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public  class  java.awt.Scrollbar
    extends  java.awt.Component  (II-§1.10)
{
        // Fields
    public final static int HORIZONTAL;	§1.37.1
    public final static int VERTICAL;	§1.37.2

        // Constructors
    public Scrollbar();	§1.37.3
    public Scrollbar(int  orientation);	§1.37.4
    public Scrollbar(int  orientation, int  value,	§1.37.5
                 int  visible, int  minimum, int  maximum);

        // Methods
    public void addNotify();	§1.37.6
    public int getLineIncrement();	§1.37.7
    public int getMaximum();	§1.37.8
    public int getMinimum();	§1.37.9
    public int getOrientation();	§1.37.10
    public int getPageIncrement();	§1.37.11
    public int getValue();	§1.37.12
    public int getVisible();	§1.37.13
    protected String paramString();	§1.37.14
    public void setLineIncrement(int  l);	§1.37.15
    public void setPageIncrement(int  l);	§1.37.16
    public void setValue(int  value);	§1.37.17
    public void setValues(int  value, int  visible,	§1.37.18
                            int  minimum, int  maximum);
}

A scroll bar provides a convenient means of allowing a user to select from a range of values. For example, the following three scrollbars could be used to pick the each of the red, green, and blue components of a color:

Each scrollbar was created with the code like 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 using a scrollbar for scrolling through text, the width of the "bubble" can represent the amount of text visible. Here is an example of a scrollbar representing a range:

The value range represented by the bubble is the visible amount of the scrollbar.

The code to produce the above scrollbar is

ranger = new Scrollbar(Scrollbar.HORIZONTAL, 0, 64, 0, 255);
add(ranger);

In addition, whenever the user changes the value of the scroll bar, AWT sends one of the following five events to the user:

• a scroll absolute event (§5.14.28) if the user drags the bubble
• a scroll line down (§5.14.29) event if the user clicks in the right arrow of
  a horizontal scroll bar or the bottom arrow of a vertical scroll bar
• a scroll line up event (II-§1.14.30) if the user clicks in the left arrow of a horizontal scroll bar or the top arrow of a vertical scroll bar
• a scroll page down (§5.14.31) event if the user clicks to the right of the
  bubble in a horizontal scroll bar or below the bubble in a vertical scroll bar
• a scroll page up (II-§1.14.32) event if the user clicks to the left of the bubble in a horizontal scroll bar or above the bubble in a vertical scroll bar

If an application wants to perform some action when the value in a scroll bar is changed, it must override handleEvent method of the scroll bar or of one of its containing windows. The code to perform that should be of the following form:

public boolean handleEvent(Event event) {
        if (event.target == scrollbar) { 
                do something
                return true;
        } else {
                return super.handleEvent(event);
        }
}    

Constant indicating to construct a horizontal scroll bar.

Constant indicating to construct a vertical scroll bar.

Constructs a new vertical scroll bar.

Constructs a new scroll bar with the specified orientation.

The orientation argument must be one of the two values Scrollbar.HORIZONTAL (II-§1.37.1) Scrollbar.VERTICAL (II-§1.37.2) indicating a horizontal or vertical scroll bar, respectively.

Parameters:

orientation - indicates the orientation of the scroll bar.

Throws

IllegalArgumentException (I-§1.32)

When an illegal orientation is given.

Constructs a new scroll bar with the specified orientation, initial value, page size, and minumum and maximum values.

The orientation argument must be one of the two values Scrollbar.HORIZONTAL (II-§1.37.1) Scrollbar.VERTICAL (II-§1.37.2) indicating a horizontal or vertical scroll bar, respectively.

If the specified maximum value is less than the minimum value, it is changed to be the same as the minimum value. If the initial value is lower than the minimum value, it is changed to be the minimum value; if it is greater than the maximum value, it is changed to be the maximum value.

Parameters:

orientation - indicates the orientation of the scroll bar.

value - the initial value of the scroll bar

visible - the size represented by the bubble in the scroll bar. The sroll bar uses this value when paging up or down by a page.

minimum - the minimum value of the scrollbar

maximum - the maximum value of the scrollbar

This method calls the createScrollbar method (II-§1.41.18) of this object's toolkit (II-§1.10.20) in order to create a ScrollbarPeer (II-§3.18) for this button. This peer allows the application to change the look of a scroll bar without changing its functionality.

Most applications do not call this method directly.

Overrides:

addNotify in class Component (II-§1.10.2).

Determines the line increment of this scrollbar, which is the amount that is added or subtracted from this scroll bar's value when the user hits the down or up gadget.

Returns:

the line increment of this scroll bar.

See Also:

setLineIncrement (II-§1.37.15).

Returns:

the maximum value of this scroll bar.

See Also:

getMinimum (II-§1.37.9)
getValue (II-§1.37.12).

Returns:

the maximum value of this scroll bar.

See Also:

getMaximum (II-§1.37.8)
getValue (II-§1.37.12).

Determines the orientation of this scroll bar. The value returned is either HORIZONTAL (II-§1.37.1) or VERTICAL (II-§1.37.2)

Returns:

the orientation of this scroll bar.

Determines the page increment of this scroll bar, which is the amount that is added to or subtracted from this scroll bar' value when the user hits the page down or page up gadget.

Returns:

the page increment for this scroll bar.

See Also:

getsetPageIncrement (II-§1.37.16).

Returns:

the current value of this scroll bar.

See Also:

getMinimum (II-§1.37.9)
getMaximum (II-§1.37.8).

Determines the "visible" amount of this scroll bar, which is the range of values represented by the width of the bubble in this scroll bar.

Returns:

the "visible" amount of this scroll bar.

Returns the parameter string representing the state of this scroll bar. This string is useful for debugging.

Returns:

the parameter string of this scroll bar.

Overrides:

paramString in class Component (II-§1.10.51).

Sets the line increment of this scroll bar.

The line increment is the value that is added to or subtracted from the value of this scroll bar when the user hits the line down or line up gadget.

Parameters:

l - the new line increment

See Also:

getLineIncrement (II-§1.37.7).

Sets the page increment of this scroll bar.

The page increment is the value that is added to or subtracted from the value of the scroll bar when the user hits the page down or page up gadget.

Parameters:

l - the new page increment

See Also:

getPageIncrement (II-§1.37.11).

Sets the value of this scroll bar to the specified value. If the specified value is below this scroll bar's current minimum or above the current maximum, it becomes the minimum or maximum value, respectively.

Parameters:

value - the new value of this scroll bar

See Also:

getValue (II-§1.37.12).

Sets several parameters of this scroll bar simultaneously..

Parameters:

value - the value of this scroll bar

visible - the amount visible per page

minimum - the minimum value of this scroll bar

maximum - the maximum value of this scroll bar

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