org.modeshape.jcr.api.monitor

Interface Statistics

All Known Implementing Classes:

StatisticalData

public interface Statistics

The immutable statistics for a sample of values. The statistics include the minimum, maximum, mean (average), variance and standard deviation.

The median value is not included in these statistics, since the median value cannot be rolled up given a series of statistics without having the original values. It is possible to compute the weighted median, but this loses effectiveness/value the more times it is rolled up.

Since:

3.0

Field Summary

Fields

Modifier and Type	Field and Description
static Statistics[]	NO_STATISTICS An empty statistics array.

Method Summary

Methods

Modifier and Type	Method and Description
int	getCount() Get the number of samples to which these statistics apply.
long	getMaximum() Get the maximum of the sampled values.
double	getMean() The mean (or average) of the sampled values.
long	getMinimum() Get the minimum of the sampled values.
double	getStandardDeviation() Get the standard deviation of the sampled values, which is a measure of how spread out the numbers are and is the square root of the variance.
double	getVariance() Get the variance of the sampled values, which is the average of the squared differences from the mean.

Field Detail

NO_STATISTICS

static final Statistics[] NO_STATISTICS

An empty statistics array.

Method Detail

getCount

int getCount()

Get the number of samples to which these statistics apply.

Returns:

the number of samples; never negative

getMaximum

long getMaximum()

Get the maximum of the sampled values.

Returns:

the maximum value

getMinimum

long getMinimum()

Get the minimum of the sampled values.

Returns:

the minimum value

getMean

double getMean()

The mean (or average) of the sampled values. This is returned as a double to reduce the lost of precision.

Returns:

the mean or average value

getVariance

double getVariance()

Get the variance of the sampled values, which is the average of the squared differences from the mean.

Returns:

the variance; never negative

getStandardDeviation

double getStandardDeviation()

Get the standard deviation of the sampled values, which is a measure of how spread out the numbers are and is the square root of the variance.

Returns:

the standard deviation; never negative