java.awt
Class Menu

java.lang.Object
  java.awt.MenuComponent
      java.awt.MenuItem
          java.awt.Menu

All Implemented Interfaces:

javax.accessibility.Accessible, MenuContainer, Serializable

Direct Known Subclasses:

PopupMenu

public class Menu

extends MenuItem

implements MenuContainer, javax.accessibility.Accessible

A Menu object is a pull-down menu component that is deployed from a menu bar.

A menu can optionally be a tear-off menu. A tear-off menu can be opened and dragged away from its parent menu bar or menu. It remains on the screen after the mouse button has been released. The mechanism for tearing off a menu is platform dependent, since the look and feel of the tear-off menu is determined by its peer. On platforms that do not support tear-off menus, the tear-off property is ignored.

Each item in a menu must belong to the MenuItem class. It can be an instance of MenuItem, a submenu (an instance of Menu), or a check box (an instance of CheckboxMenuItem).

Since:

JDK1.0

Author:

Sami Shaio

See Also:

MenuItem, CheckboxMenuItem, Serialized Form

Nested Class Summary

protected class

Menu.AccessibleAWTMenu Inner class of Menu used to provide default support for accessibility.

Nested classes inherited from class java.awt.MenuItem

MenuItem.AccessibleAWTMenuItem

Nested classes inherited from class java.awt.MenuComponent

MenuComponent.AccessibleAWTMenuComponent

Field Summary

private static String	base
(package private) boolean	isHelpMenu This field will be set to true if the Menu in question is actually a help menu.
(package private) Vector	items A vector of the items that will be part of the Menu.
private int	menuSerializedDataVersion The menu serialized Data Version.
private static int	nameCounter
private static long	serialVersionUID
(package private) boolean	tearOff This field indicates whether the menu has the tear of property or not.

Fields inherited from class java.awt.MenuItem

actionCommand, actionListener, enabled, eventMask, label

Fields inherited from class java.awt.MenuComponent

accessibleContext, actionListenerK, appContext, font, itemListenerK, newEventsOnly, parent, peer

Constructor Summary

Menu()
Constructs a new menu with an empty label.

Menu(String label)
Constructs a new menu with the specified label.

Menu(String label, boolean tearOff)
Constructs a new menu with the specified label, indicating whether the menu can be torn off.

Method Summary

MenuItem	add(MenuItem mi) Adds the specified menu item to this menu.
void	add(String label) Adds an item with the specified label to this menu.
void	addNotify() Creates the menu's peer.
void	addSeparator() Adds a separator line, or a hypen, to the menu at the current position.
(package private) String	constructComponentName() Construct a name for this MenuComponent.
int	countItems() Deprecated. As of JDK version 1.1, replaced by getItemCount().
(package private) int	countItemsImpl()
(package private) void	deleteShortcut(MenuShortcut s)
javax.accessibility.AccessibleContext	getAccessibleContext() Gets the AccessibleContext associated with this Menu.
MenuItem	getItem(int index) Gets the item located at the specified index of this menu.
int	getItemCount() Get the number of items in this menu.
(package private) MenuItem	getItemImpl(int index)
(package private) MenuItem	getShortcutMenuItem(MenuShortcut s)
(package private) boolean	handleShortcut(KeyEvent e)
private static void	initIDs() Initialize JNI field and method IDs
void	insert(MenuItem menuitem, int index) Inserts a menu item into this menu at the specified position.
void	insert(String label, int index) Inserts a menu item with the specified label into this menu at the specified position.
void	insertSeparator(int index) Inserts a separator at the specified position.
boolean	isTearOff() Indicates whether this menu is a tear-off menu.
String	paramString() Returns a string representing the state of this Menu.
private void	readObject(ObjectInputStream s) Reads the ObjectInputStream.
void	remove(int index) Removes the menu item at the specified index from this menu.
void	remove(MenuComponent item) Removes the specified menu item from this menu.
void	removeAll() Removes all items from this menu.
void	removeNotify() Removes the menu's peer.
(package private) Enumeration	shortcuts()
private void	writeObject(ObjectOutputStream s) Writes default serializable fields to stream.

