org.eclipse.jetty.util.statistic

Class SampleStatistic

• ```public class SampleStatistic
extends Object```
SampledStatistics

Provides max, total, mean, count, variance, and standard deviation of continuous sequence of samples.

Calculates estimates of mean, variance, and standard deviation characteristics of a sample using a non synchronized approximation of the on-line algorithm presented in Donald Knuth's Art of Computer Programming, Volume 2, Semi numerical Algorithms, 3rd edition, page 232, Boston: Addison-Wesley. that cites a 1962 paper by B.P. Welford that can be found by following Note on a Method for Calculating Corrected Sums of Squares and Products

This algorithm is also described in Wikipedia at Algorithms for calculating variance

• Field Summary

Fields
Modifier and Type Field and Description
`protected AtomicLong` `_count`
`protected LongAccumulator` `_max`
`protected AtomicLong` `_total`
`protected LongAdder` `_totalVariance100`
• Constructor Summary

Constructors
Constructor and Description
`SampleStatistic()`
• Method Summary

All Methods
Modifier and Type Method and Description
`long` `getCount()`
`long` `getMax()`
`double` `getMean()`
`double` `getStdDev()`
`long` `getTotal()`
`double` `getVariance()`
`void` `reset()`
`void` `set(long sample)`
`String` `toString()`
• Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`
• Field Detail

• _max

`protected final LongAccumulator _max`
• _total

`protected final AtomicLong _total`
• _count

`protected final AtomicLong _count`
• _totalVariance100

`protected final LongAdder _totalVariance100`
• Constructor Detail

• SampleStatistic

`public SampleStatistic()`
• Method Detail

• reset

`public void reset()`
• set

`public void set(long sample)`
• getMax

`public long getMax()`
Returns:
the max value
• getTotal

`public long getTotal()`
• getCount

`public long getCount()`
• getMean

`public double getMean()`
• getVariance

`public double getVariance()`
• getStdDev

`public double getStdDev()`
• toString

`public String toString()`
Overrides:
`toString` in class `Object`