java.awt
Class Scrollbar

java.lang.Object
  extended by java.awt.Component
      extended by java.awt.Scrollbar
All Implemented Interfaces:
Adjustable, ImageObserver, MenuContainer, Serializable, Accessible

public class Scrollbar
extends Component
implements Accessible, Adjustable

This class implements a scrollbar widget.

See Also:
Serialized Form

Nested Class Summary
protected  class Scrollbar.AccessibleAWTScrollBar
          This class provides accessibility support for the scrollbar.
 
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy
 
Field Summary
static int HORIZONTAL
          Constant indicating that a scrollbar is horizontal.
static int VERTICAL
          Constant indicating that a scrollbar is vertical.
 
Fields inherited from class java.awt.Component
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
 
Fields inherited from interface java.awt.Adjustable
NO_ORIENTATION
 
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 
Constructor Summary
Scrollbar()
          Initializes a new instance of Scrollbar with a vertical orientation and default values for all other parameters.
Scrollbar(int orientation)
          Initializes a new instance of Scrollbar with the specified orientation and default values for all other parameters.
Scrollbar(int orientation, int value, int visibleAmount, int minimum, int maximum)
          Initializes a new instance of Scrollbar with the specified parameters.
 
Method Summary
 void addAdjustmentListener(AdjustmentListener listener)
          Adds a new adjustment listener to the list of registered listeners for this object.
 void addNotify()
          Notifies this object to create its native peer.
 AccessibleContext getAccessibleContext()
          Gets the AccessibleContext associated with this Scrollbar.
 AdjustmentListener[] getAdjustmentListeners()
          Returns an array of all registered adjustment listeners.
 int getBlockIncrement()
          Returns the value added or subtracted when the user activates the scrollbar scroll by a "block" amount.
 int getLineIncrement()
          Deprecated. This method is deprecated in favor of getUnitIncrement().
<T extends EventListener>
T[]
getListeners(Class<T> listenerType)
          Returns an array of all the objects currently registered as FooListeners upon this Scrollbar.
 int getMaximum()
          Returns the maximum value for this scrollbar.
 int getMinimum()
          Returns the minimum value for this scrollbar.
 int getOrientation()
          Returns the orientation constant for this object.
 int getPageIncrement()
          Deprecated. This method is deprecated in favor of getBlockIncrement().
 int getUnitIncrement()
          Returns the value added or subtracted when the user activates the scrollbar scroll by a "unit" amount.
 int getValue()
          Returns the current value for this scrollbar.
 boolean getValueIsAdjusting()
          Returns true if the value is in the process of changing.
 int getVisible()
          Deprecated. This method is deprecated in favor of getVisibleAmount().
 int getVisibleAmount()
          Returns the width of the scrollbar's thumb, in units relative to the maximum and minimum value of the scrollbar.
protected  String paramString()
          Returns a debugging string for this object.
protected  void processAdjustmentEvent(AdjustmentEvent event)
          Processes adjustment events for this object by dispatching them to any registered listeners.
protected  void processEvent(AWTEvent event)
          Processes events for this scrollbar.
 void removeAdjustmentListener(AdjustmentListener listener)
          Removes the specified listener from the list of registered listeners for this object.
 void setBlockIncrement(int blockIncrement)
          Sets the value added or subtracted to the scrollbar value when the user selects the scroll by a "block" amount control.
 void setLineIncrement(int lineIncrement)
          Deprecated. This method is deprecated in favor of setUnitIncrement().
 void setMaximum(int maximum)
          Sets the maximum value for this scrollbar to the specified value.
 void setMinimum(int minimum)
          Sets the minimum value for this scrollbar to the specified value.
 void setOrientation(int orientation)
          Sets the orientation of this scrollbar to the specified value.
 void setPageIncrement(int pageIncrement)
          Deprecated. This method is deprecated in favor of setBlockIncrement().
 void setUnitIncrement(int unitIncrement)
          Sets the value added or subtracted to the scrollbar value when the user selects the scroll by a "unit" amount control.
 void setValue(int value)
          Sets the current value for this scrollbar to the specified value.
 void setValueIsAdjusting(boolean valueIsAdjusting)
          Sets the value of valueIsAdjusting.
 void setValues(int value, int visibleAmount, int minimum, int maximum)
          Sets the current value, visible amount, minimum, and maximum for this scrollbar.
 void setVisibleAmount(int visibleAmount)
          Sets the width of the scrollbar's thumb, in units relative to the maximum and minimum value of the scrollbar.
 
Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

HORIZONTAL

public static final int HORIZONTAL
Constant indicating that a scrollbar is horizontal.

See Also:
Constant Field Values

VERTICAL

public static final int VERTICAL
Constant indicating that a scrollbar is vertical.

See Also:
Constant Field Values
Constructor Detail

Scrollbar

public Scrollbar()
Initializes a new instance of Scrollbar with a vertical orientation and default values for all other parameters.

