Java™ Platform
Standard Ed. 6

javax.swing
Class JComponent

java.lang.Object
  extended by java.awt.Component
      extended by java.awt.Container
          extended by javax.swing.JComponent
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable
Direct Known Subclasses:
AbstractButton, BasicInternalFrameTitlePane, Box, Box.Filler, JColorChooser, JComboBox, JFileChooser, JInternalFrame, JInternalFrame.JDesktopIcon, JLabel, JLayeredPane, JList, JMenuBar, JOptionPane, JPanel, JPopupMenu, JProgressBar, JRootPane, JScrollBar, JScrollPane, JSeparator, JSlider, JSpinner, JSplitPane, JTabbedPane, JTable, JTableHeader, JTextComponent, JToolBar, JToolTip, JTree, JViewport

public abstract class JComponent
extends Container
implements Serializable

The base class for all Swing components except top-level containers. To use a component that inherits from JComponent, you must place the component in a containment hierarchy whose root is a top-level Swing container. Top-level Swing containers -- such as JFrame, JDialog, and JApplet -- are specialized components that provide a place for other Swing components to paint themselves. For an explanation of containment hierarchies, see Swing Components and the Containment Hierarchy, a section in The Java Tutorial.

The JComponent class provides:

For more information on these subjects, see the Swing package description and The Java Tutorial section The JComponent Class.

JComponent and its subclasses document default values for certain properties. For example, JTable documents the default row height as 16. Each JComponent subclass that has a ComponentUI will create the ComponentUI as part of its constructor. In order to provide a particular look and feel each ComponentUI may set properties back on the JComponent that created it. For example, a custom look and feel may require JTables to have a row height of 24. The documented defaults are the value of a property BEFORE the ComponentUI has been installed. If you need a specific value for a particular property you should explicitly set it.

In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section in The Java Tutorial.

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 JavaBeansTM has been added to the java.beans package. Please see XMLEncoder.

See Also:
KeyStroke, Action, setBorder(javax.swing.border.Border), registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int), JOptionPane, setDebugGraphicsOptions(int), setToolTipText(java.lang.String), setAutoscrolls(boolean)

Nested Class Summary
 class JComponent.AccessibleJComponent
          Inner class of JComponent used to provide default support for accessibility.
 
Nested classes/interfaces inherited from class java.awt.Container
Container.AccessibleAWTContainer
 
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
 
Field Summary
protected  AccessibleContext accessibleContext
          The AccessibleContext associated with this JComponent.
protected  EventListenerList listenerList
          A list of event listeners for this component.
static String TOOL_TIP_TEXT_KEY
          The comment to display when the cursor is over the component, also known as a "value tip", "flyover help", or "flyover label".
protected  ComponentUI ui
          The look and feel delegate for this component.
static int UNDEFINED_CONDITION
          Constant used by some of the APIs to mean that no condition is defined.
static int WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
          Constant used for registerKeyboardAction that means that the command should be invoked when the receiving component is an ancestor of the focused component or is itself the focused component.
static int WHEN_FOCUSED
          Constant used for registerKeyboardAction that means that the command should be invoked when the component has the focus.
static int WHEN_IN_FOCUSED_WINDOW
          Constant used for registerKeyboardAction that means that the command should be invoked when the receiving component is in the window that has the focus or is itself the focused component.
 
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
JComponent()
          Default JComponent constructor.
 
