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Class jcsp.awt.ActiveLabel

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Label
                   |
                   +----jcsp.awt.ActiveLabel

public class ActiveLabel
extends Label
implements CSProcess

Process Diagram

External View

             _______________
  configure |               |
 ----->-----|  ActiveLabel  |
            |_______________|

Internal View

             ________________
            |  ____________  |
  configure | |            | |
 ----->-------|  Configure | |
            | |____________| |
            |                |
            |    ActiveLabel |
            |________________|

Description

An ActiveLabel is a sub class of Label which uses Channels for event notification and configuration.

It is possible to register Channels to be used to notify the occurrence of other types of Event that the Label generates. This can be done by calling one of the addXXXXEventChannel() methods.

To configure the Label messages can be sent down the configure channel. If the configure Channel is not a null reference a new Configure is created. The configure process sits in an infinite loop which reads from the configure Channel and configures the component based on the Object received (see table below for details).

Channel Protocols

Input Channels
configure	String	Change the label on the Label to the value of the String
configure	Boolean	If the Boolean Object refers to the Boolean.TRUE instance the button is made active If the Boolean Object refers to the Boolean.FALSE instance the button is made inactive If the Boolean Object refers to any other Boolean instance the message is discarded
Output Channels

Example

 import java.awt.*;
 import jcsp.lang.*;
 import jcsp.awt.*;
 public class LabelExample extends Frame {
   public LabelExample() {
     super("Label Example");
     final Channel label = new One2OneChannel();
     ActiveLabel b = new ActiveLabel(label, "Close");
     add(b);
     setVisible(true);
     new Parallel(new CSProcess[] {
       b,
       new CSProcess() {
         public void run() {
           int value = 0;
           while (value < 10) {
             label.write("Value = " + value);
             value++;
             try {
               Thread.sleep(1000);
             }
             catch (InterruptedException e) {
             }
           }
           setVisible(false);
           System.exit(0);
         }
       }
     }).run();
   }
   public static void main(String argv[]) {
     new LabelExample();
   }
 }

Author:: P.D.Austin

ActiveLabel(): Constructs a ActiveLabel with no label and no configuration Channel.
ActiveLabel(Channel): Constructs a ActiveLabel with no label and the configuration Channel configure.
ActiveLabel(Channel, String): Constructs a ActiveLabel with the label s and the configuration Channel configure.
ActiveLabel(String): Constructs a ActiveLabel with the label s and no configuration Channel.

addComponentEventChannel(ChannelOutput): Add a new Channel to the Component which will be used to notify that a ComponentEvent has occurred on the component.
addFocusEventChannel(ChannelOutput): Add a new Channel to the Component which will be used to notify that a FocusEvent has occurred on the component.
addKeyEventChannel(ChannelOutput): Add a new Channel to the Component which will be used to notify that a KeyEvent has occurred on the component.
addMouseEventChannel(ChannelOutput): Add a new Channel to the Component which will be used to notify that a MouseEvent has occurred on the component.
addMouseMotionEventChannel(ChannelOutput): Add a new Channel to the Component which will be used to notify that a MouseMotionEvent has occurred on the component.
run(): The main body of this process.

ActiveLabel

 public ActiveLabel()

Constructs a ActiveLabel with no label and no configuration Channel.

ActiveLabel

 public ActiveLabel(String s)

Constructs a ActiveLabel with the label s and no configuration Channel.

Parameters:: s - The label displayed on the ActiveLabel

ActiveLabel

 public ActiveLabel(Channel configure)

Constructs a ActiveLabel with no label and the configuration Channel configure.

Parameters:: configure - The Channel configuration events should be sent down. Can be null if no configuration is required.

ActiveLabel

 public ActiveLabel(Channel configure,
                    String s)

Constructs a ActiveLabel with the label s and the configuration Channel configure.

Parameters:: configure - The Channel configuration events should be sent down. Can be null if no configuration is required.; s - The label displayed on the ActiveLabel

addComponentEventChannel

 public void addComponentEventChannel(ChannelOutput componentEvent)

Add a new Channel to the Component which will be used to notify that a ComponentEvent has occurred on the component. 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 reference passed is null no action will be taken. Otherwise a new ComponentEventHanlder will be generated for the Channel so that each Channel operates independently of the others.