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,JLayer,JLayeredPane,JList,JMenuBar,JOptionPane,JPanel,JPopupMenu,JProgressBar,JRootPane,JScrollBar,JScrollPane,JSeparator,JSlider,JSpinner,JSplitPane,JTabbedPane,JTable,JTableHeader,JTextComponent,JToolBar,JToolTip,JTree,JViewport

@JavaBean(defaultProperty="UIClassID")public abstract classJComponentextendsContainerimplementsSerializable
The base class for all Swing components except top-level containers. To use a component that inherits fromJComponent, you must place the component in a containment hierarchy whose root is a top-level Swing container. Top-level Swing containers -- such asJFrame,JDialog, andJApplet -- are specialized components that provide a place for other Swing components to paint themselves. For an explanation of containment hierarchies, seeSwing Components and the Containment Hierarchy, a section inThe Java Tutorial.

TheJComponent 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 aUI delegate -- an object that descends fromComponentUI. SeeHow to Set the Look and Feel inThe Java Tutorial for more information.
  • Comprehensive keystroke handling. See the documentHow to Use Key Bindings, an article inThe Java Tutorial, for more information.
  • Support for tool tips -- short descriptions that pop up when the cursor lingers over a component. SeeHow to Use Tool Tips inThe Java Tutorial for more information.
  • Support for accessibility.JComponent contains all of the methods in theAccessible interface, but it doesn't actually implement the interface. That is the responsibility of the individual classes that extendJComponent.
  • Support for component-specific properties. With theputClientProperty(java.lang.Object, java.lang.Object) andgetClientProperty(java.lang.Object) methods, you can associate name-object pairs with any object that descends fromJComponent.
  • An infrastructure for painting that includes double buffering and support for borders. For more information seePainting andHow to Use Borders, both of which are sections inThe Java Tutorial.
For more information on these subjects, see theSwing package description andThe Java Tutorial sectionThe JComponent Class.

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

AJComponent may contain any number of default or initial components as children. This behaviour may change according to look and feel, therefore aJComponent may contain some default or initial components as children for a particular Look and Feel, whereas it may not do so for some other Look and Feel. Within a particular Look and Feel also, this behaviour may change depending upon the configuration properties of theJComponent. In summary, it is not valid to assume a JComponent has no children just because the application did not directly add them.

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

Warning: Swing is not thread safe. For more information seeSwing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans has been added to thejava.beans package. Please seeXMLEncoder.

Since:
1.2
See Also:
  • Field Details

    • 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 forregisterKeyboardAction that means that the command should be invoked when the component has the focus.
      See Also:
    • WHEN_ANCESTOR_OF_FOCUSED_COMPONENT

      public static final int WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
      Constant used forregisterKeyboardAction 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:
    • WHEN_IN_FOCUSED_WINDOW

      public static final int WHEN_IN_FOCUSED_WINDOW
      Constant used forregisterKeyboardAction 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:
    • UNDEFINED_CONDITION

      public static final int UNDEFINED_CONDITION
      Constant used by some of the APIs to mean that no condition is defined.
      See Also:
    • 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:
  • Constructor Details

    • JComponent

      public JComponent()
      DefaultJComponent constructor. This constructor does very little initialization beyond calling theContainer constructor. For example, the initial layout manager isnull. It does, however, set the component's locale property to the value returned byJComponent.getDefaultLocale.
      See Also:
  • Method Details

    • setInheritsPopupMenu

      @BeanProperty(description="Whether or not the JPopupMenu is inherited")public void setInheritsPopupMenu(boolean value)
      Sets whether or notgetComponentPopupMenu should delegate to the parent if this component does not have aJPopupMenu assigned to it.

      The default value for this is false, but someJComponent subclasses that are implemented as a number ofJComponents may set this to true.

      This is a bound property.

      Parameters:
      value - whether or not the JPopupMenu is inherited
      Since:
      1.5
      See Also:
    • getInheritsPopupMenu

      public boolean getInheritsPopupMenu()
      Returns true if the JPopupMenu should be inherited from the parent.
      Returns:
      true if the JPopupMenu should be inherited from the parent
      Since:
      1.5
      See Also:
    • setComponentPopupMenu

      @BeanProperty(preferred=true,description="Popup to show")public void setComponentPopupMenu(JPopupMenu popup)
      Sets theJPopupMenu for thisJComponent. The UI is responsible for registering bindings and adding the necessary listeners such that theJPopupMenu will be shown at the appropriate time. When theJPopupMenu is shown depends upon the look and feel: some may show it on a mouse event, some may enable a key binding.

      Ifpopup is null, andgetInheritsPopupMenu returns true, thengetComponentPopupMenu will be delegated to the parent. This provides for a way to make all child components inherit the popupmenu of the parent.

      This is a bound property.

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

      public JPopupMenu getComponentPopupMenu()
      ReturnsJPopupMenu that assigned for this component. If this component does not have aJPopupMenu assigned to it andgetInheritsPopupMenu is true, this will returngetParent().getComponentPopupMenu() (assuming the parent is valid.)
      Returns:
      JPopupMenu assigned for this component ornull if no popup assigned
      Since:
      1.5
      See Also:
    • updateUI

      public void updateUI()
      This method is called to update 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);   }
      Implementation Requirements:
      The default implementation of this method does nothing.
      See Also:
    • getUI

      public ComponentUI getUI()
      Returns the look and feel delegate that renders this component.
      Returns:
      theComponentUI object that renders this component
      Since:
      9
    • setUI

      @BeanProperty(hidden=true,visualUpdate=true,description="The component's look and feel delegate.")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, inJSlider:
       public void setUI(SliderUI newUI) {     super.setUI(newUI); }

      AdditionallyJComponent subclasses must provide agetUI method that returns the correct type. For example:

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

      Parameters:
      newUI - the new UI delegate
      See Also:
    • getUIClassID

      @BeanProperty(bound=false,expert=true,description="UIClassID")public String getUIClassID()
      Returns theUIDefaults key used to look up the name of theswing.plaf.ComponentUI class that defines the look and feel for this component. Most applications will never need to call this method. Subclasses ofJComponent that support pluggable look and feel should override this method to return aUIDefaults key that maps to theComponentUI subclass that defines their look and feel.
      Returns:
      theUIDefaults key for aComponentUI subclass
      See Also:
    • getComponentGraphics

      protected Graphics getComponentGraphics(Graphics g)
      Returns the graphics object used to paint this component. IfDebugGraphics is turned on we create a newDebugGraphics object if necessary. Otherwise we just configure the specified graphics object's foreground and font.
      Parameters:
      g - the originalGraphics object
      Returns:
      aGraphics 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 theGraphics 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 inGraphics. For example, you should not alter the clipRectangle or modify the transform. If you need to do these operations you may find it easier to create a newGraphics from the passed inGraphics and manipulate it. Further, if you do not invoke super's implementation you must honor the opaque property, that is if this component is opaque, you must completely fill in the background in an opaque color. If you do not honor the opaque property you will likely see visual artifacts.

      The passed inGraphics object might have a transform other than the identify transform installed on it. In this case, you might get unexpected results if you cumulatively apply another transform.

      Parameters:
      g - theGraphics object to protect
      See Also:
    • paintChildren

      protected void paintChildren(Graphics g)
      Paints this component's children. IfshouldUseBuffer 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 - theGraphics context in which to paint
      See Also:
    • 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 inGraphics. For example, you should not alter the clipRectangle or modify the transform. If you need to do these operations you may find it easier to create a newGraphics from the passed inGraphics and manipulate it.

      Parameters:
      g - theGraphics context in which to paint
      See Also:
    • update

      public void update(Graphics g)
      Callspaint. Doesn't clear the background but seeComponentUI.update, which is called bypaintComponent.
      Overrides:
      update in class Container
      Parameters:
      g - theGraphics context in which to paint
      See Also:
    • paint

      public void paint(Graphics g)
      Invoked by Swing to draw components. Applications should not invokepaint directly, but should instead use therepaint method to schedule the component for redrawing.

      This method actually delegates the work of painting to three protected methods:paintComponent,paintBorder, andpaintChildren. 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'spaint method should just overridepaintComponent.

      Overrides:
      paint in class Container
      Parameters:
      g - theGraphics context in which to paint
      See Also:
    • printAll

      public void printAll(Graphics g)
      Invoke this method to print the component. This method invokesprint on the component.
      Overrides:
      printAll in class Component
      Parameters:
      g - theGraphics context in which to paint
      See Also:
    • print

      public void print(Graphics g)
      Invoke this method to print the component to the specifiedGraphics. This method will result in invocations ofprintComponent,printBorder andprintChildren. It is recommended that you override one of the previously mentioned methods rather than this one if your intention is to customize the way printing looks. However, it can be useful to override this method should you want to prepare state before invoking the superclass behavior. As an example, if you wanted to change the component's background color before printing, you could do the following:
           public void print(Graphics g) {         Color orig = getBackground();         setBackground(Color.WHITE);         // wrap in try/finally so that we always restore the state         try {             super.print(g);         } finally {             setBackground(orig);         }     }

      Alternatively, or for components that delegate painting to other objects, you can query during painting whether or not the component is in the midst of a print operation. TheisPaintingForPrint method provides this ability and its return value will be changed by this method: totrue immediately before rendering and tofalse immediately after. With each change a property change event is fired on this component with the name"paintingForPrint".

      This method sets the component's state such that the double buffer will not be used: painting will be done directly on the passed inGraphics.

      Overrides:
      print in class Container
      Parameters:
      g - theGraphics context in which to paint
      See Also:
    • printComponent

      protected void printComponent(Graphics g)
      This is invoked during a printing operation. This is implemented to invokepaintComponent on the component. Override this if you wish to add special painting behavior when printing.
      Parameters:
      g - theGraphics context in which to paint
      Since:
      1.3
      See Also:
    • printChildren

      protected void printChildren(Graphics g)
      Prints this component's children. This is implemented to invokepaintChildren on the component. Override this if you wish to print the children differently than painting.
      Parameters:
      g - theGraphics context in which to paint
      Since:
      1.3
      See Also:
    • printBorder

      protected void printBorder(Graphics g)
      Prints the component's border. This is implemented to invokepaintBorder on the component. Override this if you wish to print the border differently that it is painted.
      Parameters:
      g - theGraphics context in which to paint
      Since:
      1.3
      See Also:
    • isPaintingTile

      @BeanProperty(bound=false)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
    • isPaintingForPrint

      @BeanProperty(bound=false)public final boolean isPaintingForPrint()
      Returnstrue if the current painting operation on this component is part of aprint operation. This method is useful when you want to customize what you print versus what you show on the screen.

      You can detect changes in the value of this property by listening for property change events on this component with name"paintingForPrint".

      Note: This method provides complimentary functionality to that provided by other high level Swing printing APIs. However, it deals strictly with painting and should not be confused as providing information on higher level print processes. For example, aJTable.print() operation doesn't necessarily result in a continuous rendering of the full component, and the return value of this method can change multiple times during that operation. It is even possible for the component to be painted to the screen while the printing process is ongoing. In such a case, the return value of this method istrue when, and only when, the table is being painted as part of the printing process.

