java.awt
Class MenuComponent

java.lang.Object
  java.awt.MenuComponent

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

MenuBar, MenuItem

public abstract class MenuComponent

extends Object

implements Serializable

The abstract class MenuComponent is the superclass of all menu-related components. In this respect, the class MenuComponent is analogous to the abstract superclass Component for AWT components.

Menu components receive and process AWT events, just as components do, through the method processEvent.

Since:

JDK1.0

Author:

Arthur van Hoff

See Also:

Serialized Form

Nested Class Summary

protected class

MenuComponent.AccessibleAWTMenuComponent Inner class of MenuComponent used to provide default support for accessibility.

Field Summary

(package private) javax.accessibility.AccessibleContext	accessibleContext
(package private) static String	actionListenerK
(package private) sun.awt.AppContext	appContext The AppContext of the MenuComponent.
(package private) Font	font The menu component's font.
(package private) static String	itemListenerK
private String	name The menu component's name, which defaults to null.
private boolean	nameExplicitlySet A variable to indicate whether a name is explicitly set.
(package private) boolean	newEventsOnly Defaults to false.
(package private) MenuContainer	parent
(package private) MenuComponentPeer	peer
private Object	privateKey This object is used as a key for internal hashtables.
private static long	serialVersionUID

Constructor Summary

MenuComponent()
Creates a MenuComponent.

Method Summary

(package private) String	constructComponentName() Constructs a name for this MenuComponent.
void	dispatchEvent(AWTEvent e)
(package private) void	dispatchEventImpl(AWTEvent e)
(package private) boolean	eventEnabled(AWTEvent e)
javax.accessibility.AccessibleContext	getAccessibleContext() Gets the AccessibleContext associated with this MenuComponent.
(package private) int	getAccessibleIndexInParent() Gets the index of this object in its accessible parent.
(package private) javax.accessibility.AccessibleStateSet	getAccessibleStateSet() Gets the state of this object.
(package private) Font	getFont_NoClientCode()
Font	getFont() Gets the font used for this menu component.
String	getName() Gets the name of the menu component.
(package private) MenuContainer	getParent_NoClientCode()
MenuContainer	getParent() Returns the parent container for this menu component.
MenuComponentPeer	getPeer() Deprecated. As of JDK version 1.1, programs should not directly manipulate peers.
protected Object	getTreeLock() Gets this component's locking object (the object that owns the thread sychronization monitor) for AWT component-tree and layout operations.
private static void	initIDs() Initialize JNI field and method IDs.
protected String	paramString() Returns a string representing the state of this MenuComponent.
boolean	postEvent(Event evt) Deprecated. As of JDK version 1.1, replaced by dispatchEvent.
protected void	processEvent(AWTEvent e) Processes events occurring on this menu component.
private void	readObject(ObjectInputStream s) Reads the menu component from an object input stream.
void	removeNotify() Removes the menu component's peer.
void	setFont(Font f) Sets the font to be used for this menu component to the specified font.
void	setName(String name) Sets the name of the component to the specified string.
String	toString() Returns a representation of this menu component as a string.

Methods inherited from class java.lang.Object

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

Field Detail

peer

transient MenuComponentPeer peer

parent

transient MenuContainer parent

appContext

transient sun.awt.AppContext appContext

The AppContext of the MenuComponent. This is set in the constructor and never changes.

font

Font font

The menu component's font. This value can be null at which point a default will be used. This defaults to null.

See Also:

setFont(Font), getFont()

name

private String name

The menu component's name, which defaults to null.

See Also:

getName(), setName(String)

nameExplicitlySet

private boolean nameExplicitlySet

A variable to indicate whether a name is explicitly set. If true the name will be set explicitly. This defaults to false.

See Also:

setName(String)

newEventsOnly

boolean newEventsOnly

Defaults to false.

