class:BasicScrollPaneUI [NONE]

All Implemented Interfaces:

ScrollPaneConstants

Direct Known Subclasses:

MetalScrollPaneUI, SynthScrollPaneUI
```
public class BasicScrollPaneUI
extends ScrollPaneUI
implements ScrollPaneConstants
```
A default L&F implementation of ScrollPaneUI.

field:scrollpane [NONE]

scrollpane
```
protected JScrollPane scrollpane
```
The instance of JScrollPane.

field:vsbChangeListener [NONE]

vsbChangeListener
```
protected ChangeListener vsbChangeListener
```
ChangeListener installed on the vertical scrollbar.

field:hsbChangeListener [NONE]

hsbChangeListener
```
protected ChangeListener hsbChangeListener
```
ChangeListener installed on the horizontal scrollbar.

field:viewportChangeListener [NONE]

viewportChangeListener
```
protected ChangeListener viewportChangeListener
```
ChangeListener installed on the viewport.

field:spPropertyChangeListener [NONE]

spPropertyChangeListener
```
protected PropertyChangeListener spPropertyChangeListener
```
PropertyChangeListener installed on the scroll pane.

constructor:<init>() [NONE]

BasicScrollPaneUI
```
public BasicScrollPaneUI()
```

method:createUI(javax.swing.JComponent) [NONE]

createUI
```
public static ComponentUI createUI(JComponent x)
```
Returns a new instance of BasicScrollPaneUI.

Parameters:

x - a component.

Returns:

a new instance of BasicScrollPaneUI

method:paint(java.awt.Graphics,javax.swing.JComponent) [NONE]

paint
```
public void paint(Graphics g,
                  JComponent c)
```
Description copied from class: ComponentUI

Paints the specified component appropriately for the look and feel. This method is invoked from the 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.

Overrides:

paint in class ComponentUI

Parameters:

g - the Graphics context in which to paint

c - the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

See Also:

ComponentUI.update(java.awt.Graphics, javax.swing.JComponent)

method:getMaximumSize(javax.swing.JComponent) [NONE]

getMaximumSize
```
public Dimension getMaximumSize(JComponent c)
```
Description copied from class: ComponentUI

Returns the specified component's maximum size appropriate for the look and feel. If 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.

Overrides:

getMaximumSize in class ComponentUI

Parameters:

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 components

Returns:

new Dimension(Short.MAX_VALUE, Short.MAX_VALUE)

See Also:

JComponent.getMaximumSize(), LayoutManager2.maximumLayoutSize(java.awt.Container)

method:installDefaults(javax.swing.JScrollPane) [NONE]

installDefaults
```
protected void installDefaults(JScrollPane scrollpane)
```
Installs default properties.

Parameters:

scrollpane - an instance of JScrollPane

method:installListeners(javax.swing.JScrollPane) [NONE]

installListeners
```
protected void installListeners(JScrollPane c)
```
Registers listeners.

Parameters:

c - an instance of JScrollPane

method:installKeyboardActions(javax.swing.JScrollPane) [NONE]

installKeyboardActions
```
protected void installKeyboardActions(JScrollPane c)
```
Registers keyboard actions.

Parameters:

c - an instance of JScrollPane

method:installUI(javax.swing.JComponent) [NONE]

installUI
```
public void installUI(JComponent x)
```
Description copied from class: ComponentUI
Configures the specified component appropriately for the look and feel. This method is invoked when the 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:
1. Install default property values for color, fonts, borders, icons, opacity, etc. on the component. Whenever possible, property values initialized by the client program should not be overridden.
2. Install a LayoutManager on the component if necessary.
3. Create/add any required sub-components to the component.
4. Create/install event listeners on the component.
5. Create/install a PropertyChangeListener on the component in order to detect and respond to component property changes appropriately.
6. Install keyboard UI (mnemonics, traversal, etc.) on the component.
7. Initialize any appropriate instance data.
Overrides:

installUI in class ComponentUI

Parameters:

x - the component where this UI delegate is being installed

See Also:

ComponentUI.uninstallUI(javax.swing.JComponent), JComponent.setUI(javax.swing.plaf.ComponentUI), JComponent.updateUI()

method:uninstallDefaults(javax.swing.JScrollPane) [NONE]

uninstallDefaults
```
protected void uninstallDefaults(JScrollPane c)
```
Uninstalls default properties.

Parameters:

c - an instance of JScrollPane

method:uninstallListeners(javax.swing.JComponent) [NONE]

uninstallListeners
```
protected void uninstallListeners(JComponent c)
```
Unregisters listeners.

Parameters:

c - a component

method:uninstallKeyboardActions(javax.swing.JScrollPane) [NONE]

uninstallKeyboardActions
```
protected void uninstallKeyboardActions(JScrollPane c)
```
Unregisters keyboard actions.

