javax.swing
Class JComponent

java.lang.Object
  java.awt.Component
      java.awt.Container
          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, MetalTitlePane

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:

• The base class for both standard and custom components that use the Swing architecture.
• A "pluggable look and feel" (L&F) that can be specified by the programmer or (optionally) selected by the user at runtime. The look and feel for each component is provided by a UI delegate -- an object that descends from ComponentUI. See How to Set the Look and Feel in The Java Tutorial for more information.
• Comprehensive keystroke handling. See the document Keyboard Bindings in Swing, an article in The Swing Connection, for more information.
• Support for tool tips -- short descriptions that pop up when the cursor lingers over a component. See How to Use Tool Tips in The Java Tutorial for more information.
• Support for accessibility. JComponent contains all of the methods in the Accessible interface, but it doesn't actually implement the interface. That is the responsibility of the individual classes that extend JComponent.
• Support for component-specific properties. With the putClientProperty(java.lang.Object, java.lang.Object) and getClientProperty(java.lang.Object) methods, you can associate name-object pairs with any object that descends from JComponent.
• An infrastructure for painting that includes double buffering and support for borders. For more information see Painting and How to Use Borders, both of which are sections in The Java Tutorial.

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

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.

Author:

Hans Muller, Arnaud Weber

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), Serialized Form

Nested Class Summary

class	JComponent.AccessibleJComponent Inner class of JComponent used to provide default support for accessibility.
(package private) class	JComponent.ActionStandin ActionStandin is used as a standin for ActionListeners that are added via registerKeyboardAction.
private class	JComponent.EnableSerializationFocusListener This class is used to give us an opportunity to uninstall the UI before java.awt.Container.writeObject runs.
(package private) static class	JComponent.IntVector
(package private) static class	JComponent.KeyboardState
private class	JComponent.ReadObjectCallback This object is the ObjectInputStream callback that's called after a complete graph of objects (including at least one JComponent) has been read.

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

(package private) Rectangle	_bounds
protected javax.accessibility.AccessibleContext	accessibleContext The AccessibleContext associated with this JComponent.
private ActionMap	actionMap ActionMap.
private static int	ACTIONMAP_CREATED
private Float	alignmentX
private Float	alignmentY
private static int	ANCESTOR_INPUTMAP_CREATED
private static int	ANCESTOR_USING_BUFFER
private InputMap	ancestorInputMap Used for WHEN_ANCESTOR_OF_FOCUSED_COMPONENT bindings.
private AncestorNotifier	ancestorNotifier
private Autoscroller	autoscroller
private Border	border
private SwingPropertyChangeSupport	changeSupport
private static boolean	checkedSuppressDropSupport Indiciates if we've checked the system property for suppressing drop support.
private Hashtable	clientProperties
private static int	COMPLETELY_OBSCURED
private static int	CREATED_DOUBLE_BUFFER
private static String	defaultLocale Key used to store the default locale in an AppContext
private int	flags
private static int	FOCUS_INPUTMAP_CREATED
private InputMap	focusInputMap Used for WHEN_FOCUSED bindings.
private static String	htmlKey
private Object	htmlView
private InputVerifier	inputVerifier
private static int	IS_DOUBLE_BUFFERED Private flags
private static int	IS_OPAQUE
private static int	IS_PAINTING_TILE
private static int	IS_PRINTING
private static int	IS_PRINTING_ALL
private static int	IS_REPAINTING
private static int	KEY_EVENTS_ENABLED
private static String	KEYBOARD_BINDINGS_KEY The key used by JComponent to access keyboard bindings.
protected EventListenerList	listenerList A list of event listeners for this component.
private static Set	managingFocusBackwardTraversalKeys Keys to use for backward focus traversal when the JComponent is managing focus.
private static Set	managingFocusForwardTraversalKeys Keys to use for forward focus traversal when the JComponent is managing focus.
private Dimension	maximumSize
private Dimension	minimumSize
private static String	NEXT_FOCUS
private static int	NOT_OBSCURED
private Rectangle	paintImmediatelyClip
(package private) Component	paintingChild Set in _paintImmediately.
private static int	PARTIALLY_OBSCURED
private Dimension	preferredSize
private static Hashtable	readObjectCallbacks
private static int	REQUEST_FOCUS_DISABLED
private static int	RESERVED_1
private static int	RESERVED_2
private static int	RESERVED_3
private static int	RESERVED_4
private static int	RESERVED_5
private static int	RESERVED_6
private static boolean	suppressDropSupport Indicates if we should register a DropTarget for a non-null TransferHandler.
private Rectangle	tmpRect
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".
private TransferHandler	transfer
protected ComponentUI	ui The look and feel delegate for this component.
private static String	uiClassID
static int	UNDEFINED_CONDITION Constant used by some of the APIs to mean that no condition is defined.
private boolean	verifyInputWhenFocusTarget
private java.beans.VetoableChangeSupport	vetoableChangeSupport
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.
private static String	WHEN_IN_FOCUSED_WINDOW_BINDINGS An array of KeyStrokes used for WHEN_IN_FOCUSED_WINDOW are stashed in the client properties under this string.
private static int	WIF_INPUTMAP_CREATED
private ComponentInputMap	windowInputMap Used for WHEN_IN_FOCUSED_KEY bindings.
private static int	WRITE_OBJ_COUNTER_FIRST Bits 14-21 are used to handle nested writeObject calls.
private static int	WRITE_OBJ_COUNTER_LAST

Fields inherited from class java.awt.Container

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

(package private) void	_paintImmediately(int x, int y, int w, int h)
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	addPropertyChangeListener(java.beans.PropertyChangeListener listener) Adds a PropertyChangeListener to the listener list.
void	addPropertyChangeListener(String propertyName, java.beans.PropertyChangeListener listener) Adds a PropertyChangeListener for a specific property.
void	addVetoableChangeListener(java.beans.VetoableChangeListener listener) Adds a VetoableChangeListener to the listener list.
private void	adjustPaintFlags()
(package private) boolean	alwaysOnTop() Returns whether this component should be guaranteed to be on top.
(package private) boolean	checkIfChildObscuredBySibling() Returns true, which implies that before checking if a child should be painted it is first check that the child is not obscured by another sibling.
(package private) void	componentInputMapChanged(ComponentInputMap inputMap) Invoked from ComponentInputMap when its bindings change.
(package private) static void	computeVisibleRect(Component c, Rectangle visibleRect) Returns the Component's "visible rect rectangle" - the intersection of the visible rectangles for the component c and all of its ancestors.
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.
(package private) void	compWriteObjectNotify()
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.
private void	deregisterNextFocusableComponent()
void	disable() Deprecated. As of JDK version 1.1, replaced by java.awt.Component.setEnable(boolean).
void	enable() Deprecated. As of JDK version 1.1, replaced by java.awt.Component.setEnable(boolean).
(package private) void	enableSerialization() Called by the JComponent constructor.
void	firePropertyChange(String propertyName, boolean oldValue, boolean newValue) Reports a bound property change.
void	firePropertyChange(String propertyName, byte oldValue, byte newValue) Reports a bound property change.
void	firePropertyChange(String propertyName, char oldValue, char newValue) Reports a bound property change.
void	firePropertyChange(String propertyName, double oldValue, double newValue) Reports a bound property change.
void	firePropertyChange(String propertyName, float oldValue, float newValue) Reports a bound property change.
void	firePropertyChange(String propertyName, int oldValue, int newValue) Reports a bound property change.
void	firePropertyChange(String propertyName, long oldValue, long newValue) Reports a bound property change.
protected void	firePropertyChange(String propertyName, Object oldValue, Object newValue) Supports reporting bound property changes.
void	firePropertyChange(String propertyName, short oldValue, short newValue) Reports a bound property change.
protected void	fireVetoableChange(String propertyName, Object oldValue, Object newValue) Supports reporting constrained property changes.
javax.accessibility.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.
(package private) ActionMap	getActionMap(boolean create) Finds and returns the appropriate ActionMap.
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.
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.
private Dictionary	getClientProperties() Returns a HashTable containing all of the key/value "client properties" for this component.
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.
int	getConditionForKeyStroke(KeyStroke aKeyStroke) Returns the condition that determines whether a registered action occurs in response to the specified keystroke.
(package private) boolean	getCreatedDoubleBuffer() Returns true if the RepaintManager created the double buffer image from the component.
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.
private boolean	getFlag(int aFlag)
Graphics	getGraphics() Returns this component's graphics context, which lets you draw on a component.
int	getHeight() Returns the current height of this component.
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.
(package private) InputMap	getInputMap(int condition, boolean create) Returns the InputMap to use for condition 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.
EventListener[]	getListeners(Class 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.
(package private) static Set	getManagingFocusBackwardTraversalKeys() Returns the Set of KeyStrokes to use if the component is managing focus for backward focus traversal.
(package private) static Set	getManagingFocusForwardTraversalKeys() Returns the Set of KeyStrokes to use if the component is managing focus for forward focus traversal.
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.
private int	getObscuredState(int compIndex, int x, int y, int width, int height) Returns whether or not the region of the specified component is obscured by a sibling.
Dimension	getPreferredSize() If the preferredSize has been set to a non-null value just returns it.
java.beans.PropertyChangeListener[]	getPropertyChangeListeners() Returns an array of all the PropertyChangeListeners added to this Component with addPropertyChangeListener().
java.beans.PropertyChangeListener[]	getPropertyChangeListeners(String propertyName) Returns an array of all the listeners which have been associated with the named property.
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.
private static boolean	getSuppressDropTarget() Returns true if setTransferHandler should install a DropTarget.
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.
java.beans.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.
(package private) static byte	getWriteObjCounter(JComponent comp)
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	isMaximumSizeSet() Returns true if the maximum size has been set to a non-null value otherwise returns false.
boolean	isMinimumSizeSet() Returns true if the minimum size has been set to a non-null value otherwise returns false.
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.
(package private) boolean	isPaintingOrigin() Returns true if a paint triggered on a child component should cause painting to originate from this Component, or one of its ancestors.
boolean	isPaintingTile() Returns true if the component is currently painting a tile.
boolean	isPreferredSizeSet() Returns true if the preferred size has been set to a non-null value otherwise returns false.
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.
private boolean	paintDoubleBuffered(JComponent paintingComponent, Component bufferComponent, Graphics g, int clipX, int clipY, int clipW, int clipH)
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.
private void	paintWithOffscreenBuffer(JComponent paintingComponent, Graphics g, int clipX, int clipY, int clipW, int clipH, Image offscreen)
protected String	paramString() Returns a string representation of this JComponent.
void	print(Graphics g) Invoke this method to print the component.
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.
(package private) boolean	processKeyBindings(KeyEvent e, boolean pressed) This is invoked as the result of a KeyEvent that was not consumed by the FocusManager, KeyListeners, or the component.
(package private) static boolean	processKeyBindingsForAllComponents(KeyEvent e, Container container, boolean pressed)
protected void	processKeyEvent(KeyEvent e) Overrides processKeyEvent to process events.
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.
private void	readObject(ObjectInputStream s) We use the ObjectInputStream "registerValidation" callback to update the UI for the entire tree of components after they've all been read in.
(package private) boolean	rectangleIsObscured(int x, int y, int width, int height) If the specified rectangle is completely obscured by any of this component's opaque children then returns true.
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.
private void	registerNextFocusableComponent()
private void	registerNextFocusableComponent(Component nextFocusableComponent)
private void	registerWithKeyboardManager(boolean onlyIfNew) Registers any bound WHEN_IN_FOCUSED_WINDOW actions with the KeyboardManager.
private void	registerWithKeyboardManager(KeyStroke aKeyStroke)
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	removePropertyChangeListener(java.beans.PropertyChangeListener listener) Removes a PropertyChangeListener from the listener list.
void	removePropertyChangeListener(String propertyName, java.beans.PropertyChangeListener listener) Removes a PropertyChangeListener for a specific property.
void	removeVetoableChangeListener(java.beans.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 get the input focus, and that this Component's top-level ancestor become the focused Window.
boolean	requestFocus(boolean temporary) JComponent overrides requestFocus solely to make the method public so that UI implementations can cause temporary focus changes.
boolean	requestFocusInWindow() Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window.
protected boolean	requestFocusInWindow(boolean temporary) JComponent overrides requestFocusInWindow solely to make the method public so that UI implementations can cause temporary focus changes.
void	resetKeyboardActions() Unregisters all the bindings in the first tier InputMaps and ActionMap.
void	reshape(int x, int y, int w, int h) Moves and resizes this component.
void	revalidate() Supports deferred automatic layout.
private boolean	runInputVerifier()
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.
(package private) void	setCreatedDoubleBuffer(boolean newValue) This is invoked by the RepaintManager if createImage is called on the component.
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 the this component should use a buffer to paint.
void	setEnabled(boolean enabled) Sets whether or not this component is enabled.
private void	setFlag(int aFlag, boolean aValue)
void	setFont(Font font) Sets the font for this component.
void	setForeground(Color fg) Sets the foreground color of this component.
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.
(package private) void	setPaintingChild(Component paintingChild)
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.
(package private) static void	setWriteObjCounter(JComponent comp, byte count)
(package private) int	shouldDebugGraphics() Returns true if debug information is enabled for this JComponent or one of its parents.
(package private) void	superProcessMouseMotionEvent(MouseEvent e)
void	unregisterKeyboardAction(KeyStroke aKeyStroke) This method is now obsolete.
private void	unregisterWithKeyboardManager() Unregisters all the previously registered WHEN_IN_FOCUSED_WINDOW KeyStroke bindings.
private void	unregisterWithKeyboardManager(KeyStroke aKeyStroke)
void	update(Graphics g) Calls paint.
void	updateUI() Resets the UI property to a value from the current look and feel.
private void	writeObject(ObjectOutputStream s) Before writing a JComponent to an ObjectOutputStream we temporarily uninstall its UI.

