public abstract class ComponentUI extends Object
JComponent class
 invokes methods from this class in order to delegate operations
 (painting, layout calculations, etc.) that may vary depending on the
 look and feel installed.  Client programs should not invoke methods
 on this class directly.JComponent, 
UIManager| Constructor and Description | 
|---|
| ComponentUI()Sole constructor. | 
| Modifier and Type | Method and Description | 
|---|---|
| boolean | contains(JComponent c,
        int x,
        int y)Returns  trueif the specified x,y location is
 contained within the look and feel's defined shape of the specified
 component. | 
| static ComponentUI | createUI(JComponent c)Returns an instance of the UI delegate for the specified component. | 
| Accessible | getAccessibleChild(JComponent c,
                  int i)Returns the  ithAccessiblechild of the object. | 
| int | getAccessibleChildrenCount(JComponent c)Returns the number of accessible children in the object. | 
| int | getBaseline(JComponent c,
           int width,
           int height)Returns the baseline. | 
| Component.BaselineResizeBehavior | getBaselineResizeBehavior(JComponent c)Returns an enum indicating how the baseline of he component
 changes as the size changes. | 
| Dimension | getMaximumSize(JComponent c)Returns the specified component's maximum size appropriate for
 the look and feel. | 
| Dimension | getMinimumSize(JComponent c)Returns the specified component's minimum size appropriate for
 the look and feel. | 
| Dimension | getPreferredSize(JComponent c)Returns the specified component's preferred size appropriate for
 the look and feel. | 
| void | installUI(JComponent c)Configures the specified component appropriately for the look and feel. | 
| void | paint(Graphics g,
     JComponent c)Paints the specified component appropriately for the look and feel. | 
| void | uninstallUI(JComponent c)Reverses configuration which was done on the specified component during
  installUI. | 
| void | update(Graphics g,
      JComponent c)Notifies this UI delegate that it is time to paint the specified
 component. | 
public ComponentUI()
public void installUI(JComponent c)
ComponentUI instance is being installed
 as the UI delegate on the specified component.  This method should
 completely configure the component for the look and feel,
 including the following:
 LayoutManager on the component if necessary.
 PropertyChangeListener on the component in order
     to detect and respond to component property changes appropriately.
 c - the component where this UI delegate is being installeduninstallUI(javax.swing.JComponent), 
JComponent.setUI(javax.swing.plaf.ComponentUI), 
JComponent.updateUI()public void uninstallUI(JComponent c)
installUI.  This method is invoked when this
 UIComponent instance is being removed as the UI delegate
 for the specified component.  This method should undo the
 configuration performed in installUI, being careful to
 leave the JComponent instance in a clean state (no
 extraneous listeners, look-and-feel-specific property objects, etc.).
 This should include the following:
 c - the component from which this UI delegate is being removed;
          this argument is often ignored,
          but might be used if the UI object is stateless
          and shared by multiple componentsinstallUI(javax.swing.JComponent), 
JComponent.updateUI()public void paint(Graphics g, JComponent c)
ComponentUI.update method when
 the specified component is being painted.  Subclasses should override
 this method and use the specified Graphics object to
 render the content of the component.g - the Graphics context in which to paintc - the component being painted;
          this argument is often ignored,
          but might be used if the UI object is stateless
          and shared by multiple componentsupdate(java.awt.Graphics, javax.swing.JComponent)public void update(Graphics g, JComponent c)
JComponent
 when the specified component is being painted.
