javax.swing
Class JApplet

java.lang.Object
  java.awt.Component
      java.awt.Container
          java.awt.Panel
              java.applet.Applet
                  javax.swing.JApplet

All Implemented Interfaces:

Accessible , ImageObserver , MenuContainer , RootPaneContainer , Serializable

public class JApplet

extends Applet

implements Accessible , RootPaneContainer

An extended version of java.applet.Applet that adds support for the JFC/Swing component architecture. You can find task-oriented documentation about using JApplet in The Java Tutorial, in the section How to Make Applets .

The JApplet class is slightly incompatible with java.applet.Applet. JApplet contains a JRootPane as its it's only child. The contentPane should be the parent of any children of the JApplet. As This is different than java.applet.Applet, e.g. to add a convenience add and its variants, remove and setLayout have been overridden child to forward to the contentPane as necessary. This means you can an an java.applet.Applet you'd write:

       applet.add(child);
 

 
 applet.getContentPane().add(child);
 

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 .

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 applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans ^TM has been added to the java.beans package. Please see XMLEncoder .

See Also:

RootPaneContainer

Nested Class Summary
protected  class	JApplet.AccessibleJApplet           This class implements accessibility support for the JApplet class.

 

Nested classes inherited from class java.applet. Applet
Applet.AccessibleApplet

 

Nested classes inherited from class java.awt. Panel
Panel.AccessibleAWTPanel

 

Nested classes inherited from class java.awt. Container
Container.AccessibleAWTContainer

 

Nested classes inherited from class java.awt. Component
Component.AccessibleAWTComponent , Component.BltBufferStrategy , Component.FlipBufferStrategy

 

Field Summary
protected   AccessibleContext	accessibleContext
protected   JRootPane	rootPane
protected  boolean	rootPaneCheckingEnabled           If true then calls to add and setLayout will be forwarded to the contentPane.

 

Fields inherited from class java.awt. Component
BOTTOM_ALIGNMENT , CENTER_ALIGNMENT , LEFT_ALIGNMENT , RIGHT_ALIGNMENT , TOP_ALIGNMENT

 

Fields inherited from interface java.awt.image. ImageObserver
ABORT , ALLBITS , ERROR , FRAMEBITS , HEIGHT , PROPERTIES , SOMEBITS , WIDTH

 

Constructor Summary
JApplet ()           Creates a swing applet instance.

 

Method Summary
protected  void	addImpl ( Component  comp, Object           Adds the specified child Component.           By default, children may not be added directly to a this component, they must be added to its contentPane instead.
protected   JRootPane	createRootPane ()           Called by the constructor methods to create the default rootPane.
AccessibleContext	getAccessibleContext ()           Gets the AccessibleContext associated with this JApplet.
Container	getContentPane ()           Returns the contentPane object for this applet.
Component	getGlassPane ()           Returns the glassPane object for this applet.
JMenuBar	getJMenuBar ()           Returns the menubar set on this applet.
JLayeredPane	getLayeredPane ()           Returns the layeredPane object for this applet.
JRootPane	getRootPane ()           Returns the rootPane object for this applet.
protected  boolean	isRootPaneCheckingEnabled ()           Returns whether calls to add and setLayout are forwarded to the contentPane.
protected   String	paramString ()           Returns a string representation of this JApplet.
void	remove ( Component           Removes the specified component from the this container.
void	setContentPane ( Container  contentPane)           Sets the contentPane property.
void	setGlassPane ( Component  glassPane)           Sets the glassPane property.
void	setJMenuBar ( JMenuBar  menuBar)           Sets the menubar for this applet.
void	setLayeredPane ( JLayeredPane  layeredPane)           Sets the layeredPane property.
void	setLayout ( LayoutManager           Sets           By default the LayoutManager. layout of this component may not be set, the layout of its contentPane should be set instead.
protected  void	setRootPane ( JRootPane  root)           Sets the rootPane property.
protected  void	setRootPaneCheckingEnabled (boolean enabled)           Sets whether           If true then calls to add add() and setLayout are forwarded setLayout() will cause an exception to the contentPane. be thrown.
void	update ( Graphics  g)           Just calls paint(g).

 

Methods inherited from class java.applet. Applet
destroy , getAppletContext , getAppletInfo , getAudioClip , getAudioClip , getCodeBase , getDocumentBase , getImage , getImage , getLocale , getParameter , getParameterInfo , init , isActive , newAudioClip , play , play , resize , resize , setStub , showStatus , start , stop

 

Methods inherited from class java.awt. Panel
addNotify

 

Methods inherited from class java.awt. Container

add , add , add , add , add , addContainerListener , addPropertyChangeListener , addPropertyChangeListener , applyComponentOrientation , areFocusTraversalKeysSet , countComponents , deliverEvent , doLayout , findComponentAt , findComponentAt , getAlignmentX , getAlignmentY , getComponent , getComponentAt , getComponentAt , getComponentCount , getComponents , getComponentZOrder , getContainerListeners , getFocusTraversalKeys , getFocusTraversalPolicy , getInsets , getLayout , getListeners , getMaximumSize , getMinimumSize , getMousePosition , getPreferredSize , insets , invalidate , isAncestorOf , isFocusCycleRoot , isFocusCycleRoot , isFocusTraversalPolicyProvider , isFocusTraversalPolicySet , layout , list , list , locate , minimumSize , paint , paintComponents , preferredSize , print , printComponents , processContainerEvent , processEvent , remove , removeAll , removeContainerListener , removeNotify , setComponentZOrder , setFocusCycleRoot , setFocusTraversalKeys , setFocusTraversalPolicy , setFocusTraversalPolicyProvider , setFont , transferFocusBackward , transferFocusDownCycle , validate , validateTree

 

Methods inherited from class java.awt. Component

action , add , addComponentListener , addFocusListener , addHierarchyBoundsListener , addHierarchyListener , addInputMethodListener , addKeyListener , addMouseListener , addMouseMotionListener , addMouseWheelListener , bounds , checkImage , checkImage , coalesceEvents , contains , contains , createImage , createImage , createVolatileImage , createVolatileImage , disable , disableEvents , dispatchEvent , enable , enable , enableEvents , enableInputMethods , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , getBackground , getBounds , getBounds , getColorModel , getComponentListeners , getComponentOrientation , getCursor , getDropTarget , getFocusCycleRootAncestor , getFocusListeners , getFocusTraversalKeysEnabled , getFont , getFontMetrics , getForeground , getGraphics , getGraphicsConfiguration , getHeight , getHierarchyBoundsListeners , getHierarchyListeners , getIgnoreRepaint , getInputContext , getInputMethodListeners , getInputMethodRequests , getKeyListeners , getLocation , getLocation , getLocationOnScreen , getMouseListeners , getMouseMotionListeners , getMousePosition , getMouseWheelListeners , getName , getParent , getPeer , getPropertyChangeListeners , getPropertyChangeListeners , getSize , getSize , getToolkit , getTreeLock , getWidth , getX , getY , gotFocus , handleEvent , hasFocus , hide , imageUpdate , inside , isBackgroundSet , isCursorSet , isDisplayable , isDoubleBuffered , isEnabled , isFocusable , isFocusOwner , isFocusTraversable , isFontSet , isForegroundSet , isLightweight , isMaximumSizeSet , isMinimumSizeSet , isOpaque , isPreferredSizeSet , isShowing , isValid , isVisible , keyDown , keyUp , list , list , list , location , lostFocus , mouseDown , mouseDrag , mouseEnter , mouseExit , mouseMove , mouseUp , move , nextFocus , paintAll , postEvent , prepareImage , prepareImage , printAll , processComponentEvent , processFocusEvent , processHierarchyBoundsEvent , processHierarchyEvent , processInputMethodEvent , processKeyEvent , processMouseEvent , processMouseMotionEvent , processMouseWheelEvent , remove , removeComponentListener , removeFocusListener , removeHierarchyBoundsListener , removeHierarchyListener , removeInputMethodListener , removeKeyListener , removeMouseListener , removeMouseMotionListener , removeMouseWheelListener , removePropertyChangeListener , removePropertyChangeListener , repaint , repaint , repaint , repaint , requestFocus , requestFocus , requestFocusInWindow , requestFocusInWindow , reshape , setBackground , setBounds , setBounds , setComponentOrientation , setCursor , setDropTarget , setEnabled , setFocusable , setFocusTraversalKeysEnabled , setForeground , setIgnoreRepaint , setLocale , setLocation , setLocation , setMaximumSize , setMinimumSize , setName , setPreferredSize , setSize , setSize , setVisible , show , show , size , toString , transferFocus , transferFocusUpCycle

