Class Scrollbar

java.lang.Object

java.awt.Component

java.awt.Scrollbar

All Implemented Interfaces:

Adjustable, ImageObserver, MenuContainer, Serializable, Accessible

public class Scrollbar
extends Component
implements Adjustable, Accessible

The Scrollbar class embodies a scroll bar, a familiar user-interface object. A scroll bar provides a convenient means for allowing a user to select from a range of values. The following three vertical scroll bars could be used as slider controls to pick the red, green, and blue components of a color:

Each scroll bar in this example could be created with code similar to the following:

redSlider=new Scrollbar(Scrollbar.VERTICAL, 0, 1, 0, 255);
add(redSlider);

Alternatively, a scroll bar can represent a range of values. For example, if a scroll bar is used for scrolling through text, the width of the "bubble" (also called the "thumb" or "scroll box") can be used to represent the amount of text that is visible. Here is an example of a scroll bar that represents a range:

The value range represented by the bubble in this example is the visible amount. The horizontal scroll bar in this example could be created with code like the following:

ranger = new Scrollbar(Scrollbar.HORIZONTAL, 0, 60, 0, 300);
add(ranger);

Note that the actual maximum value of the scroll bar is the maximum minus the visible amount. In the previous example, because the maximum is 300 and the visible amount is 60, the actual maximum value is 240. The range of the scrollbar track is 0 - 300. The left side of the bubble indicates the value of the scroll bar.

Normally, the user changes the value of the scroll bar by making a gesture with the mouse. For example, the user can drag the scroll bar's bubble up and down, or click in the scroll bar's unit increment or block increment areas. Keyboard gestures can also be mapped to the scroll bar. By convention, the Page Up and Page Down keys are equivalent to clicking in the scroll bar's block increment and block decrement areas.

When the user changes the value of the scroll bar, the scroll bar receives an instance of AdjustmentEvent. The scroll bar processes this event, passing it along to any registered listeners.

Any object that wishes to be notified of changes to the scroll bar's value should implement AdjustmentListener, an interface defined in the package java.awt.event. Listeners can be added and removed dynamically by calling the methods addAdjustmentListener and removeAdjustmentListener.

The AdjustmentEvent class defines five types of adjustment event, listed here:

• AdjustmentEvent.TRACK is sent out when the user drags the scroll bar's bubble.
• AdjustmentEvent.UNIT_INCREMENT is sent out when the user clicks in the left arrow of a horizontal scroll bar, or the top arrow of a vertical scroll bar, or makes the equivalent gesture from the keyboard.
• AdjustmentEvent.UNIT_DECREMENT is sent out when the user clicks in the right arrow of a horizontal scroll bar, or the bottom arrow of a vertical scroll bar, or makes the equivalent gesture from the keyboard.
• AdjustmentEvent.BLOCK_INCREMENT is sent out when the user clicks in the track, to the left of the bubble on a horizontal scroll bar, or above the bubble on a vertical scroll bar. By convention, the Page Up key is equivalent, if the user is using a keyboard that defines a Page Up key.
• AdjustmentEvent.BLOCK_DECREMENT is sent out when the user clicks in the track, to the right of the bubble on a horizontal scroll bar, or below the bubble on a vertical scroll bar. By convention, the Page Down key is equivalent, if the user is using a keyboard that defines a Page Down key.

The JDK 1.0 event system is supported for backwards compatibility, but its use with newer versions of the platform is discouraged. The five types of adjustment events introduced with JDK 1.1 correspond to the five event types that are associated with scroll bars in previous platform versions. The following list gives the adjustment event type, and the corresponding JDK 1.0 event type it replaces.

• AdjustmentEvent.TRACK replaces Event.SCROLL_ABSOLUTE
• AdjustmentEvent.UNIT_INCREMENT replaces Event.SCROLL_LINE_UP
• AdjustmentEvent.UNIT_DECREMENT replaces Event.SCROLL_LINE_DOWN
• AdjustmentEvent.BLOCK_INCREMENT replaces Event.SCROLL_PAGE_UP
• AdjustmentEvent.BLOCK_DECREMENT replaces Event.SCROLL_PAGE_DOWN

Note: We recommend using a Scrollbar for value selection only. If you want to implement a scrollable component inside a container, we recommend you use a ScrollPane. If you use a Scrollbar for this purpose, you are likely to encounter issues with painting, key handling, sizing and positioning.

Since:

1.0

See Also:

• AdjustmentEvent
• AdjustmentListener
• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	Scrollbar.AccessibleAWTScrollBar	This class implements accessibility support for the Scrollbar class.

Nested classes/interfaces declared in class Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Modifier and Type	Class	Description
protected class	Component.AccessibleAWTComponent	Inner class of Component used to provide default support for accessibility.
static enum	Component.BaselineResizeBehavior	Enumeration of the common ways the baseline of a component can change as the size changes.
protected class	Component.BltBufferStrategy	Inner class for blitting offscreen surfaces to a component.
protected class	Component.FlipBufferStrategy	Inner class for flipping buffers on a component.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	HORIZONTAL	A constant that indicates a horizontal scroll bar.
static final int	VERTICAL	A constant that indicates a vertical scroll bar.

Fields declared in class Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Modifier and Type	Field	Description
protected AccessibleContext	accessibleContext	The AccessibleContext associated with this Component.
static final float	BOTTOM_ALIGNMENT	Ease-of-use constant for getAlignmentY.
static final float	CENTER_ALIGNMENT	Ease-of-use constant for getAlignmentY and getAlignmentX.
static final float	LEFT_ALIGNMENT	Ease-of-use constant for getAlignmentX.
static final float	RIGHT_ALIGNMENT	Ease-of-use constant for getAlignmentX.
static final float	TOP_ALIGNMENT	Ease-of-use constant for getAlignmentY().

Fields declared in interface Adjustable

NO_ORIENTATION

Modifier and Type	Field	Description
static final int	NO_ORIENTATION	Indicates that the Adjustable has no orientation.

