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Class com.sun.java.swing.JApplet 

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----java.awt.Panel
                           |
                           +----java.applet.Applet
                                   |
                                   +----com.sun.java.swing.JApplet
public class JApplet
extends Applet
implements Accessible, RootPaneContainer
An extended version of java.applet.Applet that adds support for interposing input and painting behavior in front of the applets children (see glassPane), support for special children that are managed by a LayeredPane (see rootPane) and for Swing MenuBars.

The JApplet class is slightly incompatible with java.applet.Applet. JApplet contains a JRootPane as it's only child. The contentPane should be the parent of any children of the JApplet. This is different than java.applet.Applet, e.g. to add a child to an an java.applet.Applet you'd write: 

       applet.add(child);
However using JApplet you need to add the child to the JApplet's contentPane instead: 
       applet.getContentPane().add(child);
The same is true for setting LayoutManagers, removing components, listing children, etc. All these methods should normally be sent to the contentPane() instead of the JApplet itself. The contentPane() will always be non-null. Attempting to set it to null will cause the JApplet to throw an exception. The default contentPane() will have a BorderLayout manager set on it.

Please see the JRootPane documentation for a complete description of the contentPane, glassPane, and layeredPane properties.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the JApplet key assignments.

Both Netscape Communicator and Internet Explorer 4.0 unconditionally print an error message to the Java console when an applet attempts to access the AWT system event queue. Swing applets do this once, to check if access is permitted. To prevent the warning message in a production applet one can set a client property called "defeatSystemEventQueueCheck" on the JApplets RootPane to any non null value, e.g: 

 JRootPane rp = myJApplet.getRootPane();
 rp.putClientProperty("defeatSystemEventQueueCheck", Boolean.TRUE);
We hope that future versions of the browsers will not have this limitation and we'll be able to retire this hack.

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 Swing1.0 applications. It will not be possible to load serialized Swing1.0 objects with future releases of Swing. The JDK1.2 release of Swing will be the compatibility baseline for the serialized form of Swing objects.

Variable Index

o accessibleContext
o rootPane
o rootPaneCheckingEnabled

Constructor Index

o JApplet()
Creates a swing applet instance.

Method Index

o addImpl(Component, Object, int)
By default, children may not be added directly to a this component, they must be added to its contentPane instead.
o createRootPane()
Called by the constructor methods to create the default rootPane.
o getAccessibleContext()
Get the AccessibleContext associated with this JApplet
o getContentPane()
Returns the contentPane object for this applet.
o getGlassPane()
Returns the glassPane object for this applet.
o getJMenuBar()
Returns the menubar set on this applet.
o getLayeredPane()
Returns the layeredPane object for this applet.
o getRootPane()
Returns the rootPane object for this applet.
o isRootPaneCheckingEnabled()
o processKeyEvent(KeyEvent)
o setContentPane(Container)
Sets the contentPane property.
o setGlassPane(Component)
Sets the glassPane property.
o setJMenuBar(JMenuBar)
Sets the menubar for this applet.
o setLayeredPane(JLayeredPane)
Sets the layeredPane property.
o setLayout(LayoutManager)
By default the layout of this component may not be set, the layout of its contentPane should be set instead.
o setRootPane(JRootPane)
Sets the rootPane property.
o setRootPaneCheckingEnabled(boolean)
If true then calls to add() and setLayout() will cause an exception to be thrown.
o update(Graphics)
Just calls paint(g).

Variables

o rootPane 
 protected JRootPane rootPane
See Also:
getRootPane, setRootPane
o rootPaneCheckingEnabled 
 protected boolean rootPaneCheckingEnabled
See Also:
isRootPaneCheckingEnabled, setRootPaneCheckingEnabled
o accessibleContext 
 protected AccessibleContext accessibleContext

Constructors

o JApplet 
 public JApplet()
Creates a swing applet instance.

