public class ActiveLabel extends Label
Label<TT>java.awt.Label</TT> with a channel interface.
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.createOne2One (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.
Input Channels | ||
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configure | String | Change the label on the ActiveLabel to the value of the String |
Boolean |
|
|
ActiveLabel.Configure | Invoke the user-defined Configure.configure method on the label. | |
Output Channels | ||
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 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.createOne2One (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.createOne2One (); final One2OneChannel event = Channel.createOne2One (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 (); } }
Modifiers | Name | Description |
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static interface |
ActiveLabel.Configure |
This enables general configuration of this component. |
Fields inherited from class | Fields |
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class Label |
LEFT, CENTER, RIGHT, 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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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. |
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 ActiveLabel. |
Constructs a new ActiveLabel with no label or configuration channel.
Constructs a new ActiveLabel with no configuration channel.
s
- the initial string displayed on the label.Constructs a new ActiveLabel with no initial label.
configure
- the channel for configuration events
-- can be null if no configuration is required.Constructs a new ActiveLabel.
configure
- the channel for configuration events
-- can be null if no configuration is required.s
- the initial string displayed on the label.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 ActiveLabel. 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