Method Summary
 void addAncestorListener(AncestorListener listener)
          Registers listener so that it will receive AncestorEvents when it or any of its ancestors move or are made visible or invisible.
 void addNotify()
          Notifies this component that it now has a parent component.
 void addVetoableChangeListener(VetoableChangeListener listener)
          Adds a VetoableChangeListener to the listener list.
 void computeVisibleRect(Rectangle visibleRect)
          Returns the Component's "visible rect rectangle" - the intersection of the visible rectangles for this component and all of its ancestors.
 boolean contains(int x, int y)
          Gives the UI delegate an opportunity to define the precise shape of this component for the sake of mouse processing.
 JToolTip createToolTip()
          Returns the instance of JToolTip that should be used to display the tooltip.
 void disable()
          Deprecated. As of JDK version 1.1, replaced by java.awt.Component.setEnabled(boolean).
 void enable()
          Deprecated. As of JDK version 1.1, replaced by java.awt.Component.setEnabled(boolean).
 void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
          Support for reporting bound property changes for boolean properties.
 void firePropertyChange(String propertyName, char oldValue, char newValue)
          Reports a bound property change.
 void firePropertyChange(String propertyName, int oldValue, int newValue)
          Support for reporting bound property changes for integer properties.
protected  void fireVetoableChange(String propertyName, Object oldValue, Object newValue)
          Supports reporting constrained property changes.
 AccessibleContext getAccessibleContext()
          Returns the AccessibleContext associated with this JComponent.
 ActionListener getActionForKeyStroke(KeyStroke aKeyStroke)
          Returns the object that will perform the action registered for a given keystroke.
 ActionMap getActionMap()
          Returns the ActionMap used to determine what Action to fire for particular KeyStroke binding.
 float getAlignmentX()
          Overrides Container.getAlignmentX to return the vertical alignment.
 float getAlignmentY()
          Overrides Container.getAlignmentY to return the horizontal alignment.
 AncestorListener[] getAncestorListeners()
          Returns an array of all the ancestor listeners registered on this component.
 boolean getAutoscrolls()
          Gets the autoscrolls property.
 int getBaseline(int width, int height)
          Returns the baseline.
 Component.BaselineResizeBehavior getBaselineResizeBehavior()
          Returns an enum indicating how the baseline of the component changes as the size changes.
 Border getBorder()
          Returns the border of this component or null if no border is currently set.
 Rectangle getBounds(Rectangle rv)
          Stores the bounds of this component into "return value" rv and returns rv.
 Object getClientProperty(Object key)
          Returns the value of the property with the specified key.
protected  Graphics getComponentGraphics(Graphics g)
          Returns the graphics object used to paint this component.
 JPopupMenu getComponentPopupMenu()
          Returns JPopupMenu that assigned for this component.
 int getConditionForKeyStroke(KeyStroke aKeyStroke)
          Returns the condition that determines whether a registered action occurs in response to the specified keystroke.
 int getDebugGraphicsOptions()
          Returns the state of graphics debugging.
static Locale getDefaultLocale()
          Returns the default locale used to initialize each JComponent's locale property upon creation.
 FontMetrics getFontMetrics(Font font)
          Gets the FontMetrics for the specified Font.
 Graphics getGraphics()
          Returns this component's graphics context, which lets you draw on a component.
 int getHeight()
          Returns the current height of this component.
 boolean getInheritsPopupMenu()
          Returns true if the JPopupMenu should be inherited from the parent.
 InputMap getInputMap()
          Returns the InputMap that is used when the component has focus.
 InputMap getInputMap(int condition)
          Returns the InputMap that is used during condition.
 InputVerifier getInputVerifier()
          Returns the input verifier for this component.
 Insets getInsets()
          If a border has been set on this component, returns the border's insets; otherwise calls super.getInsets.
 Insets getInsets(Insets insets)
          Returns an Insets object containing this component's inset values.
<T extends EventListener>
T[]
getListeners(Class<T> listenerType)
          Returns an array of all the objects currently registered as FooListeners upon this JComponent.
 Point getLocation(Point rv)
          Stores the x,y origin of this component into "return value" rv and returns rv.
 Dimension getMaximumSize()
          If the maximum size has been set to a non-null value just returns it.
 Dimension getMinimumSize()
          If the minimum size has been set to a non-null value just returns it.
 Component getNextFocusableComponent()
          Deprecated. As of 1.4, replaced by FocusTraversalPolicy.
 Point getPopupLocation(MouseEvent event)
          Returns the preferred location to display the popup menu in this component's coordinate system.
 Dimension getPreferredSize()
          If the preferredSize has been set to a non-null value just returns it.
 KeyStroke[] getRegisteredKeyStrokes()
          Returns the KeyStrokes that will initiate registered actions.
 JRootPane getRootPane()
          Returns the JRootPane ancestor for this component.
 Dimension getSize(Dimension rv)
          Stores the width/height of this component into "return value" rv and returns rv.
 Point getToolTipLocation(MouseEvent event)
          Returns the tooltip location in this component's coordinate system.
 String getToolTipText()
          Returns the tooltip string that has been set with setToolTipText.
 String getToolTipText(MouseEvent event)
          Returns the string to be used as the tooltip for event.
 Container getTopLevelAncestor()
          Returns the top-level ancestor of this component (either the containing Window or Applet), or null if this component has not been added to any container.