 

Methods inherited from class java.lang. Object
clone , equals , finalize , getClass , hashCode , notify , notifyAll , wait , wait , wait

 

Field Detail

rootPane

protected JRootPane rootPane

See Also:

getRootPane() , setRootPane(javax.swing.JRootPane)

rootPaneCheckingEnabled

protected boolean rootPaneCheckingEnabled

If true then calls to add and setLayout will be forwarded to the contentPane. This is initially false, but is set to true when the JApplet is constructed.

See Also:

isRootPaneCheckingEnabled() , setRootPaneCheckingEnabled(boolean) , RootPaneContainer

accessibleContext

protected AccessibleContext accessibleContext

JApplet

public JApplet()
        throws HeadlessException

Creates a swing applet instance.

This constructor sets the component's locale property to the value returned by JComponent.getDefaultLocale.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

GraphicsEnvironment.isHeadless() , JComponent.getDefaultLocale()

createRootPane

protected JRootPane createRootPane()

Called by the constructor methods to create the default rootPane.

update

public void update(Graphics g)

Just calls paint(g). This method was overridden to prevent an unnecessary call to clear the background.

Overrides:

update in class Container

Parameters:

g - the specified Graphics window

See Also:

Component.update(Graphics)

setJMenuBar

public void setJMenuBar(JMenuBar menuBar)

Sets the menubar for this applet.

Parameters:

menuBar - the menubar being placed in the applet

See Also:

getJMenuBar()

getJMenuBar

public JMenuBar getJMenuBar()

Returns the menubar set on this applet.

See Also:

setJMenuBar(javax.swing.JMenuBar)

isRootPaneCheckingEnabled

protected boolean isRootPaneCheckingEnabled()

Returns whether calls to add and setLayout are forwarded to the contentPane.

Returns:

true if add and setLayout are fowarded; false otherwise should be checked

See Also:

addImpl(java.awt.Component, java.lang.Object, int) , setLayout(java.awt.LayoutManager) , setRootPaneCheckingEnabled(boolean) , RootPaneContainer

setRootPaneCheckingEnabled

protected void setRootPaneCheckingEnabled(boolean enabled)

Sets whether calls to add and setLayout are forwarded to the contentPane. If true then calls to add() and setLayout() will cause an exception to be thrown.

Parameters:

enabled - true if add and setLayout are forwarded, false if they should operate directly on the JApplet.

See Also:

addImpl(java.awt.Component, java.lang.Object, int) , setLayout(java.awt.LayoutManager) , isRootPaneCheckingEnabled() , RootPaneContainer

addImpl

protected void addImpl(Component comp,
                       Object constraints,
                       int index)

Adds the specified child Component. This method is overridden to conditionally forwad calls to the contentPane. By default, children are added to the contentPane instead of the frame, refer to RootPaneContainer for details. 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.

