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Class jclass.bwt.JCScrollbar

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----java.awt.Panel
                           |
                           +----jclass.bwt.JCContainer
                                   |
                                   +----jclass.bwt.JCScrollbar

public class JCScrollbar

extends JCContainer

implements JCAdjustable, JCActionListener

Behavior
The scrollbar consists of two JCArrowButtons at either end, and a rectangular area called a thumb within it. The data is scrolled by clicking a button, clicking to either side of the thumb, or dragging the thumb. Clicking to either side of the thumb with the CONTROL key pressed will cause the thumb to move to the beginning or end. Hitting PAGE-UP or PAGE-DOWN will scroll up or down by a page. Hitting HOME or END will scroll to the beginning or end.

Properties

Name	Method
Background	setBackground
BlockIncrement	setBlockIncrement
FilterTime	setFilterTime
Foreground	setForeground
Maximum	setMaximum
Minimum	setMinimum
Orientation	setOrientation
PreferredSize	setPreferredSize
UnitIncrement	setUnitIncrement
UserData	setUserData
Value	setValue
VisibleAmount	setVisibleAmount

Events

Class	Listener	Description
JCAdjustmentEvent	addAdjustmentListener	Posted when the value changes

adjustmentListeners

List of JCAdjustmentEvent listeners.

decr_arrow

Down/right and up/left arrow buttons.

HORIZONTAL

incr_arrow

Down/right and up/left arrow buttons.

scrolled_window

Parent window.

thumb

Scrollbar's thumb.

VERTICAL

JCScrollbar()

Constructs a vertical scrollbar.

JCScrollbar(int)

Constructs a scrollbar with the specified orientation.

JCScrollbar(int, Applet, String)

Creates a scrollbar which reads parameters from the applet's HTML file.

JCScrollbar(int, int, int, int, int)

Constructs a scrollbar with an initial orientation, value, page size, and minumum and max values.

actionPerformed(JCActionEvent)

Scrolls by a line if an arrow key was pressed.

addAdjustmentListener(JCAdjustmentListener)

Adds the specified adjustment listener to receive adjustment events.

atEnd()

getBlockIncrement()

Gets the page increment.

getFilterTime()

Gets the FilterTime value.

getMaximum()

Gets the maximum value.

getMinimum()

Gets the minimum value.

getOrientation()

Gets the orientation.

getParameters()

Reads the parameter values from the HTML page using the component's applet.

getParameters(Applet)

Gets a parameter for this container.

getUnitIncrement()

Gets the line increment.

getValue()

Gets the current value.

getVisible()

Deprecated.

getVisibleAmount()

Returns the slider size, in user units

isFocusTraversable()

Returns whether this component can be traversed using Tab or Shift-Tab keyboard focus traversal.

keyDown(Event, int)

Moves the slider if HOME, END, PGUP, PGDN or an arrow key is hit.

layout()

Positions the thumb and arrow buttons.

mouseDown(Event, int, int)

If an arrow button is pressed, the slider will move by one line.

If the trough is clicked with the CTRL key down, the slider will move to the beginning or end.

If the trough is clicked, the slider will move by one page.

mouseDrag(Event, int, int)

Handles a mouse drag event in the slider.

mouseUp(Event, int, int)

Resets the scrollbar state after some other operation.

paintInterior(Graphics)

Draws a 1-pixel black border.

paintThumb(Graphics)

Paints the thumb.

preferredHeight()

Returns BWTEnum.SB_SIZE if this is a horizontal scrollbar; 100 otherwise.

preferredWidth()

Returns BWTEnum.SB_SIZE if this is a vertical scrollbar; 100 otherwise.

removeAdjustmentListener(JCAdjustmentListener)

Removes the specified adjustment listener so that it no longer receives adjustment events.

reshape(int, int, int, int)

Reshapes the Container to the specified bounding box.

setBackground(Color)

Sets the background color.

setBlockIncrement(int)

Sets the page increment.

setFilterTime(long)

If 2 mouse drag events are received within this interval, the 2nd is not reported (ie no events are posted) (default: 0 ms).

setForeground(Color)

Sets the foreground color.

setLayout(LayoutManager)

Sets the layout manager for this container.

setMaximum(int)

Sets the maximum value (default: 100).

setMinimum(int)

Sets the minimum value.

setOrientation(int)

Sets the orientation.

setUnitIncrement(int)

Sets the line increment (default: 10).

setValue(int)

Sets the value.

setValue(int, boolean)

Sets the value.

setValues(int, int, int, int)

Sets the values.

setVisibleAmount(int)

Sets the slider size, in user units.

  public final static int HORIZONTAL

  public final static int VERTICAL

  protected transient JCScrolledWindow scrolled_window

Parent window.

  protected JCArrowButton incr_arrow

Down/right and up/left arrow buttons.

  protected JCArrowButton decr_arrow

Down/right and up/left arrow buttons.

  protected ScrollbarThumb thumb

Scrollbar's thumb.

  protected JCVector adjustmentListeners

List of JCAdjustmentEvent listeners.

  public JCScrollbar()

Constructs a vertical scrollbar.

  public JCScrollbar(int dir)

Constructs a scrollbar with the specified orientation.

Parameters:

dir - either HORIZONTAL or VERTICAL

  public JCScrollbar(int dir,
                     Applet applet,
                     String name)

Creates a scrollbar which reads parameters from the applet's HTML file.

Parameters:

dir - either HORIZONTAL or VERTICAL

applet - the applet whose PARAM tags are to be read

name - if this is not null, only parameters preceded by this name are read

See Also:

getParameter

  public JCScrollbar(int dir,
                     int value,
                     int visible,
                     int min,
                     int max)

Constructs a scrollbar with an initial orientation, value, page size, and minumum and max values.

