org.apache.cassandra.utils

Class HistogramBuilder

java.lang.Object

org.apache.cassandra.utils.HistogramBuilder

public class HistogramBuilder
extends java.lang.Object

Simple class for constructing an EsimtatedHistogram from a set of predetermined values

Constructor Summary

Constructors

Constructor and Description
HistogramBuilder()
HistogramBuilder(long[] values)

Method Summary

Modifier and Type	Method and Description
void	add(long value)
EstimatedHistogram	buildWithStdevRangesAroundMean() See buildWithStdevRangesAroundMean(int)
EstimatedHistogram	buildWithStdevRangesAroundMean(int maxdevs) Calculate the min, mean, max and standard deviation of the items in the builder, and generate an EstimatedHistogram with upto maxdev stdev size ranges either side of the mean, until min/max are hit; if either min/max are not reached a further range is inserted at the relevant ends.

Methods inherited from class java.lang.Object

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

Constructor Detail

HistogramBuilder

public HistogramBuilder()

HistogramBuilder

public HistogramBuilder(long[] values)

Method Detail

add

public void add(long value)

buildWithStdevRangesAroundMean

public EstimatedHistogram buildWithStdevRangesAroundMean()

See buildWithStdevRangesAroundMean(int)

Returns:

buildWithStdevRangesAroundMean(3)

buildWithStdevRangesAroundMean

public EstimatedHistogram buildWithStdevRangesAroundMean(int maxdevs)

Calculate the min, mean, max and standard deviation of the items in the builder, and generate an EstimatedHistogram with upto maxdev stdev size ranges either side of the mean, until min/max are hit; if either min/max are not reached a further range is inserted at the relevant ends. e.g., with a maxdevs of 3, there may be up to 8 ranges (between 9 boundaries, the middle being the mean); the middle 6 will have the same size (stdev) with the outermost two stretching out to min and max.

Parameters:

maxdevs -

Returns: