public class ActiveScrollbar extends Scrollbar
Scrollbar<TT>java.awt.Scrollbar</TT> with a channel interface.
All channels are optional. The configure and event channels are settable from a constructor. The event channel delivers the adjusted value whenever the ActiveScrollbar is moved. Other event channels can be added to notify the occurrence of any other events the component generates (by calling the appropriate addXXXEventChannel method before the process is run). Messages can be sent down the configure channel at any time to configure the component. See the table below for details.
All channels are managed by independent internal handler processes. It is, therefore, safe for a serial application process both to service an event channel and configure the component -- no deadlock can occur.
IMPORTANT: it is essential that event channels from this process are always serviced -- otherwise the Java Event Thread will be blocked and the GUI will stop responding. A simple way to guarantee this is to use channels configured with overwriting buffers. For example:
final One2OneChannelInt myScrollbarEvent = ChannelInt.createOne2One (new OverWriteOldestBuffer (n)); final ActiveScrollbar myScrollbar = new ActiveScrollbar (null, myScrollbarEvent.out (), Scrollbar.HORIZONTAL, 0, 10, 0, 110);This will ensure that the Java Event Thread will never be blocked. Slow or inattentive readers may miss rapidly generated events, but the n most recent events will always be available.
Input Channels | ||
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configure | Integer | Sets the value of the scrollbar to the value received |
Boolean |
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ActiveScrollbar.Configure | Invoke the user-defined Configure.configure method on the scrollbar. | |
Output Channels | ||
event | int | The new value of the scrollbar |
componentEvent | ComponentEvent | See the addComponentEventChannel<TT>addComponentEventChannel</TT> method. |
focusEvent | FocusEvent | See the addFocusEventChannel<TT>addFocusEventChannel</TT> method. |
keyEvent | KeyEvent | See the addKeyEventChannel<TT>addKeyEventChannel</TT> method. |
mouseEvent | MouseEvent | See the addMouseEventChannel<TT>addMouseEventChannel</TT> method. |
mouseMotionEvent | MouseEvent | See the addMouseMotionEventChannel<TT>addMouseMotionEventChannel</TT> method. |
import java.awt.*; import java.awt.event.*; import org.jcsp.lang.*; import org.jcsp.util.ints.*; import org.jcsp.awt.*; public class ActiveScrollbarExample { public static void main (String argv[]) { final Frame root = new Frame ("ActiveScrollbar Example"); final One2OneChannelInt scrollEvent = ChannelInt.createOne2One (new OverWriteOldestBufferInt (10)); final ActiveScrollbar scrollBar = new ActiveScrollbar (null, scrollEvent.out (), Scrollbar.HORIZONTAL, 0, 10, 0, 110); root.setSize (400, 75); root.add (scrollBar); root.setVisible (true); new Parallel ( new CSProcess[] { scrollBar, new CSProcess () { public void run () { final long FREE_TIME = 10000; final long BUSY_TIME = 1000; CSTimer tim = new CSTimer (); Alternative alt = new Alternative (new Guard[] {tim, scrollEvent.in ()}); long timeout = tim.read (); tim.setAlarm (timeout + FREE_TIME); boolean running = true; while (running) { switch (alt.priSelect ()) { case 0: // timeout happened for (int i = 10; i > 0; i--) { System.out.println ("*** busy busy busy ... " + i); timeout = tim.read (); tim.after (timeout + BUSY_TIME); } System.out.println ("*** free free free ... 0"); timeout = tim.read (); tim.setAlarm (timeout + FREE_TIME); break; case 1: // scrollEvent happened int position = scrollEvent.in ().read (); System.out.println ("ScrollBar ==> " + position); running = (position != 100); break; } } root.setVisible (false); System.exit (0); } } } ).run (); } }
Modifiers | Name | Description |
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static interface |
ActiveScrollbar.Configure |
This enables general configuration of this component. |
Fields inherited from class | Fields |
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class Scrollbar |
HORIZONTAL, VERTICAL, HORIZONTAL, VERTICAL, NO_ORIENTATION, TOP_ALIGNMENT, CENTER_ALIGNMENT, BOTTOM_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, WIDTH, HEIGHT, PROPERTIES, SOMEBITS, FRAMEBITS, ALLBITS, ERROR, ABORT |
class Component |
TOP_ALIGNMENT, CENTER_ALIGNMENT, BOTTOM_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, WIDTH, HEIGHT, PROPERTIES, SOMEBITS, FRAMEBITS, ALLBITS, ERROR, ABORT |
Constructor and description |
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ActiveScrollbar
() Constructs a vertical ActiveScrollbar with no configuration or event channels. |
ActiveScrollbar
(int orientation) Constructs a ActiveScrollbar with the specified orientation, but still with no configuration or event channels. |
ActiveScrollbar
(int orientation, int value, int visible, int minimum, int maximum) Constructs a ActiveScrollbar with all its options, but still with no configuration or event channels. |
ActiveScrollbar
(ChannelInput configure, ChannelOutputInt event) Constructs a vertical ActiveScrollbar with configuration and event channels. |
ActiveScrollbar
(ChannelInput configure, ChannelOutputInt event, int orientation) Constructs a ActiveScrollbar with configuration and event channels and the specified orientation. |
ActiveScrollbar
(ChannelInput configure, ChannelOutputInt event, int orientation, int value, int visible, int minimum, int maximum) Constructs a ActiveScrollbar with configuration and event channels and all its options. |
Type | Name and description |
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void |
addComponentEventChannel(ChannelOutput componentEvent) Add a new channel to this component that will be used to notify that a ComponentEvent has occurred. |
void |
addFocusEventChannel(ChannelOutput focusEvent) Add a new channel to this component that will be used to notify that a FocusEvent has occurred. |
void |
addKeyEventChannel(ChannelOutput keyEvent) Add a new channel to this component that will be used to notify that a KeyEvent has occurred. |
void |
addMouseEventChannel(ChannelOutput mouseEvent) Add a new channel to this component that will be used to notify that a MouseEvent has occurred. |
void |
addMouseMotionEventChannel(ChannelOutput mouseMotionEvent) Add a new channel to this component that will be used to notify that a MouseMotionEvent has occurred. |
void |
run() The main body of this process. |
void |
setConfigureChannel(ChannelInput configure) Sets the configuration channel for this ActiveScrollbar. |
Constructs a vertical ActiveScrollbar with no configuration or event channels.
