JMenu objects to the
* menu bar to construct a menu. When the user selects a JMenu
* object, its associated JPopupMenu is displayed, allowing the
* user to select one of the JMenuItems on it.
* * For information and examples of using menu bars see * How to Use Menus, * a section in The Java Tutorial. *
* Warning: Swing is not thread safe. For more * information see Swing's Threading * Policy. *
* Warning:
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeans
* has been added to the java.beans package.
* Please see {@link java.beans.XMLEncoder}.
*
* Warning:
* By default, pressing the Tab key does not transfer focus from a
* Warning:
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeans
* has been added to the
* JMenuBar which is added to a container together with other Swing
* components, because the focusTraversalKeysEnabled property
* of JMenuBar is set to false. To resolve this,
* you should call the JMenuBar.setFocusTraversalKeysEnabled(true)
* method.
*
* @author Georges Saab
* @author David Karlton
* @author Arnaud Weber
* @see JMenu
* @see JPopupMenu
* @see JMenuItem
* @since 1.2
*/
@JavaBean(defaultProperty = "UI", description = "A container for holding and displaying menus.")
@SwingContainer
@SuppressWarnings("serial")
public class JMenuBar extends JComponent implements Accessible,MenuElement
{
/**
* @see #getUIClassID
* @see #readObject
*/
private static final String uiClassID = "MenuBarUI";
/*
* Model for the selected subcontrol.
*/
private transient SingleSelectionModel selectionModel;
private boolean paintBorder = true;
private Insets margin = null;
/* diagnostic aids -- should be false for production builds. */
private static final boolean TRACE = false; // trace creates and disposes
private static final boolean VERBOSE = false; // show reuse hits/misses
private static final boolean DEBUG = false; // show bad params, misc.
/**
* Creates a new menu bar.
*/
public JMenuBar() {
super();
setFocusTraversalKeysEnabled(false);
setSelectionModel(new DefaultSingleSelectionModel());
updateUI();
}
/**
* Returns the menubar's current UI.
*
* @return a {@code MenuBarUI} which is the menubar's current L&F object
* @see #setUI
*/
public MenuBarUI getUI() {
return (MenuBarUI)ui;
}
/**
* Sets the L&F object that renders this component.
*
* @param ui the new MenuBarUI L&F object
* @see UIDefaults#getUI
*/
@BeanProperty(hidden = true, visualUpdate = true, description
= "The UI object that implements the Component's LookAndFeel.")
public void setUI(MenuBarUI ui) {
super.setUI(ui);
}
/**
* Resets the UI property with a value from the current look and feel.
*
* @see JComponent#updateUI
*/
public void updateUI() {
Toolkit tk = Toolkit.getDefaultToolkit();
if (tk instanceof SunToolkit) {
((SunToolkit)tk).updateScreenMenuBarUI();
}
setUI((MenuBarUI)UIManager.getUI(this));
}
/**
* Returns the name of the L&F class that renders this component.
*
* @return the string "MenuBarUI"
* @see JComponent#getUIClassID
* @see UIDefaults#getUI
*/
@BeanProperty(bound = false)
public String getUIClassID() {
return uiClassID;
}
/**
* Returns the model object that handles single selections.
*
* @return the SingleSelectionModel property
* @see SingleSelectionModel
*/
public SingleSelectionModel getSelectionModel() {
return selectionModel;
}
/**
* Sets the model object to handle single selections.
*
* @param model the SingleSelectionModel to use
* @see SingleSelectionModel
*/
@BeanProperty(description = "The selection model, recording which child is selected.")
public void setSelectionModel(SingleSelectionModel model) {
SingleSelectionModel oldValue = selectionModel;
this.selectionModel = model;
firePropertyChange("selectionModel", oldValue, selectionModel);
}
/**
* Appends the specified menu to the end of the menu bar.
*
* @param c the JMenu component to add
* @return the menu component
*/
public JMenu add(JMenu c) {
super.add(c);
return c;
}
/**
* Returns the menu at the specified position in the menu bar.
*
* @param index an integer giving the position in the menu bar, where
* 0 is the first position
* @return the JMenu at that position, or null if
* if there is no JMenu at that position (ie. if
* it is a JMenuItem)
*/
public JMenu getMenu(int index) {
Component c = getComponentAtIndex(index);
if (c instanceof JMenu)
return (JMenu) c;
return null;
}
/**
* Returns the number of items in the menu bar.