Parameters:

dir - either HORIZONTAL or VERTICAL

value - the scrollbar's value

visible - the size of the visible portion of the scrollable area. The scrollbar will use this value when paging up or down by a page.

min - the min value

max - the max value

  protected void getParameters()

Reads the parameter values from the HTML page using the component's applet. The values will override those previously set.

Overrides:

getParameters in class JCContainer

  public void getParameters(Applet applet)

Gets a parameter for this container.

Overrides:

getParameters in class JCContainer

  public boolean isFocusTraversable()

Returns whether this component can be traversed using Tab or Shift-Tab keyboard focus traversal.

Overrides:

isFocusTraversable in class Component

  public int getOrientation()

Gets the orientation.

  public synchronized void setOrientation(int dir)

Sets the orientation. This must be called before the scollbar is visible (ie before it is added to its parent).

Parameters:

dir - either HORIZONTAL or VERTICAL

Throws: IllegalArgumentException

If an invalid value is set

  public synchronized int getValue()

Gets the current value. This will be between the minimum value and the maximum value minus the slider size.

See Also:

getMinimum, getMaximum

  public synchronized void setValue(int value)

Sets the value.

Parameters:

value - the new value. If this value is below the current minimum or above the current maximum, it becomes the new one of those values, respectively.

See Also:

getValue

  public synchronized void setValue(int value,
                                    boolean notify)

Sets the value.

Parameters:

notify - if true, an JCAdjustmentEvent is posted.

See Also:

addAdjustmentListener

  public int getMinimum()

Gets the minimum value.

See Also:

setMinimum

  public synchronized void setMinimum(int v)

Sets the minimum value.

See Also:

setValues

  public int getMaximum()

Gets the maximum value.

See Also:

setMaximum

  public synchronized void setMaximum(int v)

Sets the maximum value (default: 100).

See Also:

setValues

  public int getVisibleAmount()

Returns the slider size, in user units

See Also:

setVisibleAmount

  public int getVisible()

Note: getVisible() is deprecated.

See Also:

getVisibleAmount

  public synchronized void setVisibleAmount(int v)

Sets the slider size, in user units.

See Also:

setValues

  public void setUnitIncrement(int v)

Sets the line increment (default: 10). This is the amount that is scrolled up or down when the user clicks the arrow buttons.

  public int getUnitIncrement()

Gets the line increment.

  public void setBlockIncrement(int v)

Sets the page increment. This is the amount that will be scrolled up or down when the user clicks above/below the slider (default: slider size).

  public int getBlockIncrement()

Gets the page increment.

  public synchronized void setValues(int value,
                                     int visible,
                                     int min,
                                     int max)

Sets the values.

Parameters:

value - the scrollbar's value

visible - the amount visible per page (the slider size). The page increment is also set to this value.

min - the minimum value of the scrollbar

max - the maximum value of the scrollbar

See Also:

setBlockIncrement

  public boolean atEnd()

Returns:

true if slider is currently at min or max value

  public long getFilterTime()

Gets the FilterTime value.

See Also:

setFilterTime

  public void setFilterTime(long t)

If 2 mouse drag events are received within this interval, the 2nd is not reported (ie no events are posted) (default: 0 ms). To specify that no events are to be reported until the user releases the mouse, set this value to BWTEnum.MAXINT.

HTML param name/value: "FilterTime"/int

  protected int preferredWidth()

Returns BWTEnum.SB_SIZE if this is a vertical scrollbar; 100 otherwise.

Overrides:

preferredWidth in class JCContainer

  protected int preferredHeight()

Returns BWTEnum.SB_SIZE if this is a horizontal scrollbar; 100 otherwise.

Overrides:

preferredHeight in class JCContainer

  public void addAdjustmentListener(JCAdjustmentListener l)

Adds the specified adjustment listener to receive adjustment events.

See Also:

JCAdjustmentEvent

  public void removeAdjustmentListener(JCAdjustmentListener l)

Removes the specified adjustment listener so that it no longer receives adjustment events.

  public void actionPerformed(JCActionEvent ev)

Scrolls by a line if an arrow key was pressed.

  public boolean mouseUp(Event ev,
                         int x,
                         int y)

Resets the scrollbar state after some other operation.

Overrides:

mouseUp in class Component

  public boolean mouseDown(Event ev,
                           int x,
                           int y)

If an arrow button is pressed, the slider will move by one line.

If the trough is clicked with the CTRL key down, the slider will move to the beginning or end.

If the trough is clicked, the slider will move by one page.

Overrides:

mouseDown in class Component

  public boolean mouseDrag(Event ev,
                           int x,
                           int y)

Handles a mouse drag event in the slider.

Overrides:

mouseDrag in class Component

  public boolean keyDown(Event ev,
                         int key)

Moves the slider if HOME, END, PGUP, PGDN or an arrow key is hit.

Overrides:

keyDown in class Component

  public synchronized void reshape(int x,
                                   int y,
                                   int w,
                                   int h)

Reshapes the Container to the specified bounding box.

Overrides:

reshape in class JCContainer

  public synchronized void layout()

Positions the thumb and arrow buttons.

Overrides:

layout in class Container

  protected void paintThumb(Graphics gc)

Paints the thumb.

  public void paintInterior(Graphics gc)

Draws a 1-pixel black border.

Overrides:

paintInterior in class JCContainer

  public synchronized void setForeground(Color c)

Sets the foreground color.

Overrides:

setForeground in class Component

  public synchronized void setBackground(Color c)

Sets the background color.

Overrides:

setBackground in class Component

  public final void setLayout(LayoutManager mgr)

Sets the layout manager for this container. This method is overridden to prevent the layout mgr from being set.

Overrides:

setLayout in class Container

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