Class ActiveLabel
- java.lang.Object
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- java.awt.Component
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- java.awt.Label
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- org.jcsp.awt.ActiveLabel
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- All Implemented Interfaces:
ImageObserver
,MenuContainer
,Serializable
,Accessible
,CSProcess
public class ActiveLabel extends Label implements CSProcess
java.awt.Label
with a channel interface.Process Diagram
Description
ActiveLabel is a process extension of java.awt.Label 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 channel is settable from a constructor. Event channels can be added to notify the occurrence of any type of Event 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 myMouseEvent = Channel.one2one (new OverWriteOldestBuffer (n)); final ActiveLabel myLabel = new ActiveLabel ("Look at Me"); myContainer.addMouseEventChannel (myMouseEvent.out ());
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 ActiveLabel to the value of the String Boolean - If this is the Boolean.TRUE object, the label is made active
- If this is the Boolean.FALSE object, the label is made inactive
- Other Boolean objects are ignored
ActiveLabel.Configure Invoke the user-defined Configure.configure method on the label. Output Channels 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 ActiveLabelExample { public static void main (String argv[]) { final Frame root = new Frame ("ActiveLabel Example"); final int nLabels = 8; final int countdown = 10; final One2OneChannel[] configureLabel = Channel.one2oneArray (nLabels); final ActiveLabel[] label = new ActiveLabel[nLabels]; for (int i = 0; i < label.length; i++) { label[i] = new ActiveLabel (configureLabel[i].in (), "==> " + countdown + " <=="); label[i].setAlignment (Label.CENTER); } final One2OneChannel configureButton = Channel.one2one (); final One2OneChannel event = Channel.one2one (new OverWriteOldestBuffer (10)); final ActiveButton button = new ActiveButton (configureButton.in (), event.out (), "Start"); root.setSize (300, 200); root.setLayout (new GridLayout (3, 3)); for (int i = 0; i < nLabels + 1; i++) { if (i < 4) { root.add (label[i]); } else if (i == 4) { root.add (button); } else if (i > 4) { root.add (label[i - 1]); } } root.setVisible (true); new Parallel ( new CSProcess[] { new Parallel (label), button, new CSProcess () { public void run () { final long second = 1000; CSTimer tim = new CSTimer (); Alternative alt = new Alternative (new Guard[] {event.in (), tim}); event.in ().read (); // wait for the start signal configureButton.out ().write ("Restart"); int count = countdown; long timeout = tim.read () + second; while (count > 0) { tim.setAlarm (timeout); switch (alt.priSelect ()) { case 0: // reset signal event.in ().read (); // clear the reset timeout = tim.read () + second; count = countdown; break; case 1: // timeout signal timeout += second; count--; break; } final String newLabel = "==> " + count + " <=="; for (int i = 0; i < nLabels; i++) { configureLabel[i].out ().write (newLabel); } } root.setVisible (false); System.exit (0); } } } ).run (); } }
- Author:
- P.D. Austin and P.H. Welch
- See Also:
Label
,ComponentEvent
,FocusEvent
,KeyEvent
,MouseEvent
,OverWriteOldestBuffer
, Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description static interface
ActiveLabel.Configure
This enables general configuration of this component.-
Nested classes/interfaces inherited from class java.awt.Label
Label.AccessibleAWTLabel
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Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
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Field Summary
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Fields inherited from class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
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Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
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Constructor Summary
Constructors Constructor Description ActiveLabel()
Constructs a new ActiveLabel with no label or configuration channel.ActiveLabel(String s)
Constructs a new ActiveLabel with no configuration channel.ActiveLabel(ChannelInput configure)
Constructs a new ActiveLabel with no initial label.ActiveLabel(ChannelInput configure, String s)
Constructs a new ActiveLabel.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description 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 ActiveLabel.-
Methods inherited from class java.awt.Label
addNotify, getAccessibleContext, getAlignment, getText, paramString, setAlignment, setText
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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, getListeners, 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, processEvent, 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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Constructor Detail
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ActiveLabel
public ActiveLabel()
Constructs a new ActiveLabel with no label or configuration channel.
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ActiveLabel
public ActiveLabel(String s)
Constructs a new ActiveLabel with no configuration channel.- Parameters:
s
- the initial string displayed on the label.
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ActiveLabel
public ActiveLabel(ChannelInput configure)
Constructs a new ActiveLabel with no initial label.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.
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ActiveLabel
public ActiveLabel(ChannelInput configure, String s)
Constructs a new ActiveLabel.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.s
- the initial string displayed on the label.
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Method Detail
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setConfigureChannel
public void setConfigureChannel(ChannelInput configure)
Sets the configuration channel for this ActiveLabel. 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
public void addComponentEventChannel(ChannelOutput componentEvent)
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
public void addFocusEventChannel(ChannelOutput focusEvent)
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
public void addKeyEventChannel(ChannelOutput keyEvent)
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
public void addMouseEventChannel(ChannelOutput mouseEvent)
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
public void addMouseMotionEventChannel(ChannelOutput mouseMotionEvent)
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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