Overrides:

addImpl in class Container

Parameters:

comp - the component to be enhanced added

constraints - the constraints to be respected constraints - an object expressing layout constraints for this component

index - the index index - the position in the container's list at which to insert the component, where -1 means append to the end

Throws:

IllegalArgumentException Error - if index is invalid

IllegalArgumentException - if adding the container's parent to itself

IllegalArgumentException - if adding a window to a container - if called with rootPaneChecking true

See Also:

setRootPaneCheckingEnabled(boolean) , RootPaneContainer

remove

public void remove(Component comp)

Removes the specified component from the container. If comp is not the rootPane, this will forward the call to the contentPane. This will do nothing if comp is not a child of the JFrame or contentPane. Removes the specified component from this container.

Overrides:

remove in class Container

Parameters:

comp - the component to be removed

Throws:

NullPointerException - if comp is null

See Also:

Container.add(java.awt.Component) , RootPaneContainer

setLayout

public void setLayout(LayoutManager manager)

Sets the LayoutManager. Overridden to conditionally forward the call to the contentPane. Refer to RootPaneContainer for more information. By default the layout of this component may not be set, the layout of its contentPane should be set instead. For example:

 thisComponent.getContentPane().setLayout(new GridLayout(1, 2))
 

An attempt to set the layout of this component will cause an runtime exception to be thrown. Subclasses can disable this behavior.

Overrides:

setLayout in class Container

Parameters:

manager - the LayoutManager specified layout manager

Throws:

Error - if called with rootPaneChecking true

See Also:

setRootPaneCheckingEnabled(boolean) , RootPaneContainer

getRootPane

public JRootPane getRootPane()

Returns the rootPane object for this applet.

Specified by:

getRootPane in interface RootPaneContainer

Returns:

this components single JRootPane child.

See Also:

setRootPane(javax.swing.JRootPane) , RootPaneContainer.getRootPane()

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()

getContentPane

public Container getContentPane()

Returns the contentPane object for this applet.

Specified by:

getContentPane in interface RootPaneContainer

Returns:

the value of the contentPane property.

See Also:

setContentPane(java.awt.Container) , RootPaneContainer.getContentPane()

setContentPane

public void setContentPane(Container contentPane)

Sets the contentPane property. This method is called by the constructor.

Specified by:

setContentPane in interface RootPaneContainer

Parameters:

contentPane - the contentPane object for this applet

Throws:

IllegalComponentStateException - (a runtime exception) if the content pane parameter is null

See Also:

getContentPane() , RootPaneContainer.setContentPane(java.awt.Container)

getLayeredPane

public JLayeredPane getLayeredPane()

Returns the layeredPane object for this applet.

Specified by:

getLayeredPane in interface RootPaneContainer

Returns:

the value of the layeredPane property.

Throws:

IllegalComponentStateException - (a runtime exception) if the layered pane parameter is null

See Also:

setLayeredPane(javax.swing.JLayeredPane) , RootPaneContainer.getLayeredPane()

setLayeredPane

public void setLayeredPane(JLayeredPane layeredPane)

Sets the layeredPane property. This method is called by the constructor.

Specified by:

setLayeredPane in interface RootPaneContainer

Parameters:

layeredPane - the layeredPane object for this applet

See Also:

getLayeredPane() , RootPaneContainer.setLayeredPane(javax.swing.JLayeredPane)

getGlassPane

public Component getGlassPane()

Returns the glassPane object for this applet.

Specified by:

getGlassPane in interface RootPaneContainer

Returns:

the value of the glassPane property.

See Also:

setGlassPane(java.awt.Component) , RootPaneContainer.getGlassPane()

setGlassPane

public void setGlassPane(Component glassPane)

Sets the glassPane property. This method is called by the constructor.

Specified by:

setGlassPane in interface RootPaneContainer

Parameters:

glassPane - the glassPane object for this applet

See Also:

getGlassPane() , RootPaneContainer.setGlassPane(java.awt.Component)

paramString

protected String paramString()

Returns a string representation of this JApplet. 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 Container

Returns:

a string representation of this JApplet.

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this JApplet. For JApplets, the AccessibleContext takes the form of an AccessibleJApplet. A new AccessibleJApplet instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class Applet

Returns:

an AccessibleJApplet that serves as the AccessibleContext of this JApplet