JComponent (Java 2 Platform SE v1.4.2)

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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

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.

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

Nested Class Summary
`class`	`JComponent.AccessibleJComponent` Inner class of JComponent used to provide default support for accessibility.

Nested classes inherited from class java.awt.Container

Container.AccessibleAWTContainer

Nested classes inherited from class java.awt.Component

Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary
`protected AccessibleContext`	`accessibleContext` The `AccessibleContext` associated with this `JComponent`.
`protected EventListenerList`	`listenerList` A list of event listeners for this component.
`static String`	`TOOL_TIP_TEXT_KEY` The comment to display when the cursor is over the component, also known as a "value tip", "flyover help", or "flyover label".
`protected ComponentUI`	`ui` The look and feel delegate for this component.
`static int`	`UNDEFINED_CONDITION` Constant used by some of the APIs to mean that no condition is defined.
`static int`	`WHEN_ANCESTOR_OF_FOCUSED_COMPONENT` Constant used for `registerKeyboardAction` that means that the command should be invoked when the receiving component is an ancestor of the focused component or is itself the focused component.
`static int`	`WHEN_FOCUSED` Constant used for `registerKeyboardAction` that means that the command should be invoked when the component has the focus.
`static int`	`WHEN_IN_FOCUSED_WINDOW` Constant used for `registerKeyboardAction` that means that the command should be invoked when the receiving component is in the window that has the focus or is itself the focused component.

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary
`JComponent()` Default `JComponent` constructor.

