public class JRootPane extends JComponent implements Accessible
JFrame, JDialog, JWindow,
 JApplet, and JInternalFrame.
 For task-oriented information on functionality provided by root panes
 see How to Use Root Panes,
 a section in The Java Tutorial.
 The following image shows the relationships between the classes that use root panes.

JFrame, JDialog,
 JWindow, and JApplet) are
 shown in relation to the AWT classes they extend.
 These four components are the
 only heavyweight containers in the Swing library. The lightweight container
 JInternalFrame is also shown.
 All five of these JFC/Swing containers implement the
 RootPaneContainer interface,
 and they all delegate their operations to a
 JRootPane (shown with a little "handle" on top).
 Note: TheJComponentmethodgetRootPanecan be used to obtain theJRootPanethat contains a given component.
|   | 
JRootPane.
 A JRootpane is made up of a glassPane,
 an optional menuBar, and a contentPane.
 (The JLayeredPane manages the menuBar
 and the contentPane.)
 The glassPane sits over the top of everything,
 where it is in a position to intercept mouse movements.
 Since the glassPane (like the contentPane)
 can be an arbitrary component, it is also possible to set up the
 glassPane for drawing. Lines and images on the
 glassPane can then range
 over the frames underneath without being limited by their boundaries.
 
 Although the menuBar component is optional,
 the layeredPane, contentPane,
 and glassPane always exist.
 Attempting to set them to null generates an exception.
 
 To add components to the JRootPane (other than the
 optional menu bar), you add the object to the contentPane
 of the JRootPane, like this:
 
       rootPane.getContentPane().add(child);
 
 The same principle holds true for setting layout managers, removing
 components, listing children, etc. All these methods are invoked on
 the contentPane instead of on the JRootPane.
 Note: The default layout manager for theIf acontentPaneis aBorderLayoutmanager. However, theJRootPaneuses a customLayoutManager. So, when you want to change the layout manager for the components you added to aJRootPane, be sure to use code like this:rootPane.getContentPane().setLayout(new BoxLayout());
JMenuBar component is set on the JRootPane,
 it is positioned along the upper edge of the frame.
 The contentPane is adjusted in location and size to
 fill the remaining area.
 (The JMenuBar and the contentPane are added to the
 layeredPane component at the
 JLayeredPane.FRAME_CONTENT_LAYER layer.)
 
 The layeredPane is the parent of all children in the
 JRootPane -- both as the direct parent of the menu and
 the grandparent of all components added to the contentPane.
 It is an instance of JLayeredPane,
 which provides the ability to add components at several layers.
 This capability is very useful when working with menu popups,
 dialog boxes, and dragging -- situations in which you need to place
 a component on top of all other components in the pane.
 
 The glassPane sits on top of all other components in the
 JRootPane.
 That provides a convenient place to draw above all other components,
 and makes it possible to intercept mouse events,
 which is useful both for dragging and for drawing.
 Developers can use setVisible on the glassPane
 to control when the glassPane displays over the other children.
 By default the glassPane is not visible.
 
 The custom LayoutManager used by JRootPane
 ensures that:
 
glassPane fills the entire viewable
     area of the JRootPane (bounds - insets).
 layeredPane fills the entire viewable area of the
     JRootPane. (bounds - insets)
 menuBar is positioned at the upper edge of the
     layeredPane.
 contentPane fills the entire viewable area,
     minus the menuBar, if present.
 JRootPane view hierarchy are ignored.
 
 If you replace the LayoutManager of the JRootPane,
 you are responsible for managing all of these views.
 So ordinarily you will want to be sure that you
 change the layout manager for the contentPane rather than
 for the JRootPane itself!
 
 The painting architecture of Swing requires an opaque
 JComponent
 to exist in the containment hierarchy above all other components. This is
 typically provided by way of the content pane. If you replace the content
 pane, it is recommended that you make the content pane opaque
 by way of setOpaque(true). Additionally, if the content pane
 overrides paintComponent, it
 will need to completely fill in the background in an opaque color in
 paintComponent.
 