 TransferHandler getTransferHandler()
          Gets the transferHandler property.
 String getUIClassID()
          Returns the UIDefaults key used to look up the name of the swing.plaf.ComponentUI class that defines the look and feel for this component.
 boolean getVerifyInputWhenFocusTarget()
          Returns the value that indicates whether the input verifier for the current focus owner will be called before this component requests focus.
 VetoableChangeListener[] getVetoableChangeListeners()
          Returns an array of all the vetoable change listeners registered on this component.
 Rectangle getVisibleRect()
          Returns the Component's "visible rectangle" - the intersection of this component's visible rectangle, new Rectangle(0, 0, getWidth(), getHeight()), and all of its ancestors' visible rectangles.
 int getWidth()
          Returns the current width of this component.
 int getX()
          Returns the current x coordinate of the component's origin.
 int getY()
          Returns the current y coordinate of the component's origin.
 void grabFocus()
          Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
 boolean isDoubleBuffered()
          Returns whether this component should use a buffer to paint.
static boolean isLightweightComponent(Component c)
          Returns true if this component is lightweight, that is, if it doesn't have a native window system peer.
 boolean isManagingFocus()
          Deprecated. As of 1.4, replaced by Component.setFocusTraversalKeys(int, Set) and Container.setFocusCycleRoot(boolean).
 boolean isOpaque()
          Returns true if this component is completely opaque.
 boolean isOptimizedDrawingEnabled()
          Returns true if this component tiles its children -- that is, if it can guarantee that the children will not overlap.
 boolean isPaintingForPrint()
          Returns true if the current painting operation on this component is part of a print operation.
 boolean isPaintingTile()
          Returns true if the component is currently painting a tile.
 boolean isRequestFocusEnabled()
          Returns true if this JComponent should get focus; otherwise returns false.
 boolean isValidateRoot()
          If this method returns true, revalidate calls by descendants of this component will cause the entire tree beginning with this root to be validated.
 void paint(Graphics g)
          Invoked by Swing to draw components.
protected  void paintBorder(Graphics g)
          Paints the component's border.
protected  void paintChildren(Graphics g)
          Paints this component's children.
protected  void paintComponent(Graphics g)
          Calls the UI delegate's paint method, if the UI delegate is non-null.
 void paintImmediately(int x, int y, int w, int h)
          Paints the specified region in this component and all of its descendants that overlap the region, immediately.
 void paintImmediately(Rectangle r)
          Paints the specified region now.
protected  String paramString()
          Returns a string representation of this JComponent.
 void print(Graphics g)
          Invoke this method to print the component to the specified Graphics.
 void printAll(Graphics g)
          Invoke this method to print the component.
protected  void printBorder(Graphics g)
          Prints the component's border.
protected  void printChildren(Graphics g)
          Prints this component's children.
protected  void printComponent(Graphics g)
          This is invoked during a printing operation.
protected  void processComponentKeyEvent(KeyEvent e)
          Processes any key events that the component itself recognizes.
protected  boolean processKeyBinding(KeyStroke ks, KeyEvent e, int condition, boolean pressed)
          Invoked to process the key bindings for ks as the result of the KeyEvent e.
protected  void processKeyEvent(KeyEvent e)
          Overrides processKeyEvent to process events.
protected  void processMouseEvent(MouseEvent e)
          Processes mouse events occurring on this component by dispatching them to any registered MouseListener objects, refer to Component.processMouseEvent(MouseEvent) for a complete description of this method.
protected  void processMouseMotionEvent(MouseEvent e)
          Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.
 void putClientProperty(Object key, Object value)
          Adds an arbitrary key/value "client property" to this component.
 void registerKeyboardAction(ActionListener anAction, KeyStroke aKeyStroke, int aCondition)
          This method is now obsolete, please use a combination of getActionMap() and getInputMap() for similiar behavior.
 void registerKeyboardAction(ActionListener anAction, String aCommand, KeyStroke aKeyStroke, int aCondition)
          This method is now obsolete, please use a combination of getActionMap() and getInputMap() for similiar behavior.
 void removeAncestorListener(AncestorListener listener)
          Unregisters listener so that it will no longer receive AncestorEvents.
 void removeNotify()
          Notifies this component that it no longer has a parent component.
 void removeVetoableChangeListener(VetoableChangeListener listener)
          Removes a VetoableChangeListener from the listener list.
 void repaint(long tm, int x, int y, int width, int height)
          Adds the specified region to the dirty region list if the component is showing.
 void repaint(Rectangle r)
          Adds the specified region to the dirty region list if the component is showing.
 boolean requestDefaultFocus()
          Deprecated. As of 1.4, replaced by FocusTraversalPolicy.getDefaultComponent(Container).requestFocus()
 void requestFocus()
          Requests that this Component gets the input focus.
 boolean requestFocus(boolean temporary)
          Requests that this Component gets the input focus.
 boolean requestFocusInWindow()
          Requests that this Component gets the input focus.
protected  boolean requestFocusInWindow(boolean temporary)
          Requests that this Component gets the input focus.
 void resetKeyboardActions()
          Unregisters all the bindings in the first tier InputMaps and ActionMap.
 void reshape(int x, int y, int w, int h)
          Deprecated. As of JDK 5, replaced by Component.setBounds(int, int, int, int).