*
* @return the number of items in the menu bar
*/
@BeanProperty(bound = false)
public int getMenuCount() {
return getComponentCount();
}
/**
* Sets the help menu that appears when the user selects the
* "help" option in the menu bar. This method is not yet implemented
* and will throw an exception.
*
* @param menu the JMenu that delivers help to the user
*/
public void setHelpMenu(JMenu menu) {
throw new Error("setHelpMenu() not yet implemented.");
}
/**
* Gets the help menu for the menu bar. This method is not yet
* implemented and will throw an exception.
*
* @return the JMenu that delivers help to the user
*/
@Transient
public JMenu getHelpMenu() {
throw new Error("getHelpMenu() not yet implemented.");
}
/**
* Returns the component at the specified index.
*
* @param i an integer specifying the position, where 0 is first
* @return the Component at the position,
* or null for an invalid index
* @deprecated replaced by getComponent(int i)
*/
@Deprecated
public Component getComponentAtIndex(int i) {
if(i < 0 || i >= getComponentCount()) {
return null;
}
return getComponent(i);
}
/**
* Returns the index of the specified component.
*
* @param c the Component to find
* @return an integer giving the component's position, where 0 is first;
* or -1 if it can't be found
*/
public int getComponentIndex(Component c) {
int ncomponents = this.getComponentCount();
Component[] component = this.getComponents();
for (int i = 0 ; i < ncomponents ; i++) {
Component comp = component[i];
if (comp == c)
return i;
}
return -1;
}
/**
* Sets the currently selected component, producing a
* a change to the selection model.
*
* @param sel the Component to select
*/
public void setSelected(Component sel) {
SingleSelectionModel model = getSelectionModel();
int index = getComponentIndex(sel);
model.setSelectedIndex(index);
}
/**
* Returns true if the menu bar currently has a component selected.
*
* @return true if a selection has been made, else false
*/
@BeanProperty(bound = false)
public boolean isSelected() {
return selectionModel.isSelected();
}
/**
* Returns true if the menu bars border should be painted.
*
* @return true if the border should be painted, else false
*/
public boolean isBorderPainted() {
return paintBorder;
}
/**
* Sets whether the border should be painted.
*
* @param b if true and border property is not null,
* the border is painted.
* @see #isBorderPainted
*/
@BeanProperty(visualUpdate = true, description
= "Whether the border should be painted.")
public void setBorderPainted(boolean b) {
boolean oldValue = paintBorder;
paintBorder = b;
firePropertyChange("borderPainted", oldValue, paintBorder);
if (b != oldValue) {
revalidate();
repaint();
}
}
/**
* Paints the menubar's border if BorderPainted
* property is true.
*
* @param g the Graphics context to use for painting
* @see JComponent#paint
* @see JComponent#setBorder
*/
protected void paintBorder(Graphics g) {
if (isBorderPainted()) {
super.paintBorder(g);
}
}
/**
* Sets the margin between the menubar's border and
* its menus. Setting to null will cause the menubar to
* use the default margins.
*
* @param m an Insets object containing the margin values
* @see Insets
*/
@BeanProperty(visualUpdate = true, description
= "The space between the menubar's border and its contents")
public void setMargin(Insets m) {
Insets old = margin;
this.margin = m;
firePropertyChange("margin", old, m);
if (old == null || !old.equals(m)) {
revalidate();
repaint();
}
}
/**
* Returns the margin between the menubar's border and
* its menus. If there is no previous margin, it will create
* a default margin with zero size.
*
* @return an Insets object containing the margin values
* @see Insets
*/
public Insets getMargin() {
if(margin == null) {
return new Insets(0,0,0,0);
} else {
return margin;
}
}
/**
* Implemented to be a MenuElement -- does nothing.
*
* @see #getSubElements
*/
public void processMouseEvent(MouseEvent event,MenuElement[] path,MenuSelectionManager manager) {
}
/**
* Implemented to be a MenuElement -- does nothing.
*
* @see #getSubElements
*/
public void processKeyEvent(KeyEvent e,MenuElement[] path,MenuSelectionManager manager) {
}
/**
* Implemented to be a MenuElement -- does nothing.
