1 /*
2 * Copyright (c) 1997, 2018, 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.Component;
28 import java.awt.Graphics;
29 import java.awt.Insets;
30 import java.awt.Toolkit;
31 import java.awt.event.*;
32 import java.beans.JavaBean;
33 import java.beans.BeanProperty;
34 import java.beans.Transient;
35 import java.util.Vector;
36
37 import java.io.Serializable;
38 import java.io.ObjectOutputStream;
39 import java.io.ObjectInputStream;
40 import java.io.IOException;
41
42 import javax.swing.plaf.*;
43 import javax.accessibility.*;
44
45 import sun.awt.SunToolkit;
46
47 /**
48 * An implementation of a menu bar. You add <code>JMenu</code> objects to the
49 * menu bar to construct a menu. When the user selects a <code>JMenu</code>
50 * object, its associated <code>JPopupMenu</code> is displayed, allowing the
51 * user to select one of the <code>JMenuItems</code> on it.
52 * <p>
53 * For information and examples of using menu bars see
54 * <a
55 href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
56 * a section in <em>The Java Tutorial.</em>
57 * <p>
58 * <strong>Warning:</strong> Swing is not thread safe. For more
59 * information see <a
60 * href="package-summary.html#threading">Swing's Threading
61 * Policy</a>.
62 * <p>
63 * <strong>Warning:</strong>
64 * Serialized objects of this class will not be compatible with
65 * future Swing releases. The current serialization support is
66 * appropriate for short term storage or RMI between applications running
67 * the same version of Swing. As of 1.4, support for long term storage
68 * of all JavaBeans
69 * has been added to the <code>java.beans</code> package.
70 * Please see {@link java.beans.XMLEncoder}.
71 * <p>
72 * <strong>Warning:</strong>
73 * By default, pressing the Tab key does not transfer focus from a <code>
74 * JMenuBar</code> which is added to a container together with other Swing
75 * components, because the <code>focusTraversalKeysEnabled</code> property
76 * of <code>JMenuBar</code> is set to <code>false</code>. To resolve this,
77 * you should call the <code>JMenuBar.setFocusTraversalKeysEnabled(true)</code>
78 * method.
79 *
80 * @author Georges Saab
81 * @author David Karlton
82 * @author Arnaud Weber
83 * @see JMenu
84 * @see JPopupMenu
85 * @see JMenuItem
86 * @since 1.2
87 */
88 @JavaBean(defaultProperty = "UI", description = "A container for holding and displaying menus.")
89 @SwingContainer
90 @SuppressWarnings("serial")
91 public class JMenuBar extends JComponent implements Accessible,MenuElement
92 {
93 /**
94 * @see #getUIClassID
95 * @see #readObject
96 */
97 private static final String uiClassID = "MenuBarUI";
98
99 /*
100 * Model for the selected subcontrol.
101 */
102 private transient SingleSelectionModel selectionModel;
103
104 private boolean paintBorder = true;
105 private Insets margin = null;
106
107 /* diagnostic aids -- should be false for production builds. */
108 private static final boolean TRACE = false; // trace creates and disposes
109 private static final boolean VERBOSE = false; // show reuse hits/misses
110 private static final boolean DEBUG = false; // show bad params, misc.
111
112 /**
113 * Creates a new menu bar.
114 */
115 public JMenuBar() {
116 super();
117 setFocusTraversalKeysEnabled(false);
118 setSelectionModel(new DefaultSingleSelectionModel());
119 updateUI();
120 }
121
122 /**
123 * Returns the menubar's current UI.
124 *
125 * @return a {@code MenuBarUI} which is the menubar's current L&F object
126 * @see #setUI
127 */
128 public MenuBarUI getUI() {
129 return (MenuBarUI)ui;
130 }
131
132 /**
133 * Sets the L&F object that renders this component.