Fields declared in interface ImageObserver

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

Modifier and Type	Field	Description
static final int	ABORT	This flag in the infoflags argument to imageUpdate indicates that an image which was being tracked asynchronously was aborted before production was complete.
static final int	ALLBITS	This flag in the infoflags argument to imageUpdate indicates that a static image which was previously drawn is now complete and can be drawn again in its final form.
static final int	ERROR	This flag in the infoflags argument to imageUpdate indicates that an image which was being tracked asynchronously has encountered an error.
static final int	FRAMEBITS	This flag in the infoflags argument to imageUpdate indicates that another complete frame of a multi-frame image which was previously drawn is now available to be drawn again.
static final int	HEIGHT	This flag in the infoflags argument to imageUpdate indicates that the height of the base image is now available and can be taken from the height argument to the imageUpdate callback method.
static final int	PROPERTIES	This flag in the infoflags argument to imageUpdate indicates that the properties of the image are now available.
static final int	SOMEBITS	This flag in the infoflags argument to imageUpdate indicates that more pixels needed for drawing a scaled variation of the image are available.
static final int	WIDTH	This flag in the infoflags argument to imageUpdate indicates that the width of the base image is now available and can be taken from the width argument to the imageUpdate callback method.

Constructor Summary

Constructors

Constructor	Description
Scrollbar()	Constructs a new vertical scroll bar.
Scrollbar(int orientation)	Constructs a new scroll bar with the specified orientation.
Scrollbar(int orientation, int value, int visible, int minimum, int maximum)	Constructs a new scroll bar with the specified orientation, initial value, visible amount, and minimum and maximum values.

Method Summary

Modifier and Type	Method	Description
void	addAdjustmentListener(AdjustmentListener l)	Adds the specified adjustment listener to receive instances of AdjustmentEvent from this scroll bar.
void	addNotify()	Creates the Scrollbar's peer.
AccessibleContext	getAccessibleContext()	Gets the AccessibleContext associated with this Scrollbar.
AdjustmentListener[]	getAdjustmentListeners()	Returns an array of all the adjustment listeners registered on this scrollbar.
int	getBlockIncrement()	Gets the block increment of this scroll bar.
int	getLineIncrement()	Deprecated. As of JDK version 1.1, replaced by 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()	Gets the maximum value of this scroll bar.
int	getMinimum()	Gets the minimum value of this scroll bar.
int	getOrientation()	Returns the orientation of this scroll bar.
int	getPageIncrement()	Deprecated. As of JDK version 1.1, replaced by getBlockIncrement().
int	getUnitIncrement()	Gets the unit increment for this scrollbar.
int	getValue()	Gets the current value of this scroll bar.
boolean	getValueIsAdjusting()	Returns true if the value is in the process of changing as a result of actions being taken by the user.
int	getVisible()	Deprecated. As of JDK version 1.1, replaced by getVisibleAmount().
int	getVisibleAmount()	Gets the visible amount of this scroll bar.
protected String	paramString()	Returns a string representing the state of this Scrollbar.
protected void	processAdjustmentEvent(AdjustmentEvent e)	Processes adjustment events occurring on this scrollbar by dispatching them to any registered AdjustmentListener objects.
protected void	processEvent(AWTEvent e)	Processes events on this scroll bar.
void	removeAdjustmentListener(AdjustmentListener l)	Removes the specified adjustment listener so that it no longer receives instances of AdjustmentEvent from this scroll bar.
void	setBlockIncrement(int v)	Sets the block increment for this scroll bar.
void	setLineIncrement(int v)	Deprecated. As of JDK version 1.1, replaced by setUnitIncrement(int).
void	setMaximum(int newMaximum)	Sets the maximum value of this scroll bar.
void	setMinimum(int newMinimum)	Sets the minimum value of this scroll bar.
void	setOrientation(int orientation)	Sets the orientation for this scroll bar.
void	setPageIncrement(int v)	Deprecated. As of JDK version 1.1, replaced by setBlockIncrement().
void	setUnitIncrement(int v)	Sets the unit increment for this scroll bar.
void	setValue(int newValue)	Sets the value of this scroll bar to the specified value.
void	setValueIsAdjusting(boolean b)	Sets the valueIsAdjusting property.
void	setValues(int value, int visible, int minimum, int maximum)	Sets the values of four properties for this scroll bar: value, visibleAmount, minimum, and maximum.
void	setVisibleAmount(int newAmount)	Sets the visible amount of this scroll bar.

Methods declared in class 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, getBaseline, getBaselineResizeBehavior, 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, 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, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate

