org.apache.cassandra.utils
Class EstimatedHistogram

java.lang.Object
  org.apache.cassandra.utils.EstimatedHistogram

public class EstimatedHistogram
extends java.lang.Object

Nested Class Summary

static class

EstimatedHistogram.EstimatedHistogramSerializer

Field Summary

static EstimatedHistogram.EstimatedHistogramSerializer

serializer

Constructor Summary

EstimatedHistogram()

EstimatedHistogram(int bucketCount)

EstimatedHistogram(long[] offsets, long[] bucketData)

Method Summary

void	add(long n) Increments the count of the bucket closest to n, rounding UP.
long	count()
boolean	equals(java.lang.Object o)
long[]	getBucketOffsets()
long[]	getBuckets(boolean reset)
int	hashCode()
boolean	isOverflowed()
long	max()
long	mean()
long	min()
long	percentile(double percentile)

Methods inherited from class java.lang.Object

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

Field Detail

serializer

public static final EstimatedHistogram.EstimatedHistogramSerializer serializer

Constructor Detail

EstimatedHistogram

public EstimatedHistogram()

EstimatedHistogram

public EstimatedHistogram(int bucketCount)

EstimatedHistogram

public EstimatedHistogram(long[] offsets,
                          long[] bucketData)

Method Detail

getBucketOffsets

public long[] getBucketOffsets()

Returns:

the histogram values corresponding to each bucket index

add

public void add(long n)

Increments the count of the bucket closest to n, rounding UP.

Parameters:

n -

getBuckets

public long[] getBuckets(boolean reset)

Parameters:

reset - zero out buckets afterwards if true

Returns:

a long[] containing the current histogram buckets

min

public long min()

Returns:

the smallest value that could have been added to this histogram

max

public long max()

Returns:

the largest value that could have been added to this histogram. If the histogram overflowed, returns Long.MAX_VALUE.

percentile

public long percentile(double percentile)

Parameters:

percentile -

Returns:

estimated value at given percentile

mean

public long mean()

Returns:

the mean histogram value (average of bucket offsets, weighted by count)

Throws:

java.lang.IllegalStateException - if any values were greater than the largest bucket threshold

count

public long count()

Returns:

the total number of non-zero values

isOverflowed

public boolean isOverflowed()

Returns:

true if this histogram has overflowed -- that is, a value larger than our largest bucket could bound was added

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object