Class ActiveList
- All Implemented Interfaces:
ImageObserver
,ItemSelectable
,MenuContainer
,Serializable
,Accessible
,CSProcess
java.awt.List
with a channel interface.
Process Diagram
Description
ActiveList is a process extension of java.awt.List 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. When an item in the ActiveList is double-clicked, its label is written down the event channel. 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 myListEvent = Channel.one2one (new OverWriteOldestBuffer (n)); final One2OneChannel myListItemEvent = Channel.one2one (new OverWriteOldestBuffer (n)); final ActiveList myList = new ActiveList (null, myListEvent.out ()); myList.addItemEventChannel (myListItemEvent.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 | Empty strings are ignored. If the string is "-*", all items in the list are removed. Otherwise, if the first character is '-', the item corresponding to the tail of the string is removed from the list. Otherwise, the string is added to the end of the list. |
Integer | Sets the selected item in this ActiveList list to be the item at the specified position. | |
Boolean |
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|
ActiveList.Configure | Invoke the user-defined Configure.configure method on the list. | |
Output Channels | ||
event | String | When an item in the ActiveList is double-clicked, its label is written down this channel. |
itemEvent | ItemEvent | See the addItemEventChannel 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 java.awt.event.*; import org.jcsp.lang.*; import org.jcsp.util.*; import org.jcsp.awt.*; public class ActiveListExample { public static void main (String argv[]) { final Frame root = new Frame ("ActiveList Example"); final One2OneChannel configure = Channel.one2one (); final One2OneChannel event = Channel.one2one (new OverWriteOldestBuffer (10)); final One2OneChannel itemEvent = Channel.one2one (new OverWriteOldestBuffer (10)); final ActiveList list = new ActiveList (configure.in (), event.out (), 0, true); list.addItemEventChannel (itemEvent.out ()); final String[] menu = {"Hello World", "Rocket Science", "CSP", "Monitors", "Ignore Me", "Goodbye World"}; for (int i = 0; i < menu.length; i++) { list.add (menu[i]); } root.setSize (300, 105); root.add (list); root.setVisible (true); new Parallel ( new CSProcess[] { // respond to the event channel list, new CSProcess () { public void run () { boolean running = true; while (running) { final String s = (String) event.in ().read (); System.out.println (" Action ==> `" + s + "'"); running = (s != menu[menu.length - 1]); } root.setVisible (false); System.exit (0); } }, new CSProcess () { // respond to the itemEvent channel public void run () { while (true) { final ItemEvent e = (ItemEvent) itemEvent.in ().read (); final Integer item = (Integer) e.getItem (); if (e.getStateChange () == ItemEvent.SELECTED) { System.out.println ("Selected item " + item); } else { System.out.println ("Unselected item " + item); } } } }, new CSProcess () { // dynamically reconfigure the list public void run () { CSTimer tim = new CSTimer (); long timeout = tim.read (); while (true) { timeout += 10000; tim.after (timeout); System.out.println ("*** Removing last three items ..."); for (int i = 3; i < menu.length; i++) { configure.out ().write ("-" + menu[i]); } timeout += 10000; tim.after (timeout); System.out.println ("*** Restoring last three items ..."); for (int i = 3; i < menu.length; i++) { configure.out ().write (menu[i]); } } } } } ).run (); } }
- Author:
- P.D. Austin and P.H. Welch
- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic interface
This enables general configuration of this component.Nested classes/interfaces inherited from class java.awt.List
List.AccessibleAWTList
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
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Field Summary
Fields inherited from class java.awt.Component
accessibleContext, 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
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Constructor Summary
ConstructorsConstructorDescriptionConstructs an ActiveList with no visible lines, no configuration or event channels and only one item selectable.ActiveList
(int rows) Constructs an ActiveList with the specified number of visible lines, but with no configuration or event channels and only one item selectable.ActiveList
(int rows, boolean multipleMode) Constructs an ActiveList with the specified number of visible lines and a multiple selection option, but with no configuration or event channels.ActiveList
(ChannelInput configure, ChannelOutput event) Constructs an ActiveList with configuration and event channels, but no visible items and only one item selectable.ActiveList
(ChannelInput configure, ChannelOutput event, int rows) Constructs an ActiveList with configuration and event channels, the specified number of visible lines and only one item selectable.ActiveList
(ChannelInput configure, ChannelOutput event, int rows, boolean multipleMode) Constructs an ActiveList with configuration and event channels, the specified number of visible lines and a multiple selection option. -
Method Summary
Modifier and TypeMethodDescriptionvoid
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
addItemEventChannel
(ChannelOutput itemEvent) Add a new channel to this component that will be used to notify that an ItemEvent 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 ActiveList.Methods inherited from class java.awt.List
add, add, addActionListener, addItem, addItem, addItemListener, addNotify, allowsMultipleSelections, clear, countItems, delItem, delItems, deselect, getAccessibleContext, getActionListeners, getItem, getItemCount, getItemListeners, getItems, getListeners, getMinimumSize, getMinimumSize, getPreferredSize, getPreferredSize, getRows, getSelectedIndex, getSelectedIndexes, getSelectedItem, getSelectedItems, getSelectedObjects, getVisibleIndex, isIndexSelected, isMultipleMode, isSelected, makeVisible, minimumSize, minimumSize, paramString, preferredSize, preferredSize, processActionEvent, processEvent, processItemEvent, remove, remove, removeActionListener, removeAll, removeItemListener, removeNotify, replaceItem, select, setMultipleMode, setMultipleSelections
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, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, 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, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate
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Constructor Details
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ActiveList
public ActiveList()Constructs an ActiveList with no visible lines, no configuration or event channels and only one item selectable. -
ActiveList
public ActiveList(int rows) Constructs an ActiveList with the specified number of visible lines, but with no configuration or event channels and only one item selectable.- Parameters:
rows
- the number of visible lines.
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ActiveList
public ActiveList(int rows, boolean multipleMode) Constructs an ActiveList with the specified number of visible lines and a multiple selection option, but with no configuration or event channels.- Parameters:
rows
- the number of visible lines.multipleMode
- the multiple selection option.
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ActiveList
Constructs an ActiveList with configuration and event channels, but no visible items and only one item selectable.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.event
- the String label from a list item will be output when it is double-clicked -- can be null if no notification is required.
-
ActiveList
Constructs an ActiveList with configuration and event channels, the specified number of visible lines and only one item selectable.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.event
- the String label from a list item will be output when it is double-clicked -- can be null if no notification is required.rows
- the number of visible lines.
-
ActiveList
Constructs an ActiveList with configuration and event channels, the specified number of visible lines and a multiple selection option.- Parameters:
configure
- the channel for configuration events -- can be null if no configuration is required.event
- the String label from a list item will be output when it is double-clicked -- can be null if no notification is required.rows
- the number of visible lines.multipleMode
- the multiple selection option.
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Method Details
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setConfigureChannel
Sets the configuration channel for this ActiveList. 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.
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addItemEventChannel
Add a new channel to this component that will be used to notify that an ItemEvent has occurred. This should be used instead of registering a ItemListener 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:
itemEvent
- the channel down which to send ItemEvents.
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addComponentEventChannel
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.
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addFocusEventChannel
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.
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addKeyEventChannel
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.
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addMouseEventChannel
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.
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addMouseMotionEventChannel
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.
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run
public void run()The main body of this process.
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