Modifier and Type	Method	Description
boolean	action(Event evt, Object what)	Deprecated. As of JDK version 1.1, should register this component as ActionListener on component which fires action events.
void	add(PopupMenu popup)	Adds the specified popup menu to the component.
void	addComponentListener(ComponentListener l)	Adds the specified component listener to receive component events from this component.
void	addFocusListener(FocusListener l)	Adds the specified focus listener to receive focus events from this component when this component gains input focus.
void	addHierarchyBoundsListener(HierarchyBoundsListener l)	Adds the specified hierarchy bounds listener to receive hierarchy bounds events from this component when the hierarchy to which this container belongs changes.
void	addHierarchyListener(HierarchyListener l)	Adds the specified hierarchy listener to receive hierarchy changed events from this component when the hierarchy to which this container belongs changes.
void	addInputMethodListener(InputMethodListener l)	Adds the specified input method listener to receive input method events from this component.
void	addKeyListener(KeyListener l)	Adds the specified key listener to receive key events from this component.
void	addMouseListener(MouseListener l)	Adds the specified mouse listener to receive mouse events from this component.
void	addMouseMotionListener(MouseMotionListener l)	Adds the specified mouse motion listener to receive mouse motion events from this component.
void	addMouseWheelListener(MouseWheelListener l)	Adds the specified mouse wheel listener to receive mouse wheel events from this component.
void	addPropertyChangeListener(PropertyChangeListener listener)	Adds a PropertyChangeListener to the listener list.
void	addPropertyChangeListener(String propertyName, PropertyChangeListener listener)	Adds a PropertyChangeListener to the listener list for a specific property.
void	applyComponentOrientation(ComponentOrientation orientation)	Sets the ComponentOrientation property of this component and all components contained within it.
boolean	areFocusTraversalKeysSet(int id)	Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component.
Rectangle	bounds()	Deprecated. As of JDK version 1.1, replaced by getBounds().
int	checkImage(Image image, int width, int height, ImageObserver observer)	Returns the status of the construction of a screen representation of the specified image.
int	checkImage(Image image, ImageObserver observer)	Returns the status of the construction of a screen representation of the specified image.
protected AWTEvent	coalesceEvents(AWTEvent existingEvent, AWTEvent newEvent)	Potentially coalesce an event being posted with an existing event.
boolean	contains(int x, int y)	Checks whether this component "contains" the specified point, where x and y are defined to be relative to the coordinate system of this component.
boolean	contains(Point p)	Checks whether this component "contains" the specified point, where the point's x and y coordinates are defined to be relative to the coordinate system of this component.
Image	createImage(int width, int height)	Creates an off-screen drawable image to be used for double buffering.
Image	createImage(ImageProducer producer)	Creates an image from the specified image producer.
VolatileImage	createVolatileImage(int width, int height)	Creates a volatile off-screen drawable image to be used for double buffering.
VolatileImage	createVolatileImage(int width, int height, ImageCapabilities caps)	Creates a volatile off-screen drawable image, with the given capabilities.
void	deliverEvent(Event e)	Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e).
void	disable()	Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean).
protected final void	disableEvents(long eventsToDisable)	Disables the events defined by the specified event mask parameter from being delivered to this component.
final void	dispatchEvent(AWTEvent e)	Dispatches an event to this component or one of its sub components.
void	doLayout()	Prompts the layout manager to lay out this component.
void	enable()	Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean).
void	enable(boolean b)	Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean).
protected final void	enableEvents(long eventsToEnable)	Enables the events defined by the specified event mask parameter to be delivered to this component.
void	enableInputMethods(boolean enable)	Enables or disables input method support for this component.
protected void	firePropertyChange(String propertyName, boolean oldValue, boolean newValue)	Support for reporting bound property changes for boolean properties.
void	firePropertyChange(String propertyName, byte oldValue, byte newValue)	Reports a bound property change.
void	firePropertyChange(String propertyName, char oldValue, char newValue)	Reports a bound property change.
void	firePropertyChange(String propertyName, double oldValue, double newValue)	Reports a bound property change.
void	firePropertyChange(String propertyName, float oldValue, float newValue)	Reports a bound property change.
protected void	firePropertyChange(String propertyName, int oldValue, int newValue)	Support for reporting bound property changes for integer properties.
void	firePropertyChange(String propertyName, long oldValue, long newValue)	Reports a bound property change.
void	firePropertyChange(String propertyName, short oldValue, short newValue)	Reports a bound property change.
protected void	firePropertyChange(String propertyName, Object oldValue, Object newValue)	Support for reporting bound property changes for Object properties.
float	getAlignmentX()	Returns the alignment along the x axis.
float	getAlignmentY()	Returns the alignment along the y axis.
Color	getBackground()	Gets the background color of this component.
int	getBaseline(int width, int height)	Returns the baseline.
Component.BaselineResizeBehavior	getBaselineResizeBehavior()	Returns an enum indicating how the baseline of the component changes as the size changes.
Rectangle	getBounds()	Gets the bounds of this component in the form of a Rectangle object.
Rectangle	getBounds(Rectangle rv)	Stores the bounds of this component into "return value" rv and return rv.
ColorModel	getColorModel()	Gets the instance of ColorModel used to display the component on the output device.
Component	getComponentAt(int x, int y)	Determines if this component or one of its immediate subcomponents contains the (x, y) location, and if so, returns the containing component.
Component	getComponentAt(Point p)	Returns the component or subcomponent that contains the specified point.
ComponentListener[]	getComponentListeners()	Returns an array of all the component listeners registered on this component.
ComponentOrientation	getComponentOrientation()	Retrieves the language-sensitive orientation that is to be used to order the elements or text within this component.
Cursor	getCursor()	Gets the cursor set in the component.
DropTarget	getDropTarget()	Gets the DropTarget associated with this Component.
Container	getFocusCycleRootAncestor()	Returns the Container which is the focus cycle root of this Component's focus traversal cycle.
FocusListener[]	getFocusListeners()	Returns an array of all the focus listeners registered on this component.
Set<AWTKeyStroke>	getFocusTraversalKeys(int id)	Returns the Set of focus traversal keys for a given traversal operation for this Component.
boolean	getFocusTraversalKeysEnabled()	Returns whether focus traversal keys are enabled for this Component.
Font	getFont()	Gets the font of this component.
FontMetrics	getFontMetrics(Font font)	Gets the font metrics for the specified font.
Color	getForeground()	Gets the foreground color of this component.
Graphics	getGraphics()	Creates a graphics context for this component.
GraphicsConfiguration	getGraphicsConfiguration()	Gets the GraphicsConfiguration associated with this Component.
int	getHeight()	Returns the current height of this component.
HierarchyBoundsListener[]	getHierarchyBoundsListeners()	Returns an array of all the hierarchy bounds listeners registered on this component.
HierarchyListener[]	getHierarchyListeners()	Returns an array of all the hierarchy listeners registered on this component.
boolean	getIgnoreRepaint()	Returns whether or not paint messages received from the operating system should be ignored.
