org.javasimon.callback.quantiles
Class ExponentialBuckets

java.lang.Object
  org.javasimon.callback.quantiles.Buckets
      org.javasimon.callback.quantiles.ExponentialBuckets

All Implemented Interfaces:

LogMessageSource<Split>

public class ExponentialBuckets
extends Buckets

Exponentially organized Buckets.

Author:

Alexej Vlasov

Field Summary

private double	logMin Logarithm of the lower bound.
private double	power Power between buckets.

Fields inherited from class org.javasimon.callback.quantiles.Buckets

bucketNb, buckets, max, min

Constructor Summary

ExponentialBuckets(long min, long max, int bucketNb)
Constructor.

Method Summary

protected double	estimateQuantile(Bucket bucket, double expectedCount, double lastCount) Interpolate quantile located in given Bucket using linear regression.
protected Bucket	getBucketForValue(long value) Get the bucket containing the given value.

Methods inherited from class org.javasimon.callback.quantiles.Buckets

addValue, addValues, clear, getBucketNb, getBuckets, getLogMessage, getLogTemplate, getMax, getMedian, getMin, getQuantile, getQuantiles, getQuartiles, log, sample, setLogTemplate, toString

Methods inherited from class java.lang.Object

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

Field Detail

power

private final double power

Power between buckets.

logMin

private final double logMin

Logarithm of the lower bound.

Constructor Detail

ExponentialBuckets

public ExponentialBuckets(long min,
                          long max,
                          int bucketNb)

Constructor.

Parameters:

min - Duration min (lower bound of all buckets)

max - Duration max (upper bound of all buckets)

bucketNb - Number of buckets between min and max

Method Detail

getBucketForValue

protected Bucket getBucketForValue(long value)

Get the bucket containing the given value. Bucket should be sorted, the bucket whose min/max bounds are around the value is returned.

Override the base method making it faster thanks to exponential regression.

Overrides:

getBucketForValue in class Buckets

Parameters:

value - Value

Returns:

Bucket containing given value

estimateQuantile

protected double estimateQuantile(Bucket bucket,
                                  double expectedCount,
                                  double lastCount)

Interpolate quantile located in given Bucket using linear regression.

• Quantile is between Bucket.min and Bucket.max
• Expected count is between last count and last count+Bucket.count

Used during quantiles computation to do exponential regression over one bucket.

Overrides:

estimateQuantile in class Buckets

Parameters:

bucket - Current bucket containing the quantile

expectedCount - Searched value

lastCount - Value of the bucket lower bound

Returns:

Compute quantile