org.apache.flink.metrics

Class MeterView

java.lang.Object

org.apache.flink.metrics.MeterView

All Implemented Interfaces:

Meter, Metric, View

public class MeterView
extends Object
implements Meter, View

A MeterView provides an average rate of events per second over a given time period.

The primary advantage of this class is that the rate is neither updated by the computing thread nor for every event. Instead, a history of counts is maintained that is updated in regular intervals by a background thread. From this history a rate is derived on demand, which represents the average rate of events over the given time span.

Setting the time span to a low value reduces memory-consumption and will more accurately report short-term changes. The minimum value possible is View.UPDATE_INTERVAL_SECONDS. A high value in turn increases memory-consumption, since a longer history has to be maintained, but will result in smoother transitions between rates.

The events are counted by a Counter.

Field Summary

Fields inherited from interface org.apache.flink.metrics.View

UPDATE_INTERVAL_SECONDS

Constructor Summary

Constructors

Constructor and Description
MeterView(Counter counter, int timeSpanInSeconds)
MeterView(int timeSpanInSeconds)

Method Summary

Modifier and Type	Method and Description
long	getCount() Get number of events marked on the meter.
double	getRate() Returns the current rate of events per second.
void	markEvent() Mark occurrence of an event.
void	markEvent(long n) Mark occurrence of multiple events.
void	update() This method will be called regularly to update the metric.

Methods inherited from class java.lang.Object

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

Constructor Detail

MeterView

public MeterView(int timeSpanInSeconds)

MeterView

public MeterView(Counter counter,
                 int timeSpanInSeconds)

Method Detail

markEvent

public void markEvent()

Description copied from interface: Meter

Mark occurrence of an event.

Specified by:

markEvent in interface Meter

markEvent

public void markEvent(long n)

Description copied from interface: Meter

Mark occurrence of multiple events.

Specified by:

markEvent in interface Meter

Parameters:

n - number of events occurred

getCount

public long getCount()

Description copied from interface: Meter

Get number of events marked on the meter.

Specified by:

getCount in interface Meter

Returns:

number of events marked on the meter

getRate

public double getRate()

Description copied from interface: Meter

Returns the current rate of events per second.

Specified by:

getRate in interface Meter

Returns:

current rate of events per second

update

public void update()

Description copied from interface: View

This method will be called regularly to update the metric.

Specified by:

update in interface View