public class ActiveChoice extends Choice
Choice<TT>java.awt.Choice</TT> with a channel interface.
All channels are optional. The configure and event channels are settable from a constructor. The event channel delivers the generated java.awt.ItemEvent whenever an item from the ActiveChoice is selected. 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 myChoiceEvent = Channel.createOne2One (new OverWriteOldestBuffer (n)); final ActiveChoice myChoice = new ActiveChoice (null, myChoiceEvent.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 | Sets the selected item in this ActiveChoice menu to be the item whose name is equal to the specified ActiveChoice. If more than one item matches, the one with the smallest index is selected. |
Integer | Sets the selected item in this ActiveChoice menu to be the item at the specified position. | |
Boolean |
|
|
ActiveChoice.Configure | Invoke the user-defined Configure.configure method on the choice. | |
Output Channels | ||
event | ItemEvent | When the ActiveChoice is operated, the generated java.awt.ItemEvent is written down this channel. |
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 java.awt.event.*; import org.jcsp.lang.*; import org.jcsp.util.*; import org.jcsp.awt.*; public class ActiveChoiceExample { public static void main (String argv[]) { final Frame root = new Frame ("ActiveChoice Example"); final One2OneChannel close = Channel.createOne2One (new OverWriteOldestBuffer (1)); final ActiveChoice choice = new ActiveChoice (null, close.out ()); final String[] menu = {"Hello World", "Rocket Science", "CSP", "Monitors", "Ignore Me", "Goodbye World"}; for (int i = 0; i < menu.length; i++) { choice.add (menu[i]); } root.setSize (200, 100); root.add (choice); root.setVisible (true); new Parallel ( new CSProcess[] { choice, new CSProcess () { public void run () { boolean running = true; while (running) { ItemEvent e = (ItemEvent) close.in ().read (); String item = (String) e.getItem (); System.out.println ("Selected ==> `" + item + "'"); running = (item != menu[menu.length - 1]); } root.setVisible (false); System.exit (0); } } } ).run (); } }
Modifiers | Name | Description |
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static interface |
ActiveChoice.Configure |
This enables general configuration of this component. |
Fields inherited from class | Fields |
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class Choice |
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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ActiveChoice
() Constructs an ActiveChoice with no configuration or event channels. |
ActiveChoice
(ChannelInput configure, ChannelOutput event) Constructs an ActiveChoice with configuration and event channels. |
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 ActiveChoice. |
Constructs an ActiveChoice with no configuration or event channels.
Constructs an ActiveChoice with configuration and event channels.
configure
- the channel for configuration events
-- can be null if no configuration is required.event
- the ItemEvent will be output when the choice
is exercised -- can be null if no notification is required.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 ActiveChoice. 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