      Returns:
      true if the current painting operation on this component is part of a print operation
      Since:
      1.6
      See Also:
    • isManagingFocus

      @Deprecated@BeanProperty(bound=false)public boolean isManagingFocus()
      Deprecated.
      As of 1.4, replaced byComponent.setFocusTraversalKeys(int, Set) andContainer.setFocusCycleRoot(boolean).
      In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

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

      Returns:
      false
      See Also:
    • setNextFocusableComponent

      @Deprecatedpublic void setNextFocusableComponent(Component aComponent)
      Deprecated.
      As of 1.4, replaced byFocusTraversalPolicy
      In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

      Overrides the defaultFocusTraversalPolicy for thisJComponent's focus traversal cycle by unconditionally setting the specifiedComponent as the nextComponent in the cycle, and thisJComponent as the specifiedComponent's previousComponent in the cycle.

      Parameters:
      aComponent - theComponent that should follow thisJComponent in the focus traversal cycle
      See Also:
    • getNextFocusableComponent

      @Deprecatedpublic Component getNextFocusableComponent()
      Deprecated.
      As of 1.4, replaced byFocusTraversalPolicy.
      In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

      Returns theComponent set by a prior call tosetNextFocusableComponent(Component) on thisJComponent.

      Returns:
      theComponent that will follow thisJComponent in the focus traversal cycle, ornull if none has been explicitly specified
      See Also:
    • setRequestFocusEnabled

      public void setRequestFocusEnabled(boolean requestFocusEnabled)
      Provides a hint as to whether or not thisJComponent 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 aJComponent to steal focus, but did want theJComponent to be traversable via the keyboard. If you do not want thisJComponent focusable at all, use thesetFocusable method instead.

      Please see How to Use the Focus Subsystem, a section inThe Java Tutorial, for more information.

      Parameters:
      requestFocusEnabled - indicates whether you want thisJComponent to be focusable or not
      See Also:
    • isRequestFocusEnabled

      public boolean isRequestFocusEnabled()
      Returnstrue if thisJComponent should get focus; otherwise returnsfalse.

      Please see How to Use the Focus Subsystem, a section inThe Java Tutorial, for more information.

      Returns:
      true if this component should get focus, otherwise returnsfalse
      See Also:
    • requestFocus

      public void requestFocus()
      Requests that thisComponent gets the input focus. Refer toComponent.requestFocus() for a complete description of this method.

      Note that the use of this method is discouraged because its behavior is platform dependent. Instead we recommend the use ofrequestFocusInWindow(). If you would like more information on focus, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

      Overrides:
      requestFocus in class Component
      Since:
      1.4
      See Also:
    • requestFocus

      public boolean requestFocus(boolean temporary)
      Requests that thisComponent gets the input focus. Refer toComponent.requestFocus(boolean) for a complete description of this method.

      Note that the use of this method is discouraged because its behavior is platform dependent. Instead we recommend the use ofrequestFocusInWindow(boolean). If you would like more information on focus, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

      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:
    • requestFocusInWindow

      public boolean requestFocusInWindow()
      Requests that thisComponent gets the input focus. Refer toComponent.requestFocusInWindow() for a complete description of this method.

      If you would like more information on focus, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

      Overrides:
      requestFocusInWindow in class Component
      Returns:
      false if the focus change request is guaranteed to fail;true if it is likely to succeed
      Since:
      1.4
      See Also:
    • requestFocusInWindow

      protected boolean requestFocusInWindow(boolean temporary)
      Requests that thisComponent gets the input focus. Refer toComponent.requestFocusInWindow(boolean) for a complete description of this method.

      If you would like more information on focus, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

      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:
    • 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 userequestFocusInWindow().

      See Also:
    • setVerifyInputWhenFocusTarget

      @BeanProperty(description="Whether the Component verifies input before accepting focus.")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 theverifyInputWhenFocusTarget property
      Since:
      1.3
      See Also:
    • 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 theverifyInputWhenFocusTarget property
      Since:
      1.3
      See Also:
    • getFontMetrics

      public FontMetrics getFontMetrics(Font font)
      Gets theFontMetrics for the specifiedFont.
      Overrides:
      getFontMetrics in class Component
      Parameters:
      font - the font for which font metrics is to be obtained
      Returns:
      the font metrics forfont
      Throws:
      NullPointerException - iffont is null
      Since:
      1.5
      See Also:
    • setPreferredSize

      @BeanProperty(preferred=true,description="The preferred size of the component.")public void setPreferredSize(Dimension preferredSize)
      Sets the preferred size of this component. IfpreferredSize isnull, the UI will be asked for the preferred size.
      Overrides:
      setPreferredSize in class Component
      Parameters:
      preferredSize - The new preferred size, or null
      See Also:
    • getPreferredSize

      public Dimension getPreferredSize()
      If thepreferredSize has been set to a non-null value just returns it. If the UI delegate'sgetPreferredSize method returns a nonnull value then return that; otherwise defer to the component's layout manager.
      Overrides:
      getPreferredSize in class Container
      Returns:
      the value of thepreferredSize property
      See Also:
    • setMaximumSize

      @BeanProperty(description="The maximum size of the component.")public void setMaximumSize(Dimension maximumSize)
      Sets the maximum size of this component to a constant value. Subsequent calls togetMaximumSize will always return this value; the component's UI will not be asked to compute it. Setting the maximum size tonull restores the default behavior.

      Subclasses may choose to override this by returning their own maximum size in thegetMaximumSize method.

      Overrides:
      setMaximumSize in class Component
      Parameters:
      maximumSize - aDimension containing the desired maximum allowable size
      See Also:
    • getMaximumSize

      public Dimension getMaximumSize()
      If the maximum size has been set to a non-null value just returns it. If the UI delegate'sgetMaximumSize 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 themaximumSize property
      See Also:
    • setMinimumSize

      @BeanProperty(description="The minimum size of the component.")public void setMinimumSize(Dimension minimumSize)
      Sets the minimum size of this component to a constant value. Subsequent calls togetMinimumSize will always return this value; the component's UI will not be asked to compute it. Setting the minimum size tonull restores the default behavior.