InputContext	getInputContext()	Gets the input context used by this component for handling the communication with input methods when text is entered in this component.
InputMethodListener[]	getInputMethodListeners()	Returns an array of all the input method listeners registered on this component.
InputMethodRequests	getInputMethodRequests()	Gets the input method request handler which supports requests from input methods for this component.
KeyListener[]	getKeyListeners()	Returns an array of all the key listeners registered on this component.
Locale	getLocale()	Gets the locale of this component.
Point	getLocation()	Gets the location of this component in the form of a point specifying the component's top-left corner.
Point	getLocation(Point rv)	Stores the x,y origin of this component into "return value" rv and return rv.
Point	getLocationOnScreen()	Gets the location of this component in the form of a point specifying the component's top-left corner in the screen's coordinate space.
Dimension	getMaximumSize()	Gets the maximum size of this component.
Dimension	getMinimumSize()	Gets the minimum size of this component.
MouseListener[]	getMouseListeners()	Returns an array of all the mouse listeners registered on this component.
MouseMotionListener[]	getMouseMotionListeners()	Returns an array of all the mouse motion listeners registered on this component.
Point	getMousePosition()	Returns the position of the mouse pointer in this Component's coordinate space if the Component is directly under the mouse pointer, otherwise returns null.
MouseWheelListener[]	getMouseWheelListeners()	Returns an array of all the mouse wheel listeners registered on this component.
String	getName()	Gets the name of the component.
Container	getParent()	Gets the parent of this component.
Dimension	getPreferredSize()	Gets the preferred size of this component.
PropertyChangeListener[]	getPropertyChangeListeners()	Returns an array of all the property change listeners registered on this component.
PropertyChangeListener[]	getPropertyChangeListeners(String propertyName)	Returns an array of all the listeners which have been associated with the named property.
Dimension	getSize()	Returns the size of this component in the form of a Dimension object.
Dimension	getSize(Dimension rv)	Stores the width/height of this component into "return value" rv and return rv.
Toolkit	getToolkit()	Gets the toolkit of this component.
final Object	getTreeLock()	Gets this component's locking object (the object that owns the thread synchronization monitor) for AWT component-tree and layout operations.
int	getWidth()	Returns the current width of this component.
int	getX()	Returns the current x coordinate of the components origin.
int	getY()	Returns the current y coordinate of the components origin.
boolean	gotFocus(Event evt, Object what)	Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).
boolean	handleEvent(Event evt)	Deprecated. As of JDK version 1.1 replaced by processEvent(AWTEvent).
boolean	hasFocus()	Returns true if this Component is the focus owner.
void	hide()	Deprecated. As of JDK version 1.1, replaced by setVisible(boolean).
boolean	imageUpdate(Image img, int infoflags, int x, int y, int w, int h)	Repaints the component when the image has changed.
boolean	inside(int x, int y)	Deprecated. As of JDK version 1.1, replaced by contains(int, int).
void	invalidate()	Invalidates this component and its ancestors.
boolean	isBackgroundSet()	Returns whether the background color has been explicitly set for this Component.
boolean	isCursorSet()	Returns whether the cursor has been explicitly set for this Component.
boolean	isDisplayable()	Determines whether this component is displayable.
boolean	isDoubleBuffered()	Returns true if this component is painted to an offscreen image ("buffer") that's copied to the screen later.
boolean	isEnabled()	Determines whether this component is enabled.
boolean	isFocusable()	Returns whether this Component can be focused.
boolean	isFocusCycleRoot(Container container)	Returns whether the specified Container is the focus cycle root of this Component's focus traversal cycle.
boolean	isFocusOwner()	Returns true if this Component is the focus owner.
boolean	isFocusTraversable()	Deprecated. As of 1.4, replaced by isFocusable().
boolean	isFontSet()	Returns whether the font has been explicitly set for this Component.
boolean	isForegroundSet()	Returns whether the foreground color has been explicitly set for this Component.
boolean	isLightweight()	A lightweight component doesn't have a native toolkit peer.
boolean	isMaximumSizeSet()	Returns true if the maximum size has been set to a non-null value otherwise returns false.
boolean	isMinimumSizeSet()	Returns whether or not setMinimumSize has been invoked with a non-null value.
boolean	isOpaque()	Returns true if this component is completely opaque, returns false by default.
boolean	isPreferredSizeSet()	Returns true if the preferred size has been set to a non-null value otherwise returns false.
boolean	isShowing()	Determines whether this component is showing on screen.
boolean	isValid()	Determines whether this component is valid.
boolean	isVisible()	Determines whether this component should be visible when its parent is visible.
boolean	keyDown(Event evt, int key)	Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).
boolean	keyUp(Event evt, int key)	Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent).
void	layout()	Deprecated. As of JDK version 1.1, replaced by doLayout().
void	list()	Prints a listing of this component to the standard system output stream System.out.
void	list(PrintStream out)	Prints a listing of this component to the specified output stream.
void	list(PrintStream out, int indent)	Prints out a list, starting at the specified indentation, to the specified print stream.
void	list(PrintWriter out)	Prints a listing to the specified print writer.
void	list(PrintWriter out, int indent)	Prints out a list, starting at the specified indentation, to the specified print writer.
Component	locate(int x, int y)	Deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int).
Point	location()	Deprecated. As of JDK version 1.1, replaced by getLocation().
boolean	lostFocus(Event evt, Object what)	Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent).
Dimension	minimumSize()	Deprecated. As of JDK version 1.1, replaced by getMinimumSize().
boolean	mouseDown(Event evt, int x, int y)	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
boolean	mouseDrag(Event evt, int x, int y)	Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).
boolean	mouseEnter(Event evt, int x, int y)	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
boolean	mouseExit(Event evt, int x, int y)	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
boolean	mouseMove(Event evt, int x, int y)	Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).
boolean	mouseUp(Event evt, int x, int y)	Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).
void	move(int x, int y)	Deprecated. As of JDK version 1.1, replaced by setLocation(int, int).
void	nextFocus()	Deprecated. As of JDK version 1.1, replaced by transferFocus().
void	paint(Graphics g)	Paints this component.
void	paintAll(Graphics g)	Paints this component and all of its subcomponents.
boolean	postEvent(Event e)	Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent).
Dimension	preferredSize()	Deprecated. As of JDK version 1.1, replaced by getPreferredSize().
boolean	prepareImage(Image image, int width, int height, ImageObserver observer)	Prepares an image for rendering on this component at the specified width and height.
boolean	prepareImage(Image image, ImageObserver observer)	Prepares an image for rendering on this component.
void	print(Graphics g)	Prints this component.
void	printAll(Graphics g)	Prints this component and all of its subcomponents.
protected void	processComponentEvent(ComponentEvent e)	Processes component events occurring on this component by dispatching them to any registered ComponentListener objects.
protected void	processFocusEvent(FocusEvent e)	Processes focus events occurring on this component by dispatching them to any registered FocusListener objects.
protected void	processHierarchyBoundsEvent(HierarchyEvent e)	Processes hierarchy bounds events occurring on this component by dispatching them to any registered HierarchyBoundsListener objects.
