edu.luc.cs.trull
Class Cycle

java.lang.Object
  edu.luc.cs.trull.EmptyComponent
      edu.luc.cs.trull.TerminatingComponent
          edu.luc.cs.trull.AbstractComponent
              edu.luc.cs.trull.AbstractCombinator
                  edu.luc.cs.trull.Cycle

All Implemented Interfaces:

Combinator, Component, PropertyChangeSource, Startable, Suspendable, Terminating, java.beans.PropertyChangeListener, java.util.EventListener

Direct Known Subclasses:

SetMode

public class Cycle
extends AbstractCombinator

A combinator that cycles round-robin among several components on any event from a given set of triggering events. It is largely equivalent to this nested Watching construct, but it does not cycle to the next component when the current component terminates.

 cycle c e1 ... en =
   loop
     do e1 watching c ->
       do e2 watching c ->
         ...
           do en watching c
 

See Also:

Loop, Watching

Nested Class Summary

protected class

Cycle.LocalListener A dedicated listener that forwards the event from the currently active child component to all external listeners.

Nested classes/interfaces inherited from class edu.luc.cs.trull.AbstractCombinator

AbstractCombinator.DefaultTerminationListener

Field Summary

private int	currentComponentIndex Theh index of the currently active component.
private java.beans.PropertyChangeListener	cycleAction The action to be invoked when switching to the next component.
private java.util.Set	cycleEvents The set of triggering events for cycling among components.
private java.beans.PropertyChangeListener	internalListener An internal listener that listens to the currently active child branch of this component and forwards events to the external listeners.
private static org.apache.log4j.Logger	logger

Fields inherited from class edu.luc.cs.trull.AbstractCombinator

components

Constructor Summary

Cycle()
Constructs an empty Cycle component.

Cycle(java.lang.String[] labels, Component[] branches)
Cycle(labels, null, branches)

Cycle(java.lang.String[] labels, java.beans.PropertyChangeListener action, Component[] branches)
Constructs a Cycle component.

Cycle(java.lang.String label, Component[] branches)
Cycle(label, null, branches)

Cycle(java.lang.String label, java.beans.PropertyChangeListener action, Component[] branches)
Cycle([label], action, branches)

Method Summary

protected TerminationListener	getChildTerminationListener() Returns null because this component ignores termination of its children.
protected Component	getCurrentComponent() Returns the currently active child component of this Cycle component.
java.beans.PropertyChangeListener	getCycleAction() Returns the action to be invoked when switching to the next component.
java.lang.String[]	getCycleEvents() Returns an array of triggering event labels for this component.
void	propertyChange(java.beans.PropertyChangeEvent evt) This method forwards events received from external sources to the currently active child component.
void	removeComponent(Component c) This method removes a component from the cycle.
void	resume() Resumes this suspendable component.
void	setCycleAction(java.beans.PropertyChangeListener action) Sets the action to be invoked when switching to the next component.
void	setCycleEvent(java.lang.String label) Sets the triggering event label for this component to the given string.
void	setCycleEvents(java.util.Collection evts) Sets the triggering event labels for this component to the given collection.
void	setCycleEvents(java.lang.String[] labels) Sets the triggering event labels for this component to the given array.
void	start(java.beans.PropertyChangeEvent incoming) Starts this startable component.
protected void	startCurrent(java.beans.PropertyChangeEvent incoming) Starts the currently active component.
void	stop() Stops this startable component.
void	suspend() Suspends this suspendable component.
protected void	switchToFirstComponent() Switches (cycles) to the first child component.
protected void	switchToNextComponent() Switches (cycles) to the next child component.

Methods inherited from class edu.luc.cs.trull.AbstractCombinator

addComponent, addComponent, addComponent, getComponent, getComponentCount, getComponents, removeAllComponents, removeComponent

Methods inherited from class edu.luc.cs.trull.AbstractComponent

addPropertyChangeListener, firePropertyChange, firePropertyChange, firePropertyChange, getExternalListeners, getPropertyChangeListeners, removePropertyChangeListener

Methods inherited from class edu.luc.cs.trull.TerminatingComponent

fireTermination, getParent, getTermEvent, scheduleTermination, setTerminationListener

Methods inherited from class edu.luc.cs.trull.EmptyComponent

getTerminationListener

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.luc.cs.trull.PropertyChangeSource

addPropertyChangeListener, getPropertyChangeListeners, removePropertyChangeListener