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, 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, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMouseWheelListeners, getName, getParent, getPeer, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, 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, processMouseEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, 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

uiClassID

private static final String uiClassID

See Also:

getUIClassID(), writeObject(java.io.ObjectOutputStream), Constant Field Values

readObjectCallbacks

private static final Hashtable readObjectCallbacks

See Also:

JComponent.ReadObjectCallback, readObject(java.io.ObjectInputStream)

managingFocusForwardTraversalKeys

private static Set managingFocusForwardTraversalKeys

Keys to use for forward focus traversal when the JComponent is managing focus.

managingFocusBackwardTraversalKeys

private static Set managingFocusBackwardTraversalKeys

Keys to use for backward focus traversal when the JComponent is managing focus.

suppressDropSupport

private static boolean suppressDropSupport

Indicates if we should register a DropTarget for a non-null TransferHandler. Use getSuppressDropTarget to check.

checkedSuppressDropSupport

private static boolean checkedSuppressDropSupport

Indiciates if we've checked the system property for suppressing drop support.

NOT_OBSCURED

private static final int NOT_OBSCURED

See Also:

Constant Field Values

PARTIALLY_OBSCURED

private static final int PARTIALLY_OBSCURED

See Also:

Constant Field Values

COMPLETELY_OBSCURED

private static final int COMPLETELY_OBSCURED

See Also:

Constant Field Values

preferredSize

private Dimension preferredSize

minimumSize

private Dimension minimumSize

maximumSize

private Dimension maximumSize

alignmentX

private Float alignmentX

alignmentY

private Float alignmentY

ancestorNotifier

private AncestorNotifier ancestorNotifier

_bounds

Rectangle _bounds

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.

clientProperties

private Hashtable clientProperties

vetoableChangeSupport

private java.beans.VetoableChangeSupport vetoableChangeSupport

autoscroller

private Autoscroller autoscroller

border

private Border border

flags

private int flags

transfer

private TransferHandler transfer

inputVerifier

private InputVerifier inputVerifier

verifyInputWhenFocusTarget

private boolean verifyInputWhenFocusTarget

tmpRect

private transient Rectangle tmpRect

paintingChild

transient Component paintingChild

Set in _paintImmediately. Will indicate the child that initiated the painting operation. If paintingChild is opaque, no need to paint any child components after paintingChild. Test used in paintChildren.

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

KEYBOARD_BINDINGS_KEY

private static final String KEYBOARD_BINDINGS_KEY

The key used by JComponent to access keyboard bindings.

See Also:

Constant Field Values

WHEN_IN_FOCUSED_WINDOW_BINDINGS

private static final String WHEN_IN_FOCUSED_WINDOW_BINDINGS

An array of KeyStrokes used for WHEN_IN_FOCUSED_WINDOW are stashed in the client properties under this string.

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

NEXT_FOCUS

private static final String NEXT_FOCUS

See Also:

Constant Field Values

IS_DOUBLE_BUFFERED

private static final int IS_DOUBLE_BUFFERED

Private flags

See Also:

Constant Field Values

ANCESTOR_USING_BUFFER

private static final int ANCESTOR_USING_BUFFER

See Also:

Constant Field Values

IS_PAINTING_TILE

private static final int IS_PAINTING_TILE

See Also:

Constant Field Values

IS_OPAQUE

private static final int IS_OPAQUE

See Also:

Constant Field Values

KEY_EVENTS_ENABLED

private static final int KEY_EVENTS_ENABLED

See Also:

Constant Field Values

FOCUS_INPUTMAP_CREATED

private static final int FOCUS_INPUTMAP_CREATED

See Also:

Constant Field Values

ANCESTOR_INPUTMAP_CREATED

private static final int ANCESTOR_INPUTMAP_CREATED

See Also:

Constant Field Values

WIF_INPUTMAP_CREATED

private static final int WIF_INPUTMAP_CREATED

See Also:

Constant Field Values

ACTIONMAP_CREATED

private static final int ACTIONMAP_CREATED

See Also:

Constant Field Values

CREATED_DOUBLE_BUFFER

private static final int CREATED_DOUBLE_BUFFER

See Also:

Constant Field Values

IS_PRINTING

private static final int IS_PRINTING

See Also:

Constant Field Values

IS_PRINTING_ALL

private static final int IS_PRINTING_ALL

See Also:

Constant Field Values

IS_REPAINTING

private static final int IS_REPAINTING

See Also:

Constant Field Values

WRITE_OBJ_COUNTER_FIRST

private static final int WRITE_OBJ_COUNTER_FIRST

Bits 14-21 are used to handle nested writeObject calls.

See Also:

Constant Field Values

RESERVED_1

private static final int RESERVED_1

See Also:

Constant Field Values

RESERVED_2

private static final int RESERVED_2

See Also:

Constant Field Values

RESERVED_3

private static final int RESERVED_3

See Also:

Constant Field Values

RESERVED_4

private static final int RESERVED_4

See Also:

Constant Field Values

RESERVED_5

private static final int RESERVED_5

See Also:

Constant Field Values

RESERVED_6

private static final int RESERVED_6

See Also:

Constant Field Values

WRITE_OBJ_COUNTER_LAST

private static final int WRITE_OBJ_COUNTER_LAST

See Also:

Constant Field Values

REQUEST_FOCUS_DISABLED

private static final int REQUEST_FOCUS_DISABLED

See Also:

Constant Field Values

focusInputMap

private InputMap focusInputMap

Used for WHEN_FOCUSED bindings.

ancestorInputMap

private InputMap ancestorInputMap

Used for WHEN_ANCESTOR_OF_FOCUSED_COMPONENT bindings.

windowInputMap

private ComponentInputMap windowInputMap

Used for WHEN_IN_FOCUSED_KEY bindings.

actionMap

private ActionMap actionMap

ActionMap.

defaultLocale

private static final String defaultLocale

Key used to store the default locale in an AppContext

See Also:

Constant Field Values

accessibleContext

protected javax.accessibility.AccessibleContext accessibleContext

The AccessibleContext associated with this JComponent.

htmlKey

private static final String htmlKey

See Also:

Constant Field Values

htmlView

private Object htmlView

changeSupport

private SwingPropertyChangeSupport changeSupport

paintImmediatelyClip

private Rectangle paintImmediatelyClip

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

getManagingFocusForwardTraversalKeys

static Set getManagingFocusForwardTraversalKeys()

Returns the Set of KeyStrokes to use if the component is managing focus for forward focus traversal.

getManagingFocusBackwardTraversalKeys

static Set getManagingFocusBackwardTraversalKeys()

Returns the Set of KeyStrokes to use if the component is managing focus for backward focus traversal.

getSuppressDropTarget

private static boolean getSuppressDropTarget()

Returns true if setTransferHandler should install a DropTarget.

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 graphics object's foreground and font.

Parameters:

g - the original Graphics object

Returns:

a Graphics object configured for this component

paintComponent

protected void paintComponent(Graphics g)

Calls the UI delegate's paint method, if the UI delegate is non-null. We pass the delegate a copy of the Graphics object to protect the rest of the paint code from irrevocable changes (for example, Graphics.translate).

If you override this in a subclass you should not make permanent changes to the passed in Graphics. For example, you should not alter the clip Rectangle or modify the transform. If you need to do these operations you may find it easier to create a new Graphics from the passed in Graphics and manipulate it. Further, if you do not invoker super's implementation you must honor the opaque property, that is if this component is opaque, you must completely fill in the background in a non-opaque color. If you do not honor the opaque property you will likely see visual artifacts.

Parameters:

g - the Graphics object to protect

See Also:

paint(java.awt.Graphics), ComponentUI

paintChildren

protected void paintChildren(Graphics g)

Paints this component's children. If shouldUseBuffer is true, no component ancestor has a buffer and the component children can use a buffer if they have one. Otherwise, one ancestor has a buffer currently in use and children should not use a buffer to paint.

Parameters:

g - the Graphics context in which to paint

See Also:

paint(java.awt.Graphics), Container.paint(java.awt.Graphics)

paintBorder

protected void paintBorder(Graphics g)

Paints the component's border.

If you override this in a subclass you should not make permanent changes to the passed in Graphics. For example, you should not alter the clip Rectangle or modify the transform. If you need to do these operations you may find it easier to create a new Graphics from the passed in Graphics and manipulate it.

Parameters:

g - the Graphics context in which to paint

See Also:

paint(java.awt.Graphics), setBorder(javax.swing.border.Border)

update

public void update(Graphics g)

Calls paint. Doesn't clear the background but see ComponentUI.update, which is called by paintComponent.

Overrides:

update in class Container

Parameters:

g - the Graphics context in which to paint

See Also:

paint(java.awt.Graphics), paintComponent(java.awt.Graphics), ComponentUI

paint

public void paint(Graphics g)

Invoked by Swing to draw components. Applications should not invoke paint directly, but should instead use the repaint method to schedule the component for redrawing.

This method actually delegates the work of painting to three protected methods: paintComponent, paintBorder, and paintChildren. They're called in the order listed to ensure that children appear on top of component itself. Generally speaking, the component and its children should not paint in the insets area allocated to the border. Subclasses can just override this method, as always. A subclass that just wants to specialize the UI (look and feel) delegate's paint method should just override paintComponent.

Overrides:

paint in class Container

Parameters:

g - the Graphics context in which to paint

See Also:

paintComponent(java.awt.Graphics), paintBorder(java.awt.Graphics), paintChildren(java.awt.Graphics), getComponentGraphics(java.awt.Graphics), repaint(long, int, int, int, int)

adjustPaintFlags

private void adjustPaintFlags()

printAll

public void printAll(Graphics g)

Invoke this method to print the component. This method invokes print on the component.

Overrides:

printAll in class Component

Parameters:

g - the Graphics context in which to paint

See Also:

print(java.awt.Graphics), printComponent(java.awt.Graphics), printBorder(java.awt.Graphics), printChildren(java.awt.Graphics)

print

public void print(Graphics g)

Invoke this method to print the component. This method will result in invocations to printComponent, printBorder and printChildren. It is not recommended that you override this method, instead override one of the previously mentioned methods. This method sets the component's state such that the double buffer will not be used, eg painting will be done directly on the passed in Graphics.

Overrides:

print in class Container

Parameters:

g - the Graphics context in which to paint

See Also:

printComponent(java.awt.Graphics), printBorder(java.awt.Graphics), printChildren(java.awt.Graphics)

printComponent

protected void printComponent(Graphics g)

This is invoked during a printing operation. This is implemented to invoke paintComponent on the component. Override this if you wish to add special painting behavior when printing.

Parameters:

g - the Graphics context in which to paint

Since:

1.3

See Also:

print(java.awt.Graphics)

printChildren

protected void printChildren(Graphics g)

Prints this component's children. This is implemented to invoke paintChildren on the component. Override this if you wish to print the children differently than painting.

Parameters:

g - the Graphics context in which to paint

Since:

1.3

See Also:

print(java.awt.Graphics)

printBorder

protected void printBorder(Graphics g)

Prints the component's border. This is implemented to invoke paintBorder on the component. Override this if you wish to print the border differently that it is painted.

Parameters:

g - the Graphics context in which to paint

Since:

1.3

See Also:

print(java.awt.Graphics)

isPaintingTile

public boolean isPaintingTile()

Returns true if the component is currently painting a tile. If this method returns true, paint will be called again for another tile. This method returns false if you are not painting a tile or if the last tile is painted. Use this method to keep some state you might need between tiles.

Returns:

true if the component is currently painting a tile, false otherwise

isManagingFocus

public boolean isManagingFocus()

Deprecated. As of 1.4, replaced by Component.setFocusTraversalKeys(int, Set) and Container.setFocusCycleRoot(boolean).

Changes this JComponent's focus traversal keys to CTRL+TAB and CTRL+SHIFT+TAB. Also prevents SortingFocusTraversalPolicy from considering descendants of this JComponent when computing a focus traversal cycle.

See Also:

Component.setFocusTraversalKeys(int, java.util.Set), SortingFocusTraversalPolicy

registerNextFocusableComponent

private void registerNextFocusableComponent()

registerNextFocusableComponent

private void registerNextFocusableComponent(Component nextFocusableComponent)

deregisterNextFocusableComponent

private void deregisterNextFocusableComponent()

setNextFocusableComponent

public void setNextFocusableComponent(Component aComponent)

Deprecated. As of 1.4, replaced by FocusTraversalPolicy

Overrides the default FocusTraversalPolicy for this JComponent's focus traversal cycle by unconditionally setting the specified Component as the next Component in the cycle, and this JComponent as the specified Component's previous Component in the cycle.

Parameters:

aComponent - the Component that should follow this JComponent in the focus traversal cycle

See Also:

getNextFocusableComponent(), FocusTraversalPolicy

getNextFocusableComponent

public Component getNextFocusableComponent()

Deprecated. As of 1.4, replaced by FocusTraversalPolicy.

Returns the Component set by a prior call to setNextFocusableComponent(Component) on this JComponent.

Returns:

the Component that will follow this JComponent in the focus traversal cycle, or null if none has been explicitly specified

See Also:

setNextFocusableComponent(java.awt.Component)

setRequestFocusEnabled

public void setRequestFocusEnabled(boolean requestFocusEnabled)

Provides a hint as to whether or not this JComponent should get focus. This is only a hint, and it is up to consumers that are requesting focus to honor this property. This is typically honored for mouse operations, but not keyboard operations. For example, look and feels could verify this property is true before requesting focus during a mouse operation. This would often times be used if you did not want a mouse press on a JComponent to steal focus, but did want the JComponent to be traversable via the keyboard. If you do not want this JComponent focusable at all, use the setFocusable method instead.

Parameters:

requestFocusEnabled - Indicates if you want this JComponent to be focusable or not

See Also:

Focus Specification, Component.setFocusable(boolean)

isRequestFocusEnabled

public boolean isRequestFocusEnabled()

Returns true if this JComponent should get focus; otherwise returns false.

Returns:

true if this component should get focus, otherwise returns false

See Also:

setRequestFocusEnabled(boolean), Focus Specification, Component.isFocusable()

runInputVerifier

private boolean runInputVerifier()

requestFocus

public void requestFocus()

Description copied from class: Component

Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. This component must be displayable, visible, and focusable for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event. If this request is denied because this Component's top-level Window cannot become the focused Window, the request will be remembered and will be granted when the Window is later focused by the user.

This method cannot be used to set the focus owner to no Component at all. Use KeyboardFocusManager.clearGlobalFocusOwner() instead.

Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to use requestFocusInWindow when possible.

Overrides:

requestFocus in class Component

See Also:

Component.requestFocusInWindow(), FocusEvent, Component.addFocusListener(java.awt.event.FocusListener), Component.isFocusable(), Component.isDisplayable(), KeyboardFocusManager.clearGlobalFocusOwner()

requestFocus

public boolean requestFocus(boolean temporary)

JComponent overrides requestFocus solely to make the method public so that UI implementations can cause temporary focus changes. This method is not meant for general use, instead developers are urged to call the noarg requestFocus or requestFocusInWindow methods. If the JComponent has an InputVerifierassociated with it, the InputVerifier will be messaged.

Refer to Component.requestFocus(boolean) for a complete description of this method.

Overrides:

requestFocus in class Component

Parameters:

temporary - boolean indicating if the focus change is temporary

Returns:

false if the focus change request is guaranteed to fail; true if it is likely to succeed

Since:

1.4

See Also:

Component.requestFocus(), Component.requestFocusInWindow(), Component.requestFocus(boolean), Component.requestFocusInWindow(boolean)

requestFocusInWindow

public boolean requestFocusInWindow()

Description copied from class: Component

Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window. This component must be displayable, visible, and focusable for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.