134 *
135 * @param ui the new MenuBarUI L&F object
136 * @see UIDefaults#getUI
137 */
138 @BeanProperty(hidden = true, visualUpdate = true, description
139 = "The UI object that implements the Component's LookAndFeel.")
140 public void setUI(MenuBarUI ui) {
141 super.setUI(ui);
142 }
143
144 /**
145 * Resets the UI property with a value from the current look and feel.
146 *
147 * @see JComponent#updateUI
148 */
149 public void updateUI() {
150 Toolkit tk = Toolkit.getDefaultToolkit();
151 if (tk instanceof SunToolkit) {
152 ((SunToolkit)tk).updateScreenMenuBarUI();
153 }
154 setUI((MenuBarUI)UIManager.getUI(this));
155 }
156
157
158 /**
159 * Returns the name of the L&F class that renders this component.
160 *
161 * @return the string "MenuBarUI"
162 * @see JComponent#getUIClassID
163 * @see UIDefaults#getUI
164 */
165 @BeanProperty(bound = false)
166 public String getUIClassID() {
167 return uiClassID;
168 }
169
170
171 /**
172 * Returns the model object that handles single selections.
173 *
174 * @return the <code>SingleSelectionModel</code> property
175 * @see SingleSelectionModel
176 */
177 public SingleSelectionModel getSelectionModel() {
178 return selectionModel;
179 }
180
181 /**
182 * Sets the model object to handle single selections.
183 *
184 * @param model the <code>SingleSelectionModel</code> to use
185 * @see SingleSelectionModel
186 */
187 @BeanProperty(description = "The selection model, recording which child is selected.")
188 public void setSelectionModel(SingleSelectionModel model) {
189 SingleSelectionModel oldValue = selectionModel;
190 this.selectionModel = model;
191 firePropertyChange("selectionModel", oldValue, selectionModel);
192 }
193
194
195 /**
196 * Appends the specified menu to the end of the menu bar.
197 *
198 * @param c the <code>JMenu</code> component to add
199 * @return the menu component
200 */
201 public JMenu add(JMenu c) {
202 super.add(c);
203 return c;
204 }
205
206 /**
207 * Returns the menu at the specified position in the menu bar.
208 *
209 * @param index an integer giving the position in the menu bar, where
210 * 0 is the first position
211 * @return the <code>JMenu</code> at that position, or <code>null</code> if
212 * if there is no <code>JMenu</code> at that position (ie. if
213 * it is a <code>JMenuItem</code>)
214 */
215 public JMenu getMenu(int index) {
216 Component c = getComponentAtIndex(index);
217 if (c instanceof JMenu)
218 return (JMenu) c;
219 return null;
220 }
221
222 /**
223 * Returns the number of items in the menu bar.
224 *
225 * @return the number of items in the menu bar
226 */
227 @BeanProperty(bound = false)
228 public int getMenuCount() {
229 return getComponentCount();
230 }
231
232 /**
233 * Sets the help menu that appears when the user selects the
234 * "help" option in the menu bar. This method is not yet implemented
235 * and will throw an exception.
236 *
237 * @param menu the JMenu that delivers help to the user
238 */
239 public void setHelpMenu(JMenu menu) {
240 throw new Error("setHelpMenu() not yet implemented.");
241 }
242
243 /**
244 * Gets the help menu for the menu bar. This method is not yet
245 * implemented and will throw an exception.
246 *
247 * @return the <code>JMenu</code> that delivers help to the user
248 */
249 @Transient
250 public JMenu getHelpMenu() {
251 throw new Error("getHelpMenu() not yet implemented.");
252 }
253
254 /**
255 * Returns the component at the specified index.
256 *
257 * @param i an integer specifying the position, where 0 is first
258 * @return the <code>Component</code> at the position,
259 * or <code>null</code> for an invalid index
260 * @deprecated replaced by <code>getComponent(int i)</code>
261 */
262 @Deprecated
263 public Component getComponentAtIndex(int i) {
264 if(i < 0 || i >= getComponentCount()) {
265 return null;
266 }
267 return getComponent(i);
268 }
269
270 /**
271 * Returns the index of the specified component.
