org.springframework.integration.support.management

Class ExponentialMovingAverageRate

java.lang.Object

org.springframework.integration.support.management.ExponentialMovingAverageRate

public class ExponentialMovingAverageRate
extends java.lang.Object

Cumulative statistics for an event rate with higher weight given to recent data. 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.

For performance reasons, the calculation is performed on retrieval, window * 5 samples are retained meaning that the earliest retained value contributes just 0.5% to the sum.

Constructor Summary

Constructors

Constructor and Description
ExponentialMovingAverageRate(double period, double lapsePeriod, int window)
ExponentialMovingAverageRate(double period, double lapsePeriod, int window, boolean millis)

Method Summary

Modifier and Type	Method and Description
int	getCount()
long	getCountLong()
double	getMax()
double	getMean()
double	getMin()
double	getStandardDeviation()
Statistics	getStatistics()
double	getTimeSinceLastMeasurement()
void	increment() Add a new event to the series.
void	increment(long t) Add a new event to the series at time t.
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)

ExponentialMovingAverageRate

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

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)

millis - when true, analyze the data as milliseconds instead of the native nanoseconds

Since:

4.2

Method Detail

reset

public void reset()

increment

public void increment()

Add a new event to the series.

increment

public void increment(long t)

Add a new event to the series at time t.

Parameters:

t - a new event to the series (System.nanoTime()).

getCount

public int getCount()

Returns:

the number of measurements recorded

getCountLong

public long getCountLong()

Returns:

the number of measurements recorded

Since:

3.0

getTimeSinceLastMeasurement

public double getTimeSinceLastMeasurement()

Returns:

the time in milliseconds 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