Class JMenu

• java.lang.Object
• • java.awt.Component
  • • java.awt.Container
    • • javax.swing.JComponent
      • • javax.swing.AbstractButton
        • • javax.swing.JMenuItem
          • • javax.swing.JMenu

All Implemented Interfaces:

ImageObserver, ItemSelectable, MenuContainer, Serializable, Accessible, MenuElement, SwingConstants

public class JMenu
extends JMenuItem
implements Accessible, MenuElement

See Also:

JMenuItem, JSeparator, JMenuBar, JPopupMenu

Nested Classes

Nested Classes

Modifier and Type	Class and Description
protected class	JMenu.AccessibleJMenu This class implements accessibility support for the JMenu class.
protected class	JMenu.WinListener A listener class that watches for a popup window closing.

Nested classes/interfaces inherited from class javax.swing.JMenuItem

JMenuItem.AccessibleJMenuItem

Nested classes/interfaces inherited from class javax.swing.AbstractButton

AbstractButton.AccessibleAbstractButton, AbstractButton.ButtonChangeListener

Nested classes/interfaces inherited from class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces inherited from class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Fields

popupListener

protected JMenu.WinListener popupListener

The window-closing listener for the popup.

See Also:

JMenu.WinListener

Constructors

JMenu

public JMenu()

Constructs a new JMenu with no text.

JMenu

public JMenu(String s)

Constructs a new JMenu with the supplied string as its text.

Parameters:

s - the text for the menu label

JMenu

public JMenu(Action a)

Constructs a menu whose properties are taken from the Action supplied.

Parameters:

a - an Action

Since:

1.3

JMenu

public JMenu(String s,
             boolean b)

Constructs a new JMenu with the supplied string as its text and specified as a tear-off menu or not.

Parameters:

s - the text for the menu label

b - can the menu be torn off (not yet implemented)

Methods

updateUI

public void updateUI()

Resets the UI property with a value from the current look and feel.

Overrides:

updateUI in class JMenuItem

See Also:

JComponent.updateUI()

getUIClassID

public String getUIClassID()

Returns the name of the L&F class that renders this component.

Overrides:

getUIClassID in class JMenuItem

Returns:

the string "MenuUI"

See Also:

JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

setModel

public void setModel(ButtonModel newModel)

Sets the data model for the "menu button" -- the label that the user clicks to open or close the menu.

Overrides:

setModel in class JMenuItem

Parameters:

newModel - the ButtonModel

See Also:

AbstractButton.getModel()

isSelected

public boolean isSelected()

Returns true if the menu is currently selected (highlighted).

Overrides:

isSelected in class AbstractButton

Returns:

true if the menu is selected, else false

setSelected

public void setSelected(boolean b)

Sets the selection status of the menu.

Overrides:

setSelected in class AbstractButton

Parameters:

b - true to select (highlight) the menu; false to de-select the menu

isPopupMenuVisible

public boolean isPopupMenuVisible()

Returns true if the menu's popup window is visible.

Returns:

true if the menu is visible, else false

setPopupMenuVisible

public void setPopupMenuVisible(boolean b)

Sets the visibility of the menu's popup. If the menu is not enabled, this method will have no effect.

Parameters:

b - a boolean value -- true to make the menu visible, false to hide it

getPopupMenuOrigin

protected Point getPopupMenuOrigin()

Computes the origin for the JMenu's popup menu. This method uses Look and Feel properties named Menu.menuPopupOffsetX, Menu.menuPopupOffsetY, Menu.submenuPopupOffsetX, and Menu.submenuPopupOffsetY to adjust the exact location of popup.

Returns:

a Point in the coordinate space of the menu which should be used as the origin of the JMenu's popup menu

Since:

1.3

getDelay

public int getDelay()

Returns the suggested delay, in milliseconds, before submenus are popped up or down. Each look and feel (L&F) may determine its own policy for observing the delay property. In most cases, the delay is not observed for top level menus or while dragging. The default for delay is 0. This method is a property of the look and feel code and is used to manage the idiosyncrasies of the various UI implementations.

Returns:

the delay property

setDelay

public void setDelay(int d)

Sets the suggested delay before the menu's PopupMenu is popped up or down. Each look and feel (L&F) may determine it's own policy for observing the delay property. In most cases, the delay is not observed for top level menus or while dragging. This method is a property of the look and feel code and is used to manage the idiosyncrasies of the various UI implementations.

Parameters:

d - the number of milliseconds to delay

Throws:

IllegalArgumentException - if d is less than 0

setMenuLocation

public void setMenuLocation(int x,
                            int y)

Sets the location of the popup component.

Parameters:

x - the x coordinate of the popup's new position

y - the y coordinate of the popup's new position

add

public JMenuItem add(JMenuItem menuItem)

Appends a menu item to the end of this menu. Returns the menu item added.

Parameters:

menuItem - the JMenuitem to be added

Returns:

the JMenuItem added

add

public Component add(Component c)

Appends a component to the end of this menu. Returns the component added.