      Subclasses may choose to override this by returning their own minimum size in thegetMinimumSize method.

      Overrides:
      setMinimumSize in class Component
      Parameters:
      minimumSize - the new minimum size of this component
      See Also:
    • getMinimumSize

      public Dimension getMinimumSize()
      If the minimum size has been set to a non-null value just returns it. If the UI delegate'sgetMinimumSize 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 theminimumSize property
      See Also:
    • 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 - thex coordinate of the point
      y - they coordinate of the point
      Returns:
      true if this component logically contains x,y
      See Also:
    • setBorder

      @BeanProperty(preferred=true,visualUpdate=true,description="The component's border.")public void setBorder(Border border)
      Sets the border of this component. TheBorder 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.

      Although technically you can set the border on any object that inherits fromJComponent, the look and feel implementation of many standard Swing components doesn't work well with user-set borders. In general, when you want to set a border on a standard Swing component other thanJPanel orJLabel, we recommend that you put the component in aJPanel and set the border on theJPanel.

      This is a bound property.

      Parameters:
      border - the border to be rendered for this component
      See Also:
    • getBorder

      public Border getBorder()
      Returns the border of this component ornull if no border is currently set.
      Returns:
      the border object for this component
      See Also:
    • getInsets

      @BeanProperty(expert=true)public Insets getInsets()
      If a border has been set on this component, returns the border's insets; otherwise callssuper.getInsets.
      Overrides:
      getInsets in class Container
      Returns:
      the value of the insets property
      See Also:
    • getInsets

      public Insets getInsets(Insets insets)
      Returns anInsets object containing this component's inset values. The passed-inInsets 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. Ifinsets is null, this will allocate a new one.
      Parameters:
      insets - theInsets object, which can be reused
      Returns:
      theInsets object
      See Also:
    • getAlignmentY

      public float getAlignmentY()
      OverridesContainer.getAlignmentY to return the vertical alignment.
      Overrides:
      getAlignmentY in class Container
      Returns:
      the value of thealignmentY property
      See Also:
    • setAlignmentY

      @BeanProperty(description="The preferred vertical alignment of the component.")public void setAlignmentY(float alignmentY)
      Sets the vertical alignment.
      Parameters:
      alignmentY - the new vertical alignment
      See Also:
    • getAlignmentX

      public float getAlignmentX()
      OverridesContainer.getAlignmentX to return the horizontal alignment.
      Overrides:
      getAlignmentX in class Container
      Returns:
      the value of thealignmentX property
      See Also:
    • setAlignmentX

      @BeanProperty(description="The preferred horizontal alignment of the component.")public void setAlignmentX(float alignmentX)
      Sets the horizontal alignment.
      Parameters:
      alignmentX - the new horizontal alignment
      See Also:
    • setInputVerifier

      @BeanProperty(description="The component's input verifier.")public void setInputVerifier(InputVerifier inputVerifier)
      Sets the input verifier for this component.
      Parameters:
      inputVerifier - the new input verifier
      Since:
      1.3
      See Also:
    • getInputVerifier

      public InputVerifier getInputVerifier()
      Returns the input verifier for this component.
      Returns:
      theinputVerifier property
      Since:
      1.3
      See Also:
    • getGraphics

      @BeanProperty(bound=false)public Graphics getGraphics()
      Returns this component's graphics context, which lets you draw on a component. Use this method to get aGraphics 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:
    • setDebugGraphicsOptions

      @BeanProperty(bound=false,preferred=true,enumerationValues={"DebugGraphics.NONE_OPTION","DebugGraphics.LOG_OPTION","DebugGraphics.FLASH_OPTION","DebugGraphics.BUFFERED_OPTION"},description="Diagnostic options for graphics operations.")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 anExternalWindow 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 anExternalWindow 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:
    • registerKeyboardAction

      public void registerKeyboardAction(ActionListener anAction,String aCommand,KeyStroke aKeyStroke, int aCondition)
      This method is now obsolete, please use a combination ofgetActionMap() andgetInputMap() for similar behavior. For example, to bind theKeyStrokeaKeyStroke to theActionanAction now use:
         component.getInputMap().put(aKeyStroke, aCommand);   component.getActionMap().put(aCommmand, anAction);
      The above assumes you want the binding to be applicable forWHEN_FOCUSED. To register bindings for other focus states use thegetInputMap method that takes an integer.

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

      TheaCommand will be set in the delivered event if specified.

      TheaCondition 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, wheneverany 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 - theAction to be registered
      aCommand - the command to be set in the delivered event
      aKeyStroke - theKeyStroke to bind to the action
      aCondition - the condition that needs to be met, see above
      See Also:
    • registerKeyboardAction

      public void registerKeyboardAction(ActionListener anAction,KeyStroke aKeyStroke, int aCondition)
      This method is now obsolete, please use a combination ofgetActionMap() andgetInputMap() for similar behavior.
      Parameters:
      anAction - action to be registered to given keystroke and condition
      aKeyStroke - aKeyStroke
      aCondition - the condition to be associated with given keystroke and action
      See Also:
    • unregisterKeyboardAction

      public void unregisterKeyboardAction(KeyStroke aKeyStroke)
      This method is now obsolete. To unregister an existing binding you can either remove the binding from theActionMap/InputMap, or place a dummy binding theInputMap. Removing the binding from theInputMap allows bindings in parentInputMaps to be active, whereas putting a dummy binding in theInputMap effectively disables the binding from ever happening.

