org.jcsp.awt
Class ActiveTextField

java.lang.Object
  java.awt.Component
      java.awt.TextComponent
          java.awt.TextField
              org.jcsp.awt.ActiveTextField

All Implemented Interfaces:

ImageObserver, MenuContainer, Serializable, Accessible, CSProcess

public class ActiveTextField
extends TextField
implements CSProcess

java.awt.TextField with a channel interface.

Process Diagram

Description

ActiveTextField is a process extension of java.awt.TextField 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 updated text whenever the ActiveTextField is changed. 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.

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 myTextFieldEvent = Channel.one2one (new OverWriteOldestBuffer (n));
 
   final ActiveTextField myTextField =
     new ActiveTextField (null, myTextFieldEvent.out (), "Edit Me");
 

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	Set the text in this ActiveTextField to the value of the String
	Boolean	If this is the Boolean.TRUE object, the text field is made active If this is the Boolean.FALSE object, the text field is made inactive Other Boolean objects are ignored
	ActiveTextField.Configure	Invoke the user-defined Configure.configure method on the textField.
	otherwise	Append the toString form of the object to the text in this ActiveTextField.
Output Channels
event	String	The text in the ActiveTextField (whenever the text field is altered)
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 org.jcsp.lang.*;
 import org.jcsp.util.*;
 import org.jcsp.awt.*;
 import java.awt.*;
 
 public class ActiveTextFieldExample {
 
   public static void main (String argv[]) {
 
     final ActiveClosingFrame frame =
       new ActiveClosingFrame ("ActiveTextFieldExample Example");
 
     final Any2OneChannel event = Channel.any2one (new OverWriteOldestBuffer (10));
 
     final String[] string =
       {"Entia Non Sunt Multiplicanda Praeter Necessitatem",
        "Less is More ... More or Less",
        "Everything we do, we do it to you",
        "Race Hazards - What Rice Hozzers?",
        "Cogito Ergo Occam"};
 
     final String goodbye = "Goodbye World";
 
     final ActiveTextField[] activeText =
       new ActiveTextField[string.length];
 
     for (int i = 0; i < string.length; i++) {
       activeText[i] = new ActiveTextField (null, event.out (), string[i]);
     }
 
     Panel panel = new Panel (new GridLayout (string.length, 1));
     for (int i = 0; i < string.length; i++) {
       panel.add (activeText[i]);
     }
 
     final Frame realFrame = frame.getActiveFrame ();
     realFrame.setBackground (Color.green);
     realFrame.add (panel);
     realFrame.pack ();
     realFrame.setVisible (true);
 
     new Parallel (
       new CSProcess[] {
         frame,
         new Parallel (activeText),
         new CSProcess () {
           public void run () {
             boolean running = true;
             while (running) {
               String s = (String) event.in ().read ();
               System.out.println (s);
               running = (! s.equals (goodbye));
             }
             realFrame.setVisible (false);
             System.exit (0);
           }
         }
       }
     ).run ();
   }
 
 }
 

Author:

P.D. Austin and P.H. Welch

See Also:

ActiveTextEnterField, TextField, ComponentEvent, FocusEvent, KeyEvent, MouseEvent, OverWriteOldestBuffer, Serialized Form

Nested Class Summary

static interface

ActiveTextField.Configure This enables general configuration of this component.

Nested classes/interfaces inherited from class java.awt.TextField

TextField.AccessibleAWTTextField

Nested classes/interfaces inherited from class java.awt.TextComponent

TextComponent.AccessibleAWTTextComponent

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

Fields inherited from class java.awt.TextComponent

textListener

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

ActiveTextField()
Constructs a new ActiveTextField with no initial text, configuration or event channels.

ActiveTextField(ChannelInput configure, ChannelOutput event)
Constructs a new ActiveTextField with configuration and event channels, but no initial text.

ActiveTextField(ChannelInput configure, ChannelOutput event, String s)
Constructs a new ActiveTextField with configuration and event channels, initial text and default width.

ActiveTextField(ChannelInput configure, ChannelOutput event, String s, int columns)
Constructs a new ActiveTextField with configuration and event channels, initial text and width.

ActiveTextField(String s)
Constructs a new ActiveTextField with initial text and default width, but no configuration or event channels.

ActiveTextField(String s, int columns)
Constructs a new ActiveTextField with initial text and width, but no configuration or event channels.

Method Summary

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 ActiveTextField.

Methods inherited from class java.awt.TextField

addActionListener, addNotify, echoCharIsSet, getAccessibleContext, getActionListeners, getColumns, getEchoChar, getListeners, getMinimumSize, getMinimumSize, getPreferredSize, getPreferredSize, minimumSize, minimumSize, paramString, preferredSize, preferredSize, processActionEvent, processEvent, removeActionListener, setColumns, setEchoChar, setEchoCharacter, setText

Methods inherited from class java.awt.TextComponent

addTextListener, enableInputMethods, getBackground, getCaretPosition, getInputMethodRequests, getSelectedText, getSelectionEnd, getSelectionStart, getText, getTextListeners, isEditable, processTextEvent, removeNotify, removeTextListener, select, selectAll, setBackground, setCaretPosition, setEditable, setSelectionEnd, setSelectionStart

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, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, 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, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, prepareImage, prepareImage, print, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, 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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ActiveTextField

public ActiveTextField()

Constructs a new ActiveTextField with no initial text, configuration or event channels.

ActiveTextField

public ActiveTextField(String s)

Constructs a new ActiveTextField with initial text and default width, but no configuration or event channels.

Parameters:

s - the initial text displayed in the field.

ActiveTextField

public ActiveTextField(String s,
                       int columns)

Constructs a new ActiveTextField with initial text and width, but no configuration or event channels.

Parameters:

s - the initial text displayed in the field.

columns - the width of the field.

ActiveTextField

public ActiveTextField(ChannelInput configure,
                       ChannelOutput event)

Constructs a new ActiveTextField with configuration and event channels, but no initial text.

Parameters:

configure - the channel for configuration events -- can be null if no configuration is required.

event - the current text will be output when the text field is changed -- can be null if no notification is required.

ActiveTextField

public ActiveTextField(ChannelInput configure,
                       ChannelOutput event,
                       String s)

Constructs a new ActiveTextField with configuration and event channels, initial text and default width.

Parameters:

configure - the channel for configuration events -- can be null if no configuration is required.

event - the current text will be output when the text field is changed -- can be null if no notification is required.

s - the initial text displayed in the field.

ActiveTextField

public ActiveTextField(ChannelInput configure,
                       ChannelOutput event,
                       String s,
                       int columns)

Constructs a new ActiveTextField with configuration and event channels, initial text and width.

Parameters:

configure - the channel for configuration events -- can be null if no configuration is required.

event - the current text will be output when the text field is changed -- can be null if no notification is required.

s - the initial text displayed in the field.

columns - the width of the field.

Method Detail

setConfigureChannel

public void setConfigureChannel(ChannelInput configure)

Sets the configuration channel for this ActiveTextField. This method overwrites any configuration channel set in the constructor.

Parameters:

configure - the channel for configuration events. If the channel passed is null, no action will be taken.

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