 By default this method fills the specified component with
 its background color if its opaque property is true,
 and then immediately calls paint. In general this method need
 not be overridden by subclasses; all look-and-feel rendering code should
 reside in the paint method.
g - the Graphics context in which to paintc - the component being painted;
          this argument is often ignored,
          but might be used if the UI object is stateless
          and shared by multiple componentspaint(java.awt.Graphics, javax.swing.JComponent), 
JComponent.paintComponent(java.awt.Graphics)public Dimension getPreferredSize(JComponent c)
null is returned, the preferred
 size will be calculated by the component's layout manager instead
 (this is the preferred approach for any component with a specific
 layout manager installed).  The default implementation of this
 method returns null.c - the component whose preferred size is being queried;
          this argument is often ignored,
          but might be used if the UI object is stateless
          and shared by multiple componentsJComponent.getPreferredSize(), 
LayoutManager.preferredLayoutSize(java.awt.Container)public Dimension getMinimumSize(JComponent c)
null is returned, the minimum
 size will be calculated by the component's layout manager instead
 (this is the preferred approach for any component with a specific
 layout manager installed).  The default implementation of this
 method invokes getPreferredSize and returns that value.c - the component whose minimum size is being queried;
          this argument is often ignored,
          but might be used if the UI object is stateless
          and shared by multiple componentsDimension object or nullJComponent.getMinimumSize(), 
LayoutManager.minimumLayoutSize(java.awt.Container), 
getPreferredSize(javax.swing.JComponent)public Dimension getMaximumSize(JComponent c)
null is returned, the maximum
 size will be calculated by the component's layout manager instead
 (this is the preferred approach for any component with a specific
 layout manager installed).  The default implementation of this
 method invokes getPreferredSize and returns that value.c - the component whose maximum size is being queried;
          this argument is often ignored,
          but might be used if the UI object is stateless
          and shared by multiple componentsDimension object or nullJComponent.getMaximumSize(), 
LayoutManager2.maximumLayoutSize(java.awt.Container)public boolean contains(JComponent c, int x, int y)
true if the specified x,y location is
 contained within the look and feel's defined shape of the specified
 component. x and y are defined to be relative
 to the coordinate system of the specified component.  Although
 a component's bounds is constrained to a rectangle,
 this method provides the means for defining a non-rectangular
 shape within those bounds for the purpose of hit detection.c - the component where the x,y location is being queried;
          this argument is often ignored,
          but might be used if the UI object is stateless
          and shared by multiple componentsx - the x coordinate of the pointy - the y coordinate of the pointJComponent.contains(int, int), 
Component.contains(int, int)public static ComponentUI createUI(JComponent c)
createUI
 method that returns an instance of that UI delegate subclass.
 If the UI delegate subclass is stateless, it may return an instance
 that is shared by multiple components.  If the UI delegate is
 stateful, then it should return a new instance per component.
 The default implementation of this method throws an error, as it
 should never be invoked.public int getBaseline(JComponent c, int width, int height)
LayoutManagers to align components along their
 baseline.  A return value less than 0 indicates this component
 does not have a reasonable baseline and that
 LayoutManagers should not align this component on
 its baseline.
 This method returns -1. Subclasses that have a meaningful baseline should override appropriately.
c - JComponent baseline is being requested forwidth - the width to get the baseline forheight - the height to get the baseline forNullPointerException - if c is nullIllegalArgumentException - if width or height is < 0JComponent.getBaseline(int,int)public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
 This method returns BaselineResizeBehavior.OTHER.
 Subclasses that support a baseline should override appropriately.
c - JComponent to return baseline resize behavior forNullPointerException - if c is nullJComponent.getBaseline(int, int)public int getAccessibleChildrenCount(JComponent c)
Accessible,
 this
 method should return the number of children of this object.
 UIs might wish to override this if they present areas on the
 screen that can be viewed as components, but actual components
 are not used for presenting those areas.
 Note: As of v1.3, it is recommended that developers call
 Component.AccessibleAWTComponent.getAccessibleChildrenCount() instead
 of this method.getAccessibleChild(javax.swing.JComponent, int)public Accessible getAccessibleChild(JComponent c, int i)
ith Accessible child of the object.
 UIs might need to override this if they present areas on the
 screen that can be viewed as components, but actual components
 are not used for presenting those areas.
 
 Note: As of v1.3, it is recommended that developers call
 Component.AccessibleAWTComponent.getAccessibleChild() instead of
 this method.
i - zero-based index of childith Accessible child of the objectgetAccessibleChildrenCount(javax.swing.JComponent) Submit a bug or feature 
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