272 *
273 * @param c the <code>Component</code> to find
274 * @return an integer giving the component's position, where 0 is first;
275 * or -1 if it can't be found
276 */
277 public int getComponentIndex(Component c) {
278 int ncomponents = this.getComponentCount();
279 Component[] component = this.getComponents();
280 for (int i = 0 ; i < ncomponents ; i++) {
281 Component comp = component[i];
282 if (comp == c)
283 return i;
284 }
285 return -1;
286 }
287
288 /**
289 * Sets the currently selected component, producing a
290 * a change to the selection model.
291 *
292 * @param sel the <code>Component</code> to select
293 */
294 public void setSelected(Component sel) {
295 SingleSelectionModel model = getSelectionModel();
296 int index = getComponentIndex(sel);
297 model.setSelectedIndex(index);
298 }
299
300 /**
301 * Returns true if the menu bar currently has a component selected.
302 *
303 * @return true if a selection has been made, else false
304 */
305 @BeanProperty(bound = false)
306 public boolean isSelected() {
307 return selectionModel.isSelected();
308 }
309
310 /**
311 * Returns true if the menu bars border should be painted.
312 *
313 * @return true if the border should be painted, else false
314 */
315 public boolean isBorderPainted() {
316 return paintBorder;
317 }
318
319 /**
320 * Sets whether the border should be painted.
321 *
322 * @param b if true and border property is not <code>null</code>,
323 * the border is painted.
324 * @see #isBorderPainted
325 */
326 @BeanProperty(visualUpdate = true, description
327 = "Whether the border should be painted.")
328 public void setBorderPainted(boolean b) {
329 boolean oldValue = paintBorder;
330 paintBorder = b;
331 firePropertyChange("borderPainted", oldValue, paintBorder);
332 if (b != oldValue) {
333 revalidate();
334 repaint();
335 }
336 }
337
338 /**
339 * Paints the menubar's border if <code>BorderPainted</code>
340 * property is true.
341 *
342 * @param g the <code>Graphics</code> context to use for painting
343 * @see JComponent#paint
344 * @see JComponent#setBorder
345 */
346 protected void paintBorder(Graphics g) {
347 if (isBorderPainted()) {
348 super.paintBorder(g);
349 }
350 }
351
352 /**
353 * Sets the margin between the menubar's border and
354 * its menus. Setting to <code>null</code> will cause the menubar to
355 * use the default margins.
356 *
357 * @param m an Insets object containing the margin values
358 * @see Insets
359 */
360 @BeanProperty(visualUpdate = true, description
361 = "The space between the menubar's border and its contents")
362 public void setMargin(Insets m) {
363 Insets old = margin;
364 this.margin = m;
365 firePropertyChange("margin", old, m);
366 if (old == null || !old.equals(m)) {
367 revalidate();
368 repaint();
369 }
370 }
371
372 /**
373 * Returns the margin between the menubar's border and
374 * its menus. If there is no previous margin, it will create
375 * a default margin with zero size.
376 *
377 * @return an <code>Insets</code> object containing the margin values
378 * @see Insets
379 */
380 public Insets getMargin() {
381 if(margin == null) {
382 return new Insets(0,0,0,0);
383 } else {
384 return margin;
385 }
386 }
387
388
389 /**
390 * Implemented to be a <code>MenuElement</code> -- does nothing.
391 *
392 * @see #getSubElements
393 */
394 public void processMouseEvent(MouseEvent event,MenuElement[] path,MenuSelectionManager manager) {
395 }
396
397 /**
398 * Implemented to be a <code>MenuElement</code> -- does nothing.