Methods inherited from class java.awt.MenuItem

addActionListener, deleteShortcut, disable, disableEvents, doMenuEvent, enable, enable, enableEvents, eventEnabled, getActionCommand, getActionListeners, getLabel, getListeners, getShortcut, isEnabled, processActionEvent, processEvent, removeActionListener, setActionCommand, setEnabled, setLabel, setShortcut

Methods inherited from class java.awt.MenuComponent

dispatchEvent, dispatchEventImpl, getAccessibleIndexInParent, getAccessibleStateSet, getFont_NoClientCode, getFont, getName, getParent_NoClientCode, getParent, getPeer, getTreeLock, postEvent, setFont, setName, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.awt.MenuContainer

getFont, postEvent

Field Detail

items

Vector items

A vector of the items that will be part of the Menu.

See Also:

countItems()

tearOff

boolean tearOff

This field indicates whether the menu has the tear of property or not. It will be set to true if the menu has the tear off property and it will be set to false> if it does not. A torn off menu can be deleted by a user when it is no longer needed.

See Also:

isTearOff()

isHelpMenu

boolean isHelpMenu

This field will be set to true if the Menu in question is actually a help menu. Otherwise it will be set to false.

base

private static final String base

See Also:

Constant Field Values

nameCounter

private static int nameCounter

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

menuSerializedDataVersion

private int menuSerializedDataVersion

The menu serialized Data Version.

Constructor Detail

Menu

public Menu()
     throws HeadlessException

Constructs a new menu with an empty label. This menu is not a tear-off menu.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

Since:

JDK1.1

See Also:

GraphicsEnvironment.isHeadless()

Menu

public Menu(String label)
     throws HeadlessException

Constructs a new menu with the specified label. This menu is not a tear-off menu.

Parameters:

label - the menu's label in the menu bar, or in another menu of which this menu is a submenu.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

GraphicsEnvironment.isHeadless()

Menu

public Menu(String label,
            boolean tearOff)
     throws HeadlessException

Constructs a new menu with the specified label, indicating whether the menu can be torn off.

Tear-off functionality may not be supported by all implementations of AWT. If a particular implementation doesn't support tear-off menus, this value is silently ignored.

Parameters:

label - the menu's label in the menu bar, or in another menu of which this menu is a submenu.

tearOff - if true, the menu is a tear-off menu.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

Since:

JDK1.0.

See Also:

GraphicsEnvironment.isHeadless()

Method Detail

constructComponentName

String constructComponentName()

Construct a name for this MenuComponent. Called by getName() when the name is null.

Overrides:

constructComponentName in class MenuItem

addNotify

public void addNotify()

Creates the menu's peer. The peer allows us to modify the appearance of the menu without changing its functionality.

Overrides:

addNotify in class MenuItem

removeNotify

public void removeNotify()

Removes the menu's peer. The peer allows us to modify the appearance of the menu without changing its functionality.

Overrides:

removeNotify in class MenuComponent

isTearOff

public boolean isTearOff()

Indicates whether this menu is a tear-off menu.

Tear-off functionality may not be supported by all implementations of AWT. If a particular implementation doesn't support tear-off menus, this value is silently ignored.

Returns:

true if this is a tear-off menu; false otherwise.

getItemCount

public int getItemCount()

Get the number of items in this menu.

Returns:

the number of items in this menu.

Since:

JDK1.1

countItems

public int countItems()

Deprecated. As of JDK version 1.1, replaced by getItemCount().

countItemsImpl

final int countItemsImpl()

getItem

public MenuItem getItem(int index)

Gets the item located at the specified index of this menu.

Parameters:

index - the position of the item to be returned.

