Class ActiveButton
- All Implemented Interfaces:
ImageObserver
,MenuContainer
,Serializable
,Accessible
,CSProcess
java.awt.Button
with a channel interface.
Process Diagram
Description
ActiveButton is a process extension of java.awt.Button 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 current button label whenever the ActiveButton is pressed. 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 One2OneChannel myButtonEvent = Channel.one2one (new OverWriteOldestBuffer (n)); final ActiveButton myButton = new ActiveButton (null, myButtonEvent.out (), "Press Me");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 | ||
---|---|---|
configure | String | Change the label on the ActiveButton to the value of the String. |
Boolean |
|
|
ActiveButton.Configure | Invoke the user-defined Configure.configure method on the button. | |
Output Channels | ||
event | String | The label on the ActiveButton (when the button is pressed and released). |
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 org.jcsp.lang.*; import org.jcsp.util.*; import org.jcsp.awt.*; public class ActiveButtonExample { public static void main (String argv[]) { final Frame root = new Frame ("ActiveButton Example"); final String[] label = {"Hello World", "Rocket Science", "CSP", "Monitors", "Ignore Me", "Goodbye World"}; final Any2OneChannel event = Channel.any2one (new OverWriteOldestBuffer (10)); final ActiveButton[] button = new ActiveButton[label.length]; for (int i = 0; i invalid input: '<' label.length; i++) { button[i] = new ActiveButton (null, event.out (), label[i]); button[i].setBackground (Color.green); } root.setSize (300, 200); root.setLayout (new GridLayout (label.length/2, 2)); for (int i = 0; i invalid input: '<' label.length; i++) { root.add (button[i]); } root.setVisible (true); new Parallel ( new CSProcess[] { new Parallel (button), new CSProcess () { public void run () { boolean running = true; while (running) { final String s = (String) event.in ().read (); System.out.println ("Button `" + s + "' pressed ..."); running = (s != label[label.length - 1]); } root.setVisible (false); System.exit (0); } } } ).run (); } }
- Author:
- P.D. Austin and P.H. Welch
- See Also:
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic interface
This enables general configuration of this component.Nested classes/interfaces inherited from class java.awt.Button
Button.AccessibleAWTButton
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
-
Field Summary
Fields inherited from class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
-
Constructor Summary
ConstructorsConstructorDescriptionConstructs a new ActiveButton with no label, configuration or event channels.Constructs a new ActiveButton with no configuration or event channels.ActiveButton
(ChannelInput configure, ChannelOutput event) Constructs a new ActiveButton with no initial label.ActiveButton
(ChannelInput configure, ChannelOutput event, String s) Constructs a new ActiveButton. -
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
addEventChannel
(ChannelOutput event) Add a new channel to this component that will be used to notify that the button has been pressed.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 ActiveButton.Methods inherited from class java.awt.Button
addActionListener, addNotify, getAccessibleContext, getActionCommand, getActionListeners, getLabel, getListeners, paramString, processActionEvent, processEvent, removeActionListener, setActionCommand, setLabel
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, 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
-
Constructor Details
-
ActiveButton
public ActiveButton()Constructs a new ActiveButton with no label, configuration or event channels. -
ActiveButton
Constructs a new ActiveButton with no configuration or event channels.- Parameters:
s
- the initial label displayed on the button.
-
ActiveButton
Constructs a new ActiveButton with no initial label.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.event
- the current label will be output when the button is pressed -- can be null if no notification is required.
-
ActiveButton
Constructs a new ActiveButton.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.event
- the current label will be output when the button is pressed -- can be null if no notification is required.s
- the initial label displayed on the button.
-
-
Method Details
-
setConfigureChannel
Sets the configuration channel for this ActiveButton. 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.
-
addEventChannel
Add a new channel to this component that will be used to notify that the button has been pressed. This should be used instead of registering an ActionListener 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. This method is an alternative to setting such a channel in the constructor.NOTE: This method must be called before this process is run.
- Parameters:
event
- the channel down which to send the current label when the button is pressed.
-
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.
-
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.
-
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.
-
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.
-
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.
-
run
public void run()The main body of this process.
-