protected void	processHierarchyEvent(HierarchyEvent e)	Processes hierarchy events occurring on this component by dispatching them to any registered HierarchyListener objects.
protected void	processInputMethodEvent(InputMethodEvent e)	Processes input method events occurring on this component by dispatching them to any registered InputMethodListener objects.
protected void	processKeyEvent(KeyEvent e)	Processes key events occurring on this component by dispatching them to any registered KeyListener objects.
protected void	processMouseEvent(MouseEvent e)	Processes mouse events occurring on this component by dispatching them to any registered MouseListener objects.
protected void	processMouseMotionEvent(MouseEvent e)	Processes mouse motion events occurring on this component by dispatching them to any registered MouseMotionListener objects.
protected void	processMouseWheelEvent(MouseWheelEvent e)	Processes mouse wheel events occurring on this component by dispatching them to any registered MouseWheelListener objects.
void	remove(MenuComponent popup)	Removes the specified popup menu from the component.
void	removeComponentListener(ComponentListener l)	Removes the specified component listener so that it no longer receives component events from this component.
void	removeFocusListener(FocusListener l)	Removes the specified focus listener so that it no longer receives focus events from this component.
void	removeHierarchyBoundsListener(HierarchyBoundsListener l)	Removes the specified hierarchy bounds listener so that it no longer receives hierarchy bounds events from this component.
void	removeHierarchyListener(HierarchyListener l)	Removes the specified hierarchy listener so that it no longer receives hierarchy changed events from this component.
void	removeInputMethodListener(InputMethodListener l)	Removes the specified input method listener so that it no longer receives input method events from this component.
void	removeKeyListener(KeyListener l)	Removes the specified key listener so that it no longer receives key events from this component.
void	removeMouseListener(MouseListener l)	Removes the specified mouse listener so that it no longer receives mouse events from this component.
void	removeMouseMotionListener(MouseMotionListener l)	Removes the specified mouse motion listener so that it no longer receives mouse motion events from this component.
void	removeMouseWheelListener(MouseWheelListener l)	Removes the specified mouse wheel listener so that it no longer receives mouse wheel events from this component.
void	removeNotify()	Makes this Component undisplayable by destroying it native screen resource.
void	removePropertyChangeListener(PropertyChangeListener listener)	Removes a PropertyChangeListener from the listener list.
void	removePropertyChangeListener(String propertyName, PropertyChangeListener listener)	Removes a PropertyChangeListener from the listener list for a specific property.
void	repaint()	Repaints this component.
void	repaint(int x, int y, int width, int height)	Repaints the specified rectangle of this component.
void	repaint(long tm)	Repaints the component.
void	repaint(long tm, int x, int y, int width, int height)	Repaints the specified rectangle of this component within tm milliseconds.
void	requestFocus()	Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
protected boolean	requestFocus(boolean temporary)	Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
protected boolean	requestFocus(boolean temporary, FocusEvent.Cause cause)	Requests by the reason of cause that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
void	requestFocus(FocusEvent.Cause cause)	Requests by the reason of cause that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.
boolean	requestFocusInWindow()	Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window.
protected boolean	requestFocusInWindow(boolean temporary)	Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window.
boolean	requestFocusInWindow(FocusEvent.Cause cause)	Requests by the reason of cause that this Component get the input focus, if this Component's top-level ancestor is already the focused Window.
void	reshape(int x, int y, int width, int height)	Deprecated. As of JDK version 1.1, replaced by setBounds(int, int, int, int).
void	resize(int width, int height)	Deprecated. As of JDK version 1.1, replaced by setSize(int, int).
void	resize(Dimension d)	Deprecated. As of JDK version 1.1, replaced by setSize(Dimension).
void	revalidate()	Revalidates the component hierarchy up to the nearest validate root.
void	setBackground(Color c)	Sets the background color of this component.
void	setBounds(int x, int y, int width, int height)	Moves and resizes this component.
void	setBounds(Rectangle r)	Moves and resizes this component to conform to the new bounding rectangle r.
void	setComponentOrientation(ComponentOrientation o)	Sets the language-sensitive orientation that is to be used to order the elements or text within this component.
void	setCursor(Cursor cursor)	Sets the cursor image to the specified cursor.
void	setDropTarget(DropTarget dt)	Associate a DropTarget with this component.
void	setEnabled(boolean b)	Enables or disables this component, depending on the value of the parameter b.
void	setFocusable(boolean focusable)	Sets the focusable state of this Component to the specified value.
void	setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)	Sets the focus traversal keys for a given traversal operation for this Component.
void	setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)	Sets whether focus traversal keys are enabled for this Component.
void	setFont(Font f)	Sets the font of this component.
void	setForeground(Color c)	Sets the foreground color of this component.
void	setIgnoreRepaint(boolean ignoreRepaint)	Sets whether or not paint messages received from the operating system should be ignored.
void	setLocale(Locale l)	Sets the locale of this component.
void	setLocation(int x, int y)	Moves this component to a new location.
void	setLocation(Point p)	Moves this component to a new location.
void	setMaximumSize(Dimension maximumSize)	Sets the maximum size of this component to a constant value.
void	setMinimumSize(Dimension minimumSize)	Sets the minimum size of this component to a constant value.
void	setMixingCutoutShape(Shape shape)	Sets a 'mixing-cutout' shape for this lightweight component.
void	setName(String name)	Sets the name of the component to the specified string.
void	setPreferredSize(Dimension preferredSize)	Sets the preferred size of this component to a constant value.
void	setSize(int width, int height)	Resizes this component so that it has width width and height height.
void	setSize(Dimension d)	Resizes this component so that it has width d.width and height d.height.
void	setVisible(boolean b)	Shows or hides this component depending on the value of parameter b.
void	show()	Deprecated. As of JDK version 1.1, replaced by setVisible(boolean).
void	show(boolean b)	Deprecated. As of JDK version 1.1, replaced by setVisible(boolean).
Dimension	size()	Deprecated. As of JDK version 1.1, replaced by getSize().
String	toString()	Returns a string representation of this component and its values.
void	transferFocus()	Transfers the focus to the next component, as though this Component were the focus owner.
void	transferFocusBackward()	Transfers the focus to the previous component, as though this Component were the focus owner.
void	transferFocusUpCycle()	Transfers the focus up one focus traversal cycle.
void	update(Graphics g)	Updates this component.
void	validate()	Validates this component.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Creates and returns a copy of this object.
boolean	equals(Object obj)	Indicates whether some other object is "equal to" this one.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
final Class<?>	getClass()	Returns the runtime class of this Object.
int	hashCode()	Returns a hash code value for this object.
final void	notify()	Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll()	Wakes up all threads that are waiting on this object's monitor.
final void	wait()	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
final void	wait(long timeoutMillis)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
final void	wait(long timeoutMillis, int nanos)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Field Details

