org.springframework.integration.monitor
Class ExponentialMovingAverageRate

java.lang.Object
  org.springframework.integration.monitor.ExponentialMovingAverageRate

public class ExponentialMovingAverageRate
extends java.lang.Object

Cumulative statistics for an event rate with higher weight given to recent data but without storing any history. Clients call increment() when a new event occurs, and then use convenience methods (e.g. getMean()) to retrieve estimates of the rate of event arrivals and the statistics of the series. Older values are given exponentially smaller weight, with a decay factor determined by a duration chosen by the client. The rate measurement weights decay in two dimensions:

• in time according to the lapse period supplied: weight = exp((t0-t)/T) where t0 is the last measurement time, t is the current time and T is the lapse period)
• per measurement according to the lapse window supplied: weight = exp(-i/L) where L is the lapse window and i is the sequence number of the measurement.

Author:

Dave Syer, Gary Russell

Constructor Summary

ExponentialMovingAverageRate(double period, double lapsePeriod, int window)

Method Summary

int	getCount()
double	getMax()
double	getMean()
double	getMin()
double	getStandardDeviation()
Statistics	getStatistics()
double	getTimeSinceLastMeasurement()
void	increment() Add a new event to the series.
void	reset()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ExponentialMovingAverageRate

public ExponentialMovingAverageRate(double period,
                                    double lapsePeriod,
                                    int window)

Parameters:

period - the period to base the rate measurement (in seconds)

lapsePeriod - the exponential lapse rate for the rate average (in seconds)

window - the exponential lapse window (number of measurements)

Method Detail

reset

public void reset()

increment

public void increment()

Add a new event to the series.

getCount

public int getCount()

Returns:

the number of measurements recorded

getTimeSinceLastMeasurement

public double getTimeSinceLastMeasurement()

Returns:

the time in seconds since the last measurement

getMean

public double getMean()

Returns:

the mean value

getStandardDeviation

public double getStandardDeviation()

Returns:

the approximate standard deviation

getMax

public double getMax()

Returns:

the maximum value recorded (not weighted)

getMin

public double getMin()

Returns:

the minimum value recorded (not weighted)

getStatistics

public Statistics getStatistics()

Returns:

summary statistics (count, mean, standard deviation etc.)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object