Module java.desktop
Package java.awt

# 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 java.awt.Component

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

## 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 java.awt.Component

`accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT`

### Fields declared in interface java.awt.Adjustable

`NO_ORIENTATION`

### Fields declared in interface java.awt.image.ImageObserver

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

## 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 `FooListener`s 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 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, 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`

### Methods declared in class java.lang.Object

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

## 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(java.awt.event.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(java.awt.event.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 `AdjustmentListener`s or an empty array if no adjustment listeners are currently registered
Since:
  1.4
See Also:
  - `addAdjustmentListener(java.awt.event.AdjustmentListener)`
  - `removeAdjustmentListener(java.awt.event.AdjustmentListener)`
  - `AdjustmentEvent`
  - `AdjustmentListener`

### getListeners

public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as `FooListener`s upon this `Scrollbar`. `FooListener`s 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 `FooListener`s 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(java.awt.event.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(java.awt.event.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