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

      Parameters:
      aKeyStroke - the keystroke for which to unregister its keyboard action
    • getRegisteredKeyStrokes

      @BeanProperty(bound=false)public KeyStroke[] getRegisteredKeyStrokes()
      Returns theKeyStrokes that will initiate registered actions.
      Returns:
      an array ofKeyStroke objects
      See Also:
    • 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, aKeyStroke can be associated with more than one condition. For example, 'a' could be bound for the two conditionsWHEN_FOCUSED andWHEN_IN_FOCUSED_WINDOW condition.

      Parameters:
      aKeyStroke - the keystroke for which to request an action-keystroke 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.
      Parameters:
      aKeyStroke - the keystroke for which to return a listener
      Returns:
      theActionListener object invoked when the keystroke occurs
    • resetKeyboardActions

      public void resetKeyboardActions()
      Unregisters all the bindings in the first tierInputMaps andActionMap. This has the effect of removing any local bindings, and allowing the bindings defined in parentInputMap/ActionMaps (the UI is usually defined in the second tier) to persist.
    • setInputMap

      public final void setInputMap(int condition,InputMap map)
      Sets theInputMap to use under the conditioncondition tomap. Anull value implies you do not want any bindings to be used, even from the UI. This will not reinstall the UIInputMap (if there was one).condition has one of the following values:
      • WHEN_IN_FOCUSED_WINDOW
      • WHEN_FOCUSED
      • WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
      Ifcondition isWHEN_IN_FOCUSED_WINDOW andmap is not aComponentInputMap, anIllegalArgumentException will be thrown. Similarly, ifcondition is not one of the values listed, anIllegalArgumentException will be thrown.
      Parameters:
      condition - one of the values listed above
      map - theInputMap to use for the given condition
      Throws:
      IllegalArgumentException - ifcondition isWHEN_IN_FOCUSED_WINDOW andmap is not an instance ofComponentInputMap; or ifcondition is not one of the legal values specified above
      Since:
      1.3
    • getInputMap

      public final InputMap getInputMap(int condition)
      Returns theInputMap that is used duringcondition.
      Parameters:
      condition - one of WHEN_IN_FOCUSED_WINDOW, WHEN_FOCUSED, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
      Returns:
      theInputMap for the specifiedcondition
      Since:
      1.3
    • getInputMap

      public final InputMap getInputMap()
      Returns theInputMap that is used when the component has focus. This is convenience method forgetInputMap(WHEN_FOCUSED).
      Returns:
      theInputMap used when the component has focus
      Since:
      1.3
    • setActionMap

      public final void setActionMap(ActionMap am)
      Sets theActionMap toam. This does not set the parent of theam to be theActionMap from the UI (if there was one), it is up to the caller to have done this.
      Parameters:
      am - the newActionMap
      Since:
      1.3
    • getActionMap

      public final ActionMap getActionMap()
      Returns theActionMap used to determine whatAction to fire for particularKeyStroke binding. The returnedActionMap, unless otherwise set, will have theActionMap from the UI set as the parent.
      Returns:
      theActionMap containing the key/action bindings
      Since:
      1.3
    • getBaseline

      public int getBaseline(int width, int height)
      Returns the baseline. The baseline is measured from the top of the component. This method is primarily meant forLayoutManagers to align components along their baseline. A return value less than 0 indicates this component does not have a reasonable baseline and thatLayoutManagers should not align this component on its baseline.

      This method calls into theComponentUI method of the same name. If this component does not have aComponentUI -1 will be returned. If a value >= 0 is returned, then the component has a valid baseline for any size >= the minimum size andgetBaselineResizeBehavior can be used to determine how the baseline changes with size.

      Overrides:
      getBaseline in class Component
      Parameters:
      width - the width to get the baseline for
      height - the height to get the baseline for
      Returns:
      the baseline or < 0 indicating there is no reasonable baseline
      Throws:
      IllegalArgumentException - if width or height is < 0
      Since:
      1.6
      See Also:
    • getBaselineResizeBehavior

      @BeanProperty(bound=false)public Component.BaselineResizeBehavior getBaselineResizeBehavior()
      Returns an enum indicating how the baseline of the component changes as the size changes. This method is primarily meant for layout managers and GUI builders.

      This method calls into theComponentUI method of the same name. If this component does not have aComponentUIBaselineResizeBehavior.OTHER will be returned. Subclasses should never returnnull; if the baseline can not be calculated returnBaselineResizeBehavior.OTHER. Callers should first ask for the baseline usinggetBaseline and if a value >= 0 is returned use this method. It is acceptable for this method to return a value other thanBaselineResizeBehavior.OTHER even ifgetBaseline returns a value less than 0.

      Overrides:
      getBaselineResizeBehavior in class Component
      Returns:
      an enum indicating how the baseline changes as the component size changes
      Since:
      1.6
      See Also:
    • requestDefaultFocus

      @Deprecatedpublic boolean requestDefaultFocus()
      Deprecated.
      As of 1.4, replaced byFocusTraversalPolicy.getDefaultComponent(Container).requestFocus()
      In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section inThe Java Tutorial.

      Requests focus on thisJComponent'sFocusTraversalPolicy's defaultComponent. If thisJComponent is a focus cycle root, then itsFocusTraversalPolicy is used. Otherwise, theFocusTraversalPolicy of thisJComponent's focus-cycle-root ancestor is used.

      Returns:
      true if this component can request to get the input focus, false if it can not
      See Also:
    • setVisible

      @BeanProperty(hidden=true,visualUpdate=true)public void setVisible(boolean aFlag)
      Makes the component visible or invisible. OverridesComponent.setVisible.
      Overrides:
      setVisible in class Component
      Parameters:
      aFlag - true to make the component visible; false to make it invisible
      See Also:
    • setEnabled

      @BeanProperty(expert=true,preferred=true,visualUpdate=true,description="The enabled state of the component.")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 its 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:
    • setForeground

      @BeanProperty(preferred=true,visualUpdate=true,description="The foreground color of the component.")public void setForeground(Color fg)
      Sets the foreground color of this component. It is up to the look and feel to honor this property, some may choose to ignore it.
      Overrides:
      setForeground in class Component
      Parameters:
      fg - the desired foregroundColor
      See Also:
    • setBackground

      @BeanProperty(preferred=true,visualUpdate=true,description="The background color of the component.")public void setBackground(Color bg)
      Sets the background color of this component. The background color is used only if the component is opaque, and only by subclasses ofJComponent orComponentUI implementations. Direct subclasses ofJComponent must overridepaintComponent to honor this property.

