HistogramBuilder (apache-cassandra API)

java.lang.Object

org.apache.cassandra.utils.HistogramBuilder

public class HistogramBuilder extends Object

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

Field Summary

Fields

Modifier and Type

Field

Description

static final long[]

EMPTY_LONG_ARRAY

static final long[]

ZERO
Constructor Summary

Constructors

Constructor

Description

HistogramBuilder()

HistogramBuilder(long[] values)
Method Summary

Modifier and Type

Method

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

Field Details
- EMPTY_LONG_ARRAY
  
  public static final long[] EMPTY_LONG_ARRAY
- ZERO
  
  public static final long[] ZERO
Constructor Details
- HistogramBuilder
  
  public HistogramBuilder()
- HistogramBuilder
  
  public HistogramBuilder(long[] values)
Method Details
- 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: