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

All Implemented Interfaces:: java.util.function.DoubleToLongFunction

public class EstimatedHistogram
extends java.lang.Object
implements java.util.function.DoubleToLongFunction

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class EstimatedHistogram.EstimatedHistogramSerializer

Field Summary

Fields
Modifier and Type Field Description

static int DEFAULT_BUCKET_COUNT

static EstimatedHistogram.EstimatedHistogramSerializer serializer

Constructor Summary

Constructors
Constructor	Description
`EstimatedHistogram()`
`EstimatedHistogram(int bucketCount)`
`EstimatedHistogram(int bucketCount, boolean considerZeroes)`
`EstimatedHistogram(long[] bucketData)`	Create EstimatedHistogram from only bucket data.
`EstimatedHistogram(long[] offsets, long[] bucketData)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`add(long n)`	Increments the count of the bucket closest to n, rounding UP.
`void`	`add(long n, long delta)`	Increments the count of the bucket closest to n, rounding UP by delta
`long`	`applyAsLong(double value)`
`void`	`clearOverflow()`	Resets the count in the overflow bucket to zero.
`long`	`count()`
`boolean`	`equals(java.lang.Object o)`
`long[]`	`getBucketOffsets()`
`long[]`	`getBuckets(boolean reset)`
`long`	`getLargestBucketOffset()`
`int`	`hashCode()`
`boolean`	`isOverflowed()`
`void`	`log(org.slf4j.Logger log)`	log.debug() every record in the histogram
`long`	`max()`
`long`	`mean()`
`long`	`min()`
`static long[]`	`newOffsets(int size, boolean considerZeroes)`
`long`	`overflowCount()`
`long`	`percentile(double percentile)`
`double`	`rawMean()`

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
```
  - DEFAULT_BUCKET_COUNT
```
public static final int DEFAULT_BUCKET_COUNT
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - EstimatedHistogram
```
public EstimatedHistogram()
```
  - EstimatedHistogram
```
public EstimatedHistogram(int bucketCount)
```
  - EstimatedHistogram
```
public EstimatedHistogram(int bucketCount,
                          boolean considerZeroes)
```
  - EstimatedHistogram
```
public EstimatedHistogram(long[] bucketData)
```
    Create EstimatedHistogram from only bucket data.
    
    Parameters:
    
    bucketData - bucket data
  - EstimatedHistogram
```
public EstimatedHistogram(long[] offsets,
                          long[] bucketData)
```
- Method Detail
  - newOffsets
```
public static long[] newOffsets(int size,
                                boolean considerZeroes)
```
  - 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 -
  - add
```
public void add(long n,
                long delta)
```
    Increments the count of the bucket closest to n, rounding UP by delta
    
    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 ceil of mean histogram value (average of bucket offsets, weighted by count)
    
    Throws:
    
    java.lang.IllegalStateException - if any values were greater than the largest bucket threshold
  - rawMean
```
public double rawMean()
```
    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
  - getLargestBucketOffset
```
public long getLargestBucketOffset()
```
    Returns:
    
    the largest bucket offset
  - isOverflowed
```
public boolean isOverflowed()
```
    Returns:
    
    true if a value larger than our largest bucket offset has been recorded, and false otherwise
  - overflowCount
```
public long overflowCount()
```
    Returns:
    
    the number of recorded values larger than the largest bucket offset
  - clearOverflow
```
public void clearOverflow()
```
    Resets the count in the overflow bucket to zero. Subsequent calls to isOverflowed() will return false.
  - log
```
public void log(org.slf4j.Logger log)
```
    log.debug() every record in the histogram
    
    Parameters:
    
    log -
  - 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
  - applyAsLong
```
public long applyAsLong(double value)
```
    Specified by:
    
    applyAsLong in interface java.util.function.DoubleToLongFunction

Modifier and Type	Field	Description
`static int`	`DEFAULT_BUCKET_COUNT`
`static EstimatedHistogram.EstimatedHistogramSerializer`	`serializer`

Class EstimatedHistogram

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

serializer

DEFAULT_BUCKET_COUNT

Constructor Detail

EstimatedHistogram

EstimatedHistogram

EstimatedHistogram

EstimatedHistogram

EstimatedHistogram

Method Detail

newOffsets

getBucketOffsets

add

add

getBuckets

min

max

percentile

mean

rawMean

count

getLargestBucketOffset

isOverflowed

overflowCount

clearOverflow

log

equals

hashCode

applyAsLong