Moves and resizes this component.

 void revalidate()
          Supports deferred automatic layout.
 void scrollRectToVisible(Rectangle aRect)
          Forwards the scrollRectToVisible() message to the JComponent's parent.
 void setActionMap(ActionMap am)
          Sets the ActionMap to am.
 void setAlignmentX(float alignmentX)
          Sets the the vertical alignment.
 void setAlignmentY(float alignmentY)
          Sets the the horizontal alignment.
 void setAutoscrolls(boolean autoscrolls)
          Sets the autoscrolls property.
 void setBackground(Color bg)
          Sets the background color of this component.
 void setBorder(Border border)
          Sets the border of this component.
 void setComponentPopupMenu(JPopupMenu popup)
          Sets the JPopupMenu for this JComponent.
 void setDebugGraphicsOptions(int debugOptions)
          Enables or disables diagnostic information about every graphics operation performed within the component or one of its children.
static void setDefaultLocale(Locale l)
          Sets the default locale used to initialize each JComponent's locale property upon creation.
 void setDoubleBuffered(boolean aFlag)
          Sets whether this component should use a buffer to paint.
 void setEnabled(boolean enabled)
          Sets whether or not this component is enabled.
 void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
          Sets the focus traversal keys for a given traversal operation for this Component.
 void setFont(Font font)
          Sets the font for this component.
 void setForeground(Color fg)
          Sets the foreground color of this component.
 void setInheritsPopupMenu(boolean value)
          Sets whether or not getComponentPopupMenu should delegate to the parent if this component does not have a JPopupMenu assigned to it.
 void setInputMap(int condition, InputMap map)
          Sets the InputMap to use under the condition condition to map.
 void setInputVerifier(InputVerifier inputVerifier)
          Sets the input verifier for this component.
 void setMaximumSize(Dimension maximumSize)
          Sets the maximum size of this component to a constant value.
 void setMinimumSize(Dimension minimumSize)
          Sets the minimum size of this component to a constant value.
 void setNextFocusableComponent(Component aComponent)
          Deprecated. As of 1.4, replaced by FocusTraversalPolicy
 void setOpaque(boolean isOpaque)
          If true the component paints every pixel within its bounds.
 void setPreferredSize(Dimension preferredSize)
          Sets the preferred size of this component.
 void setRequestFocusEnabled(boolean requestFocusEnabled)
          Provides a hint as to whether or not this JComponent should get focus.
 void setToolTipText(String text)
          Registers the text to display in a tool tip.
 void setTransferHandler(TransferHandler newHandler)
          Sets the transferHandler property, which is null if the component does not support data transfer operations.
protected  void setUI(ComponentUI newUI)
          Sets the look and feel delegate for this component.
 void setVerifyInputWhenFocusTarget(boolean verifyInputWhenFocusTarget)
          Sets the value to indicate whether input verifier for the current focus owner will be called before this component requests focus.
 void setVisible(boolean aFlag)
          Makes the component visible or invisible.
 void unregisterKeyboardAction(KeyStroke aKeyStroke)
          This method is now obsolete.
 void update(Graphics g)
          Calls paint.
 void updateUI()
          Resets the UI property to a value from the current look and feel.
 
Methods inherited from class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, 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, 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, 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, hide, 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, transferFocusUpCycle
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

ui

protected transient ComponentUI ui
The look and feel delegate for this component.


listenerList

protected EventListenerList listenerList
A list of event listeners for this component.


WHEN_FOCUSED

public static final int WHEN_FOCUSED
Constant used for registerKeyboardAction that means that the command should be invoked when the component has the focus.

See Also:
Constant Field Values

WHEN_ANCESTOR_OF_FOCUSED_COMPONENT

public static final int WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
Constant used for registerKeyboardAction that means that the command should be invoked when the receiving component is an ancestor of the focused component or is itself the focused component.