*
* @see #getSubElements
*/
public void menuSelectionChanged(boolean isIncluded) {
}
/**
* Implemented to be a MenuElement -- returns the
* menus in this menu bar.
* This is the reason for implementing the MenuElement
* interface -- so that the menu bar can be treated the same as
* other menu elements.
* @return an array of menu items in the menu bar.
*/
@BeanProperty(bound = false)
public MenuElement[] getSubElements() {
MenuElement[] result;
VectorMenuElement. Returns this object.
*
* @return the current Component (this)
* @see #getSubElements
*/
public Component getComponent() {
return this;
}
/**
* Returns a string representation of this JMenuBar.
* This method
* is intended to be used only for debugging purposes, and the
* content and format of the returned string may vary between
* implementations. The returned string may be empty but may not
* be null.
*
* @return a string representation of this JMenuBar
*/
protected String paramString() {
String paintBorderString = (paintBorder ?
"true" : "false");
String marginString = (margin != null ?
margin.toString() : "");
return super.paramString() +
",margin=" + marginString +
",paintBorder=" + paintBorderString;
}
/////////////////
// Accessibility support
////////////////
/**
* Gets the AccessibleContext associated with this JMenuBar.
* For JMenuBars, the AccessibleContext takes the form of an
* AccessibleJMenuBar.
* A new AccessibleJMenuBar instance is created if necessary.
*
* @return an AccessibleJMenuBar that serves as the
* AccessibleContext of this JMenuBar
*/
@BeanProperty(bound = false)
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new AccessibleJMenuBar();
}
return accessibleContext;
}
/**
* This class implements accessibility support for the
* JMenuBar class. It provides an implementation of the
* Java Accessibility API appropriate to menu bar user-interface
* elements.
* java.beans package.
* Please see {@link java.beans.XMLEncoder}.
*/
@SuppressWarnings("serial")
protected class AccessibleJMenuBar extends AccessibleJComponent
implements AccessibleSelection {
/**
* Get the accessible state set of this object.
*
* @return an instance of AccessibleState containing the current state
* of the object
*/
public AccessibleStateSet getAccessibleStateSet() {
AccessibleStateSet states = super.getAccessibleStateSet();
return states;
}
/**
* Get the role of this object.
*
* @return an instance of AccessibleRole describing the role of the
* object
*/
public AccessibleRole getAccessibleRole() {
return AccessibleRole.MENU_BAR;
}
/**
* Get the AccessibleSelection associated with this object. In the
* implementation of the Java Accessibility API for this class,
* return this object, which is responsible for implementing the
* AccessibleSelection interface on behalf of itself.
*
* @return this object
*/
public AccessibleSelection getAccessibleSelection() {
return this;
}
/**
* Returns 1 if a menu is currently selected in this menu bar.
*
* @return 1 if a menu is currently selected, else 0
*/
public int getAccessibleSelectionCount() {
if (isSelected()) {
return 1;
} else {
return 0;
}
}
/**
* Returns the currently selected menu if one is selected,
* otherwise null.
*/
public Accessible getAccessibleSelection(int i) {
if (isSelected()) {
if (i != 0) { // single selection model for JMenuBar
return null;
}
int j = getSelectionModel().getSelectedIndex();
if (getComponentAtIndex(j) instanceof Accessible) {
return (Accessible) getComponentAtIndex(j);
}
}
return null;
}
/**
* Returns true if the current child of this object is selected.
*
* @param i the zero-based index of the child in this Accessible
* object.
* @see AccessibleContext#getAccessibleChild
*/
public boolean isAccessibleChildSelected(int i) {
return (i == getSelectionModel().getSelectedIndex());
}
/**
* Selects the nth menu in the menu bar, forcing it to
* pop up. If another menu is popped up, this will force
* it to close. If the nth menu is already selected, this
* method has no effect.
*
* @param i the zero-based index of selectable items
* @see #getAccessibleStateSet
*/
public void addAccessibleSelection(int i) {
// first close up any open menu
int j = getSelectionModel().getSelectedIndex();
if (i == j) {
return;
}
if (j >= 0 && j < getMenuCount()) {
JMenu menu = getMenu(j);
if (menu != null) {
MenuSelectionManager.defaultManager().setSelectedPath(null);
// menu.setPopupMenuVisible(false);
}
}
// now popup the new menu
getSelectionModel().setSelectedIndex(i);
JMenu menu = getMenu(i);
if (menu != null) {
MenuElement[] me = new MenuElement[3];
me[0] = JMenuBar.this;
me[1] = menu;
me[2] = menu.getPopupMenu();
MenuSelectionManager.defaultManager().setSelectedPath(me);
// menu.setPopupMenuVisible(true);
}
}
/**
* Removes the nth selected item in the object from the object's
* selection. If the nth item isn't currently selected, this
* method has no effect. Otherwise, it closes the popup menu.
