com.netflix.spectator.api.histogram

Class PercentileBuckets

java.lang.Object

com.netflix.spectator.api.histogram.PercentileBuckets

public final class PercentileBuckets
extends Object

Bucket values for estimating a percentile from a set of non-negative long values. This class acts as an immutable array of the buckets along with providing some helper functions.

Method Summary

Modifier and Type	Method and Description
static long[]	asArray() Returns a copy of the bucket values array.
static long	bucket(long v) Returns the value of the bucket that should be used for v.
static long	get(int i) Return the value of the bucket at index i.
static int	indexOf(long v) Returns the value the index of the bucket that should be used for v.
static int	length() Returns the number of buckets.
static <T> T[]	map(Class<T> c, Function<Long,T> f) Map the bucket values to a new array of a different type.
static double	percentile(long[] counts, double p) Compute a percentile based on the counts for the buckets.
static void	percentiles(long[] counts, double[] pcts, double[] results) Compute a set of percentiles based on the counts for the buckets.

Methods inherited from class java.lang.Object

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

Method Detail

asArray

public static long[] asArray()

Returns a copy of the bucket values array.

map

public static <T> T[] map(Class<T> c,
                          Function<Long,T> f)

Map the bucket values to a new array of a different type.

get

public static long get(int i)

Return the value of the bucket at index i.

length

public static int length()

Returns the number of buckets.

indexOf

public static int indexOf(long v)

Returns the value the index of the bucket that should be used for v. The bucket value can be retrieved using get(int).

bucket

public static long bucket(long v)

Returns the value of the bucket that should be used for v.

percentiles

public static void percentiles(long[] counts,
                               double[] pcts,
                               double[] results)

Compute a set of percentiles based on the counts for the buckets.

Parameters:

counts - Counts for each of the buckets. The size must be the same as length() and the positions must correspond to the positions of the bucket values.

pcts - Array with the requested percentile values. The length must be at least 1 and the array should be sorted. Each value, v, should adhere to 0.0 <= v <= 100.0.

results - The calculated percentile values will be written to the results array. It should have the same length as pcts.

percentile

public static double percentile(long[] counts,
                                double p)

Compute a percentile based on the counts for the buckets.

Parameters:

counts - Counts for each of the buckets. The size must be the same as length() and the positions must correspond to the positions of the bucket values.

p - Percentile to compute, the value should be 0.0 <= p <= 100.0.

Returns:

The calculated percentile value.