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Class jcsp.awt.event.WindowEventHandler

java.lang.Object
   |
   +----jcsp.awt.event.WindowEventHandler

public class WindowEventHandler

extends Object

implements CSProcess, WindowListener

Process Diagram

   ____________________
  |                    | event
  | WindowEventHandler |--->---
  |____________________|
 

Description

The WindowEventHandler class implements the WindowListener interface and can be used for any Component which allows the addition of a WindowListener. When the Component is created a new instance of the WindowEventHandler should be created and added as a WindowListener to the Component. The process must be set running (either asynchronously using ProcessNetwork or as part of a Parallel construct).

The main body of this process waits to be notified by a component invoking the windowOpened(), windowClosing(), windowClosed(), windowIconified(), windowDeiconified(), windowActivated() or windowDeactivated() methods. The process then wakes up and sends the WindowEvent object down the event Channel. Any further calls to the methods while the process is writing will be discarded so as not to block the main Java event Thread. When another process reads from the Channel this process loops round and waits to be notified again.

Channel Protocols

Example

Extending an Existing Component

 import java.awt.*;
 import jcsp.lang.*;
 import jcsp.awt.event.*;
 public class ChannelFrame extends Frame implements CSProcess {
   WindowEventHanlder handler;
   public ChannelComponent() {
   }
   public void addWindowEventChannel(ChannelOutput event) {
     if (event !=null) {
       handler = new WindowEventHanlder(event);
       addWindowListener(handler);
     }
   }
   public void run() {
     if (handler != null) {
       handler.run();
     }
   }
 }
 

Listening to a Component

 import java.awt.*;
 import jcsp.awt.event.*;
 import jcsp.lang.*;
        :
        :
   {
     final Channel event = new One2OneChannel();
     Window c = new Frame("Active");
     add(c);
     WindowEventHanlder handler = new WindowEventHanlder(event);
     c.addWindowListener(handler);
     new Parallel(new CSProcess[] {
       c,
       handler,
       new CSProcess() {
         public void run() {
           while (true) {
             Object o = event.read();
             System.out.println("WindowEvent '" + o);
           }
         }
       }
     }).run();
   }
 }
 

Author:

P.D.Austin

WindowEventHandler(ChannelOutput)

constructs a new WindowEventHandler with the specified output Channel.

run()

The main body of the process.

windowActivated(WindowEvent)

Invoked when the Component the event handler is listening to has the window activated.

windowClosed(WindowEvent)

Invoked when the Component the event handler is listening to has the window closed.

windowClosing(WindowEvent)

Invoked when the Component the event handler is listening to has the window start to close.

windowDeactivated(WindowEvent)

Invoked when the Component the event handler is listening to has the window deactivated.

windowDeiconified(WindowEvent)

Invoked when the Component the event handler is listening to has the window deiconified.

windowIconified(WindowEvent)

Invoked when the Component the event handler is listening to has the window iconified.

windowOpened(WindowEvent)

Invoked when the Component the event handler is listening to has the window opened.

 public WindowEventHandler(ChannelOutput event)

constructs a new WindowEventHandler with the specified output Channel.

Parameters:

event - The Channel to send the event notification down

 public void windowOpened(WindowEvent e)

Invoked when the Component the event handler is listening to has the window opened. Notifies the event process that a WindowEvent has occurred by sending the WindowEvent Object. Some notifications will be lost so there are no guarantees that all events generated will be processed.

Parameters:

e - The parameters associated with this event

 public void windowClosing(WindowEvent e)

Invoked when the Component the event handler is listening to has the window start to close. Notifies the event process that a WindowEvent has occurred by sending the WindowEvent Object. Some notifications will be lost so there are no guarantees that all events generated will be processed.

Parameters:

e - The parameters associated with this event

 public void windowClosed(WindowEvent e)

Invoked when the Component the event handler is listening to has the window closed. Notifies the event process that a WindowEvent has occurred by sending the WindowEvent Object. Some notifications will be lost so there are no guarantees that all events generated will be processed.

Parameters:

e - The parameters associated with this event

 public void windowIconified(WindowEvent e)

Invoked when the Component the event handler is listening to has the window iconified. Notifies the event process that a WindowEvent has occurred by sending the WindowEvent Object. Some notifications will be lost so there are no guarantees that all events generated will be processed.

Parameters:

e - The parameters associated with this event

 public void windowDeiconified(WindowEvent e)

Invoked when the Component the event handler is listening to has the window deiconified. Notifies the event process that a WindowEvent has occurred by sending the WindowEvent Object. Some notifications will be lost so there are no guarantees that all events generated will be processed.

Parameters:

e - The parameters associated with this event

 public void windowActivated(WindowEvent e)

Invoked when the Component the event handler is listening to has the window activated. Notifies the event process that a WindowEvent has occurred by sending the WindowEvent Object. Some notifications will be lost so there are no guarantees that all events generated will be processed.

Parameters:

e - The parameters associated with this event

 public void windowDeactivated(WindowEvent e)

Invoked when the Component the event handler is listening to has the window deactivated. Notifies the event process that a WindowEvent has occurred by sending the WindowEvent Object. Some notifications will be lost so there are no guarantees that all events generated will be processed.

Parameters:

e - The parameters associated with this event

 public void run()

The main body of the process. Executes the functionality described above.

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