Method Summary
`void`	`addAncestorListener(AncestorListener listener)` Registers `listener` so that it will receive `AncestorEvents` when it or any of its ancestors move or are made visible or invisible.
`void`	`addNotify()` Notifies this component that it now has a parent component.
`void`	`addPropertyChangeListener(PropertyChangeListener listener)` Adds a `PropertyChangeListener` to the listener list.
`void`	`addPropertyChangeListener(String propertyName, PropertyChangeListener listener)` Adds a `PropertyChangeListener` for a specific property.
`void`	`addVetoableChangeListener(VetoableChangeListener listener)` Adds a `VetoableChangeListener` to the listener list.
`void`	`computeVisibleRect(Rectangle visibleRect)` Returns the `Component`'s "visible rect rectangle" - the intersection of the visible rectangles for this component and all of its ancestors.
`boolean`	`contains(int x, int y)` Gives the UI delegate an opportunity to define the precise shape of this component for the sake of mouse processing.
`JToolTip`	`createToolTip()` Returns the instance of `JToolTip` that should be used to display the tooltip.
`void`	`disable()` Deprecated. As of JDK version 1.1, replaced by `java.awt.Component.setEnable(boolean)`.
`void`	`enable()` Deprecated. As of JDK version 1.1, replaced by `java.awt.Component.setEnable(boolean)`.
`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.
`AccessibleContext`	`getAccessibleContext()` Returns the `AccessibleContext` associated with this `JComponent`.
`ActionListener`	`getActionForKeyStroke(KeyStroke aKeyStroke)` Returns the object that will perform the action registered for a given keystroke.
`ActionMap`	`getActionMap()` Returns the `ActionMap` used to determine what `Action` to fire for particular `KeyStroke` binding.
`float`	`getAlignmentX()` Overrides `Container.getAlignmentX` to return the vertical alignment.
`float`	`getAlignmentY()` Overrides `Container.getAlignmentY` to return the horizontal alignment.
`AncestorListener[]`	`getAncestorListeners()` Returns an array of all the ancestor listeners registered on this component.
`boolean`	`getAutoscrolls()` Gets the `autoscrolls` property.
`Border`	`getBorder()` Returns the border of this component or `null` if no border is currently set.
`Rectangle`	`getBounds(Rectangle rv)` Stores the bounds of this component into "return value" `rv` and returns `rv`.
`Object`	`getClientProperty(Object key)` Returns the value of the property with the specified key.
`protected Graphics`	`getComponentGraphics(Graphics g)` Returns the graphics object used to paint this component.
`int`	`getConditionForKeyStroke(KeyStroke aKeyStroke)` Returns the condition that determines whether a registered action occurs in response to the specified keystroke.
`int`	`getDebugGraphicsOptions()` Returns the state of graphics debugging.
`static Locale`	`getDefaultLocale()` Returns the default locale used to initialize each JComponent's locale property upon creation.
`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`.
`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 `FooListener`s upon this `JComponent`.
`Point`	`getLocation(Point rv)` Stores the x,y origin of this component into "return value" `rv` and returns `rv`.
`Dimension`	`getMaximumSize()` If the maximum size has been set to a non-`null` value just returns it.
`Dimension`	`getMinimumSize()` If the minimum size has been set to a non-`null` value just returns it.
`Component`	`getNextFocusableComponent()` Deprecated. As of 1.4, replaced by `FocusTraversalPolicy`.
`Dimension`	`getPreferredSize()` If the `preferredSize` has been set to a non-`null` value just returns it.
`PropertyChangeListener[]`	`getPropertyChangeListeners()` Returns an array of all the `PropertyChangeListener`s added to this Component with addPropertyChangeListener().
`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`.
`Point`	`getToolTipLocation(MouseEvent event)` Returns the tooltip location in this component's coordinate system.
`String`	`getToolTipText()` Returns the tooltip string that has been set with `setToolTipText`.
`String`	`getToolTipText(MouseEvent event)` Returns the string to be used as the tooltip for event.
`Container`	`getTopLevelAncestor()` Returns the top-level ancestor of this component (either the containing `Window` or `Applet`), or `null` if this component has not been added to any container.
`TransferHandler`	`getTransferHandler()` Gets the `transferHandler` property.
`String`	`getUIClassID()` Returns the `UIDefaults` key used to look up the name of the `swing.plaf.ComponentUI` class that defines the look and feel for this component.
`boolean`	`getVerifyInputWhenFocusTarget()` Returns the value that indicates whether the input verifier for the current focus owner will be called before this component requests focus.
`VetoableChangeListener[]`	`getVetoableChangeListeners()` Returns an array of all the vetoable change listeners registered on this component.
`Rectangle`	`getVisibleRect()` Returns the `Component`'s "visible rectangle" - the intersection of this component's visible rectangle:
`int`	`getWidth()` Returns the current width of this component.
`int`	`getX()` Returns the current x coordinate of the component's origin.
`int`	`getY()` Returns the current y coordinate of the component's origin.
`void`	`grabFocus()` Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
`boolean`	`isDoubleBuffered()` Returns whether this component should use a buffer to paint.
`static boolean`	`isLightweightComponent(Component c)` Returns true if this component is lightweight, that is, if it doesn't have a native window system peer.
`boolean`	`isManagingFocus()` Deprecated. As of 1.4, replaced by `Component.setFocusTraversalKeys(int, Set)` and `Container.setFocusCycleRoot(boolean)`.
`boolean`	`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.
`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`.
`void`	`paintImmediately(int x, int y, int w, int h)` Paints the specified region in this component and all of its descendants that overlap the region, immediately.
