org.apache.hadoop.metrics2.util
Class SampleStat

java.lang.Object
  org.apache.hadoop.metrics2.util.SampleStat

public class SampleStat
extends Object

Helper to compute running sample stats

Nested Class Summary

static class

SampleStat.MinMax Helper to keep running min/max

Constructor Summary

SampleStat()
Construct a new running sample stat

Method Summary

SampleStat	add(double x) Add a sample the running stat.
SampleStat	add(long nSamples, double x) Add some sample and a partial sum to the running stat.
void	copyTo(SampleStat other) Copy the values to other (saves object creation and gc.)
double	max()
double	mean()
double	min()
long	numSamples()
void	reset()
double	stddev()
double	variance()

Methods inherited from class java.lang.Object

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

Constructor Detail

SampleStat

public SampleStat()

Construct a new running sample stat

Method Detail

reset

public void reset()

copyTo

public void copyTo(SampleStat other)

Copy the values to other (saves object creation and gc.)

Parameters:

other - the destination to hold our values

add

public SampleStat add(double x)

Add a sample the running stat.

Parameters:

x - the sample number

Returns:

self

add

public SampleStat add(long nSamples,
                      double x)

Add some sample and a partial sum to the running stat. Note, min/max is not evaluated using this method.

Parameters:

nSamples - number of samples

x - the partial sum

Returns:

self

numSamples

public long numSamples()

Returns:

the total number of samples

mean

public double mean()

Returns:

the arithmetic mean of the samples

variance

public double variance()

Returns:

the variance of the samples

stddev

public double stddev()

Returns:

the standard deviation of the samples

min

public double min()

Returns:

the minimum value of the samples

max

public double max()

Returns:

the maximum value of the samples