Class ActiveFileDialog

java.lang.Object
java.awt.Component
java.awt.Container
java.awt.Window
java.awt.Dialog
java.awt.FileDialog
org.jcsp.awt.ActiveFileDialog
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible, CSProcess
public class ActiveFileDialog extends FileDialog implements CSProcess
java.awt.FileDialog with a channel interface.

Process Diagram

Description

ActiveFileDialog is a process extension of java.awt.FileDialog 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 directory and file names (see next paragraph). 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.

The ActiveFileDialog is made visible by sending a Boolean.TRUE down its configure channel. A modal dialogue takes place to select a file and the selected directory and file names are output down its event channel.

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 myFileDialogConfigure = Channel.one2one ();
  final One2OneChannel myFileDialogEvent = Channel.one2one (new OverWriteOldestBuffer (n));

  final ActiveFileDialog myFileDialog =
    new ActiveFileDialog (myFileDialogConfigure.in (), myFileDialogEvent.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 The start directory for the fileDialog
Boolean
  1. If this is the Boolean.TRUE object, the fileDialog is made visible
  2. If this is the Boolean.FALSE object, the fileDialog is made invisible
  3. Other Boolean objects are ignored
ActiveFileDialog.Configure Invoke the user-defined Configure.configure method on the activeFileDialog.
Output Channels
event String, String The directory and file names generated by the fileDialog – these may be null
windowEvent WindowEvent See the addWindowEventChannel method.
containerEvent ContainerEvent See the addContainerEventChannel method.
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 ActiveFileDialogExample {

  public static void main (String argv[]) {

    final Frame root = new Frame ();

    final One2OneChannel configure = Channel.one2one ();

    final One2OneChannel event = Channel.one2one (new OverWriteOldestBuffer (10));

    final ActiveFileDialog fileDialog =
      new ActiveFileDialog (configure.in (), event.out (), root, "ActiveFileDialog Example");

    new Parallel (
      new CSProcess[] {
        fileDialog,
        new CSProcess () {
          public void run () {
            String dir = ".";           // start directory for the file dialogue
            String file = "";
            while (file != null) {
              configure.out ().write (dir);
              configure.out ().write (Boolean.TRUE);
              dir = (String) event.in ().read ();
              file = (String) event.in ().read ();
              if (file != null)
                System.out.println ("Chosen file = `" + dir + file + "'");
            }
          System.exit (0);
          }
        }
      }
    ).run ();
  }

}
See Also:

  • Field Details

    • vec

      private Vector vec
      The Vector construct containing the handlers.

    • configure

      private ChannelInput configure
      The channel from which configuration messages arrive.

    • event

      private ChannelOutput event
      The channel to which the selected directory and file names are sent.

  • Constructor Details

    • ActiveFileDialog

      public ActiveFileDialog(Frame parent)
      Constructs a new ActiveDialog with a blank title for loading a file and with no configuration or event channels. Constructs a new ActiveFileDialog.
      Parameters:
      parent - the parent frame for the fileDialog.

    • ActiveFileDialog

      public ActiveFileDialog(Frame parent, int mode)
      Constructs a new ActiveFileDialog with a blank title and no configuration or event channels.
      Parameters:
      parent - the parent frame for the fileDialog.
      mode - java.awt.FileDialog.LOAD or java.awt.FileDialog.SAVE.

    • ActiveFileDialog

      public ActiveFileDialog(Frame parent, String title)
      Constructs a new ActiveFileDialog for loading a file and no configuration or event channels.
      Parameters:
      parent - the parent frame for the fileDialog.
      title - the title of the fileDialog.

    • ActiveFileDialog

      public ActiveFileDialog(Frame parent, String title, int mode)
      Constructs a new ActiveFileDialog with no configuration or event channels.
      Parameters:
      parent - the parent frame for the fileDialog.
      title - the title of the fileDialog.
      mode - java.awt.FileDialog.LOAD or java.awt.FileDialog.SAVE.

    • ActiveFileDialog

      public ActiveFileDialog(ChannelInput configure, ChannelOutput event, Frame parent)
      Constructs a new ActiveFileDialog with a blank title for loading a file.
      Parameters:
      configure - the channel for configuration events – can be null if no configuration is required.
      event - the directory and file names will be output whenever selected – can be null if no notification is required.
      parent - the parent frame for the fileDialog.

    • ActiveFileDialog

      public ActiveFileDialog(ChannelInput configure, ChannelOutput event, Frame parent, int mode)
      Constructs a new ActiveFileDialog with a blank title.
      Parameters:
      configure - the channel for configuration events – can be null if no configuration is required.
      event - the directory and file names will be output whenever selected – can be null if no notification is required.
      parent - the parent frame for the fileDialog.
      mode - java.awt.FileDialog.LOAD or java.awt.FileDialog.SAVE.

    • ActiveFileDialog

      public ActiveFileDialog(ChannelInput configure, ChannelOutput event, Frame parent, String title)
      Constructs a new ActiveFileDialog for loading a file.
      Parameters:
      configure - the channel for configuration events – can be null if no configuration is required.
      event - the directory and file names will be output whenever selected – can be null if no notification is required.
      parent - the parent frame for the fileDialog.
      title - the title of the fileDialog.

    • ActiveFileDialog

      public ActiveFileDialog(ChannelInput configure, ChannelOutput event, Frame parent, String title, int mode)
      Constructs a new ActiveFileDialog.
      Parameters:
      configure - the channel for configuration events – can be null if no configuration is required.
      event - the directory and file names will be output whenever selected – can be null if no notification is required.
      parent - the parent frame for the fileDialog.
      title - the title of the fileDialog.
      mode - java.awt.FileDialog.LOAD or java.awt.FileDialog.SAVE.

  • Method Details

    • setConfigureChannel

      public void setConfigureChannel(ChannelInput configure)
      Sets the configuration channel for this ActiveFileDialog. 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.

    • addWindowEventChannel

      public void addWindowEventChannel(ChannelOutput windowEvent)
      Add a new channel to this component that will be used to notify that a WindowEvent has occurred. This should be used instead of registering a WindowListener 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:
      windowEvent - the channel down which to send ContainerEvents.

    • addContainerEventChannel

      public void addContainerEventChannel(ChannelOutput containerEvent)
      Add a new channel to this component that will be used to notify that a ContainerEvent has occurred. This should be used instead of registering a ContainerListener 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:
      containerEvent - the channel down which to send ContainerEvents.

    • 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.

    • 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.

    • 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.

    • 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.

    • 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.

    • run

      public void run()
      The main body of this process.
      Specified by:
      run in interface CSProcess