*
* @param i the zero-based index of selectable items
*/
public void removeAccessibleSelection(int i) {
if (i >= 0 && i < getMenuCount()) {
JMenu menu = getMenu(i);
if (menu != null) {
MenuSelectionManager.defaultManager().setSelectedPath(null);
// menu.setPopupMenuVisible(false);
}
getSelectionModel().setSelectedIndex(-1);
}
}
/**
* Clears the selection in the object, so that nothing in the
* object is selected. This will close any open menu.
*/
public void clearAccessibleSelection() {
int i = getSelectionModel().getSelectedIndex();
if (i >= 0 && i < getMenuCount()) {
JMenu menu = getMenu(i);
if (menu != null) {
MenuSelectionManager.defaultManager().setSelectedPath(null);
// menu.setPopupMenuVisible(false);
}
}
getSelectionModel().setSelectedIndex(-1);
}
/**
* Normally causes every selected item in the object to be selected
* if the object supports multiple selections. This method
* makes no sense in a menu bar, and so does nothing.
*/
public void selectAllAccessibleSelection() {
}
} // internal class AccessibleJMenuBar
/**
* Subclassed to check all the child menus.
* @since 1.3
*/
protected boolean processKeyBinding(KeyStroke ks, KeyEvent e,
int condition, boolean pressed) {
// See if we have a local binding.
boolean retValue = super.processKeyBinding(ks, e, condition, pressed);
if (!retValue) {
MenuElement[] subElements = getSubElements();
for (MenuElement subElement : subElements) {
if (processBindingForKeyStrokeRecursive(
subElement, ks, e, condition, pressed)) {
return true;
}
}
}
return retValue;
}
static boolean processBindingForKeyStrokeRecursive(MenuElement elem,
KeyStroke ks, KeyEvent e, int condition, boolean pressed) {
if (elem == null) {
return false;
}
Component c = elem.getComponent();
if ( !(c.isVisible() || (c instanceof JPopupMenu)) || !c.isEnabled() ) {
return false;
}
if (c != null && c instanceof JComponent &&
((JComponent)c).processKeyBinding(ks, e, condition, pressed)) {
return true;
}
MenuElement[] subElements = elem.getSubElements();
for (MenuElement subElement : subElements) {
if (processBindingForKeyStrokeRecursive(subElement, ks, e, condition, pressed)) {
return true;
// We don't, pass along to children JMenu's
}
}
return false;
}
/**
* Overrides JComponent.addNotify to register this
* menu bar with the current keyboard manager.
*/
public void addNotify() {
super.addNotify();
KeyboardManager.getCurrentManager().registerMenuBar(this);
}
/**
* Overrides JComponent.removeNotify to unregister this
* menu bar with the current keyboard manager.
*/
public void removeNotify() {
super.removeNotify();
KeyboardManager.getCurrentManager().unregisterMenuBar(this);
}
private void writeObject(ObjectOutputStream s) throws IOException {
s.defaultWriteObject();
if (getUIClassID().equals(uiClassID)) {
byte count = JComponent.getWriteObjCounter(this);
JComponent.setWriteObjCounter(this, --count);
if (count == 0 && ui != null) {
ui.installUI(this);
}
}
Object[] kvData = new Object[4];
int n = 0;
if (selectionModel instanceof Serializable) {
kvData[n++] = "selectionModel";
kvData[n++] = selectionModel;
}
s.writeObject(kvData);
}
/**
* See JComponent.readObject() for information about serialization
* in Swing.
*/
private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException
{
s.defaultReadObject();
Object[] kvData = (Object[])(s.readObject());
for(int i = 0; i < kvData.length; i += 2) {
if (kvData[i] == null) {
break;
}
else if (kvData[i].equals("selectionModel")) {
selectionModel = (SingleSelectionModel)kvData[i + 1];
}
}
}
}