This method returns a boolean value. If false is returned, the request is guaranteed to fail. If true is returned, the request will succeed unless it is vetoed, or an extraordinary event, such as disposal of the Component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value of true indicates that the request is likely to succeed, developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.

This method cannot be used to set the focus owner to no Component at all. Use KeyboardFocusManager.clearGlobalFocusOwner() instead.

The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method over requestFocus when possible. Code which relies on requestFocus may exhibit different focus behavior on different platforms.

Overrides:

requestFocusInWindow in class Component

Returns:

false if the focus change request is guaranteed to fail; true if it is likely to succeed

See Also:

Component.requestFocus(), FocusEvent, Component.addFocusListener(java.awt.event.FocusListener), Component.isFocusable(), Component.isDisplayable(), KeyboardFocusManager.clearGlobalFocusOwner()

requestFocusInWindow

protected boolean requestFocusInWindow(boolean temporary)

JComponent overrides requestFocusInWindow solely to make the method public so that UI implementations can cause temporary focus changes. This method is not meant for general use, instead developers are urged to call the noarg requestFocus or requestFocusInWindow methods. If the JComponent has an InputVerifierassociated with it, the InputVerifier will be messaged.

Refer to Component.requestFocusInWindow(boolean) for a complete description of this method.

Overrides:

requestFocusInWindow in class Component

Parameters:

temporary - boolean indicating if the focus change is temporary

Returns:

false if the focus change request is guaranteed to fail; true if it is likely to succeed

Since:

1.4

See Also:

Component.requestFocus(), Component.requestFocusInWindow(), Component.requestFocus(boolean), Component.requestFocusInWindow(boolean)

grabFocus

public void grabFocus()

Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. This component must be displayable, visible, and focusable for the request to be granted.

This method is intended for use by focus implementations. Client code should not use this method; instead, it should use requestFocus().

See Also:

requestFocus()

setVerifyInputWhenFocusTarget

public 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. The default is true. Set to false on components such as a Cancel button or a scrollbar, which should activate even if the input in the current focus owner is not "passed" by the input verifier for that component.

Parameters:

verifyInputWhenFocusTarget - value for the verifyInputWhenFocusTarget property

Since:

1.3

See Also:

InputVerifier, setInputVerifier(javax.swing.InputVerifier), getInputVerifier(), getVerifyInputWhenFocusTarget()

getVerifyInputWhenFocusTarget

public boolean getVerifyInputWhenFocusTarget()

Returns the value that indicates whether the input verifier for the current focus owner will be called before this component requests focus.

Returns:

value of the verifyInputWhenFocusTarget property

Since:

1.3

See Also:

InputVerifier, setInputVerifier(javax.swing.InputVerifier), getInputVerifier(), setVerifyInputWhenFocusTarget(boolean)

setPreferredSize

public void setPreferredSize(Dimension preferredSize)

Sets the preferred size of this component. If preferredSize is null, the UI will be asked for the preferred size.

getPreferredSize

public Dimension getPreferredSize()

If the preferredSize has been set to a non-null value just returns it. If the UI delegate's getPreferredSize method returns a non null value then return that; otherwise defer to the component's layout manager.

Overrides:

getPreferredSize in class Container

Returns:

the value of the preferredSize property

See Also:

setPreferredSize(java.awt.Dimension), ComponentUI

setMaximumSize

public void setMaximumSize(Dimension maximumSize)

Sets the maximum size of this component to a constant value. Subsequent calls to getMaximumSize will always return this value; the component's UI will not be asked to compute it. Setting the maximum size to null restores the default behavior.

Parameters:

maximumSize - a Dimension containing the desired maximum allowable size

See Also:

getMaximumSize()

getMaximumSize

public Dimension getMaximumSize()

If the maximum size has been set to a non-null value just returns it. If the UI delegate's getMaximumSize method returns a non-null value then return that; otherwise defer to the component's layout manager.

Overrides:

getMaximumSize in class Container

Returns:

the value of the maximumSize property

See Also:

setMaximumSize(java.awt.Dimension), ComponentUI

setMinimumSize

public void setMinimumSize(Dimension minimumSize)

Sets the minimum size of this component to a constant value. Subsequent calls to getMinimumSize will always return this value; the component's UI will not be asked to compute it. Setting the minimum size to null restores the default behavior.

Parameters:

minimumSize - the new minimum size of this component

See Also:

getMinimumSize()

getMinimumSize

public Dimension getMinimumSize()

If the minimum size has been set to a non-null value just returns it. If the UI delegate's getMinimumSize method returns a non-null value then return that; otherwise defer to the component's layout manager.

Overrides:

getMinimumSize in class Container

Returns:

the value of the minimumSize property

See Also:

setMinimumSize(java.awt.Dimension), ComponentUI

isMinimumSizeSet

public boolean isMinimumSizeSet()

Returns true if the minimum size has been set to a non-null value otherwise returns false.

Returns:

true if minimumSize is non-null, false otherwise

Since:

1.3

isPreferredSizeSet

public boolean isPreferredSizeSet()

Returns true if the preferred size has been set to a non-null value otherwise returns false.

Returns:

true if preferredSize is non-null, false otherwise

Since:

1.3

isMaximumSizeSet

public boolean isMaximumSizeSet()

Returns true if the maximum size has been set to a non-null value otherwise returns false.

Returns:

true if maximumSize is non-null, false otherwise

Since:

1.3

contains

public 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.

Overrides:

contains in class Component

Parameters:

x - the x coordinate of the point

y - the y coordinate of the point

Returns:

true if this component logically contains x,y

See Also:

Component.contains(int, int), ComponentUI

setBorder

public void setBorder(Border border)

Sets the border of this component. The Border object is responsible for defining the insets for the component (overriding any insets set directly on the component) and for optionally rendering any border decorations within the bounds of those insets. Borders should be used (rather than insets) for creating both decorative and non-decorative (such as margins and padding) regions for a swing component. Compound borders can be used to nest multiple borders within a single component.

This is a bound property.

Parameters:

border - the border to be rendered for this component

See Also:

Border, CompoundBorder

getBorder

public Border getBorder()

Returns the border of this component or null if no border is currently set.

Returns:

the border object for this component

See Also:

setBorder(javax.swing.border.Border)

getInsets

public Insets getInsets()

If a border has been set on this component, returns the border's insets; otherwise calls super.getInsets.

Overrides:

getInsets in class Container

Returns:

the value of the insets property

See Also:

setBorder(javax.swing.border.Border)

getInsets

public Insets getInsets(Insets insets)

Returns an Insets object containing this component's inset values. The passed-in Insets object will be reused if possible. Calling methods cannot assume that the same object will be returned, however. All existing values within this object are overwritten. If insets is null, this will allocate a new one.

Parameters:

insets - the Insets object, which can be reused

Returns:

the Insets object

See Also:

getInsets()

getAlignmentY

public float getAlignmentY()

Overrides Container.getAlignmentY to return the horizontal alignment.

Overrides:

getAlignmentY in class Container

Returns:

the value of the alignmentY property

See Also:

setAlignmentY(float), Component.getAlignmentY()

setAlignmentY

public void setAlignmentY(float alignmentY)

Sets the the horizontal alignment.

Parameters:

alignmentY - the new horizontal alignment

See Also:

getAlignmentY()

getAlignmentX

public float getAlignmentX()

Overrides Container.getAlignmentX to return the vertical alignment.

Overrides:

getAlignmentX in class Container

Returns:

the value of the alignmentX property

See Also:

setAlignmentX(float), Component.getAlignmentX()

setAlignmentX

public void setAlignmentX(float alignmentX)

Sets the the vertical alignment.

Parameters:

alignmentX - the new vertical alignment

See Also:

getAlignmentX()

setInputVerifier

public void setInputVerifier(InputVerifier inputVerifier)

Sets the input verifier for this component.

Parameters:

inputVerifier - the new input verifier

Since:

1.3

See Also:

InputVerifier

getInputVerifier

public InputVerifier getInputVerifier()

Returns the input verifier for this component.

Returns:

the inputVerifier property

Since:

1.3

See Also:

InputVerifier

getGraphics

public Graphics getGraphics()

Returns this component's graphics context, which lets you draw on a component. Use this method get a Graphics object and then invoke operations on that object to draw on the component.

Overrides:

getGraphics in class Component

Returns:

this components graphics context

See Also:

Component.paint(java.awt.Graphics)

setDebugGraphicsOptions

public void setDebugGraphicsOptions(int debugOptions)

Enables or disables diagnostic information about every graphics operation performed within the component or one of its children.

Parameters:

debugOptions - determines how the component should display the information; one of the following options:

• DebugGraphics.LOG_OPTION - causes a text message to be printed.
• DebugGraphics.FLASH_OPTION - causes the drawing to flash several times.
• DebugGraphics.BUFFERED_OPTION - creates an ExternalWindow that displays the operations performed on the View's offscreen buffer.
• DebugGraphics.NONE_OPTION disables debugging.
• A value of 0 causes no changes to the debugging options.

debugOptions is bitwise OR'd into the current value

getDebugGraphicsOptions

public int getDebugGraphicsOptions()

Returns the state of graphics debugging.

Returns:

a bitwise OR'd flag of zero or more of the following options:

• DebugGraphics.LOG_OPTION - causes a text message to be printed.
• DebugGraphics.FLASH_OPTION - causes the drawing to flash several times.
• DebugGraphics.BUFFERED_OPTION - creates an ExternalWindow that displays the operations performed on the View's offscreen buffer.
• DebugGraphics.NONE_OPTION disables debugging.
• A value of 0 causes no changes to the debugging options.

