class,
540 * return this object, which is responsible for implementing the
541 * AccessibleSelection interface on behalf of itself.
542 *
543 * @return this object
544 */
545 public AccessibleSelection getAccessibleSelection() {
546 return this;
547 }
548
549 /**
550 * Returns 1 if a menu is currently selected in this menu bar.
551 *
552 * @return 1 if a menu is currently selected, else 0
553 */
554 public int getAccessibleSelectionCount() {
555 if (isSelected()) {
556 return 1;
557 } else {
558 return 0;
559 }
560 }
561
562 /**
563 * Returns the currently selected menu if one is selected,
564 * otherwise null.
565 */
566 public Accessible getAccessibleSelection(int i) {
567 if (isSelected()) {
568 if (i != 0) { // single selection model for JMenuBar
569 return null;
570 }
571 int j = getSelectionModel().getSelectedIndex();
572 if (getComponentAtIndex(j) instanceof Accessible) {
573 return (Accessible) getComponentAtIndex(j);
574 }
575 }
576 return null;
577 }
578
579 /**
580 * Returns true if the current child of this object is selected.
581 *
582 * @param i the zero-based index of the child in this Accessible
583 * object.
584 * @see AccessibleContext#getAccessibleChild
585 */
586 public boolean isAccessibleChildSelected(int i) {
587 return (i == getSelectionModel().getSelectedIndex());
588 }
589
590 /**
591 * Selects the nth menu in the menu bar, forcing it to
592 * pop up. If another menu is popped up, this will force
593 * it to close. If the nth menu is already selected, this
594 * method has no effect.
595 *
596 * @param i the zero-based index of selectable items
597 * @see #getAccessibleStateSet
598 */
599 public void addAccessibleSelection(int i) {
600 // first close up any open menu
601 int j = getSelectionModel().getSelectedIndex();
602 if (i == j) {
603 return;
604 }
605 if (j >= 0 && j < getMenuCount()) {
606 JMenu menu = getMenu(j);
607 if (menu != null) {
608 MenuSelectionManager.defaultManager().setSelectedPath(null);
609 // menu.setPopupMenuVisible(false);
610 }
611 }
612 // now popup the new menu
613 getSelectionModel().setSelectedIndex(i);
614 JMenu menu = getMenu(i);
615 if (menu != null) {
616 MenuElement me[] = new MenuElement[3];
617 me[0] = JMenuBar.this;
618 me[1] = menu;
619 me[2] = menu.getPopupMenu();
620 MenuSelectionManager.defaultManager().setSelectedPath(me);
621 // menu.setPopupMenuVisible(true);
622 }
623 }
624
625 /**
626 * Removes the nth selected item in the object from the object's
627 * selection. If the nth item isn't currently selected, this
628 * method has no effect. Otherwise, it closes the popup menu.
629 *
630 * @param i the zero-based index of selectable items
631 */
632 public void removeAccessibleSelection(int i) {
633 if (i >= 0 && i < getMenuCount()) {
634 JMenu menu = getMenu(i);
635 if (menu != null) {
636 MenuSelectionManager.defaultManager().setSelectedPath(null);
637 // menu.setPopupMenuVisible(false);
638 }
639 getSelectionModel().setSelectedIndex(-1);
640 }
641 }
642
643 /**
644 * Clears the selection in the object, so that nothing in the
645 * object is selected. This will close any open menu.
646 */
647 public void clearAccessibleSelection() {
648 int i = getSelectionModel().getSelectedIndex();
649 if (i >= 0 && i < getMenuCount()) {
650 JMenu menu = getMenu(i);
651 if (menu != null) {
652 MenuSelectionManager.defaultManager().setSelectedPath(null);
653 // menu.setPopupMenuVisible(false);
654 }
655 }
656 getSelectionModel().setSelectedIndex(-1);
657 }
658
659 /**
660 * Normally causes every selected item in the object to be selected
661 * if the object supports multiple selections. This method
662 * makes no sense in a menu bar, and so does nothing.
663 */
664 public void selectAllAccessibleSelection() {
665 }
666 } // internal class AccessibleJMenuBar
667
668
669 /**
670 * Subclassed to check all the child menus.
671 * @since 1.3
672 */
673 protected boolean processKeyBinding(KeyStroke ks, KeyEvent e,
674 int condition, boolean pressed) {
675 // See if we have a local binding.
676 boolean retValue = super.processKeyBinding(ks, e, condition, pressed);
677 if (!retValue) {
678 MenuElement[] subElements = getSubElements();
679 for (MenuElement subElement : subElements) {
680 if (processBindingForKeyStrokeRecursive(
681 subElement, ks, e, condition, pressed)) {
682 return true;
683 }
684 }
685 }
686 return retValue;
687 }
688
689 static boolean processBindingForKeyStrokeRecursive(MenuElement elem,
690 KeyStroke ks, KeyEvent e, int condition, boolean pressed) {
691 if (elem == null) {
692 return false;
693 }
694
695 Component c = elem.getComponent();
696
697 if ( !(c.isVisible() || (c instanceof JPopupMenu)) || !c.isEnabled() ) {
698 return false;
699 }
700
701 if (c != null && c instanceof JComponent &&
702 ((JComponent)c).processKeyBinding(ks, e, condition, pressed)) {
703
704 return true;
705 }
706
707 MenuElement[] subElements = elem.getSubElements();
708 for (MenuElement subElement : subElements) {
709 if (processBindingForKeyStrokeRecursive(subElement, ks, e, condition, pressed)) {
710 return true;
711 // We don't, pass along to children JMenu's
712 }
713 }
714 return false;
715 }
716
717 /**
718 * Overrides <code>JComponent.addNotify</code> to register this
719 * menu bar with the current keyboard manager.
720 */
721 public void addNotify() {
722 super.addNotify();
723 KeyboardManager.getCurrentManager().registerMenuBar(this);
724 }
725
726 /**
727 * Overrides <code>JComponent.removeNotify</code> to unregister this
728 * menu bar with the current keyboard manager.
729 */
730 public void removeNotify() {
731 super.removeNotify();
732 KeyboardManager.getCurrentManager().unregisterMenuBar(this);
733 }
734
735
736 private void writeObject(ObjectOutputStream s) throws IOException {
737 s.defaultWriteObject();
738 if (getUIClassID().equals(uiClassID)) {
739 byte count = JComponent.getWriteObjCounter(this);
740 JComponent.setWriteObjCounter(this, --count);
741 if (count == 0 && ui != null) {
742 ui.installUI(this);
743 }
744 }
745
746 Object[] kvData = new Object[4];
747 int n = 0;
748
749 if (selectionModel instanceof Serializable) {
750 kvData[n++] = "selectionModel";
751 kvData[n++] = selectionModel;
752 }
753
754 s.writeObject(kvData);
755 }
756
757
758 /**
759 * See JComponent.readObject() for information about serialization
760 * in Swing.
761 */
762 private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException
763 {
764 s.defaultReadObject();
765 Object[] kvData = (Object[])(s.readObject());
766
767 for(int i = 0; i < kvData.length; i += 2) {
768 if (kvData[i] == null) {
769 break;
770 }
771 else if (kvData[i].equals("selectionModel")) {
772 selectionModel = (SingleSelectionModel)kvData[i + 1];
773 }
774 }
775
776 }
777 }