Returns:

the item located at the specified index.

getItemImpl

final MenuItem getItemImpl(int index)

add

public MenuItem add(MenuItem mi)

Adds the specified menu item to this menu. If the menu item has been part of another menu, removes it from that menu.

Parameters:

mi - the menu item to be added

Returns:

the menu item added

See Also:

insert(java.lang.String, int), insert(java.awt.MenuItem, int)

add

public void add(String label)

Adds an item with the specified label to this menu.

Parameters:

label - the text on the item

See Also:

insert(java.lang.String, int), insert(java.awt.MenuItem, int)

insert

public void insert(MenuItem menuitem,
                   int index)

Inserts a menu item into this menu at the specified position.

Parameters:

menuitem - the menu item to be inserted.

index - the position at which the menu item should be inserted.

Throws:

IllegalArgumentException - if the value of index is less than zero

Since:

JDK1.1

See Also:

add(java.lang.String), add(java.awt.MenuItem)

insert

public void insert(String label,
                   int index)

Inserts a menu item with the specified label into this menu at the specified position. This is a convenience method for insert(menuItem, index).

Parameters:

label - the text on the item

index - the position at which the menu item should be inserted

Throws:

IllegalArgumentException - if the value of index is less than zero

Since:

JDK1.1

See Also:

add(java.lang.String), add(java.awt.MenuItem)

addSeparator

public void addSeparator()

Adds a separator line, or a hypen, to the menu at the current position.

See Also:

insertSeparator(int)

insertSeparator

public void insertSeparator(int index)

Inserts a separator at the specified position.

Parameters:

index - the position at which the menu separator should be inserted.

Throws:

IllegalArgumentException - if the value of index is less than 0.

Since:

JDK1.1

See Also:

addSeparator()

remove

public void remove(int index)

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

Parameters:

index - the position of the item to be removed.

remove

public void remove(MenuComponent item)

Removes the specified menu item from this menu.

Specified by:

remove in interface MenuContainer

Parameters:

item - the item to be removed from the menu. If item is null or is not in this menu, this method does nothing.

removeAll

public void removeAll()

Removes all items from this menu.

Since:

JDK1.0.

handleShortcut

boolean handleShortcut(KeyEvent e)

Overrides:

handleShortcut in class MenuItem

getShortcutMenuItem

MenuItem getShortcutMenuItem(MenuShortcut s)

Overrides:

getShortcutMenuItem in class MenuItem

shortcuts

Enumeration shortcuts()

deleteShortcut

void deleteShortcut(MenuShortcut s)

Overrides:

deleteShortcut in class MenuItem

writeObject

private void writeObject(ObjectOutputStream s)
                  throws IOException

Writes default serializable fields to stream.

Parameters:

s - the ObjectOutputStream to write

Throws:

IOException

See Also:

AWTEventMulticaster.save(ObjectOutputStream, String, EventListener), readObject(ObjectInputStream)

readObject

private void readObject(ObjectInputStream s)
                 throws IOException,
                        ClassNotFoundException,
                        HeadlessException

Reads the ObjectInputStream. Unrecognized keys or values will be ignored.

Parameters:

s - the ObjectInputStream to read

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless returns true

IOException

ClassNotFoundException

See Also:

GraphicsEnvironment.isHeadless(), writeObject(ObjectOutputStream)

paramString

public String paramString()

Returns a string representing the state of this Menu. 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 MenuItem

Returns:

the parameter string of this menu

initIDs

private static void initIDs()

Initialize JNI field and method IDs

getAccessibleContext

public javax.accessibility.AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this Menu. For menus, the AccessibleContext takes the form of an AccessibleAWTMenu. A new AccessibleAWTMenu instance is created if necessary.

Specified by:

getAccessibleContext in interface javax.accessibility.Accessible

Overrides:

getAccessibleContext in class MenuItem

Returns:

an AccessibleAWTMenu that serves as the AccessibleContext of this Menu