Methods inherited from interface edu.luc.cs.trull.Terminating

getTerminationListener, setTerminationListener

Field Detail

currentComponentIndex

private int currentComponentIndex

Theh index of the currently active component.

cycleAction

private java.beans.PropertyChangeListener cycleAction

The action to be invoked when switching to the next component.

cycleEvents

private java.util.Set cycleEvents

The set of triggering events for cycling among components.

internalListener

private java.beans.PropertyChangeListener internalListener

An internal listener that listens to the currently active child branch of this component and forwards events to the external listeners.

logger

private static final org.apache.log4j.Logger logger

Constructor Detail

Cycle

public Cycle()

Constructs an empty Cycle component. Specific properties can be changed later.

Cycle

public Cycle(java.lang.String[] labels,
             Component[] branches)

Cycle(labels, null, branches)

Cycle

public Cycle(java.lang.String[] labels,
             java.beans.PropertyChangeListener action,
             Component[] branches)

Constructs a Cycle component.

Parameters:

labels - the array of String event labels triggering a switch.

action - the action invoked when a switch is triggered. May be null.

branches - the components among which this component cycles.

Cycle

public Cycle(java.lang.String label,
             Component[] branches)

Cycle(label, null, branches)

Cycle

public Cycle(java.lang.String label,
             java.beans.PropertyChangeListener action,
             Component[] branches)

Cycle([label], action, branches)

Method Detail

getChildTerminationListener

protected TerminationListener getChildTerminationListener()

Returns null because this component ignores termination of its children.

Specified by:

getChildTerminationListener in class AbstractCombinator

Returns:

null.

getCurrentComponent

protected Component getCurrentComponent()

Returns the currently active child component of this Cycle component.

Returns:

the currently active child component.

getCycleAction

public java.beans.PropertyChangeListener getCycleAction()

Returns the action to be invoked when switching to the next component.

Returns:

action the action to be invoked when switching to the next component.

getCycleEvents

public java.lang.String[] getCycleEvents()

Returns an array of triggering event labels for this component.

Returns:

label the array of triggering event labels.

propertyChange

public void propertyChange(java.beans.PropertyChangeEvent evt)

This method forwards events received from external sources to the currently active child component.

Specified by:

propertyChange in interface java.beans.PropertyChangeListener

Overrides:

propertyChange in class EmptyComponent

Parameters:

evt - the event received.

removeComponent

public void removeComponent(Component c)

This method removes a component from the cycle.

Specified by:

removeComponent in interface Combinator

Overrides:

removeComponent in class AbstractCombinator

Parameters:

c - the component to be removed.

resume

public void resume()

Description copied from interface: Suspendable

Resumes this suspendable component.

Specified by:

resume in interface Suspendable

Overrides:

resume in class EmptyComponent

setCycleAction

public void setCycleAction(java.beans.PropertyChangeListener action)

Sets the action to be invoked when switching to the next component.

Parameters:

action - the action to be invoked when switching to the next component. May be null.

setCycleEvent

public void setCycleEvent(java.lang.String label)

Sets the triggering event label for this component to the given string.

Parameters:

label - the triggering event label.

setCycleEvents

public void setCycleEvents(java.util.Collection evts)

Sets the triggering event labels for this component to the given collection.

Parameters:

evts - the collection of triggering event labels.

setCycleEvents

public void setCycleEvents(java.lang.String[] labels)

Sets the triggering event labels for this component to the given array.

Parameters:

labels - the array of triggering event labels.

start

public void start(java.beans.PropertyChangeEvent incoming)

Description copied from interface: Startable

Starts this startable component.

Specified by:

start in interface Startable

Overrides:

start in class EmptyComponent

Parameters:

incoming - the event that triggered the invocation of this method. May be null.

startCurrent

protected void startCurrent(java.beans.PropertyChangeEvent incoming)

Starts the currently active component.

Parameters:

incoming - the triggering event.

stop

public void stop()

Description copied from interface: Startable

Stops this startable component.

Specified by:

stop in interface Startable

Overrides:

stop in class EmptyComponent

suspend

public void suspend()

Description copied from interface: Suspendable

Suspends this suspendable component.

Specified by:

suspend in interface Suspendable

Overrides:

suspend in class EmptyComponent

switchToFirstComponent

protected void switchToFirstComponent()

Switches (cycles) to the first child component.

switchToNextComponent

protected void switchToNextComponent()

Switches (cycles) to the next child component.