Methods

o createRootPane 
 protected JRootPane createRootPane()
Called by the constructor methods to create the default rootPane.

o processKeyEvent 
 protected void processKeyEvent(KeyEvent e)
Overrides:
processKeyEvent in class Component
o update 
 public void update(Graphics g)
Just calls paint(g). This method was overridden to prevent an unneccessary call to clear the background.

Overrides:
update in class Container
o setJMenuBar 
 public void setJMenuBar(JMenuBar menuBar)
Sets the menubar for this applet.

Parameters:
menubar - the menubar being placed in the applet
See Also:
getJMenuBar
o getJMenuBar 
 public JMenuBar getJMenuBar()
Returns the menubar set on this applet.

See Also:
setJMenuBar
o isRootPaneCheckingEnabled 
 protected boolean isRootPaneCheckingEnabled()
Returns:
true if add and setLayout should be checked
See Also:
addImpl, setLayout, setRootPaneCheckingEnabled
o setRootPaneCheckingEnabled 
 protected void setRootPaneCheckingEnabled(boolean enabled)
If true then calls to add() and setLayout() will cause an exception to be thrown.

See Also:
addImpl, setLayout, isRootPaneCheckingEnabled
o addImpl 
 protected void addImpl(Component comp,
                        Object constraints,
                        int index)
By default, children may not be added directly to a this component, they must be added to its contentPane instead. For example: 
 thiComponent.getContentPane().add(child)
An attempt to add to directly to this component will cause an runtime exception to be thrown. Subclasses can disable this behavior.

Throws: Error
if called with rootPaneChecking true
Overrides:
addImpl in class Container
See Also:
setRootPaneCheckingEnabled
o setLayout 
 public void setLayout(LayoutManager manager)
By default the layout of this component may not be set, the layout of its contentPane should be set instead. For example: 
 thiComponent.getContentPane().setLayout(new BorderLayout())
An attempt to set the layout of this component will cause an runtime exception to be thrown. Subclasses can disable this behavior.

Throws: Error
if called with rootPaneChecking true
Overrides:
setLayout in class Container
See Also:
setRootPaneCheckingEnabled
o getRootPane 
 public JRootPane getRootPane()
Returns the rootPane object for this applet.

See Also:
setRootPane, getRootPane
o setRootPane 
 protected void setRootPane(JRootPane root)
Sets the rootPane property. This method is called by the constructor.

Parameters:
root - the rootPane object for this applet
See Also:
getRootPane
o getContentPane 
 public Container getContentPane()
Returns the contentPane object for this applet.

See Also:
setContentPane, getContentPane
o setContentPane 
 public void setContentPane(Container contentPane)
Sets the contentPane property. This method is called by the constructor.

Parameters:
contentPane - the contentPane object for this applet
Throws: IllegalComponentStateException
(a runtime exception) if the content pane parameter is null
See Also:
getContentPane, setContentPane
o getLayeredPane 
 public JLayeredPane getLayeredPane()
Returns the layeredPane object for this applet.

Throws: IllegalComponentStateException
(a runtime exception) if the layered pane parameter is null
See Also:
setLayeredPane, getLayeredPane
o setLayeredPane 
 public void setLayeredPane(JLayeredPane layeredPane)
Sets the layeredPane property. This method is called by the constructor.

Parameters:
layeredPane - the layeredPane object for this applet
See Also:
getLayeredPane, setLayeredPane
o getGlassPane 
 public Component getGlassPane()
Returns the glassPane object for this applet.

See Also:
setGlassPane, getGlassPane
o setGlassPane 
 public void setGlassPane(Component glassPane)
Sets the glassPane property. This method is called by the constructor.

Parameters:
glassPane - the glassPane object for this applet
See Also:
getGlassPane, setGlassPane
o getAccessibleContext 
 public AccessibleContext getAccessibleContext()
Get the AccessibleContext associated with this JApplet

Returns:
the AccessibleContext of this JApplet 
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