Warning: Swing is not thread safe. For more information see Swing's Threading Policy.
 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™
 has been added to the java.beans package.
 Please see XMLEncoder.
| Modifier and Type | Class and Description | 
|---|---|
| protected class  | JRootPane.AccessibleJRootPaneThis class implements accessibility support for the
  JRootPaneclass. | 
| protected class  | JRootPane.RootLayoutA custom layout manager that is responsible for the layout of
 layeredPane, glassPane, and menuBar. | 
JComponent.AccessibleJComponentContainer.AccessibleAWTContainerComponent.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy| Modifier and Type | Field and Description | 
|---|---|
| static int | COLOR_CHOOSER_DIALOGConstant used for the windowDecorationStyle property. | 
| protected Container | contentPaneThe content pane. | 
| protected JButton | defaultButtonThe button that gets activated when the pane has the focus and
 a UI-specific action like pressing the Enter key occurs. | 
| protected javax.swing.JRootPane.DefaultAction | defaultPressActionDeprecated. 
 As of Java 2 platform v1.3. | 
| protected javax.swing.JRootPane.DefaultAction | defaultReleaseActionDeprecated. 
 As of Java 2 platform v1.3. | 
| static int | ERROR_DIALOGConstant used for the windowDecorationStyle property. | 
| static int | FILE_CHOOSER_DIALOGConstant used for the windowDecorationStyle property. | 
| static int | FRAMEConstant used for the windowDecorationStyle property. | 
| protected Component | glassPaneThe glass pane that overlays the menu bar and content pane,
  so it can intercept mouse movements and such. | 
| static int | INFORMATION_DIALOGConstant used for the windowDecorationStyle property. | 
| protected JLayeredPane | layeredPaneThe layered pane that manages the menu bar and content pane. | 
| protected JMenuBar | menuBarThe menu bar. | 
| static int | NONEConstant used for the windowDecorationStyle property. | 
| static int | PLAIN_DIALOGConstant used for the windowDecorationStyle property. | 
| static int | QUESTION_DIALOGConstant used for the windowDecorationStyle property. | 
| static int | WARNING_DIALOGConstant used for the windowDecorationStyle property. | 
listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOWaccessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENTABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH| Constructor and Description | 
|---|
| JRootPane()Creates a  JRootPane, setting up itsglassPane,layeredPane,
 andcontentPane. | 
| Modifier and Type | Method and Description | 
|---|---|
| protected void | addImpl(Component comp,
       Object constraints,
       int index)Overridden to enforce the position of the glass component as
 the zero child. | 
| void | addNotify()Notifies this component that it now has a parent component. | 
| protected Container | createContentPane()Called by the constructor methods to create the default
  contentPane. | 
| protected Component | createGlassPane()Called by the constructor methods to create the default
  glassPane. | 
| protected JLayeredPane | createLayeredPane()Called by the constructor methods to create the default
  layeredPane. | 
| protected LayoutManager | createRootLayout()Called by the constructor methods to create the default
  layoutManager. | 
| AccessibleContext | getAccessibleContext()Gets the  AccessibleContextassociated with thisJRootPane. | 
| Container | getContentPane()Returns the content pane -- the container that holds the components
 parented by the root pane. | 
| JButton | getDefaultButton()Returns the value of the  defaultButtonproperty. | 
| Component | getGlassPane()Returns the current glass pane for this  JRootPane. | 
| JMenuBar | getJMenuBar()Returns the menu bar from the layered pane. | 
| JLayeredPane | getLayeredPane()Gets the layered pane used by the root pane. | 
| JMenuBar | getMenuBar()Deprecated. 
 As of Swing version 1.0.3
  replaced by  getJMenuBar(). | 
| RootPaneUI | getUI()Returns the L&F object that renders this component. | 
| String | getUIClassID()Returns a string that specifies the name of the L&F class
 that renders this component. | 
| int | getWindowDecorationStyle()Returns a constant identifying the type of Window decorations the
  JRootPaneis providing. | 
| boolean | isOptimizedDrawingEnabled()The  glassPaneandcontentPanehave the same bounds, which meansJRootPanedoes not tiles its children and this should return false. | 
| boolean | isValidateRoot()If a descendant of this  JRootPanecallsrevalidate, validate from here on down. | 
| protected String | paramString()Returns a string representation of this  JRootPane. | 
| void | removeNotify()Notifies this component that it no longer has a parent component. | 
| void | setContentPane(Container content)Sets the content pane -- the container that holds the components
 parented by the root pane. | 
| void | setDefaultButton(JButton defaultButton)Sets the  defaultButtonproperty,