399 *
400 * @see #getSubElements
401 */
402 public void processKeyEvent(KeyEvent e,MenuElement[] path,MenuSelectionManager manager) {
403 }
404
405 /**
406 * Implemented to be a <code>MenuElement</code> -- does nothing.
407 *
408 * @see #getSubElements
409 */
410 public void menuSelectionChanged(boolean isIncluded) {
411 }
412
413 /**
414 * Implemented to be a <code>MenuElement</code> -- returns the
415 * menus in this menu bar.
416 * This is the reason for implementing the <code>MenuElement</code>
417 * interface -- so that the menu bar can be treated the same as
418 * other menu elements.
419 * @return an array of menu items in the menu bar.
420 */
421 @BeanProperty(bound = false)
422 public MenuElement[] getSubElements() {
423 MenuElement[] result;
424 Vector<MenuElement> tmp = new Vector<MenuElement>();
425 int c = getComponentCount();
426 int i;
427 Component m;
428
429 for(i=0 ; i < c ; i++) {
430 m = getComponent(i);
431 if(m instanceof MenuElement)
432 tmp.addElement((MenuElement) m);
433 }
434
435 result = new MenuElement[tmp.size()];
436 for(i=0,c=tmp.size() ; i < c ; i++)
437 result[i] = tmp.elementAt(i);
438 return result;
439 }
440
441 /**
442 * Implemented to be a <code>MenuElement</code>. Returns this object.
443 *
444 * @return the current <code>Component</code> (this)
445 * @see #getSubElements
446 */
447 public Component getComponent() {
448 return this;
449 }
450
451
452 /**
453 * Returns a string representation of this <code>JMenuBar</code>.
454 * This method
455 * is intended to be used only for debugging purposes, and the
456 * content and format of the returned string may vary between
457 * implementations. The returned string may be empty but may not
458 * be <code>null</code>.
459 *
460 * @return a string representation of this <code>JMenuBar</code>
461 */
462 protected String paramString() {
463 String paintBorderString = (paintBorder ?
464 "true" : "false");
465 String marginString = (margin != null ?
466 margin.toString() : "");
467
468 return super.paramString() +
469 ",margin=" + marginString +
470 ",paintBorder=" + paintBorderString;
471 }
472
473 /////////////////
474 // Accessibility support
475 ////////////////
476
477 /**
478 * Gets the AccessibleContext associated with this JMenuBar.
479 * For JMenuBars, the AccessibleContext takes the form of an
480 * AccessibleJMenuBar.
481 * A new AccessibleJMenuBar instance is created if necessary.
482 *
483 * @return an AccessibleJMenuBar that serves as the
484 * AccessibleContext of this JMenuBar
485 */
486 @BeanProperty(bound = false)
487 public AccessibleContext getAccessibleContext() {
488 if (accessibleContext == null) {
489 accessibleContext = new AccessibleJMenuBar();
490 }
491 return accessibleContext;
492 }
493
494 /**
495 * This class implements accessibility support for the
496 * <code>JMenuBar</code> class. It provides an implementation of the
497 * Java Accessibility API appropriate to menu bar user-interface
498 * elements.
499 * <p>
500 * <strong>Warning:</strong>
501 * Serialized objects of this class will not be compatible with
502 * future Swing releases. The current serialization support is
503 * appropriate for short term storage or RMI between applications running
504 * the same version of Swing. As of 1.4, support for long term storage
505 * of all JavaBeans
506 * has been added to the <code>java.beans</code> package.
507 * Please see {@link java.beans.XMLEncoder}.
508 */
509 @SuppressWarnings("serial")
510 protected class AccessibleJMenuBar extends AccessibleJComponent
511 implements AccessibleSelection {
512
513 /**
514 * Get the accessible state set of this object.
515 *
516 * @return an instance of AccessibleState containing the current state
517 * of the object
518 */
519 public AccessibleStateSet getAccessibleStateSet() {
520 AccessibleStateSet states = super.getAccessibleStateSet();
521 return states;
522 }
523
524 /**
525 * Get the role of this object.