See Also:
Constant Field Values

WHEN_IN_FOCUSED_WINDOW

public static final int WHEN_IN_FOCUSED_WINDOW
Constant used for registerKeyboardAction that means that the command should be invoked when the receiving component is in the window that has the focus or is itself the focused component.

See Also:
Constant Field Values

UNDEFINED_CONDITION

public static final int UNDEFINED_CONDITION
Constant used by some of the APIs to mean that no condition is defined.

See Also:
Constant Field Values

TOOL_TIP_TEXT_KEY

public static final String TOOL_TIP_TEXT_KEY
The comment to display when the cursor is over the component, also known as a "value tip", "flyover help", or "flyover label".

See Also:
Constant Field Values

accessibleContext

protected AccessibleContext accessibleContext
The AccessibleContext associated with this JComponent.

Constructor Detail

JComponent

public JComponent()
Default JComponent constructor. This constructor does very little initialization beyond calling the Container constructor. For example, the initial layout manager is null. It does, however, set the component's locale property to the value returned by JComponent.getDefaultLocale.

See Also:
getDefaultLocale()
Method Detail

setInheritsPopupMenu

public void setInheritsPopupMenu(boolean value)
Sets whether or not getComponentPopupMenu should delegate to the parent if this component does not have a JPopupMenu assigned to it.

The default value for this is false, but some JComponent subclasses that are implemented as a number of JComponents may set this to true.

This is a bound property.

Parameters:
value - whether or not the JPopupMenu is inherited
Since:
1.5
See Also:
setComponentPopupMenu(javax.swing.JPopupMenu)

getInheritsPopupMenu

public boolean getInheritsPopupMenu()
Returns true if the JPopupMenu should be inherited from the parent.

Since:
1.5
See Also:
setComponentPopupMenu(javax.swing.JPopupMenu)

setComponentPopupMenu

public void setComponentPopupMenu(JPopupMenu popup)
Sets the JPopupMenu for this JComponent. The UI is responsible for registering bindings and adding the necessary listeners such that the JPopupMenu will be shown at the appropriate time. When the JPopupMenu is shown depends upon the look and feel: some may show it on a mouse event, some may enable a key binding.

If popup is null, and getInheritsPopupMenu returns true, then getComponentPopupMenu will be delegated to the parent. This provides for a way to make all child components inherit the popupmenu of the parent.

This is a bound property.

Parameters:
popup - - the popup that will be assigned to this component may be null
Since:
1.5
See Also:
getComponentPopupMenu()

getComponentPopupMenu

public JPopupMenu getComponentPopupMenu()
Returns JPopupMenu that assigned for this component. If this component does not have a JPopupMenu assigned to it and getInheritsPopupMenu is true, this will return getParent().getComponentPopupMenu() (assuming the parent is valid.)

Returns:
JPopupMenu assigned for this component or null if no popup assigned
Since:
1.5
See Also:
setComponentPopupMenu(javax.swing.JPopupMenu)

updateUI

public void updateUI()
Resets the UI property to a value from the current look and feel. JComponent subclasses must override this method like this:
   public void updateUI() {
      setUI((SliderUI)UIManager.getUI(this);
   }
  

See Also:
setUI(javax.swing.plaf.ComponentUI), UIManager.getLookAndFeel(), UIManager.getUI(javax.swing.JComponent)

setUI

protected void setUI(ComponentUI newUI)
Sets the look and feel delegate for this component. JComponent subclasses generally override this method to narrow the argument type. For example, in JSlider:
 public void setUI(SliderUI newUI) {
     super.setUI(newUI);
 }
  

Additionally JComponent subclasses must provide a getUI method that returns the correct type. For example:

 public SliderUI getUI() {
     return (SliderUI)ui;
 }
 

Parameters:
newUI - the new UI delegate
See Also:
updateUI(), UIManager.getLookAndFeel(), UIManager.getUI(javax.swing.JComponent)

getUIClassID

public String getUIClassID()
Returns the UIDefaults key used to look up the name of the swing.plaf.ComponentUI class that defines the look and feel for this component. Most applications will never need to call this method. Subclasses of JComponent that support pluggable look and feel should override this method to return a UIDefaults key that maps to the ComponentUI subclass that defines their look and feel.

Returns:
the UIDefaults key for a ComponentUI subclass
See Also:
UIDefaults.getUI(javax.swing.JComponent)

getComponentGraphics

protected Graphics getComponentGraphics(Graphics g)
Returns the graphics object used to paint this component. If DebugGraphics is turned on we create a new DebugGraphics object if necessary. Otherwise we just configure the specified graphic