HORIZONTAL

public static final int HORIZONTAL

A constant that indicates a horizontal scroll bar.

See Also:

• Constant Field Values

VERTICAL

public static final int VERTICAL

A constant that indicates a vertical scroll bar.

See Also:

• Constant Field Values

Constructor Details

Scrollbar

public Scrollbar()
          throws HeadlessException

Constructs a new vertical scroll bar. The default properties of the scroll bar are listed in the following table:

Scrollbar default properties

Property	Description	Default Value
orientation	indicates whether the scroll bar is vertical or horizontal	Scrollbar.VERTICAL
value	value which controls the location of the scroll bar's bubble	0
visible amount	visible amount of the scroll bar's range, typically represented by the size of the scroll bar's bubble	10
minimum	minimum value of the scroll bar	0
maximum	maximum value of the scroll bar	100
unit increment	amount the value changes when the Line Up or Line Down key is pressed, or when the end arrows of the scrollbar are clicked	1
block increment	amount the value changes when the Page Up or Page Down key is pressed, or when the scrollbar track is clicked on either side of the bubble	10

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

• GraphicsEnvironment.isHeadless()

Scrollbar

public Scrollbar(int orientation)
          throws HeadlessException

Constructs a new scroll bar with the specified orientation.

The orientation argument must take one of the two values Scrollbar.HORIZONTAL, or Scrollbar.VERTICAL, indicating a horizontal or vertical scroll bar, respectively.

Parameters:

orientation - indicates the orientation of the scroll bar

Throws:

IllegalArgumentException - when an illegal value for the orientation argument is supplied

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

• GraphicsEnvironment.isHeadless()

Scrollbar

public Scrollbar(int orientation,
 int value,
 int visible,
 int minimum,
 int maximum)
          throws HeadlessException

Constructs a new scroll bar with the specified orientation, initial value, visible amount, and minimum and maximum values.

The orientation argument must take one of the two values Scrollbar.HORIZONTAL, or Scrollbar.VERTICAL, indicating a horizontal or vertical scroll bar, respectively.

The parameters supplied to this constructor are subject to the constraints described in setValues(int, int, int, int).

Parameters:

orientation - indicates the orientation of the scroll bar.

value - the initial value of the scroll bar

visible - the visible amount of the scroll bar, typically represented by the size of the bubble

minimum - the minimum value of the scroll bar

maximum - the maximum value of the scroll bar

Throws:

IllegalArgumentException - when an illegal value for the orientation argument is supplied

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

• setValues(int, int, int, int)
• GraphicsEnvironment.isHeadless()

Method Details

addNotify

public void addNotify()

Creates the Scrollbar's peer. The peer allows you to modify the appearance of the Scrollbar without changing any of its functionality.

Overrides:

addNotify in class Component

See Also:

• Component.isDisplayable()
• Component.removeNotify()
• Component.invalidate()

getOrientation

public int getOrientation()

Returns the orientation of this scroll bar.

Specified by:

getOrientation in interface Adjustable

Returns:

the orientation of this scroll bar, either Scrollbar.HORIZONTAL or Scrollbar.VERTICAL

See Also:

• setOrientation(int)

setOrientation

public void setOrientation(int orientation)

Sets the orientation for this scroll bar.

Parameters:

orientation - the orientation of this scroll bar, either Scrollbar.HORIZONTAL or Scrollbar.VERTICAL

Throws:

IllegalArgumentException - if the value supplied for orientation is not a legal value

Since:

1.1

See Also:

• getOrientation()

getValue

public int getValue()

Gets the current value of this scroll bar.

Specified by:

getValue in interface Adjustable

Returns:

the current value of this scroll bar

See Also:

• getMinimum()
• getMaximum()

setValue

public void setValue(int newValue)

Sets the value of this scroll bar to the specified value.

If the value supplied is less than the current minimum or greater than the current maximum - visibleAmount, then either minimum or maximum - visibleAmount is substituted, as appropriate.

Normally, a program should change a scroll bar's value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

Calling this method does not fire an AdjustmentEvent.

Specified by:

setValue in interface Adjustable

Parameters:

newValue - the new value of the scroll bar

See Also:

• setValues(int, int, int, int)
• getValue()
• getMinimum()
• getMaximum()

getMinimum

public int getMinimum()

Gets the minimum value of this scroll bar.