526 *
527 * @return an instance of AccessibleRole describing the role of the
528 * object
529 */
530 public AccessibleRole getAccessibleRole() {
531 return AccessibleRole.MENU_BAR;
532 }
533
534 /**
535 * Get the AccessibleSelection associated with this object. In the
536 * implementation of the Java Accessibility API for this class,
537 * return this object, which is responsible for implementing the
538 * AccessibleSelection interface on behalf of itself.
539 *
540 * @return this object
541 */
542 public AccessibleSelection getAccessibleSelection() {
543 return this;
544 }
545
546 /**
547 * Returns 1 if a menu is currently selected in this menu bar.
548 *
549 * @return 1 if a menu is currently selected, else 0
550 */
551 public int getAccessibleSelectionCount() {
552 if (isSelected()) {
553 return 1;
554 } else {
555 return 0;
556 }
557 }
558
559 /**
560 * Returns the currently selected menu if one is selected,
561 * otherwise null.
562 */
563 public Accessible getAccessibleSelection(int i) {
564 if (isSelected()) {
565 if (i != 0) { // single selection model for JMenuBar
566 return null;
567 }
568 int j = getSelectionModel().getSelectedIndex();
569 if (getComponentAtIndex(j) instanceof Accessible) {
570 return (Accessible) getComponentAtIndex(j);
571 }
572 }
573 return null;
574 }
575
576 /**
577 * Returns true if the current child of this object is selected.
578 *
579 * @param i the zero-based index of the child in this Accessible
580 * object.
581 * @see AccessibleContext#getAccessibleChild
582 */
583 public boolean isAccessibleChildSelected(int i) {
584 return (i == getSelectionModel().getSelectedIndex());
585 }
586
587 /**
588 * Selects the nth menu in the menu bar, forcing it to
589 * pop up. If another menu is popped up, this will force
590 * it to close. If the nth menu is already selected, this
591 * method has no effect.
592 *
593 * @param i the zero-based index of selectable items
594 * @see #getAccessibleStateSet
595 */
596 public void addAccessibleSelection(int i) {
597 // first close up any open menu
598 int j = getSelectionModel().getSelectedIndex();
599 if (i == j) {
600 return;
601 }
602 if (j >= 0 && j < getMenuCount()) {
603 JMenu menu = getMenu(j);
604 if (menu != null) {
605 MenuSelectionManager.defaultManager().setSelectedPath(null);
606 // menu.setPopupMenuVisible(false);
607 }
608 }
609 // now popup the new menu
610 getSelectionModel().setSelectedIndex(i);
611 JMenu menu = getMenu(i);
612 if (menu != null) {
613 MenuElement[] me = new MenuElement[3];
614 me[0] = JMenuBar.this;
615 me[1] = menu;
616 me[2] = menu.getPopupMenu();
617 MenuSelectionManager.defaultManager().setSelectedPath(me);
618 // menu.setPopupMenuVisible(true);
619 }
620 }
621
622 /**
623 * Removes the nth selected item in the object from the object's
624 * selection. If the nth item isn't currently selected, this
625 * method has no effect. Otherwise, it closes the popup menu.
626 *
627 * @param i the zero-based index of selectable items
628 */
629 public void removeAccessibleSelection(int i) {
630 if (i >= 0 && i < getMenuCount()) {
631 JMenu menu = getMenu(i);
632 if (menu != null) {
633 MenuSelectionManager.defaultManager().setSelectedPath(null);
634 // menu.setPopupMenuVisible(false);
635 }
636 getSelectionModel().setSelectedIndex(-1);
637 }
638 }
639
640 /**
641 * Clears the selection in the object, so that nothing in the
642 * object is selected. This will close any open menu.