See Also:

setDebugGraphicsOptions(int)

shouldDebugGraphics

int shouldDebugGraphics()

Returns true if debug information is enabled for this JComponent or one of its parents.

registerKeyboardAction

public 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. For example, to bind the KeyStroke aKeyStroke to the Action anAction now use:

   component.getInputMap().put(aKeyStroke, aCommand);
   component.getActionMap().put(aCommmand, anAction);
 

The above assumes you want the binding to be applicable for WHEN_FOCUSED. To register bindings for other focus states use the getInputMap method that takes an integer.

Register a new keyboard action. anAction will be invoked if a key event matching aKeyStroke occurs and aCondition is verified. The KeyStroke object defines a particular combination of a keyboard key and one or more modifiers (alt, shift, ctrl, meta).

The aCommand will be set in the delivered event if specified.

The aCondition can be one of:

WHEN_FOCUSED

The action will be invoked only when the keystroke occurs while the component has the focus.

WHEN_IN_FOCUSED_WINDOW

The action will be invoked when the keystroke occurs while the component has the focus or if the component is in the window that has the focus. Note that the component need not be an immediate descendent of the window -- it can be anywhere in the window's containment hierarchy. In other words, whenever any component in the window has the focus, the action registered with this component is invoked.

WHEN_ANCESTOR_OF_FOCUSED_COMPONENT

The action will be invoked when the keystroke occurs while the component has the focus or if the component is an ancestor of the component that has the focus.

The combination of keystrokes and conditions lets you define high level (semantic) action events for a specified keystroke+modifier combination (using the KeyStroke class) and direct to a parent or child of a component that has the focus, or to the component itself. In other words, in any hierarchical structure of components, an arbitrary key-combination can be immediately directed to the appropriate component in the hierarchy, and cause a specific method to be invoked (usually by way of adapter objects).

If an action has already been registered for the receiving container, with the same charCode and the same modifiers, anAction will replace the action.

Parameters:

anAction - the Action to be registered

aCommand - the command to be set in the delivered event

aKeyStroke - the KeyStroke to bind to the action

aCondition - the condition that needs to be met, see above

See Also:

KeyStroke

registerWithKeyboardManager

private void registerWithKeyboardManager(boolean onlyIfNew)

Registers any bound WHEN_IN_FOCUSED_WINDOW actions with the KeyboardManager. If onlyIfNew is true only actions that haven't been registered are pushed to the KeyboardManager; otherwise all actions are pushed to the KeyboardManager.

Parameters:

onlyIfNew - if true, only actions that haven't been registered are pushed to the KeyboardManager

unregisterWithKeyboardManager

private void unregisterWithKeyboardManager()

Unregisters all the previously registered WHEN_IN_FOCUSED_WINDOW KeyStroke bindings.

componentInputMapChanged

void componentInputMapChanged(ComponentInputMap inputMap)

Invoked from ComponentInputMap when its bindings change. If inputMap is the current windowInputMap (or a parent of the window InputMap) the KeyboardManager is notified of the new bindings.

Parameters:

inputMap - the map containing the new bindings

registerWithKeyboardManager

private void registerWithKeyboardManager(KeyStroke aKeyStroke)

unregisterWithKeyboardManager

private void unregisterWithKeyboardManager(KeyStroke aKeyStroke)

registerKeyboardAction

public void registerKeyboardAction(ActionListener anAction,
                                   KeyStroke aKeyStroke,
                                   int aCondition)

This method is now obsolete, please use a combination of getActionMap() and getInputMap() for similiar behavior.

unregisterKeyboardAction

public void unregisterKeyboardAction(KeyStroke aKeyStroke)

This method is now obsolete. To unregister an existing binding you can either remove the binding from the ActionMap/InputMap, or place a dummy binding the InputMap. Removing the binding from the InputMap allows bindings in parent InputMaps to be active, whereas putting a dummy binding in the InputMap effectively disables the binding from ever happening.

Unregisters a keyboard action. This will remove the binding from the ActionMap (if it exists) as well as the InputMaps.

getRegisteredKeyStrokes

public KeyStroke[] getRegisteredKeyStrokes()

Returns the KeyStrokes that will initiate registered actions.

Returns:

an array of KeyStroke objects

See Also:

registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)

getConditionForKeyStroke

public int getConditionForKeyStroke(KeyStroke aKeyStroke)

Returns the condition that determines whether a registered action occurs in response to the specified keystroke.

For Java 2 platform v1.3, a KeyStroke can be associated with more than one condition. For example, 'a' could be bound for the two conditions WHEN_FOCUSED and WHEN_IN_FOCUSED_WINDOW condition.

Returns:

the action-keystroke condition

getActionForKeyStroke

public ActionListener getActionForKeyStroke(KeyStroke aKeyStroke)

Returns the object that will perform the action registered for a given keystroke.

Returns:

the ActionListener object invoked when the keystroke occurs

resetKeyboardActions

public void resetKeyboardActions()

Unregisters all the bindings in the first tier InputMaps and ActionMap. This has the effect of removing any local bindings, and allowing the bindings defined in parent InputMap/ActionMaps (the UI is usually defined in the second tier) to persist.

setInputMap

public final void setInputMap(int condition,
                              InputMap map)

Sets the InputMap to use under the condition condition to map. A null value implies you do not want any bindings to be used, even from the UI. This will not reinstall the UI InputMap (if there was one). condition has one of the following values:

• WHEN_IN_FOCUSED_WINDOW
• WHEN_FOCUSED
• WHEN_ANCESTOR_OF_FOCUSED_COMPONENT

If condition is WHEN_IN_FOCUSED_WINDOW and map is not a ComponentInputMap, an IllegalArgumentException will be thrown. Similarly, if condition is not one of the values listed, an IllegalArgumentException will be thrown.

Parameters:

condition - one of the values listed above

map - the InputMap to use for the given condition

Throws:

IllegalArgumentException - if condition is WHEN_IN_FOCUSED_WINDOW and map is not an instance of ComponentInputMap; or if condition is not one of the legal values specified above

Since:

1.3

getInputMap

public final InputMap getInputMap(int condition)

Returns the InputMap that is used during condition.

Parameters:

condition - one of WHEN_IN_FOCUSED_WINDOW, WHEN_FOCUSED, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT

Returns:

the InputMap for the specified condition

Since:

1.3

getInputMap

public final InputMap getInputMap()

Returns the InputMap that is used when the component has focus. This is convenience method for getInputMap(WHEN_FOCUSED).

Returns:

the InputMap used when the component has focus

Since:

JDK1.3

setActionMap

public final void setActionMap(ActionMap am)

Sets the ActionMap to am. This does not set the parent of the am to be the ActionMap from the UI (if there was one), it is up to the caller to have done this.

Parameters:

am - the new ActionMap

Since:

1.3

getActionMap

public final ActionMap getActionMap()

Returns the ActionMap used to determine what Action to fire for particular KeyStroke binding. The returned ActionMap, unless otherwise set, will have the ActionMap from the UI set as the parent.

Returns:

the ActionMap containing the key/action bindings

Since:

1.3

getInputMap

final InputMap getInputMap(int condition,
                           boolean create)

Returns the InputMap to use for condition condition. If the InputMap hasn't been created, and create is true, it will be created.

Parameters:

condition - one of the following values:

• JComponent.FOCUS_INPUTMAP_CREATED
• JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
• JComponent.WHEN_IN_FOCUSED_WINDOW

create - if true, create the InputMap if it is not already created

Returns:

the InputMap for the given condition; if create is false and the InputMap hasn't been created, returns null

Throws:

IllegalArgumentException - if condition is not one of the legal values listed above

getActionMap

final ActionMap getActionMap(boolean create)

Finds and returns the appropriate ActionMap.

Parameters:

create - if true, create the ActionMap if it is not already created

Returns:

the ActionMap for this component; if the create flag is false and there is no current ActionMap, returns null

requestDefaultFocus

public boolean requestDefaultFocus()

Deprecated. As of 1.4, replaced by FocusTraversalPolicy.getDefaultComponent(Container).requestFocus()

Requests focus on this JComponent's FocusTraversalPolicy's default Component. If this JComponent is a focus cycle root, then its FocusTraversalPolicy is used. Otherwise, the FocusTraversalPolicy of this JComponent's focus-cycle-root ancestor is used.

See Also:

FocusTraversalPolicy.getDefaultComponent(java.awt.Container)

setVisible

public void setVisible(boolean aFlag)

Makes the component visible or invisible. Overrides Component.setVisible.

Overrides:

setVisible in class Component

Parameters:

aFlag - true to make the component visible; false to make it invisible

See Also:

Component.isVisible()

setEnabled

public void setEnabled(boolean enabled)

Sets whether or not this component is enabled. A component that is enabled may respond to user input, while a component that is not enabled cannot respond to user input. Some components may alter their visual representation when they are disabled in order to provide feedback to the user that they cannot take input.

Note: Disabling a component does not disable it's children.

Note: Disabling a lightweight component does not prevent it from receiving MouseEvents.

Overrides:

setEnabled in class Component

Parameters:

enabled - true if this component should be enabled, false otherwise

See Also:

Component.isEnabled(), Component.isLightweight()

setForeground

public void setForeground(Color fg)

Sets the foreground color of this component.

Overrides:

setForeground in class Component

Parameters:

fg - the desired foreground Color

See Also:

Component.getForeground()

setBackground

public void setBackground(Color bg)

Sets the background color of this component.

Overrides:

setBackground in class Component

Parameters:

bg - the desired background Color

See Also:

Component.getBackground()

setFont

public void setFont(Font font)

Sets the font for this component.

Overrides:

setFont in class Container

Parameters:

font - the desired Font for this component

See Also:

Component.getFont()

getDefaultLocale

public static Locale getDefaultLocale()

Returns the default locale used to initialize each JComponent's locale property upon creation. The default locale has "AppContext" scope so that applets (and potentially multiple lightweight applications running in a single VM) can have their own setting. An applet can safely alter its default locale because it will have no affect on other applets (or the browser).