Specified by:

getMinimum in interface Adjustable

Returns:

the minimum value of this scroll bar

See Also:

• getValue()
• getMaximum()

setMinimum

public void setMinimum(int newMinimum)

Sets the minimum value of this scroll bar.

When setMinimum is called, the minimum value is changed, and other values (including the maximum, the visible amount, and the current scroll bar value) are changed to be consistent with the new minimum.

Normally, a program should change a scroll bar's minimum value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

Note that setting the minimum value to Integer.MAX_VALUE will result in the new minimum value being set to Integer.MAX_VALUE - 1.

Specified by:

setMinimum in interface Adjustable

Parameters:

newMinimum - the new minimum value for this scroll bar

Since:

1.1

See Also:

• setValues(int, int, int, int)
• setMaximum(int)

getMaximum

public int getMaximum()

Gets the maximum value of this scroll bar.

Specified by:

getMaximum in interface Adjustable

Returns:

the maximum value of this scroll bar

See Also:

• getValue()
• getMinimum()

setMaximum

public void setMaximum(int newMaximum)

Sets the maximum value of this scroll bar.

When setMaximum is called, the maximum value is changed, and other values (including the minimum, the visible amount, and the current scroll bar value) are changed to be consistent with the new maximum.

Normally, a program should change a scroll bar's maximum value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

Note that setting the maximum value to Integer.MIN_VALUE will result in the new maximum value being set to Integer.MIN_VALUE + 1.

Specified by:

setMaximum in interface Adjustable

Parameters:

newMaximum - the new maximum value for this scroll bar

Since:

1.1

See Also:

• setValues(int, int, int, int)
• setMinimum(int)

getVisibleAmount

public int getVisibleAmount()

Gets the visible amount of this scroll bar.

When a scroll bar is used to select a range of values, the visible amount is used to represent the range of values that are currently visible. The size of the scroll bar's bubble (also called a thumb or scroll box), usually gives a visual representation of the relationship of the visible amount to the range of the scroll bar. Note that depending on platform, the value of the visible amount property may not be visually indicated by the size of the bubble.

The scroll bar's bubble may not be displayed when it is not moveable (e.g. when it takes up the entire length of the scroll bar's track, or when the scroll bar is disabled). Whether the bubble is displayed or not will not affect the value returned by getVisibleAmount.

Specified by:

getVisibleAmount in interface Adjustable

Returns:

the visible amount of this scroll bar

Since:

1.1

See Also:

• setVisibleAmount(int)

getVisible

@Deprecated
public int getVisible()

Deprecated.

As of JDK version 1.1, replaced by getVisibleAmount().

Returns the visible amount of this scroll bar.

Returns:

the visible amount of this scroll bar

setVisibleAmount

public void setVisibleAmount(int newAmount)

Sets the visible amount of this scroll bar.

When a scroll bar is used to select a range of values, the visible amount is used to represent the range of values that are currently visible. The size of the scroll bar's bubble (also called a thumb or scroll box), usually gives a visual representation of the relationship of the visible amount to the range of the scroll bar. Note that depending on platform, the value of the visible amount property may not be visually indicated by the size of the bubble.

The scroll bar's bubble may not be displayed when it is not moveable (e.g. when it takes up the entire length of the scroll bar's track, or when the scroll bar is disabled). Whether the bubble is displayed or not will not affect the value returned by getVisibleAmount.

If the visible amount supplied is less than one or greater than the current maximum - minimum, then either one or maximum - minimum is substituted, as appropriate.

Normally, a program should change a scroll bar's value only by calling setValues. The setValues method simultaneously and synchronously sets the minimum, maximum, visible amount, and value properties of a scroll bar, so that they are mutually consistent.

Specified by:

setVisibleAmount in interface Adjustable

Parameters:

newAmount - the new visible amount

Since:

1.1

See Also:

• getVisibleAmount()
• setValues(int, int, int, int)

setUnitIncrement

public void setUnitIncrement(int v)

Sets the unit increment for this scroll bar.

The unit increment is the value that is added or subtracted when the user activates the unit increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The unit increment must be greater than zero. Attempts to set the unit increment to a value lower than 1 will result in a value of 1 being set.

In some operating systems, this property can be ignored by the underlying controls.

Specified by:

setUnitIncrement in interface Adjustable

Parameters:

v - the amount by which to increment or decrement the scroll bar's value

Since:

1.1

See Also:

• getUnitIncrement()

setLineIncrement

@Deprecated
public void setLineIncrement(int v)

Deprecated.

As of JDK version 1.1, replaced by setUnitIncrement(int).

Sets the unit increment for this scroll bar.

Parameters:

v - the increment value

getUnitIncrement

public int getUnitIncrement()

Gets the unit increment for this scrollbar.

The unit increment is the value that is added or subtracted when the user activates the unit increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The unit increment must be greater than zero.

In some operating systems, this property can be ignored by the underlying controls.

Specified by:

getUnitIncrement in interface Adjustable

Returns:

the unit increment of this scroll bar

Since:

1.1

See Also:

• setUnitIncrement(int)

getLineIncrement

@Deprecated
public int getLineIncrement()

Deprecated.

As of JDK version 1.1, replaced by getUnitIncrement().

Returns the unit increment for this scrollbar.

Returns:

the unit increment for this scrollbar

setBlockIncrement

public void setBlockIncrement(int v)

Sets the block increment for this scroll bar.

The block increment is the value that is added or subtracted when the user activates the block increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The block increment must be greater than zero. Attempts to set the block increment to a value lower than 1 will result in a value of 1 being set.

Specified by:

setBlockIncrement in interface Adjustable

Parameters:

v - the amount by which to increment or decrement the scroll bar's value

Since:

1.1

See Also:

• getBlockIncrement()

setPageIncrement

@Deprecated
public void setPageIncrement(int v)

Deprecated.