Overrides:

add in class Container

Parameters:

c - the Component to add

Returns:

the Component added

See Also:

Container.addImpl(java.awt.Component, java.lang.Object, int), Container.invalidate(), Container.validate(), JComponent.revalidate()

add

public Component add(Component c,
                     int index)

Adds the specified component to this container at the given position. If index equals -1, the component will be appended to the end.

Overrides:

add in class Container

Parameters:

c - the Component to add

index - the position at which to insert the component

Returns:

the Component added

See Also:

remove(javax.swing.JMenuItem), Container.add(Component, int)

add

public JMenuItem add(String s)

Creates a new menu item with the specified text and appends it to the end of this menu.

Parameters:

s - the string for the menu item to be added

add

public JMenuItem add(Action a)

Creates a new menu item attached to the specified Action object and appends it to the end of this menu.

Parameters:

a - the Action for the menu item to be added

See Also:

Action

createActionComponent

protected JMenuItem createActionComponent(Action a)

Factory method which creates the JMenuItem for Actions added to the JMenu.

Parameters:

a - the Action for the menu item to be added

Returns:

the new menu item

Since:

1.3

See Also:

Action

createActionChangeListener

protected PropertyChangeListener createActionChangeListener(JMenuItem b)

Returns a properly configured PropertyChangeListener which updates the control as changes to the Action occur.

addSeparator

public void addSeparator()

Appends a new separator to the end of the menu.

insert

public void insert(String s,
                   int pos)

Inserts a new menu item with the specified text at a given position.

Parameters:

s - the text for the menu item to add

pos - an integer specifying the position at which to add the new menu item

Throws:

IllegalArgumentException - when the value of pos < 0

insert

public JMenuItem insert(JMenuItem mi,
                        int pos)

Inserts the specified JMenuitem at a given position.

Parameters:

mi - the JMenuitem to add

pos - an integer specifying the position at which to add the new JMenuitem

Returns:

the new menu item

Throws:

IllegalArgumentException - if the value of pos < 0

insert

public JMenuItem insert(Action a,
                        int pos)

Inserts a new menu item attached to the specified Action object at a given position.

Parameters:

a - the Action object for the menu item to add

pos - an integer specifying the position at which to add the new menu item

Throws:

IllegalArgumentException - if the value of pos < 0

insertSeparator

public void insertSeparator(int index)

Inserts a separator at the specified position.

Parameters:

index - an integer specifying the position at which to insert the menu separator

Throws:

IllegalArgumentException - if the value of index < 0

getItem

public JMenuItem getItem(int pos)

Returns the JMenuItem at the specified position. If the component at pos is not a menu item, null is returned. This method is included for AWT compatibility.

Parameters:

pos - an integer specifying the position

Returns:

the menu item at the specified position; or null if the item as the specified position is not a menu item

Throws:

IllegalArgumentException - if the value of pos < 0

getItemCount

public int getItemCount()

Returns the number of items on the menu, including separators. This method is included for AWT compatibility.

Returns:

an integer equal to the number of items on the menu

See Also:

getMenuComponentCount()

isTearOff

public boolean isTearOff()

Returns true if the menu can be torn off. This method is not yet implemented.

Returns:

true if the menu can be torn off, else false

Throws:

Error - if invoked -- this method is not yet implemented

remove

public void remove(JMenuItem item)

Removes the specified menu item from this menu. If there is no popup menu, this method will have no effect.

Parameters:

item - the JMenuItem to be removed from the menu

remove

public void remove(int pos)

Removes the menu item at the specified index from this menu.

Overrides:

remove in class Container

Parameters:

pos - the position of the item to be removed

Throws:

IllegalArgumentException - if the value of pos < 0, or if pos is greater than the number of menu items

See Also:

Container.add(java.awt.Component), Container.invalidate(), Container.validate(), Container.getComponentCount()

remove

public void remove(Component c)

Removes the component c from this menu.

Overrides:

remove in class Container

Parameters:

c - the component to be removed

See Also:

Container.add(java.awt.Component), Container.invalidate(), Container.validate(), Container.remove(int)

removeAll

public void removeAll()

Removes all menu items from this menu.

Overrides:

removeAll in class Container

See Also:

Container.add(java.awt.Component), Container.remove(int), Container.invalidate()

getMenuComponentCount

public int getMenuComponentCount()

Returns the number of components on the menu.

Returns:

an integer containing the number of components on the menu

getMenuComponent

public Component getMenuComponent(int n)

Returns the component at position n.

Parameters:

n - the position of the component to be returned

Returns:

the component requested, or null if there is no popup menu

getMenuComponents

public Component[] getMenuComponents()

Returns an array of Components of the menu's subcomponents. Note that this returns all Components in the popup menu, including separators.

Returns:

an array of Components or an empty array if there is no popup menu

isTopLevelMenu

public boolean isTopLevelMenu()

Returns true if the menu is a 'top-level menu', that is, if it is the direct child of a menubar.

Returns:

true if the menu is activated from the menu bar; false if the menu is activated from a menu item on another menu

isMenuComponent

public boolean isMenuComponent(Component c)

Returns true if the specified component exists in the submenu hierarchy.

