java.awt
Class MenuComponent

java.lang.Object
  extended byjava.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