As of JDK version 1.1, replaced by setBlockIncrement().

Sets the block increment for this scroll bar.

Parameters:

v - the block increment

getBlockIncrement

public int getBlockIncrement()

Gets the block increment of this scroll bar.

The block increment is the value that is added or subtracted when the user activates the block increment area of the scroll bar, generally through a mouse or keyboard gesture that the scroll bar receives as an adjustment event. The block increment must be greater than zero.

Specified by:

getBlockIncrement in interface Adjustable

Returns:

the block increment of this scroll bar

Since:

1.1

See Also:

• setBlockIncrement(int)

getPageIncrement

@Deprecated
public int getPageIncrement()

Deprecated.

As of JDK version 1.1, replaced by getBlockIncrement().

Returns the block increment of this scroll bar.

Returns:

the block increment of this scroll bar

setValues

public void setValues(int value,
 int visible,
 int minimum,
 int maximum)

Sets the values of four properties for this scroll bar: value, visibleAmount, minimum, and maximum. If the values supplied for these properties are inconsistent or incorrect, they will be changed to ensure consistency.

This method simultaneously and synchronously sets the values of four scroll bar properties, assuring that the values of these properties are mutually consistent. It enforces the following constraints: maximum must be greater than minimum, maximum - minimum must not be greater than Integer.MAX_VALUE, visibleAmount must be greater than zero. visibleAmount must not be greater than maximum - minimum, value must not be less than minimum, and value must not be greater than maximum - visibleAmount

Calling this method does not fire an AdjustmentEvent.

Parameters:

value - is the position in the current window

visible - is the visible amount of the scroll bar

minimum - is the minimum value of the scroll bar

maximum - is the maximum value of the scroll bar

See Also:

• setMinimum(int)
• setMaximum(int)
• setVisibleAmount(int)
• setValue(int)

getValueIsAdjusting

public boolean getValueIsAdjusting()

Returns true if the value is in the process of changing as a result of actions being taken by the user.

Returns:

the value of the valueIsAdjusting property

Since:

1.4

See Also:

• setValueIsAdjusting(boolean)

setValueIsAdjusting

public void setValueIsAdjusting(boolean b)

Sets the valueIsAdjusting property.

Parameters:

b - new adjustment-in-progress status

Since:

1.4

See Also:

• getValueIsAdjusting()

addAdjustmentListener

public void addAdjustmentListener(AdjustmentListener l)

Adds the specified adjustment listener to receive instances of AdjustmentEvent from this scroll bar. If l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

Specified by:

addAdjustmentListener in interface Adjustable

Parameters:

l - the adjustment listener

Since:

1.1

See Also:

• removeAdjustmentListener(AdjustmentListener)
• getAdjustmentListeners()
• AdjustmentEvent
• AdjustmentListener

removeAdjustmentListener

public void removeAdjustmentListener(AdjustmentListener l)

Removes the specified adjustment listener so that it no longer receives instances of AdjustmentEvent from this scroll bar. If l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

Specified by:

removeAdjustmentListener in interface Adjustable

Parameters:

l - the adjustment listener

Since:

1.1

See Also:

• addAdjustmentListener(AdjustmentListener)
• getAdjustmentListeners()
• AdjustmentEvent
• AdjustmentListener

getAdjustmentListeners

public AdjustmentListener[] getAdjustmentListeners()

Returns an array of all the adjustment listeners registered on this scrollbar.

Returns:

all of this scrollbar's AdjustmentListeners or an empty array if no adjustment listeners are currently registered

Since:

1.4

See Also:

• addAdjustmentListener(AdjustmentListener)
• removeAdjustmentListener(AdjustmentListener)
• AdjustmentEvent
• AdjustmentListener

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.

You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a Scrollbar c 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 Component

Type Parameters:

T - the type of the listeners

Parameters:

listenerType - the type of listeners requested; this parameter should specify an interface that descends from java.util.EventListener

Returns:

an array of all objects registered as FooListeners on this component, or an empty array if no such listeners have been added

Throws:

ClassCastException - if listenerType doesn't specify a class or interface that implements java.util.EventListener

Since:

1.3

See Also:

• Component.getComponentListeners()
• Component.getFocusListeners()
• Component.getHierarchyListeners()
• Component.getHierarchyBoundsListeners()
• Component.getKeyListeners()
• Component.getMouseListeners()
• Component.getMouseMotionListeners()
• Component.getMouseWheelListeners()
• Component.getInputMethodListeners()
• Component.getPropertyChangeListeners()

processEvent

protected void processEvent(AWTEvent e)

Processes events on this scroll bar. If the event is an instance of AdjustmentEvent, it invokes the processAdjustmentEvent method. Otherwise, it invokes its superclass's processEvent method.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

Overrides:

processEvent in class Component

Parameters:

e - the event

Since:

1.1

See Also:

• AdjustmentEvent
• processAdjustmentEvent(AdjustmentEvent)

processAdjustmentEvent

protected void processAdjustmentEvent(AdjustmentEvent e)

Processes adjustment events occurring on this scrollbar by dispatching them to any registered AdjustmentListener objects.

This method is not called unless adjustment events are enabled for this component. Adjustment events are enabled when one of the following occurs:

• An AdjustmentListener object is registered via addAdjustmentListener.
• Adjustment events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

Parameters:

e - the adjustment event

Since:

1.1

See Also:

• AdjustmentEvent
• AdjustmentListener
• addAdjustmentListener(AdjustmentListener)
• Component.enableEvents(long)

paramString

protected String paramString()

Returns a string representing the state of this Scrollbar. 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 be null.

Overrides:

paramString in class Component

Returns:

the parameter string of this scroll bar

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this Scrollbar. For scrollbars, the AccessibleContext takes the form of an AccessibleAWTScrollBar. A new AccessibleAWTScrollBar instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class Component

Returns:

an AccessibleAWTScrollBar that serves as the AccessibleContext of this ScrollBar

Since:

1.3