      It is up to the look and feel to honor this property, some may choose to ignore it.

      Overrides:
      setBackground in class Component
      Parameters:
      bg - the desired backgroundColor
      See Also:
    • setFont

      @BeanProperty(preferred=true,visualUpdate=true,description="The font for the component.")public void setFont(Font font)
      Sets the font for this component.
      Overrides:
      setFont in class Container
      Parameters:
      font - the desiredFont for this component
      See Also:
    • 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 defaultLocale.
      Since:
      1.4
      See Also:
    • 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). Passingnull will reset the current locale back to VM's default locale.
      Parameters:
      l - the desired defaultLocale for new components.
      Since:
      1.4
      See Also:
    • 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.

      Parameters:
      e - the event to be processed
    • processKeyEvent

    • processKeyBinding

      protected boolean processKeyBinding(KeyStroke ks,KeyEvent e, int condition, boolean pressed)
      Invoked to process the key bindings forks as the result of theKeyEvente. This obtains the appropriateInputMap, gets the binding, gets the action from theActionMap, and then (if the action is found and the component is enabled) invokesnotifyAction to notify the action.
      Parameters:
      ks - theKeyStroke queried
      e - theKeyEvent
      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
    • setToolTipText

      @BeanProperty(bound=false,preferred=true,description="The text to display in a tool tip.")public void setToolTipText(String text)
      Registers the text to display in a tool tip. The text displays when the cursor lingers over the component.

      SeeHow to Use Tool Tips inThe Java Tutorial for further documentation.

      Parameters:
      text - the string to display; if the text isnull, the tool tip is turned off for this component
      See Also:
    • getToolTipText

      public String getToolTipText()
      Returns the tooltip string that has been set withsetToolTipText.
      Returns:
      the text of the tool tip
      See Also:
    • getToolTipText

      public String getToolTipText(MouseEvent event)
      Returns the string to be used as the tooltip forevent. By default this returns any string set usingsetToolTipText. If a component provides more extensive API to support differing tooltips at different locations, this method should be overridden.
      Parameters:
      event - theMouseEvent that initiated theToolTip display
      Returns:
      a string containing the tooltip
    • getToolTipLocation

      public Point getToolTipLocation(MouseEvent event)
      Returns the tooltip location in this component's coordinate system. Ifnull is returned, Swing will choose a location. The default implementation returnsnull.
      Parameters:
      event - theMouseEvent that caused theToolTipManager to show the tooltip
      Returns:
      always returnsnull
    • getPopupLocation

      public Point getPopupLocation(MouseEvent event)
      Returns the preferred location to display the popup menu in this component's coordinate system. It is up to the look and feel to honor this property, some may choose to ignore it. Ifnull, the look and feel will choose a suitable location.
      Parameters:
      event - theMouseEvent that triggered the popup to be shown, ornull if the popup is not being shown as the result of a mouse event
      Returns:
      location to display theJPopupMenu, ornull
      Since:
      1.5
    • createToolTip

      public JToolTip createToolTip()
      Returns the instance ofJToolTip 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:
      theJToolTip used to display this toolTip
    • scrollRectToVisible

      public void scrollRectToVisible(Rectangle aRect)
      Forwards thescrollRectToVisible() message to theJComponent's parent. Components that can service the request, such asJViewport, override this method and perform the scrolling.
      Parameters:
      aRect - the visibleRectangle
      See Also:
    • setAutoscrolls

      @BeanProperty(bound=false,expert=true,description="Determines if this component automatically scrolls its contents when dragged.")public void setAutoscrolls(boolean autoscrolls)
      Sets theautoscrolls property. Iftrue 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 handlemouseDragged events by callingscrollRectToVisible with a rectangle that contains the mouse event's location. All of the Swing components that support item selection and are typically displayed in aJScrollPane (JTable,JList,JTree,JTextArea, andJEditorPane) already handle mouse dragged events in this way. To enable autoscrolling in any other component, add a mouse motion listener that callsscrollRectToVisible. For example, given aJPanel,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 theautoScrolls property isfalse.
      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

      public boolean getAutoscrolls()
      Gets theautoscrolls property.
      Returns:
      the value of theautoscrolls property
      See Also:
    • setTransferHandler

      @BeanProperty(hidden=true,description="Mechanism for transfer of data to and from the component")public void setTransferHandler(TransferHandler newHandler)
      Sets theTransferHandler, which provides support for transfer of data into and out of this component via cut/copy/paste and drag and drop. This may benull if the component does not support data transfer operations.

      If the newTransferHandler is notnull, this method also installs anewDropTarget on the component to activate drop handling through theTransferHandler and activate any built-in support (such as calculating and displaying potential drop locations). If you do not wish for this component to respond in any way to drops, you can disable drop support entirely either by removing the drop target (setDropTarget(null)) or by de-activating it (getDropTaget().setActive(false)).

      If the newTransferHandler isnull, this method removes the drop target.

      Under two circumstances, this method does not modify the drop target: First, if the existing drop target on this component was explicitly set by the developer to anon-null value. Second, if the system propertysuppressSwingDropSupport istrue. The default value for the system property isfalse.

      Please see How to Use Drag and Drop and Data Transfer, a section inThe Java Tutorial, for more information.