`void`	`paintImmediately(Rectangle r)` Paints the specified region now.
`protected String`	`paramString()` Returns a string representation of this `JComponent`.
`void`	`print(Graphics g)` Invoke this method to print the component.
`void`	`printAll(Graphics g)` Invoke this method to print the component.
`protected void`	`printBorder(Graphics g)` Prints the component's border.
`protected void`	`printChildren(Graphics g)` Prints this component's children.
`protected void`	`printComponent(Graphics g)` This is invoked during a printing operation.
`protected void`	`processComponentKeyEvent(KeyEvent e)` Processes any key events that the component itself recognizes.
`protected boolean`	`processKeyBinding(KeyStroke ks, KeyEvent e, int condition, boolean pressed)` Invoked to process the key bindings for `ks` as the result of the `KeyEvent` `e`.
`protected void`	`processKeyEvent(KeyEvent e)` Overrides `processKeyEvent` to process events.
`protected void`	`processMouseMotionEvent(MouseEvent e)` Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.
`void`	`putClientProperty(Object key, Object value)` Adds an arbitrary key/value "client property" to this component.
`void`	`registerKeyboardAction(ActionListener anAction, KeyStroke aKeyStroke, int aCondition)` This method is now obsolete, please use a combination of `getActionMap()` and `getInputMap()` for similiar behavior.
`void`	`registerKeyboardAction(ActionListener anAction, String aCommand, KeyStroke aKeyStroke, int aCondition)` This method is now obsolete, please use a combination of `getActionMap()` and `getInputMap()` for similiar behavior.
`void`	`removeAncestorListener(AncestorListener listener)` Unregisters `listener` so that it will no longer receive `AncestorEvents`.
`void`	`removeNotify()` Notifies this component that it no longer has a parent component.
`void`	`removePropertyChangeListener(PropertyChangeListener listener)` Removes a `PropertyChangeListener` from the listener list.
`void`	`removePropertyChangeListener(String propertyName, PropertyChangeListener listener)` Removes a `PropertyChangeListener` for a specific property.
`void`	`removeVetoableChangeListener(VetoableChangeListener listener)` Removes a `VetoableChangeListener` from the listener list.
`void`	`repaint(long tm, int x, int y, int width, int height)` Adds the specified region to the dirty region list if the component is showing.
`void`	`repaint(Rectangle r)` Adds the specified region to the dirty region list if the component is showing.
`boolean`	`requestDefaultFocus()` Deprecated. As of 1.4, replaced by `FocusTraversalPolicy.getDefaultComponent(Container).requestFocus()`
`void`	`requestFocus()` Requests that this Component 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.
`void`	`scrollRectToVisible(Rectangle aRect)` Forwards the `scrollRectToVisible()` message to the `JComponent`'s parent.
`void`	`setActionMap(ActionMap am)` Sets the `ActionMap` to `am`.
`void`	`setAlignmentX(float alignmentX)` Sets the the vertical alignment.
`void`	`setAlignmentY(float alignmentY)` Sets the the horizontal alignment.
`void`	`setAutoscrolls(boolean autoscrolls)` Sets the `autoscrolls` property.
`void`	`setBackground(Color bg)` Sets the background color of this component.
`void`	`setBorder(Border border)` Sets the border of this component.
`void`	`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.
`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.
`void`	`setPreferredSize(Dimension preferredSize)` Sets the preferred size of this component.
`void`	`setRequestFocusEnabled(boolean requestFocusEnabled)` Provides a hint as to whether or not this `JComponent` should get focus.
`void`	`setToolTipText(String text)` Registers the text to display in a tool tip.
`void`	`setTransferHandler(TransferHandler newHandler)` Sets the `transferHandler` property, which is `null` if the component does not support data transfer operations.
`protected void`	`setUI(ComponentUI newUI)` Sets the look and feel delegate for this component.
`void`	`setVerifyInputWhenFocusTarget(boolean verifyInputWhenFocusTarget)` Sets the value to indicate whether input verifier for the current focus owner will be called before this component requests focus.
`void`	`setVisible(boolean aFlag)` Makes the component visible or invisible.
`void`	`unregisterKeyboardAction(KeyStroke aKeyStroke)` This method is now obsolete.
`void`	`update(Graphics g)` Calls `paint`.
`void`	`updateUI()` Resets the UI property to a value from the current look and feel.

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, 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

ui

protected transient ComponentUI ui

The look and feel delegate for this component.

listenerList

protected EventListenerList listenerList

A list of event listeners for this component.

WHEN_FOCUSED

public static final int WHEN_FOCUSED

Constant used for registerKeyboardAction that means that the command should be invoked when the component has the focus.

See Also:: Constant Field Values

WHEN_ANCESTOR_OF_FOCUSED_COMPONENT

public static final int WHEN_ANCESTOR_OF_FOCUSED_COMPONENT

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

See Also:: Constant Field Values

WHEN_IN_FOCUSED_WINDOW

public static final int WHEN_IN_FOCUSED_WINDOW

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

See Also:: Constant Field Values

UNDEFINED_CONDITION

public static final int UNDEFINED_CONDITION

Constant used by some of the APIs to mean that no condition is defined.

See Also:: Constant Field Values

TOOL_TIP_TEXT_KEY

public static final String TOOL_TIP_TEXT_KEY

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

See Also:: Constant Field Values

accessibleContext

protected AccessibleContext accessibleContext

The AccessibleContext associated with this JComponent.

Constructor Detail

JComponent

public JComponent()

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

Method Detail

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.

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)

javax.swing Class JComponent

ui