Class ActiveScrollbar
- All Implemented Interfaces:
Adjustable
,ImageObserver
,MenuContainer
,Serializable
,Accessible
,CSProcess
java.awt.Scrollbar
with a channel interface.
Process Diagram
Description
ActiveScrollbar is a process extension of java.awt.Scrollbar with channels for run-time configuration and event notification. The event channels should be connected to one or more application-specific server processes (instead of registering a passive object as a Listener to this component).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 = Channel.one2oneInt (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.
Channel Protocols
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 method. |
focusEvent | FocusEvent | See the addFocusEventChannel method. |
keyEvent | KeyEvent | See the addKeyEventChannel method. |
mouseEvent | MouseEvent | See the addMouseEventChannel method. |
mouseMotionEvent | MouseEvent | See the addMouseMotionEventChannel method. |
Example
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 ActiveClosingFrame activeFrame = new ActiveClosingFrame ("ActiveScrollbar Example"); final One2OneChannel configure = Channel.one2one (); final One2OneChannelInt scrollEvent = Channel.one2oneInt (new OverWriteOldestBufferInt (10)); final ActiveScrollbar scrollBar = new ActiveScrollbar ( null, scrollEvent.out (), Scrollbar.HORIZONTAL, 0, 10, 0, 110 ); final Frame realFrame = activeFrame.getActiveFrame (); realFrame.setSize (400, 75); realFrame.add (scrollBar); realFrame.setVisible (true); new Parallel ( new CSProcess[] { activeFrame, scrollBar, new CSProcess () { public void run () { final long FREE_TIME = 10000, BUSY_TIME = 250; CSTimer tim = new CSTimer (); Alternative alt = new Alternative (new Guard[] {tim, scrollEvent.in ()}); final int TIM = 0, SCROLL = 1; long timeout = tim.read (); tim.setAlarm (timeout + FREE_TIME); boolean running = true; while (running) { switch (alt.priSelect ()) { case TIM: // timeout happened configure.out ().write (Boolean.FALSE); // disable scrollbar for (int i = 40; 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"); configure.out ().write (Boolean.TRUE); // enable scrollbar timeout = tim.read (); tim.setAlarm (timeout + FREE_TIME); break; case SCROLL: // scrollEvent happened int position = scrollEvent.in ().read (); System.out.println ("ScrollBar ==> " + position); running = (position != 100); break; } } realFrame.setVisible (false); System.exit (0); } } } ).run (); } }
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic interface
This enables general configuration of this component.Nested classes/interfaces inherited from class java.awt.Scrollbar
Scrollbar.AccessibleAWTScrollBar
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate ChannelInput
The channel from which configuration messages arrive.private Vector
The Vector construct containing the handlers.Fields inherited from class java.awt.Scrollbar
HORIZONTAL, VERTICAL
Fields inherited from class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
Fields inherited from interface java.awt.Adjustable
NO_ORIENTATION
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
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Constructor Summary
ConstructorsConstructorDescriptionConstructs 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. -
Method Summary
Modifier and TypeMethodDescriptionvoid
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.Methods inherited from class java.awt.Scrollbar
addAdjustmentListener, addNotify, getAccessibleContext, getAdjustmentListeners, getBlockIncrement, getLineIncrement, getListeners, getMaximum, getMinimum, getOrientation, getPageIncrement, getUnitIncrement, getValue, getValueIsAdjusting, getVisible, getVisibleAmount, paramString, processAdjustmentEvent, processEvent, removeAdjustmentListener, setBlockIncrement, setLineIncrement, setMaximum, setMinimum, setOrientation, setPageIncrement, setUnitIncrement, setValue, setValueIsAdjusting, setValues, setVisibleAmount
Methods inherited from 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, getPeer, 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, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate
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Field Details
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vec
The Vector construct containing the handlers. -
configure
The channel from which configuration messages arrive.
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Constructor Details
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ActiveScrollbar
public ActiveScrollbar()Constructs a vertical ActiveScrollbar with no configuration or event channels. -
ActiveScrollbar
public ActiveScrollbar(int orientation) 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.- Parameters:
orientation
- indicates the orientation of the scroll bar (Scrollbar.VERTICAL, Scrollbar.HORIZONTAL).
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ActiveScrollbar
public 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.- Parameters:
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.
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ActiveScrollbar
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.- Parameters:
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.
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ActiveScrollbar
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.- Parameters:
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).
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ActiveScrollbar
public 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.- Parameters:
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.
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Method Details
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setConfigureChannel
Sets the configuration channel for this ActiveScrollbar. This method overwrites any configuration channel set in the constructor.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.
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addComponentEventChannel
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.
- Parameters:
componentEvent
- the channel down which to send ComponentEvents.
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addFocusEventChannel
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.
- Parameters:
focusEvent
- the channel down which to send FocusEvents.
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addKeyEventChannel
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.
- Parameters:
keyEvent
- the channel down which to send KeyEvents.
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addMouseEventChannel
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.
- Parameters:
mouseEvent
- the channel down which to send MouseEvents.
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addMouseMotionEventChannel
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.
- Parameters:
mouseMotionEvent
- the channel down which to send MouseMotionEvents.
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run
public void run()The main body of this process.
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