      Parameters:
      newHandler - the newTransferHandler
      Since:
      1.4
      See Also:
    • getTransferHandler

      public TransferHandler getTransferHandler()
      Gets thetransferHandler property.
      Returns:
      the value of thetransferHandler property
      Since:
      1.4
      See Also:
    • processMouseEvent

      protected void processMouseEvent(MouseEvent e)
      Processes mouse events occurring on this component by dispatching them to any registeredMouseListener objects, refer toComponent.processMouseEvent(MouseEvent) for a complete description of this method.
      Overrides:
      processMouseEvent in class Component
      Parameters:
      e - the mouse event
      Since:
      1.5
      See Also:
    • processMouseMotionEvent

      protected void processMouseMotionEvent(MouseEvent e)
      Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.
      Overrides:
      processMouseMotionEvent in class Component
      Parameters:
      e - theMouseEvent
      See Also:
    • enable

      @Deprecatedpublic void enable()
      Deprecated.
      As of JDK version 1.1, replaced byjava.awt.Component.setEnabled(boolean).
      Overrides:
      enable in class Component
    • disable

      @Deprecatedpublic void disable()
      Deprecated.
      As of JDK version 1.1, replaced byjava.awt.Component.setEnabled(boolean).
      Overrides:
      disable in class Component
    • getClientProperty

      public final Object getClientProperty(Object key)
      Returns the value of the property with the specified key. Only properties added withputClientProperty will return a non-null value.
      Parameters:
      key - the being queried
      Returns:
      the value of this property ornull
      See Also:
    • putClientProperty

      public final void putClientProperty(Object key,Object value)
      Adds an arbitrary key/value "client property" to this component.

      Theget/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 isnull this method will remove the property. Changes to client properties are reported withPropertyChange events. The name of the property (for the sake of PropertyChange events) iskey.toString().

      TheclientProperty 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; ifnull this method will remove the property
      See Also:
    • setFocusTraversalKeys

      public void setFocusTraversalKeys(int id,Set<? extendsAWTKeyStroke> keystrokes)
      Sets the focus traversal keys for a given traversal operation for this Component. Refer toComponent.setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>) for a complete description of this method.

      This method may throw aClassCastException if anyObject inkeystrokes is not anAWTKeyStroke.

      Overrides:
      setFocusTraversalKeys in class Container
      Parameters:
      id - one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
      keystrokes - the Set of AWTKeyStroke for the specified operation
      Throws:
      IllegalArgumentException - if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or if keystrokes contains null, or if any keystroke represents a KEY_TYPED event, or if any keystroke already maps to another focus traversal operation for this Component
      Since:
      1.5
      See Also:
    • 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.
      Parameters:
      c - theComponent to be checked
      Returns:
      true if this component is lightweight
    • reshape

      @Deprecatedpublic void reshape(int x, int y, int w, int h)
      Deprecated.
      As of JDK 5, replaced byComponent.setBounds(int, int, int, int).

      Moves and resizes this component.

      Description copied from class: Component
      Reshapes the bounding rectangle for 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:
    • getBounds

      public Rectangle getBounds(Rectangle rv)
      Stores the bounds of this component into "return value"rv and returnsrv. Ifrv isnull a newRectangle is allocated. This version ofgetBounds is useful if the caller wants to avoid allocating a newRectangle object on the heap.
      Overrides:
      getBounds in class Component
      Parameters:
      rv - the return value, modified to the component's bounds
      Returns:
      rv; ifrv isnull return a newly createdRectangle with this component's bounds
    • getSize

      public Dimension getSize(Dimension rv)
      Stores the width/height of this component into "return value"rv and returnsrv. Ifrv isnull a newDimension object is allocated. This version ofgetSize is useful if the caller wants to avoid allocating a newDimension 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 returnsrv. Ifrv isnull a newPoint is allocated. This version ofgetLocation is useful if the caller wants to avoid allocating a newPoint object on the heap.
      Overrides:
      getLocation in class Component
      Parameters:
      rv - the return value, modified to the component's location
      Returns:
      rv
    • getX

      @BeanProperty(bound=false)public int getX()
      Returns the current x coordinate of the component's origin. This method is preferable to writingcomponent.getBounds().x, orcomponent.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

      @BeanProperty(bound=false)public int getY()
      Returns the current y coordinate of the component's origin. This method is preferable to writingcomponent.getBounds().y, orcomponent.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

      @BeanProperty(bound=false)public int getWidth()
      Returns the current width of this component. This method is preferable to writingcomponent.getBounds().width, orcomponent.getSize().width because it doesn't cause any heap allocations.
      Overrides:
      getWidth in class Component
      Returns:
      the current width of this component
    • getHeight

      @BeanProperty(bound=false)public int getHeight()
      Returns the current height of this component. This method is preferable to writingcomponent.getBounds().height, orcomponent.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

      @BeanProperty(expert=true,description="The component's opacity")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 forJComponent. However, the default value for this property on most standardJComponent subclasses (such asJButton andJTree) is look-and-feel dependent.

