Module com.pi4j.crowpi

Package com.pi4j.crowpi.components.events

Class FlappingEventProvider<V>

java.lang.Object

com.pi4j.crowpi.components.events.FlappingEventProvider<V>

Type Parameters:

V - Type of value which gets passed to event handlers.

All Implemented Interfaces:

EventHandler<V>

public class FlappingEventProvider<V>
extends Object
implements EventHandler<V>

Generic event provider to trigger a SimpleEventHandler once a value has flapped between two values for a couple times. The threshold once an event should be dispatched as well as the max idle time can be configured. Any instance should be registered in a component using EventProvider.addListener(EventHandler) to actually monitor value changes.

Constructor Summary

Constructors

Constructor	Description
FlappingEventProvider(long maxIdleTime, V valueA, V valueB)	Initializes a new FlappingEventProvider with the two given values.
FlappingEventProvider(V valueA, V valueB)	Initializes a new FlappingEventProvider with the two given values.

Method Summary

Modifier and Type	Method	Description
void	handle(V value)	Implementation of EventHandler which must be added as a listener for this event provider to work.
void	setOptions(int threshold, SimpleEventHandler handler)	Sets the threshold and event handler for this instance.

Methods inherited from class java.lang.Object

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

Constructor Details

FlappingEventProvider

public FlappingEventProvider(V valueA,
 V valueB)

Initializes a new FlappingEventProvider with the two given values. A default maximum idle time between transitions will be used by this method.

Parameters:

valueA - First value to watch for transitions to second value

valueB - Second value to watch for transitions to first value

See Also:

• FlappingEventProvider(long, Object, Object)

FlappingEventProvider

public FlappingEventProvider(long maxIdleTime,
 V valueA,
 V valueB)

Initializes a new FlappingEventProvider with the two given values. Whenever the value changes from A to B or vice-versa, an internal counter gets increased. Once a certain threshold has been reached, a user-specified handler will be called.

Parameters:

maxIdleTime - Maximum idle time between transitions in milliseconds before counter is reset

valueA - First value to watch for transitions to second value

valueB - Second value to watch for transitions to first value

Method Details

setOptions

public void setOptions(int threshold,
 SimpleEventHandler handler)

Sets the threshold and event handler for this instance. These changes will immediately apply and the counter does not get reset.

Parameters:

threshold - Threshold before event should be fired

handler - Event handler to call, null to disable

handle

public void handle(V value)

Implementation of EventHandler which must be added as a listener for this event provider to work. It will track all state changes between value A and B and automatically resets or fires the handler accordingly.

Specified by:

handle in interface EventHandler<V>

Parameters:

value - Event value