Constructs a ActiveScrollbar with the specified orientation, but still with no configuration or event channels. The minimum and maximum values default to 0 and 100, with the initial setting at 0.
orientation
- indicates the orientation of the scroll bar
(Scrollbar.VERTICAL, Scrollbar.HORIZONTAL).Constructs a ActiveScrollbar with all its options, but still with no configuration or event channels.
orientation
- indicates the orientation of the scroll bar
(Scrollbar.VERTICAL, Scrollbar.HORIZONTAL).value
- the initial value of the scroll bar.visible
- the size of the scroll bar's bubble, representing the visible portion; the scroll bar uses this value when paging up or down by a page.minimum
- the minimum value of the scroll bar.maximum
- the maximum value of the scroll bar.Constructs a vertical ActiveScrollbar with configuration and event channels. The minimum and maximum values default to 0 and 100, with the initial setting at 0.
configure
- the channel for configuration events
-- can be null if no configuration is required.event
- the adjusted value will be output when the scrollbar is moved
-- can be null if no notification is required.Constructs a ActiveScrollbar with configuration and event channels and the specified orientation. The minimum and maximum values default to 0 and 100, with the initial setting at 0.
configure
- the channel for configuration events
-- can be null if no configuration is required.event
- the adjusted value will be output when the scrollbar is moved
-- can be null if no notification is required.orientation
- indicates the orientation of the scroll bar
(Scrollbar.VERTICAL, Scrollbar.HORIZONTAL).Constructs a ActiveScrollbar with configuration and event channels and all its options.
configure
- the channel for configuration events
-- can be null if no configuration is required.event
- the adjusted value will be output when the scrollbar is moved
-- can be null if no notification is required.orientation
- indicates the orientation of the scroll bar
(Scrollbar.VERTICAL, Scrollbar.HORIZONTAL).value
- the initial value of the scroll bar.visible
- the size of the scroll bar's bubble, representing the visible portion; the scroll bar uses this value when paging up or down by a page.minimum
- the minimum value of the scroll bar.maximum
- the maximum value of the scroll bar.Add a new channel to this component that will be used to notify that a ComponentEvent has occurred. This should be used instead of registering a ComponentListener with the component. It is possible to add more than one channel by calling this method multiple times If the channel passed is null, no action will be taken.
NOTE: This method must be called before this process is run.
componentEvent
- the channel down which to send ComponentEvents.Add a new channel to this component that will be used to notify that a FocusEvent has occurred. This should be used instead of registering a FocusListener with the component. It is possible to add more than one channel by calling this method multiple times If the channel passed is null, no action will be taken.
NOTE: This method must be called before this process is run.
focusEvent
- the channel down which to send FocusEvents.Add a new channel to this component that will be used to notify that a KeyEvent has occurred. This should be used instead of registering a KeyListener with the component. It is possible to add more than one channel by calling this method multiple times If the channel passed is null, no action will be taken.
NOTE: This method must be called before this process is run.
keyEvent
- the channel down which to send KeyEvents.Add a new channel to this component that will be used to notify that a MouseEvent has occurred. This should be used instead of registering a MouseListener with the component. It is possible to add more than one channel by calling this method multiple times If the channel passed is null, no action will be taken.
NOTE: This method must be called before this process is run.
mouseEvent
- the channel down which to send MouseEvents.Add a new channel to this component that will be used to notify that a MouseMotionEvent has occurred. This should be used instead of registering a MouseMotionListener with the component. It is possible to add more than one channel by calling this method multiple times If the channel passed is null, no action will be taken.
NOTE: This method must be called before this process is run.
mouseMotionEvent
- the channel down which to send MouseMotionEvents.The main body of this process.
Sets the configuration channel for this ActiveScrollbar. This method overwrites any configuration channel set in the constructor.
configure
- the channel for configuration events
-- can be null if no configuration is required.JCSP for Java 1.8 generated 14-10-2016 by Jon Kerridge, Edinburgh Napier University - j dot kerridge at napier dot ac dot uk