643 */
644 public void clearAccessibleSelection() {
645 int i = getSelectionModel().getSelectedIndex();
646 if (i >= 0 && i < getMenuCount()) {
647 JMenu menu = getMenu(i);
648 if (menu != null) {
649 MenuSelectionManager.defaultManager().setSelectedPath(null);
650 // menu.setPopupMenuVisible(false);
651 }
652 }
653 getSelectionModel().setSelectedIndex(-1);
654 }
655
656 /**
657 * Normally causes every selected item in the object to be selected
658 * if the object supports multiple selections. This method
659 * makes no sense in a menu bar, and so does nothing.
660 */
661 public void selectAllAccessibleSelection() {
662 }
663 } // internal class AccessibleJMenuBar
664
665
666 /**
667 * Subclassed to check all the child menus.
668 * @since 1.3
669 */
670 protected boolean processKeyBinding(KeyStroke ks, KeyEvent e,
671 int condition, boolean pressed) {
672 // See if we have a local binding.
673 boolean retValue = super.processKeyBinding(ks, e, condition, pressed);
674 if (!retValue) {
675 MenuElement[] subElements = getSubElements();
676 for (MenuElement subElement : subElements) {
677 if (processBindingForKeyStrokeRecursive(
678 subElement, ks, e, condition, pressed)) {
679 return true;
680 }
681 }
682 }
683 return retValue;
684 }
685
686 static boolean processBindingForKeyStrokeRecursive(MenuElement elem,
687 KeyStroke ks, KeyEvent e, int condition, boolean pressed) {
688 if (elem == null) {
689 return false;
690 }
691
692 Component c = elem.getComponent();
693
694 if ( !(c.isVisible() || (c instanceof JPopupMenu)) || !c.isEnabled() ) {
695 return false;
696 }
697
698 if (c != null && c instanceof JComponent &&
699 ((JComponent)c).processKeyBinding(ks, e, condition, pressed)) {
700
701 return true;
702 }
703
704 MenuElement[] subElements = elem.getSubElements();
705 for (MenuElement subElement : subElements) {
706 if (processBindingForKeyStrokeRecursive(subElement, ks, e, condition, pressed)) {
707 return true;
708 // We don't, pass along to children JMenu's
709 }
710 }
711 return false;
712 }
713
714 /**
715 * Overrides <code>JComponent.addNotify</code> to register this
716 * menu bar with the current keyboard manager.
717 */
718 public void addNotify() {
719 super.addNotify();
720 KeyboardManager.getCurrentManager().registerMenuBar(this);
721 }
722
723 /**
724 * Overrides <code>JComponent.removeNotify</code> to unregister this
725 * menu bar with the current keyboard manager.
726 */
727 public void removeNotify() {
728 super.removeNotify();
729 KeyboardManager.getCurrentManager().unregisterMenuBar(this);
730 }
731
732
733 private void writeObject(ObjectOutputStream s) throws IOException {
734 s.defaultWriteObject();
735 if (getUIClassID().equals(uiClassID)) {
736 byte count = JComponent.getWriteObjCounter(this);
737 JComponent.setWriteObjCounter(this, --count);
738 if (count == 0 && ui != null) {
739 ui.installUI(this);
740 }
741 }
742
743 Object[] kvData = new Object[4];
744 int n = 0;
745
746 if (selectionModel instanceof Serializable) {
747 kvData[n++] = "selectionModel";
748 kvData[n++] = selectionModel;
749 }
750
751 s.writeObject(kvData);
752 }
753
754
755 /**
756 * See JComponent.readObject() for information about serialization
757 * in Swing.
758 */
759 private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException
760 {
761 s.defaultReadObject();
762 Object[] kvData = (Object[])(s.readObject());
763
764 for(int i = 0; i < kvData.length; i += 2) {
765 if (kvData[i] == null) {
766 break;
767 }
768 else if (kvData[i].equals("selectionModel")) {
769 selectionModel = (SingleSelectionModel)kvData[i + 1];
770 }
771 }
772
773 }
774 }