See Also:

dispatchEvent(AWTEvent)

actionListenerK

static final String actionListenerK

See Also:

Constant Field Values

itemListenerK

static final String itemListenerK

See Also:

Constant Field Values

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

privateKey

private transient Object privateKey

This object is used as a key for internal hashtables.

accessibleContext

javax.accessibility.AccessibleContext accessibleContext

Constructor Detail

MenuComponent

public MenuComponent()
              throws HeadlessException

Creates a MenuComponent.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless returns true

See Also:

GraphicsEnvironment.isHeadless()

Method Detail

constructComponentName

String constructComponentName()

Constructs a name for this MenuComponent. Called by getName when the name is null.

Returns:

a name for this MenuComponent

getName

public String getName()

Gets the name of the menu component.

Returns:

the name of the menu component

Since:

JDK1.1

See Also:

setName(java.lang.String)

setName

public void setName(String name)

Sets the name of the component to the specified string.

Parameters:

name - the name of the menu component

Since:

JDK1.1

See Also:

getName()

getParent

public MenuContainer getParent()

Returns the parent container for this menu component.

Returns:

the menu component containing this menu component, or null if this menu component is the outermost component, the menu bar itself

getParent_NoClientCode

final MenuContainer getParent_NoClientCode()

getPeer

public MenuComponentPeer getPeer()

Deprecated. As of JDK version 1.1, programs should not directly manipulate peers.

getFont

public Font getFont()

Gets the font used for this menu component.

Returns:

the font used in this menu component, if there is one; null otherwise

See Also:

setFont(java.awt.Font)

getFont_NoClientCode

final Font getFont_NoClientCode()

setFont

public void setFont(Font f)

Sets the font to be used for this menu component to the specified font. This font is also used by all subcomponents of this menu component, unless those subcomponents specify a different font.

Some platforms may not support setting the font of a menu component; in this case, calling setFont will have no effect.

Parameters:

f - the font to be set

See Also:

getFont()

removeNotify

public void removeNotify()

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

postEvent

public boolean postEvent(Event evt)

Deprecated. As of JDK version 1.1, replaced by dispatchEvent.

Posts the specified event to the menu. This method is part of the Java 1.0 event system and it is maintained only for backwards compatibility. Its use is discouraged, and it may not be supported in the future.

Parameters:

evt - the event which is to take place

dispatchEvent

public final void dispatchEvent(AWTEvent e)

dispatchEventImpl

void dispatchEventImpl(AWTEvent e)

eventEnabled

boolean eventEnabled(AWTEvent e)

processEvent

protected void processEvent(AWTEvent e)

Processes events occurring on this menu component.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

Parameters:

e - the event

Since:

JDK1.1

paramString

protected String paramString()

Returns a string representing the state of this MenuComponent. 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.

Returns:

the parameter string of this menu component

toString

public String toString()

Returns a representation of this menu component as a string.

Overrides:

toString in class Object

Returns:

a string representation of this menu component

getTreeLock

protected final Object getTreeLock()

Gets this component's locking object (the object that owns the thread sychronization monitor) for AWT component-tree and layout operations.

Returns:

this component's locking object

readObject

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

Reads the menu component from an object input stream.

Parameters:

s - the ObjectInputStream to read

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless returns true

ClassNotFoundException

IOException

See Also:

GraphicsEnvironment.isHeadless()

initIDs

private static void initIDs()

Initialize JNI field and method IDs.

getAccessibleContext

public javax.accessibility.AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this MenuComponent. The method implemented by this base class returns null. Classes that extend MenuComponent should implement this method to return the AccessibleContext associated with the subclass.

Returns:

the AccessibleContext of this MenuComponent

getAccessibleIndexInParent

int getAccessibleIndexInParent()

Gets the index of this object in its accessible parent.

Returns:

-1 of this object does not have an accessible parent; otherwise, the index of the child in its accessible parent.

getAccessibleStateSet

javax.accessibility.AccessibleStateSet getAccessibleStateSet()

Gets the state of this object.

Returns:

an instance of AccessibleStateSet containing the current state set of the object

See Also:

AccessibleState