Parameters:

c - an instance of JScrollPane

method:uninstallUI(javax.swing.JComponent) [NONE]

uninstallUI
```
public void uninstallUI(JComponent c)
```
Description copied from class: ComponentUI
Reverses configuration which was done on the specified component during 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:
1. Remove any UI-set borders from the component.
2. Remove any UI-set layout managers on the component.
3. Remove any UI-added sub-components from the component.
4. Remove any UI-added event/property listeners from the component.
5. Remove any UI-installed keyboard UI from the component.
6. Nullify any allocated instance data objects to allow for GC.
Overrides:

uninstallUI in class ComponentUI

Parameters:

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 components

See Also:

ComponentUI.installUI(javax.swing.JComponent), JComponent.updateUI()

method:syncScrollPaneWithViewport() [NONE]

syncScrollPaneWithViewport
```
protected void syncScrollPaneWithViewport()
```
Synchronizes the JScrollPane with Viewport.

method:getBaseline(javax.swing.JComponent,int,int) [NONE]

getBaseline
```
public int getBaseline(JComponent c,
                       int width,
                       int height)
```
Returns the baseline.

Overrides:

getBaseline in class ComponentUI

Parameters:

c - JComponent baseline is being requested for

width - the width to get the baseline for

height - the height to get the baseline for

Returns:

baseline or a value < 0 indicating there is no reasonable baseline

Throws:

NullPointerException - if c is null

IllegalArgumentException - if width or height is < 0

Since:

1.6

See Also:

JComponent.getBaseline(int, int)

method:getBaselineResizeBehavior(javax.swing.JComponent) [NONE]

getBaselineResizeBehavior
```
public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
```
Returns an enum indicating how the baseline of the component changes as the size changes.

Overrides:

getBaselineResizeBehavior in class ComponentUI

Parameters:

c - JComponent to return baseline resize behavior for

Returns:

an enum indicating how the baseline changes as the component size changes

Throws:

NullPointerException - if c is null

Since:

1.6

See Also:

JComponent.getBaseline(int, int)

method:createViewportChangeListener() [NONE]

createViewportChangeListener
```
protected ChangeListener createViewportChangeListener()
```
Returns an instance of viewport ChangeListener.

Returns:

an instance of viewport ChangeListener

method:createHSBChangeListener() [NONE]

createHSBChangeListener
```
protected ChangeListener createHSBChangeListener()
```
Returns an instance of horizontal scroll bar ChangeListener.

Returns:

an instance of horizontal scroll bar ChangeListener

method:createVSBChangeListener() [NONE]

createVSBChangeListener
```
protected ChangeListener createVSBChangeListener()
```
Returns an instance of vertical scroll bar ChangeListener.

Returns:

an instance of vertical scroll bar ChangeListener

method:createMouseWheelListener() [NONE]

createMouseWheelListener
```
protected MouseWheelListener createMouseWheelListener()
```
Creates an instance of MouseWheelListener, which is added to the JScrollPane by installUI(). The returned MouseWheelListener is used to handle mouse wheel-driven scrolling.

Returns:

MouseWheelListener which implements wheel-driven scrolling

Since:

1.4

See Also:

installUI(javax.swing.JComponent), BasicScrollPaneUI.MouseWheelHandler

method:updateScrollBarDisplayPolicy(java.beans.PropertyChangeEvent) [NONE]

updateScrollBarDisplayPolicy
```
protected void updateScrollBarDisplayPolicy(PropertyChangeEvent e)
```
Updates a scroll bar display policy.

Parameters:

e - the property change event

method:updateViewport(java.beans.PropertyChangeEvent) [NONE]

updateViewport
```
protected void updateViewport(PropertyChangeEvent e)
```
Updates viewport.

Parameters:

e - the property change event

method:updateRowHeader(java.beans.PropertyChangeEvent) [NONE]

updateRowHeader
```
protected void updateRowHeader(PropertyChangeEvent e)
```
Updates row header.

Parameters:

e - the property change event

method:updateColumnHeader(java.beans.PropertyChangeEvent) [NONE]

updateColumnHeader
```
protected void updateColumnHeader(PropertyChangeEvent e)
```
Updates column header.

Parameters:

e - the property change event

method:createPropertyChangeListener() [NONE]

createPropertyChangeListener

protected PropertyChangeListener createPropertyChangeListener()

Creates an instance of PropertyChangeListener that's added to the JScrollPane by installUI(). Subclasses can override this method to return a custom PropertyChangeListener, e.g.

 class MyScrollPaneUI extends BasicScrollPaneUI {
    protected PropertyChangeListener createPropertyChangeListener() {
        return new MyPropertyChangeListener();
    }
    public class MyPropertyChangeListener extends PropertyChangeListener {
        public void propertyChange(PropertyChangeEvent e) {
            if (e.getPropertyName().equals("viewport")) {
                // do some extra work when the viewport changes
            }
            super.propertyChange(e);
        }
    }
 }

Returns:: an instance of PropertyChangeListener
See Also:: PropertyChangeListener, installUI(javax.swing.JComponent)