 which determines the current default button for thisJRootPane. | 
| void | setDoubleBuffered(boolean aFlag)Sets whether this component should use a buffer to paint. | 
| void | setGlassPane(Component glass)Sets a specified  Componentto be the glass pane for this
 root pane. | 
| void | setJMenuBar(JMenuBar menu)Adds or changes the menu bar used in the layered pane. | 
| void | setLayeredPane(JLayeredPane layered)Sets the layered pane for the root pane. | 
| void | setMenuBar(JMenuBar menu)Deprecated. 
 As of Swing version 1.0.3
  replaced by  setJMenuBar(JMenuBar menu). | 
| void | setUI(RootPaneUI ui)Sets the L&F object that renders this component. | 
| void | setWindowDecorationStyle(int windowDecorationStyle)Sets the type of Window decorations (such as borders, widgets for
 closing a Window, title ...) the  JRootPaneshould
 provide. | 
| void | updateUI()Resets the UI property to a value from the current look and feel. | 
addAncestorListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, updateadd, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTreeaction, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCyclepublic static final int NONE
JRootPane should not provide any sort of
 Window decorations.public static final int FRAME
JRootPane should provide decorations appropriate for
 a Frame.public static final int PLAIN_DIALOG
JRootPane should provide decorations appropriate for
 a Dialog.public static final int INFORMATION_DIALOG
JRootPane should provide decorations appropriate for
 a Dialog used to display an informational message.public static final int ERROR_DIALOG
JRootPane should provide decorations appropriate for
 a Dialog used to display an error message.public static final int COLOR_CHOOSER_DIALOG
JRootPane should provide decorations appropriate for
 a Dialog used to display a JColorChooser.public static final int FILE_CHOOSER_DIALOG
JRootPane should provide decorations appropriate for
 a Dialog used to display a JFileChooser.public static final int QUESTION_DIALOG
JRootPane should provide decorations appropriate for
 a Dialog used to present a question to the user.public static final int WARNING_DIALOG
JRootPane should provide decorations appropriate for
 a Dialog used to display a warning message.protected JMenuBar menuBar
protected Container contentPane
protected JLayeredPane layeredPane
protected Component glassPane
protected JButton defaultButton
@Deprecated protected javax.swing.JRootPane.DefaultAction defaultPressAction
Action
 in the JRootPane's ActionMap. Please refer to
 the key bindings specification for further details.defaultButton@Deprecated protected javax.swing.JRootPane.DefaultAction defaultReleaseAction
Action
 in the JRootPane's ActionMap. Please refer to
 the key bindings specification for further details.defaultButtonpublic JRootPane()
JRootPane, setting up its
 glassPane, layeredPane,
 and contentPane.public void setDoubleBuffered(boolean aFlag)
Component is buffered and one of its ancestor
  is also buffered, the ancestor buffer will be used.setDoubleBuffered in class JComponentaFlag - if true, set this component to be double bufferedpublic int getWindowDecorationStyle()
JRootPane is providing.NONE, FRAME,
        PLAIN_DIALOG, INFORMATION_DIALOG,
        ERROR_DIALOG, COLOR_CHOOSER_DIALOG,
        FILE_CHOOSER_DIALOG, QUESTION_DIALOG or
        WARNING_DIALOG.setWindowDecorationStyle(int)public void setWindowDecorationStyle(int windowDecorationStyle)
JRootPane should
 provide. The default is to provide no Window decorations
 (NONE).
 This is only a hint, and some look and feels may not support this. This is a bound property.
windowDecorationStyle - Constant identifying Window decorations
        to provide.IllegalArgumentException - if style is
        not one of: NONE, FRAME,
        PLAIN_DIALOG, INFORMATION_DIALOG,
        ERROR_DIALOG, COLOR_CHOOSER_DIALOG,
        FILE_CHOOSER_DIALOG, QUESTION_DIALOG, or
        WARNING_DIALOG.JDialog.setDefaultLookAndFeelDecorated(boolean), 
JFrame.setDefaultLookAndFeelDecorated(boolean), 
LookAndFeel.getSupportsWindowDecorations()public RootPaneUI getUI()
LabelUI objectpublic void setUI(RootPaneUI ui)
ui - the LabelUI L&F objectUIDefaults.getUI(javax.swing.JComponent)public void updateUI()
updateUI in class JComponentJComponent.updateUI()public String getUIClassID()
getUIClassID in class JComponentJComponent.getUIClassID(), 
UIDefaults.getUI(javax.swing.JComponent)protected JLayeredPane createLayeredPane()
layeredPane.
 Bt default it creates a new JLayeredPane.layeredPaneprotected Container createContentPane()
contentPane.
 By default this method creates a new JComponent add sets a
 BorderLayout as its LayoutManager.contentPaneprotected Component createGlassPane()
glassPane.
 By default this method creates a new JComponent
 with visibility set to false.glassPaneprotected LayoutManager createRootLayout()
layoutManager.layoutManager.public void setJMenuBar(JMenuBar menu)