Throws:
HeadlessException - If GraphicsEnvironment.isHeadless() is true,

Scrollbar

public Scrollbar(int orientation)
          throws IllegalArgumentException
Initializes a new instance of Scrollbar with the specified orientation and default values for all other parameters. The orientation must be either the constant HORIZONTAL or VERTICAL from this class. An incorrect value will throw an exception.

Parameters:
orientation - The orientation of this scrollbar.
Throws:
HeadlessException - If GraphicsEnvironment.isHeadless() is true,
IllegalArgumentException - If the orientation value is not valid.

Scrollbar

public Scrollbar(int orientation,
                 int value,
                 int visibleAmount,
                 int minimum,
                 int maximum)
          throws IllegalArgumentException
Initializes a new instance of Scrollbar with the specified parameters. The orientation must be either the constant HORIZONTAL or VERTICAL. An incorrect value will throw an exception. Inconsistent values for other parameters are silently corrected to valid values.

Parameters:
orientation - The orientation of this scrollbar.
value - The initial value of the scrollbar.
visibleAmount - The width of the scrollbar thumb.
minimum - The minimum value of the scrollbar.
maximum - The maximum value of the scrollbar.
Throws:
HeadlessException - If GraphicsEnvironment.isHeadless() is true,
IllegalArgumentException - If the orientation value is not valid.
Method Detail

getOrientation

public int getOrientation()
Returns the orientation constant for this object.

Specified by:
getOrientation in interface Adjustable
Returns:
The orientation constant for this object.
See Also:
Adjustable.HORIZONTAL, Adjustable.VERTICAL, Adjustable.NO_ORIENTATION

setOrientation

public void setOrientation(int orientation)
Sets the orientation of this scrollbar to the specified value. This value must be either the constant HORIZONTAL or VERTICAL from this class or an exception will be thrown.

Parameters:
orientation - The new orientation value.
Throws:
IllegalArgumentException - If the orientation value is not valid.

getValue

public int getValue()
Returns the current value for this scrollbar.

Specified by:
getValue in interface Adjustable
Returns:
The current value for this scrollbar.

setValue

public void setValue(int value)
Sets the current value for this scrollbar to the specified value. If this is inconsistent with the minimum and maximum values for this scrollbar, the value is silently adjusted.

Specified by:
setValue in interface Adjustable
Parameters:
value - The new value for this scrollbar.

getMaximum

public int getMaximum()
Returns the maximum value for this scrollbar.

Specified by:
getMaximum in interface Adjustable
Returns:
The maximum value for this scrollbar.

setMaximum

public void setMaximum(int maximum)
Sets the maximum value for this scrollbar to the specified value. If the value is less than the current minimum value, it is silent set to equal the minimum value.

Specified by:
setMaximum in interface Adjustable
Parameters:
maximum - The new maximum value for this scrollbar.

getMinimum

public int getMinimum()
Returns the minimum value for this scrollbar.

Specified by:
getMinimum in interface Adjustable
Returns:
The minimum value for this scrollbar.

setMinimum

public void setMinimum(int minimum)
Sets the minimum value for this scrollbar to the specified value. If this is not consistent with the current value and maximum, it is silently adjusted to be consistent.

Specified by:
setMinimum in interface Adjustable
Parameters:
minimum - The new minimum value for this scrollbar.

getVisibleAmount

public int getVisibleAmount()
Returns the width of the scrollbar's thumb, in units relative to the maximum and minimum value of the scrollbar.

Specified by:
getVisibleAmount in interface Adjustable
Returns:
The width of the scrollbar's thumb.

getVisible

public int getVisible()
Deprecated. This method is deprecated in favor of getVisibleAmount().

Returns the width of the scrollbar's thumb, in units relative to the maximum and minimum value of the scrollbar.

Returns:
The width of the scrollbar's thumb.

setVisibleAmount

public void setVisibleAmount(int visibleAmount)
Sets the width of the scrollbar's thumb, in units relative to the maximum and minimum value of the scrollbar.

Specified by:
setVisibleAmount in interface Adjustable
Parameters:
visibleAmount - The new visible amount value of the scrollbar.

setValues

public void setValues(int value,
                      int visibleAmount,
                      int minimum,
                      int maximum)
Sets the current value, visible amount, minimum, and maximum for this scrollbar. These values are adjusted to be internally consistent if necessary.

Parameters:
value - The new value for this scrollbar.
visibleAmount - The new visible amount for this scrollbar.
minimum - The new minimum value for this scrollbar.
maximum - The new maximum value for this scrollbar.

getUnitIncrement

public int getUnitIncrement()
Returns the value added or subtracted when the user activates the scrollbar scroll by a "unit" amount.

Specified by:
getUnitIncrement in interface Adjustable
Returns:
The unit increment value.

getLineIncrement

public int getLineIncrement()
Deprecated. This method is deprecated in favor of getUnitIncrement().

Returns the value added or subtracted when the user selects the scrollbar scroll by a "unit" amount control.