      Parameters:
      isOpaque - true if this component should be opaque
      See Also:
    • computeVisibleRect

      public void computeVisibleRect(Rectangle visibleRect)
      Returns theComponent's "visible rect rectangle" - the intersection of the visible rectangles for this component and all of its ancestors. The return value is stored invisibleRect.
      Parameters:
      visibleRect - aRectangle 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

      @BeanProperty(bound=false)public Rectangle getVisibleRect()
      Returns theComponent'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

      public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
      Support for reporting bound property changes for boolean properties. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.
      Overrides:
      firePropertyChange in class Component
      Parameters:
      propertyName - the property whose value has changed
      oldValue - the property's previous value
      newValue - the property's new value
    • firePropertyChange

      public void firePropertyChange(String propertyName, int oldValue, int newValue)
      Support for reporting bound property changes for integer properties. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.
      Overrides:
      firePropertyChange in class Component
      Parameters:
      propertyName - the property whose value has changed
      oldValue - the property's previous value
      newValue - the property's new value
    • fireVetoableChange

      protected void fireVetoableChange(String propertyName,Object oldValue,Object newValue) throwsPropertyVetoException
      Supports reporting constrained property changes. This method can be called when a constrained property has changed and it will send the appropriatePropertyChangeEvent to any registeredVetoableChangeListeners.
      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:
      PropertyVetoException - when the attempt to set the property is vetoed by the component
    • addVetoableChangeListener

      public void addVetoableChangeListener(VetoableChangeListener listener)
      Adds aVetoableChangeListener to the listener list. The listener is registered for all properties.
      Parameters:
      listener - theVetoableChangeListener to be added
    • removeVetoableChangeListener

      public void removeVetoableChangeListener(VetoableChangeListener listener)
      Removes aVetoableChangeListener from the listener list. This removes aVetoableChangeListener that was registered for all properties.
      Parameters:
      listener - theVetoableChangeListener to be removed
    • getVetoableChangeListeners

      @BeanProperty(bound=false)public VetoableChangeListener[] getVetoableChangeListeners()
      Returns an array of all the vetoable change listeners registered on this component.
      Returns:
      all of the component'sVetoableChangeListeners or an empty array if no vetoable change listeners are currently registered
      Since:
      1.4
      See Also:
    • getTopLevelAncestor

      @BeanProperty(bound=false)public Container getTopLevelAncestor()
      Returns the top-level ancestor of this component (either the containingWindow orApplet), ornull if this component has not been added to any container.
      Returns:
      the top-levelContainer that this component is in, ornull if not in any container
    • addAncestorListener

      public void addAncestorListener(AncestorListener listener)
      Registerslistener so that it will receiveAncestorEvents 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 - theAncestorListener to register
      See Also:
    • removeAncestorListener

      public void removeAncestorListener(AncestorListener listener)
      Unregisterslistener so that it will no longer receiveAncestorEvents.
      Parameters:
      listener - theAncestorListener to be removed
      See Also:
    • getAncestorListeners

      @BeanProperty(bound=false)public AncestorListener[] getAncestorListeners()
      Returns an array of all the ancestor listeners registered on this component.
      Returns:
      all of the component'sAncestorListeners or an empty array if no ancestor listeners are currently registered
      Since:
      1.4
      See Also:
    • getListeners

      public <T extendsEventListener> T[] getListeners(Class<T> listenerType)
      Returns an array of all the objects currently registered asFooListeners upon thisJComponent.FooListeners are registered using theaddFooListener method.

      You can specify thelistenerType argument with a class literal, such asFooListener.class. For example, you can query aJComponentc 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
      Type Parameters:
      T - the type of the listeners
      Parameters:
      listenerType - the type of listeners requested; this parameter should specify an interface that descends fromjava.util.EventListener
      Returns:
      an array of all objects registered asFooListeners on this component, or an empty array if no such listeners have been added
      Throws:
      ClassCastException - iflistenerType doesn't specify a class or interface that implementsjava.util.EventListener
      Since:
      1.3
      See Also:
    • 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 withKeyboardAction event listeners. This method is called by the toolkit internally and should not be called directly by programs.
      Overrides:
      addNotify in class Container
      See Also:
    • removeNotify

      public void removeNotify()
      Notifies this component that it no longer has a parent component. When this method is invoked, anyKeyboardActions set up in the chain of parent components are removed. This method is called by the toolkit internally and should not be called directly by programs.
      Overrides:
      removeNotify in class Container
      See Also:
    • 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:
    • 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 - aRectangle containing the dirty region
      See Also:
    • revalidate

      public void revalidate()
      Supports deferred automatic layout.

      Callsinvalidate and then adds this component'svalidateRoot 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, andJTextField return true fromisValidateRoot.

      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 invokevalidate to get the contents of the GUI to update.

      Overrides:
      revalidate in class Component
      See Also:
    • 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.
      Overrides:
      isValidateRoot in class Container
      Returns:
      always returns false
      See Also:
    • isOptimizedDrawingEnabled

      @BeanProperty(bound=false)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 asJLayeredPane, should override this method to return false.
      Returns:
      always returns true
    • isPaintingOrigin

      protected boolean isPaintingOrigin()
      Returnstrue if a paint triggered on a child component should cause painting to originate from this Component, or one of its ancestors.

      Callingrepaint(long, int, int, int, int) orpaintImmediately(int, int, int, int) on a Swing component will result in calling thepaintImmediately(int, int, int, int) method of the first ancestor whichisPaintingOrigin() returnstrue, if there are any.

      JComponent subclasses that need to be painted when any of their children are repainted should override this method to returntrue.

      Returns:
      always returnsfalse
      See Also:
    • 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.

      This method is to be overridden when the dirty region needs to be changed for components that are painting origins.

      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:
    • paintImmediately

      public void paintImmediately(Rectangle r)
      Paints the specified region now.
      Parameters:
      r - aRectangle containing the region to be painted
    • setDoubleBuffered

      public void setDoubleBuffered(boolean aFlag)
      Sets whether 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. If aComponent 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

      @BeanProperty(bound=false)public JRootPane getRootPane()
      Returns theJRootPane ancestor for this component.
      Returns:
      theJRootPane that contains this component, ornull if noJRootPane is found
    • paramString

      protected String paramString()
      Returns a string representation of thisJComponent. 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 benull.
      Overrides:
      paramString in class Container
      Returns:
      a string representation of thisJComponent
    • hide

      @Deprecatedpublic void hide()
      Deprecated.
      Overrides:
      hide in class Component