Returns:

the default Locale.

Since:

1.4

See Also:

setDefaultLocale(java.util.Locale), Component.getLocale(), Component.setLocale(java.util.Locale)

setDefaultLocale

public static void setDefaultLocale(Locale l)

Sets the default locale used to initialize each JComponent's locale property upon creation. The initial value is the VM's default locale. The default locale has "AppContext" scope so that applets (and potentially multiple lightweight applications running in a single VM) can have their own setting. An applet can safely alter its default locale because it will have no affect on other applets (or the browser).

Parameters:

l - the desired default Locale for new components.

Since:

1.4

See Also:

getDefaultLocale(), Component.getLocale(), Component.setLocale(java.util.Locale)

processComponentKeyEvent

protected void processComponentKeyEvent(KeyEvent e)

Processes any key events that the component itself recognizes. This is called after the focus manager and any interested listeners have been given a chance to steal away the event. This method is called only if the event has not yet been consumed. This method is called prior to the keyboard UI logic.

This method is implemented to do nothing. Subclasses would normally override this method if they process some key events themselves. If the event is processed, it should be consumed.

processKeyEvent

protected void processKeyEvent(KeyEvent e)

Overrides processKeyEvent to process events.

Overrides:

processKeyEvent in class Component

Parameters:

e - the key event

See Also:

KeyEvent, KeyListener, Component.addKeyListener(java.awt.event.KeyListener), Component.enableEvents(long), Component.isShowing()

processKeyBinding

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. This obtains the appropriate InputMap, gets the binding, gets the action from the ActionMap, and then (if the action is found and the component is enabled) invokes notifyAction to notify the action.

Parameters:

ks - the KeyStroke queried

e - the KeyEvent

condition - one of the following values:

• JComponent.WHEN_FOCUSED
• JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
• JComponent.WHEN_IN_FOCUSED_WINDOW

pressed - true if the key is pressed

Returns:

true if there was a binding to an action, and the action was enabled

Since:

1.3

processKeyBindings

boolean processKeyBindings(KeyEvent e,
                           boolean pressed)

This is invoked as the result of a KeyEvent that was not consumed by the FocusManager, KeyListeners, or the component. It will first try WHEN_FOCUSED bindings, then WHEN_ANCESTOR_OF_FOCUSED_COMPONENT bindings, and finally WHEN_IN_FOCUSED_WINDOW bindings.

Parameters:

e - the unconsumed KeyEvent

pressed - true if the key is pressed

Returns:

true if there is a key binding for e

processKeyBindingsForAllComponents

static boolean processKeyBindingsForAllComponents(KeyEvent e,
                                                  Container container,
                                                  boolean pressed)

setToolTipText

public void setToolTipText(String text)

Registers the text to display in a tool tip. The text displays when the cursor lingers over the component.

See How to Use Tool Tips in The Java Tutorial for further documentation.

Parameters:

text - the string to display; if the text is null, the tool tip is turned off for this component

See Also:

TOOL_TIP_TEXT_KEY

getToolTipText

public String getToolTipText()

Returns the tooltip string that has been set with setToolTipText.

Returns:

the text of the tool tip

See Also:

TOOL_TIP_TEXT_KEY

getToolTipText

public String getToolTipText(MouseEvent event)

Returns the string to be used as the tooltip for event. By default this returns any string set using setToolTipText. If a component provides more extensive API to support differing tooltips at different locations, this method should be overridden.

getToolTipLocation

public Point getToolTipLocation(MouseEvent event)

Returns the tooltip location in this component's coordinate system. If null is returned, Swing will choose a location. The default implementation returns null.

Parameters:

event - the MouseEvent that caused the ToolTipManager to show the tooltip

Returns:

always returns null

createToolTip

public JToolTip createToolTip()

Returns the instance of JToolTip that should be used to display the tooltip. Components typically would not override this method, but it can be used to cause different tooltips to be displayed differently.

Returns:

the JToolTip used to display this toolTip

scrollRectToVisible

public void scrollRectToVisible(Rectangle aRect)

Forwards the scrollRectToVisible() message to the JComponent's parent. Components that can service the request, such as JViewport, override this method and perform the scrolling.

Parameters:

aRect - the visible Rectangle

See Also:

JViewport

setAutoscrolls

public void setAutoscrolls(boolean autoscrolls)

Sets the autoscrolls property. If true mouse dragged events will be synthetically generated when the mouse is dragged outside of the component's bounds and mouse motion has paused (while the button continues to be held down). The synthetic events make it appear that the drag gesture has resumed in the direction established when the component's boundary was crossed. Components that support autoscrolling must handle mouseDragged events by calling scrollRectToVisible with a rectangle that contains the mouse event's location. All of the Swing components that support item selection and are typically displayed in a JScrollPane (JTable, JList, JTree, JTextArea, and JEditorPane) already handle mouse dragged events in this way. To enable autoscrolling in any other component, add a mouse motion listener that calls scrollRectToVisible. For example, given a JPanel, myPanel:

 MouseMotionListener doScrollRectToVisible = new MouseMotionAdapter() {
     public void mouseDragged(MouseEvent e) {
        Rectangle r = new Rectangle(e.getX(), e.getY(), 1, 1);
        ((JPanel)e.getSource()).scrollRectToVisible(r);
    }
 };
 myPanel.addMouseMotionListener(doScrollRectToVisible);
 

The default value of the autoScrolls property is false.

Parameters:

autoscrolls - if true, synthetic mouse dragged events are generated when the mouse is dragged outside of a component's bounds and the mouse button continues to be held down; otherwise false

See Also:

getAutoscrolls(), JViewport, JScrollPane

getAutoscrolls

public boolean getAutoscrolls()

Gets the autoscrolls property.

Returns:

the value of the autoscrolls property

See Also:

JViewport, setAutoscrolls(boolean)

setTransferHandler

public void setTransferHandler(TransferHandler newHandler)

Sets the transferHandler property, which is null if the component does not support data transfer operations.

If newHandler is not null, and the system property suppressSwingDropSupport is not true, this will install a DropTarget on the JComponent. The default for the system property is false, so that a DropTarget will be added.

Parameters:

newHandler - mechanism for transfer of data to and from the component

Since:

1.4

See Also:

TransferHandler, getTransferHandler()

getTransferHandler

public TransferHandler getTransferHandler()

Gets the transferHandler property.

Returns:

the value of the transferHandler property

Since:

1.4

See Also:

TransferHandler, setTransferHandler(javax.swing.TransferHandler)

processMouseMotionEvent

protected void processMouseMotionEvent(MouseEvent e)

Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.

Overrides:

processMouseMotionEvent in class Component

Parameters:

e - the MouseEvent

See Also:

MouseEvent

superProcessMouseMotionEvent

void superProcessMouseMotionEvent(MouseEvent e)

setCreatedDoubleBuffer

void setCreatedDoubleBuffer(boolean newValue)

This is invoked by the RepaintManager if createImage is called on the component.

Parameters:

newValue - true if the double buffer image was created from this component

getCreatedDoubleBuffer

boolean getCreatedDoubleBuffer()

Returns true if the RepaintManager created the double buffer image from the component.

Returns:

true if this component had a double buffer image, false otherwise

enable

public void enable()

Deprecated. As of JDK version 1.1, replaced by java.awt.Component.setEnable(boolean).

Overrides:

enable in class Component

disable

public void disable()

Deprecated. As of JDK version 1.1, replaced by java.awt.Component.setEnable(boolean).

Overrides:

disable in class Component

getAccessibleContext

public javax.accessibility.AccessibleContext getAccessibleContext()

Returns the AccessibleContext associated with this JComponent. The method implemented by this base class returns null. Classes that extend JComponent should implement this method to return the AccessibleContext associated with the subclass.

Overrides:

getAccessibleContext in class Component

Returns:

the AccessibleContext of this JComponent

getClientProperties

private Dictionary getClientProperties()

Returns a HashTable containing all of the key/value "client properties" for this component. If the clientProperties hash table doesn't previously exist, an empty one (of size 2) will be created.

Returns:

a small Hashtable

See Also:

putClientProperty(java.lang.Object, java.lang.Object), getClientProperty(java.lang.Object)

getClientProperty

public final Object getClientProperty(Object key)

Returns the value of the property with the specified key. Only properties added with putClientProperty will return a non-null value.

Parameters:

key - the being queried

Returns:

the value of this property or null

See Also:

putClientProperty(java.lang.Object, java.lang.Object)

putClientProperty

public final void putClientProperty(Object key,
                                    Object value)

Adds an arbitrary key/value "client property" to this component.

The get/putClientProperty methods provide access to a small per-instance hashtable. Callers can use get/putClientProperty to annotate components that were created by another module. For example, a layout manager might store per child constraints this way. For example:

 componentA.putClientProperty("to the left of", componentB);
 

If value is null this method will remove the property. Changes to client properties are reported with PropertyChange events. The name of the property (for the sake of PropertyChange events) is key.toString().

The clientProperty dictionary is not intended to support large scale extensions to JComponent nor should be it considered an alternative to subclassing when designing a new component.

Parameters:

key - the new client property key

value - the new client property value; if null this method will remove the property

See Also:

getClientProperty(java.lang.Object), addPropertyChangeListener(java.beans.PropertyChangeListener)

isLightweightComponent

public static boolean isLightweightComponent(Component c)

Returns true if this component is lightweight, that is, if it doesn't have a native window system peer.

Returns:

true if this component is lightweight

reshape

public void reshape(int x,
                    int y,
                    int w,
                    int h)

Moves and resizes this component.

Overrides:

reshape in class Component

Parameters:

x - the new horizontal location

y - the new vertical location

w - the new width

h - the new height

See Also:

Component.setBounds(int, int, int, int)

getBounds

public Rectangle getBounds(Rectangle rv)

Stores the bounds of this component into "return value" rv and returns rv. If rv is null a new Rectangle is allocated. This version of getBounds is useful if the caller wants to avoid allocating a new Rectangle object on the heap.

