Package de.gsi.dataset.event

Class EventRateLimiter

java.lang.Object

de.gsi.dataset.event.EventRateLimiter

All Implemented Interfaces:

EventListener

public class EventRateLimiter
extends java.lang.Object
implements EventListener

EventRateLimiter that acts as an EventListener and forwards the received UpdateEvents to a secondary EventListener at a predefined maximum rate. This class may be useful in an UI contexts where the visualisation cannot be updated in time due to its numerical complexity, or for contexts where the numerical post-processing can be skipped or dropped if new UpdateEvents arrive.

Basic usage:

 
  evtSource.addListener(new EventRateLimiter(evt -> {  ... do stuff with the event ... }, MAX_UPDATE_PERIOD));
  // or, more explicitly:
  evtSource.addListener(new EventRateLimiter(evt -> {  ... do stuff with the event ... }, MAX_UPDATE_PERIOD,
              UpdateStrategy.INSTANTANEOUS_RATE));
 
 

Author:

rstein

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	EventRateLimiter.DelayedUpdateTask
static class	EventRateLimiter.UpdateStrategy	EventRateLimter UpdateStrategy EventRateLimiter.UpdateStrategy.INSTANTANEOUS_RATE notify if the time w.r.t.

Constructor Summary

Constructors

Constructor	Description
EventRateLimiter(EventListener eventListener, long minUpdatePeriod)
EventRateLimiter(EventListener eventListener, long minUpdatePeriod, EventRateLimiter.UpdateStrategy updateStrategy)

Method Summary

Modifier and Type	Method	Description
double	getRateEstimate()
void	handle(UpdateEvent event)	This method needs to be provided by an implementation of UpdateListener.

Methods inherited from class java.lang.Object

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

Constructor Detail

EventRateLimiter

public EventRateLimiter(EventListener eventListener,
                        long minUpdatePeriod)

Parameters:

eventListener - the secondary event listener that should be called if the time-out or rate-limited is not activated

minUpdatePeriod - the minimum time in milliseconds. With EventRateLimiter.UpdateStrategy.INSTANTANEOUS_RATE this implies a minimum update time-out defaults to EventRateLimiter.UpdateStrategy.INSTANTANEOUS_RATE, see EventRateLimiter.UpdateStrategy for details

EventRateLimiter

public EventRateLimiter(EventListener eventListener,
                        long minUpdatePeriod,
                        EventRateLimiter.UpdateStrategy updateStrategy)

Parameters:

eventListener - the secondary event listener that should be called if the time-out or rate-limited is not activated

minUpdatePeriod - the minimum time in milliseconds. With EventRateLimiter.UpdateStrategy.INSTANTANEOUS_RATE this implies a minimum update time-out

updateStrategy - if null defaults to EventRateLimiter.UpdateStrategy.INSTANTANEOUS_RATE, see EventRateLimiter.UpdateStrategy for details

Method Detail

getRateEstimate

public double getRateEstimate()

handle

public void handle(UpdateEvent event)

Description copied from interface: EventListener

This method needs to be provided by an implementation of UpdateListener. It is called if an EventSource has been modified/updated.

In general is is considered bad practice to modify the observed value in this method.

Specified by:

handle in interface EventListener

Parameters:

event - The UpdateEvent issued by the modified UpdateSource