Parameters:

c - the Component to be tested

Returns:

true if the Component exists, false otherwise

getPopupMenu

public JPopupMenu getPopupMenu()

Returns the popupmenu associated with this menu. If there is no popupmenu, it will create one.

addMenuListener

public void addMenuListener(MenuListener l)

Adds a listener for menu events.

Parameters:

l - the listener to be added

removeMenuListener

public void removeMenuListener(MenuListener l)

Removes a listener for menu events.

Parameters:

l - the listener to be removed

getMenuListeners

public MenuListener[] getMenuListeners()

Returns an array of all the MenuListeners added to this JMenu with addMenuListener().

Returns:

all of the MenuListeners added or an empty array if no listeners have been added

Since:

1.4

fireMenuSelected

protected void fireMenuSelected()

Notifies all listeners that have registered interest for notification on this event type. The event instance is created lazily.

Throws:

Error - if there is a null listener

See Also:

EventListenerList

fireMenuDeselected

protected void fireMenuDeselected()

Notifies all listeners that have registered interest for notification on this event type. The event instance is created lazily.

Throws:

Error - if there is a null listener

See Also:

EventListenerList

fireMenuCanceled

protected void fireMenuCanceled()

Notifies all listeners that have registered interest for notification on this event type. The event instance is created lazily.

Throws:

Error - if there is a null listener

See Also:

EventListenerList

createWinListener

protected JMenu.WinListener createWinListener(JPopupMenu p)

Creates a window-closing listener for the popup.

Parameters:

p - the JPopupMenu

Returns:

the new window-closing listener

See Also:

JMenu.WinListener

menuSelectionChanged

public void menuSelectionChanged(boolean isIncluded)

Messaged when the menubar selection changes to activate or deactivate this menu. Overrides JMenuItem.menuSelectionChanged.

Specified by:

menuSelectionChanged in interface MenuElement

Overrides:

menuSelectionChanged in class JMenuItem

Parameters:

isIncluded - true if this menu is active, false if it is not

See Also:

MenuSelectionManager.setSelectedPath(MenuElement[])

getSubElements

public MenuElement[] getSubElements()

Returns an array of MenuElements containing the submenu for this menu component. If popup menu is null returns an empty array. This method is required to conform to the MenuElement interface. Note that since JSeparators do not conform to the MenuElement interface, this array will only contain JMenuItems.

Specified by:

getSubElements in interface MenuElement

Overrides:

getSubElements in class JMenuItem

Returns:

an array of MenuElement objects

getComponent

public Component getComponent()

Returns the java.awt.Component used to paint this MenuElement. The returned component is used to convert events and detect if an event is inside a menu component.

Specified by:

getComponent in interface MenuElement

Overrides:

getComponent in class JMenuItem

Returns:

the Component that paints this menu item

applyComponentOrientation

public void applyComponentOrientation(ComponentOrientation o)

Sets the ComponentOrientation property of this menu and all components contained within it. This includes all components returned by getMenuComponents.

Overrides:

applyComponentOrientation in class Container

Parameters:

o - the new component orientation of this menu and the components contained within it.

Throws:

NullPointerException - if orientation is null.

Since:

1.4

See Also:

Component.setComponentOrientation(java.awt.ComponentOrientation), Component.getComponentOrientation()

setComponentOrientation

public void setComponentOrientation(ComponentOrientation o)

Description copied from class: Component

Overrides:

setComponentOrientation in class Component

See Also:

ComponentOrientation, Component.invalidate()

setAccelerator

public void setAccelerator(KeyStroke keyStroke)

setAccelerator is not defined for JMenu. Use setMnemonic instead.

Overrides:

setAccelerator in class JMenuItem

Parameters:

keyStroke - the keystroke combination which will invoke the JMenuItem's actionlisteners without navigating the menu hierarchy

Throws:

Error - if invoked -- this method is not defined for JMenu. Use setMnemonic instead

processKeyEvent

protected void processKeyEvent(KeyEvent evt)

Processes key stroke events such as mnemonics and accelerators.

Overrides:

processKeyEvent in class JComponent

Parameters:

evt - the key event to be processed

See Also:

KeyEvent, KeyListener, KeyboardFocusManager, DefaultKeyboardFocusManager, Component.processEvent(java.awt.AWTEvent), Component.dispatchEvent(java.awt.AWTEvent), Component.addKeyListener(java.awt.event.KeyListener), Component.enableEvents(long), Component.isShowing()

doClick

public void doClick(int pressTime)

Programmatically performs a "click". This overrides the method AbstractButton.doClick in order to make the menu pop up.

Overrides:

doClick in class AbstractButton

Parameters:

pressTime - indicates the number of milliseconds the button was pressed for

paramString

protected String paramString()

Returns a string representation of this JMenu. 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.

Overrides:

paramString in class JMenuItem

Returns:

a string representation of this JMenu.

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this JMenu. For JMenus, the AccessibleContext takes the form of an AccessibleJMenu. A new AccessibleJMenu instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class JMenuItem

Returns:

an AccessibleJMenu that serves as the AccessibleContext of this JMenu