menu - the JMenuBar to add@Deprecated public void setMenuBar(JMenuBar menu)
setJMenuBar(JMenuBar menu).menu - the JMenuBar to add.public JMenuBar getJMenuBar()
JMenuBar used in the pane@Deprecated public JMenuBar getMenuBar()
getJMenuBar().JMenuBar used in the panepublic void setContentPane(Container content)
 Swing's painting architecture requires an opaque JComponent
 in the containment hierarchy. This is typically provided by the
 content pane. If you replace the content pane it is recommended you
 replace it with an opaque JComponent.
content - the Container to use for component-contentsIllegalComponentStateException - (a runtime
            exception) if the content pane parameter is nullpublic Container getContentPane()
Container that holds the component-contentspublic void setLayeredPane(JLayeredPane layered)
JMenuBar.layered - the JLayeredPane to useIllegalComponentStateException - (a runtime
            exception) if the layered pane parameter is nullpublic JLayeredPane getLayeredPane()
JMenuBar.JLayeredPane currently in usepublic void setGlassPane(Component glass)
Component to be the glass pane for this
 root pane.  The glass pane should normally be a lightweight,
 transparent component, because it will be made visible when
 ever the root pane needs to grab input events.
 The new glass pane's visibility is changed to match that of the current glass pane. An implication of this is that care must be taken when you want to replace the glass pane and make it visible. Either of the following will work:
root.setGlassPane(newGlassPane); newGlassPane.setVisible(true);or:
root.getGlassPane().setVisible(true); root.setGlassPane(newGlassPane);
glass - the Component to use as the glass pane
              for this JRootPaneNullPointerException - if the glass parameter is
          nullpublic Component getGlassPane()
JRootPane.setGlassPane(java.awt.Component)public boolean isValidateRoot()
JRootPane calls
 revalidate, validate from here on down.
 Deferred requests to layout a component and its descendents again.
 For example, calls to revalidate, are pushed upwards to
 either a JRootPane or a JScrollPane
 because both classes override isValidateRoot to return true.
isValidateRoot in class JComponentJComponent.isValidateRoot(), 
Container.isValidateRoot()public boolean isOptimizedDrawingEnabled()
glassPane and contentPane
 have the same bounds, which means JRootPane
 does not tiles its children and this should return false.
 On the other hand, the glassPane
 is normally not visible, and so this can return true if the
 glassPane isn't visible. Therefore, the
 return value here depends upon the visibility of the
 glassPane.isOptimizedDrawingEnabled in class JComponentpublic void addNotify()
KeyboardAction event listeners.
 This method is called by the toolkit internally and should
 not be called directly by programs.public void removeNotify()
KeyboardActions
 set up in the the chain of parent components are removed.
 This method is called by the toolkit internally and should
 not be called directly by programs.public void setDefaultButton(JButton defaultButton)
defaultButton property,
 which determines the current default button for this JRootPane.
 The default button is the button which will be activated
 when a UI-defined activation event (typically the Enter key)
 occurs in the root pane regardless of whether or not the button
 has keyboard focus (unless there is another component within
 the root pane which consumes the activation event,
 such as a JTextPane).
 For default activation to work, the button must be an enabled
 descendent of the root pane when activation occurs.
 To remove a default button from this root pane, set this
 property to null.defaultButton - the JButton which is to be the default buttonJButton.isDefaultButton()public JButton getDefaultButton()
defaultButton property.JButton which is currently the default buttonsetDefaultButton(javax.swing.JButton)protected void addImpl(Component comp, Object constraints, int index)
addImpl in class Containercomp - the component to be enhancedconstraints - the constraints to be respectedindex - the indexContainer.add(Component), 
Container.add(Component, int), 
Container.add(Component, java.lang.Object), 
Container.invalidate(), 
LayoutManager, 
LayoutManager2protected String paramString()
JRootPane.
 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.paramString in class JComponentJRootPane.public AccessibleContext getAccessibleContext()
AccessibleContext associated with this
 JRootPane. For root panes, the
 AccessibleContext takes the form of an
 AccessibleJRootPane.
 A new AccessibleJRootPane instance is created if necessary.getAccessibleContext in interface AccessiblegetAccessibleContext in class ComponentAccessibleJRootPane that serves as the
         AccessibleContext of this JRootPane Submit a bug or feature 
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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