java.awt

Class Scrollbar

Implemented Interfaces:
Accessible, Adjustable, ImageObserver, MenuContainer, Serializable

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

HORIZONTAL, NO_ORIENTATION, VERTICAL

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.
extends EventListener> T[] getListeners(Class listenerType)
Returns an array of all the objects currently registered as FooListeners upon this Scrollbar.
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().
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, addNotify, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, extends EventListener> T[] getListeners, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAccessibleContext, 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, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFocusable, 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, paramString, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, 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, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFocusable, 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, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

HORIZONTAL

public static final int HORIZONTAL
Constant indicating that a scrollbar is horizontal.
Field Value:
0

VERTICAL

public static final int VERTICAL
Constant indicating that a scrollbar is vertical.
Field Value:
1

Constructor Details

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 Details

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.

addNotify

public void addNotify()
Notifies this object to create its native peer.
Overrides:
addNotify in interface Component

extends EventListener> T[] getListeners

public extends EventListener> T[] getListeners(Class listenerType)
Returns an array of all the objects currently registered as FooListeners upon this Scrollbar. FooListeners are registered using the addFooListener method.
Overrides:
extends EventListener> T[] getListeners in interface Component
Throws:
ClassCastException - If listenerType doesn't specify a class or interface that implements java.util.EventListener.

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 interface Component
Returns:
the associated context

getAdjustmentListeners

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

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.

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.

getMaximum

public int getMaximum()
Returns the maximum value for this scrollbar.
Specified by:
getMaximum in interface Adjustable
Returns:
The 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.

getOrientation

public int getOrientation()
Returns the orientation constant for this object.
Specified by:
getOrientation in interface Adjustable
Returns:
The orientation constant for this object.

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.

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.

getValue

public int getValue()
Returns the current value for this scrollbar.
Specified by:
getValue in interface Adjustable
Returns:
The current value for this scrollbar.

getValueIsAdjusting

public boolean getValueIsAdjusting()
Returns true if the value is in the process of changing.
Since:
1.4

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.

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.

paramString

protected String paramString()
Returns a debugging string for this object.
Overrides:
paramString in interface Component
Returns:
A debugging string for this object.

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.

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 interface Component
Parameters:
event - The event to process.

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.

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.

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.

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.

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.

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.

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.

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.

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.

setValueIsAdjusting

public void setValueIsAdjusting(boolean valueIsAdjusting)
Sets the value of valueIsAdjusting.
Since:
1.4

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.

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.

Scrollbar.java -- AWT Scrollbar widget Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.