Overrides:

getBounds in class Component

Parameters:

rv - the return value, modified to the component's bounds

Returns:

rv; if rv is null return a newly created Rectangle with this component's bounds

getSize

public Dimension getSize(Dimension rv)

Stores the width/height of this component into "return value" rv and returns rv. If rv is null a new Dimension object is allocated. This version of getSize is useful if the caller wants to avoid allocating a new Dimension object on the heap.

Overrides:

getSize in class Component

Parameters:

rv - the return value, modified to the component's size

Returns:

rv

getLocation

public Point getLocation(Point rv)

Stores the x,y origin of this component into "return value" rv and returns rv. If rv is null a new Point is allocated. This version of getLocation is useful if the caller wants to avoid allocating a new Point object on the heap.

Overrides:

getLocation in class Component

Parameters:

rv - the return value, modified to the component's location

Returns:

rv

getX

public int getX()

Returns the current x coordinate of the component's origin. This method is preferable to writing component.getBounds().x, or component.getLocation().x because it doesn't cause any heap allocations.

Overrides:

getX in class Component

Returns:

the current x coordinate of the component's origin

getY

public int getY()

Returns the current y coordinate of the component's origin. This method is preferable to writing component.getBounds().y, or component.getLocation().y because it doesn't cause any heap allocations.

Overrides:

getY in class Component

Returns:

the current y coordinate of the component's origin

getWidth

public int getWidth()

Returns the current width of this component. This method is preferable to writing component.getBounds().width, or component.getSize().width because it doesn't cause any heap allocations.

Overrides:

getWidth in class Component

Returns:

the current width of this component

getHeight

public int getHeight()

Returns the current height of this component. This method is preferable to writing component.getBounds().height, or component.getSize().height because it doesn't cause any heap allocations.

Overrides:

getHeight in class Component

Returns:

the current height of this component

isOpaque

public boolean isOpaque()

Returns true if this component is completely opaque.

An opaque component paints every pixel within its rectangular bounds. A non-opaque component paints only a subset of its pixels or none at all, allowing the pixels underneath it to "show through". Therefore, a component that does not fully paint its pixels provides a degree of transparency.

Subclasses that guarantee to always completely paint their contents should override this method and return true.

Overrides:

isOpaque in class Component

Returns:

true if this component is completely opaque

See Also:

setOpaque(boolean)

setOpaque

public void setOpaque(boolean isOpaque)

If true the component paints every pixel within its bounds. Otherwise, the component may not paint some or all of its pixels, allowing the underlying pixels to show through.

The default value of this property is false for JComponent. However, the default value for this property on most standard JComponent subclasses (such as JButton and JTree) is look-and-feel dependent.

Parameters:

isOpaque - true if this component should be opaque

See Also:

isOpaque()

rectangleIsObscured

boolean rectangleIsObscured(int x,
                            int y,
                            int width,
                            int height)

If the specified rectangle is completely obscured by any of this component's opaque children then returns true. Only direct children are considered, more distant descendants are ignored. A JComponent is opaque if JComponent.isOpaque() returns true, other lightweight components are always considered transparent, and heavyweight components are always considered opaque.

Parameters:

x - x value of specified rectangle

y - y value of specified rectangle

width - width of specified rectangle

height - height of specified rectangle

Returns:

true if the specified rectangle is obscured by an opaque child

computeVisibleRect

static final void computeVisibleRect(Component c,
                                     Rectangle visibleRect)

Returns the Component's "visible rect rectangle" - the intersection of the visible rectangles for the component c and all of its ancestors. The return value is stored in visibleRect.

Parameters:

c - the component

visibleRect - a Rectangle computed as the intersection of all visible rectangles for the component c and all of its ancestors -- this is the return value for this method

See Also:

getVisibleRect()

computeVisibleRect

public 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. The return value is stored in visibleRect.

Parameters:

visibleRect - a Rectangle computed as the intersection of all visible rectangles for this component and all of its ancestors -- this is the return value for this method

See Also:

getVisibleRect()

getVisibleRect

public 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.

Returns:

the visible rectangle

firePropertyChange

protected void firePropertyChange(String propertyName,
                                  Object oldValue,
                                  Object newValue)

Supports reporting bound property changes. If oldValue and newValue are not equal and the PropertyChangeEvent listener list isn't empty, then fire a PropertyChange event to each listener. This method has an overloaded method for each primitive type. For example, here's how to write a bound property set method whose value is an integer:

 public void setFoo(int newValue) {
     int oldValue = foo;
     foo = newValue;
     firePropertyChange("foo", oldValue, newValue);
 }
 

Overrides:

firePropertyChange in class Component

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as an Object)

newValue - the new value of the property (as an Object)

See Also:

PropertyChangeSupport

firePropertyChange

public void firePropertyChange(String propertyName,
                               byte oldValue,
                               byte newValue)

Reports a bound property change.

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as a byte)

newValue - the new value of the property (as a byte)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

firePropertyChange

public void firePropertyChange(String propertyName,
                               char oldValue,
                               char newValue)

Reports a bound property change.

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as a char)

newValue - the new value of the property (as a char)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

firePropertyChange

public void firePropertyChange(String propertyName,
                               short oldValue,
                               short newValue)

Reports a bound property change.

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as a short)

newValue - the old value of the property (as a short)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

firePropertyChange

public void firePropertyChange(String propertyName,
                               int oldValue,
                               int newValue)

Reports a bound property change.

Overrides:

firePropertyChange in class Component

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as an int)

newValue - the new value of the property (as an int)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

firePropertyChange

public void firePropertyChange(String propertyName,
                               long oldValue,
                               long newValue)

Reports a bound property change.

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as a long)

newValue - the new value of the property (as a long)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

firePropertyChange

public void firePropertyChange(String propertyName,
                               float oldValue,
                               float newValue)

Reports a bound property change.

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as a float)

newValue - the new value of the property (as a float)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

firePropertyChange

public void firePropertyChange(String propertyName,
                               double oldValue,
                               double newValue)

Reports a bound property change.

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as a double)

newValue - the new value of the property (as a double)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

firePropertyChange

public void firePropertyChange(String propertyName,
                               boolean oldValue,
                               boolean newValue)

Reports a bound property change.

Overrides:

firePropertyChange in class Component

Parameters:

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property (as a boolean)

newValue - the new value of the property (as a boolean)

See Also:

firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)

addPropertyChangeListener

public void addPropertyChangeListener(java.beans.PropertyChangeListener listener)

Adds a PropertyChangeListener to the listener list. The listener is registered for all properties.

A PropertyChangeEvent will get fired in response to setting a bound property, such as setFont, setBackground, or setForeground.

Note that if the current component is inheriting its foreground, background, or font from its container, then no event will be fired in response to a change in the inherited property.

Overrides:

addPropertyChangeListener in class Container

Parameters:

listener - the PropertyChangeListener to be added

See Also:

Component.removePropertyChangeListener(java.beans.PropertyChangeListener), Container.addPropertyChangeListener(java.lang.String,java.beans.PropertyChangeListener)

addPropertyChangeListener

public void addPropertyChangeListener(String propertyName,
                                      java.beans.PropertyChangeListener listener)

Adds a PropertyChangeListener for a specific property. The listener will be invoked only when a call on firePropertyChange names that specific property.

If listener is null, no exception is thrown and no action is performed.

Overrides:

addPropertyChangeListener in class Container

Parameters:

propertyName - the name of the property to listen on

listener - the PropertyChangeListener to be added

See Also:

Container.addPropertyChangeListener(java.beans.PropertyChangeListener), Component.removePropertyChangeListener(java.beans.PropertyChangeListener)

removePropertyChangeListener

public void removePropertyChangeListener(java.beans.PropertyChangeListener listener)

Removes a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties.

Overrides:

removePropertyChangeListener in class Component

Parameters:

listener - the PropertyChangeListener to be removed

See Also:

Component.addPropertyChangeListener(java.beans.PropertyChangeListener), Component.getPropertyChangeListeners(), Component.removePropertyChangeListener(java.lang.String,java.beans.PropertyChangeListener)

removePropertyChangeListener

public void removePropertyChangeListener(String propertyName,
                                         java.beans.PropertyChangeListener listener)

Removes a PropertyChangeListener for a specific property. If listener is null, no exception is thrown and no action is performed.

Overrides:

removePropertyChangeListener in class Component

Parameters:

propertyName - the name of the property that was listened on

listener - the PropertyChangeListener to be removed

See Also:

Component.addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener), Component.getPropertyChangeListeners(java.lang.String), Component.removePropertyChangeListener(java.beans.PropertyChangeListener)

getPropertyChangeListeners

public java.beans.PropertyChangeListener[] getPropertyChangeListeners()

Returns an array of all the PropertyChangeListeners added to this Component with addPropertyChangeListener().

Overrides:

getPropertyChangeListeners in class Component

Returns:

all of the PropertyChangeListeners added or an empty array if no listeners have been added

Since:

1.4

See Also:

addPropertyChangeListener(java.beans.PropertyChangeListener), removePropertyChangeListener(java.beans.PropertyChangeListener), getPropertyChangeListeners(java.lang.String), PropertyChangeSupport.getPropertyChangeListeners()

getPropertyChangeListeners

public java.beans.PropertyChangeListener[] getPropertyChangeListeners(String propertyName)

Returns an array of all the listeners which have been associated with the named property.

Overrides:

getPropertyChangeListeners in class Component

Returns:

all of the PropertyChangeListeners associated with the named property or an empty array if no listeners have been added

Since:

1.4

See Also:

getPropertyChangeListeners()

fireVetoableChange

protected void fireVetoableChange(String propertyName,
                                  Object oldValue,
                                  Object newValue)
                           throws java.beans.PropertyVetoException

Supports reporting constrained property changes. This method can be called when a constrained property has changed and it will send the appropriate PropertyChangeEvent to any registered VetoableChangeListeners.