Returns:
The unit increment value.

setUnitIncrement

public void setUnitIncrement(int unitIncrement)
Sets the value added or subtracted to the scrollbar value when the user selects the scroll by a "unit" amount control.

Specified by:
setUnitIncrement in interface Adjustable
Parameters:
unitIncrement - The new unit increment amount.

setLineIncrement

public void setLineIncrement(int lineIncrement)
Deprecated. This method is deprecated in favor of setUnitIncrement().

Sets the value added or subtracted to the scrollbar value when the user selects the scroll by a "unit" amount control.

Parameters:
lineIncrement - The new unit increment amount.

getBlockIncrement

public int getBlockIncrement()
Returns the value added or subtracted when the user activates the scrollbar scroll by a "block" amount.

Specified by:
getBlockIncrement in interface Adjustable
Returns:
The block increment value.

getPageIncrement

public int getPageIncrement()
Deprecated. This method is deprecated in favor of getBlockIncrement().

Returns the value added or subtracted when the user selects the scrollbar scroll by a "block" amount control.

Returns:
The block increment value.

setBlockIncrement

public void setBlockIncrement(int blockIncrement)
Sets the value added or subtracted to the scrollbar value when the user selects the scroll by a "block" amount control.

Specified by:
setBlockIncrement in interface Adjustable
Parameters:
blockIncrement - The new block increment amount.

setPageIncrement

public void setPageIncrement(int pageIncrement)
Deprecated. This method is deprecated in favor of setBlockIncrement().

Sets the value added or subtracted to the scrollbar value when the user selects the scroll by a "block" amount control.

Parameters:
pageIncrement - The new block increment amount.

addNotify

public void addNotify()
Notifies this object to create its native peer.

Overrides:
addNotify in class Component
See Also:
Component.isDisplayable(), Component.removeNotify()

addAdjustmentListener

public void addAdjustmentListener(AdjustmentListener listener)
Adds a new adjustment listener to the list of registered listeners for this object.

Specified by:
addAdjustmentListener in interface Adjustable
Parameters:
listener - The listener to add.
See Also:
AdjustmentEvent

removeAdjustmentListener

public void removeAdjustmentListener(AdjustmentListener listener)
Removes the specified listener from the list of registered listeners for this object.

Specified by:
removeAdjustmentListener in interface Adjustable
Parameters:
listener - The listener to remove.
See Also:
AdjustmentEvent

processEvent

protected void processEvent(AWTEvent event)
Processes events for this scrollbar. It does this by calling processAdjustmentEvent() if the event is an instance of AdjustmentEvent, otherwise it calls the superclass to process the event.

Overrides:
processEvent in class Component
Parameters:
event - The event to process.
See Also:
Component.processComponentEvent(ComponentEvent), Component.processFocusEvent(FocusEvent), Component.processKeyEvent(KeyEvent), Component.processMouseEvent(MouseEvent), Component.processMouseMotionEvent(MouseEvent), Component.processInputMethodEvent(InputMethodEvent), Component.processHierarchyEvent(HierarchyEvent), Component.processMouseWheelEvent(MouseWheelEvent)

processAdjustmentEvent

protected void processAdjustmentEvent(AdjustmentEvent event)
Processes adjustment events for this object by dispatching them to any registered listeners. Note that this method will only be called if adjustment events are enabled. This will happen automatically if any listeners are registered. Otherwise, it can be enabled by a call to enableEvents().

Parameters:
event - The event to process.

paramString

protected String paramString()
Returns a debugging string for this object.

Overrides:
paramString in class Component
Returns:
A debugging string for this object.

getListeners

public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListeners upon this Scrollbar. FooListeners are registered using the addFooListener method.

Overrides:
getListeners in class Component
Parameters:
listenerType - the class of listeners to filter (null not permitted).
Returns:
An array of registered listeners.
Throws:
ClassCastException - If listenerType doesn't specify a class or interface that implements java.util.EventListener.
See Also:
Component.getComponentListeners(), Component.getFocusListeners(), Component.getHierarchyListeners(), Component.getHierarchyBoundsListeners(), Component.getKeyListeners(), Component.getMouseListeners(), Component.getMouseMotionListeners(), Component.getMouseWheelListeners(), Component.getInputMethodListeners(), Component.getPropertyChangeListeners()

getAdjustmentListeners

public AdjustmentListener[] getAdjustmentListeners()
Returns an array of all registered adjustment listeners.


getValueIsAdjusting

public boolean getValueIsAdjusting()
Returns true if the value is in the process of changing.

Since:
1.4

setValueIsAdjusting

public void setValueIsAdjusting(boolean valueIsAdjusting)
Sets the value of valueIsAdjusting.

Since:
1.4

getAccessibleContext

public AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this Scrollbar. The context is created, if necessary.

Specified by:
getAccessibleContext in interface Accessible
Overrides:
getAccessibleContext in class Component
Returns:
the associated context