Parameters:

propertyName - the name of the property that was listened on

oldValue - the old value of the property

newValue - the new value of the property

Throws:

java.beans.PropertyVetoException - when the attempt to set the property is vetoed by the component

addVetoableChangeListener

public void addVetoableChangeListener(java.beans.VetoableChangeListener listener)

Adds a VetoableChangeListener to the listener list. The listener is registered for all properties.

Parameters:

listener - the VetoableChangeListener to be added

removeVetoableChangeListener

public void removeVetoableChangeListener(java.beans.VetoableChangeListener listener)

Removes a VetoableChangeListener from the listener list. This removes a VetoableChangeListener that was registered for all properties.

Parameters:

listener - the VetoableChangeListener to be removed

getVetoableChangeListeners

public java.beans.VetoableChangeListener[] getVetoableChangeListeners()

Returns an array of all the vetoable change listeners registered on this component.

Returns:

all of the component's VetoableChangeListeners or an empty array if no vetoable change listeners are currently registered

Since:

1.4

See Also:

addVetoableChangeListener(java.beans.VetoableChangeListener), removeVetoableChangeListener(java.beans.VetoableChangeListener)

getTopLevelAncestor

public 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.

Returns:

the top-level Container that this component is in, or null if not in any container

addAncestorListener

public 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. Events are also sent when the component or its ancestors are added or removed from the containment hierarchy.

Parameters:

listener - the AncestorListener to register

See Also:

AncestorEvent

removeAncestorListener

public void removeAncestorListener(AncestorListener listener)

Unregisters listener so that it will no longer receive AncestorEvents.

Parameters:

listener - the AncestorListener to be removed

See Also:

addAncestorListener(javax.swing.event.AncestorListener)

getAncestorListeners

public AncestorListener[] getAncestorListeners()

Returns an array of all the ancestor listeners registered on this component.

Returns:

all of the component's AncestorListeners or an empty array if no ancestor listeners are currently registered

Since:

1.4

See Also:

addAncestorListener(javax.swing.event.AncestorListener), removeAncestorListener(javax.swing.event.AncestorListener)

getListeners

public EventListener[] getListeners(Class listenerType)

Returns an array of all the objects currently registered as FooListeners upon this JComponent. FooListeners are registered using the addFooListener method.

You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a JComponent c for its mouse listeners with the following code:

MouseListener[] mls = (MouseListener[])(c.getListeners(MouseListener.class));

If no such listeners exist, this method returns an empty array.

Overrides:

getListeners in class Container

Parameters:

listenerType - the type of listeners requested; this parameter should specify an interface that descends from java.util.EventListener

Returns:

an array of all objects registered as FooListeners on this component, or an empty array if no such listeners have been added

Throws:

ClassCastException - if listenerType doesn't specify a class or interface that implements java.util.EventListener

Since:

1.3

See Also:

getVetoableChangeListeners(), getAncestorListeners()

addNotify

public void addNotify()

Notifies this component that it now has a parent component. When this method is invoked, the chain of parent components is set up with KeyboardAction event listeners.

Overrides:

addNotify in class Container

See Also:

registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)

removeNotify

public void removeNotify()

Notifies this component that it no longer has a parent component. When this method is invoked, any KeyboardActions set up in the the chain of parent components are removed.

Overrides:

removeNotify in class Container

See Also:

registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)

repaint

public 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. The component will be repainted after all of the currently pending events have been dispatched.

Overrides:

repaint in class Component

Parameters:

tm - this parameter is not used

x - the x value of the dirty region

y - the y value of the dirty region

width - the width of the dirty region

height - the height of the dirty region

See Also:

Component.isShowing(), RepaintManager.addDirtyRegion(javax.swing.JComponent, int, int, int, int)

repaint

public void repaint(Rectangle r)

Adds the specified region to the dirty region list if the component is showing. The component will be repainted after all of the currently pending events have been dispatched.

Parameters:

r - a Rectangle containing the dirty region

See Also:

Component.isShowing(), RepaintManager.addDirtyRegion(javax.swing.JComponent, int, int, int, int)

revalidate

public void revalidate()

Supports deferred automatic layout.

Calls invalidate and then adds this component's validateRoot to a list of components that need to be validated. Validation will occur after all currently pending events have been dispatched. In other words after this method is called, the first validateRoot (if any) found when walking up the containment hierarchy of this component will be validated. By default, JRootPane, JScrollPane, and JTextField return true from isValidateRoot.

This method will automatically be called on this component when a property value changes such that size, location, or internal layout of this component has been affected. This automatic updating differs from the AWT because programs generally no longer need to invoke validate to get the contents of the GUI to update.

See Also:

Component.invalidate(), Container.validate(), isValidateRoot(), RepaintManager.addInvalidComponent(javax.swing.JComponent)

isValidateRoot

public 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. Returns false by default. JScrollPane overrides this method and returns true.

Returns:

always returns false

See Also:

revalidate(), Component.invalidate(), Container.validate()

isOptimizedDrawingEnabled

public boolean isOptimizedDrawingEnabled()

Returns true if this component tiles its children -- that is, if it can guarantee that the children will not overlap. The repainting system is substantially more efficient in this common case. JComponent subclasses that can't make this guarantee, such as JLayeredPane, should override this method to return false.

Returns:

always returns true

isPaintingOrigin

boolean isPaintingOrigin()

Returns true if a paint triggered on a child component should cause painting to originate from this Component, or one of its ancestors.

Returns:

true if painting should originate from this Component or one of its ancestors.

paintImmediately

public 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.

It's rarely necessary to call this method. In most cases it's more efficient to call repaint, which defers the actual painting and can collapse redundant requests into a single paint call. This method is useful if one needs to update the display while the current event is being dispatched.

Parameters:

x - the x value of the region to be painted

y - the y value of the region to be painted

w - the width of the region to be painted

h - the height of the region to be painted

See Also:

repaint(long, int, int, int, int)

paintImmediately

public void paintImmediately(Rectangle r)

Paints the specified region now.

Parameters:

r - a Rectangle containing the region to be painted

alwaysOnTop

boolean alwaysOnTop()

Returns whether this component should be guaranteed to be on top. For example, it would make no sense for Menus to pop up under another component, so they would always return true. Most components will want to return false, hence that is the default.

Returns:

always returns false

setPaintingChild

void setPaintingChild(Component paintingChild)

_paintImmediately

void _paintImmediately(int x,
                       int y,
                       int w,
                       int h)

paintDoubleBuffered

private boolean paintDoubleBuffered(JComponent paintingComponent,
                                    Component bufferComponent,
                                    Graphics g,
                                    int clipX,
                                    int clipY,
                                    int clipW,
                                    int clipH)

paintWithOffscreenBuffer

private void paintWithOffscreenBuffer(JComponent paintingComponent,
                                      Graphics g,
                                      int clipX,
                                      int clipY,
                                      int clipW,
                                      int clipH,
                                      Image offscreen)

getObscuredState

private int getObscuredState(int compIndex,
                             int x,
                             int y,
                             int width,
                             int height)

Returns whether or not the region of the specified component is obscured by a sibling.

Returns:

NOT_OBSCURED if non of the siblings above the Component obscure it, COMPLETELY_OBSCURED if one of the siblings completely obscures the Component or PARTIALLY_OBSCURED if the Comonent is only partially obscured.

checkIfChildObscuredBySibling

boolean checkIfChildObscuredBySibling()

Returns true, which implies that before checking if a child should be painted it is first check that the child is not obscured by another sibling. This is only checked if isOptimizedDrawingEnabled returns false.

Returns:

always returns true

setFlag

private void setFlag(int aFlag,
                     boolean aValue)

getFlag

private boolean getFlag(int aFlag)

setWriteObjCounter

static void setWriteObjCounter(JComponent comp,
                               byte count)

getWriteObjCounter

static byte getWriteObjCounter(JComponent comp)

setDoubleBuffered

public void setDoubleBuffered(boolean aFlag)

Sets whether the this component should use a buffer to paint. If set to true, all the drawing from this component will be done in an offscreen painting buffer. The offscreen painting buffer will the be copied onto the screen. Swings painting system always uses a maximum of one double buffer. If a Component is buffered and one of its ancestor is also buffered, the ancestor buffer will be used.

Parameters:

aFlag - if true, set this component to be double buffered

isDoubleBuffered

public boolean isDoubleBuffered()

Returns whether this component should use a buffer to paint.

Overrides:

isDoubleBuffered in class Component

Returns:

true if this component is double buffered, otherwise false

getRootPane

public JRootPane getRootPane()

Returns the JRootPane ancestor for this component.

Returns:

the JRootPane that contains this component, or null if no JRootPane is found

compWriteObjectNotify

void compWriteObjectNotify()

enableSerialization

void enableSerialization()

Called by the JComponent constructor. Adds a fake FocusListener whose real purpose is to uninstall the component's UI early.

readObject

private void readObject(ObjectInputStream s)
                 throws IOException,
                        ClassNotFoundException

We use the ObjectInputStream "registerValidation" callback to update the UI for the entire tree of components after they've all been read in.

Parameters:

s - the ObjectInputStream from which to read

Throws:

IOException

ClassNotFoundException

See Also:

JComponent.ReadObjectCallback

writeObject

private void writeObject(ObjectOutputStream s)
                  throws IOException

Before writing a JComponent to an ObjectOutputStream we temporarily uninstall its UI. This is tricky to do because we want to uninstall the UI before any of the JComponent's children (or its LayoutManager etc.) are written, and we don't want to restore the UI until the most derived JComponent subclass has been been stored.

Parameters:

s - the ObjectOutputStream in which to write

Throws:

IOException

paramString

protected String paramString()

Returns a string representation of this JComponent. 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 JComponent