com.google.instrumentation.stats

Class DistributionAggregation

java.lang.Object

com.google.instrumentation.stats.DistributionAggregation

public final class DistributionAggregation
extends Object

An aggregation of data based on distributions.

A distribution contains summary statistics for a population of values and, optionally, a histogram representing the distribution of those values across a specified set of histogram buckets, as defined in DistributionAggregationDescriptor.getBucketBoundaries().

Although not forbidden, it is generally a bad idea to include non-finite values (infinities or NaNs) in the population of values, as this will render the mean meaningless.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DistributionAggregation.Range Describes a range of population values.

Method Summary

Modifier and Type	Method and Description
static DistributionAggregation	create(long count, double mean, double sum, DistributionAggregation.Range range, List<Tag> tags) Constructs a new DistributionAggregation.
static DistributionAggregation	create(long count, double mean, double sum, DistributionAggregation.Range range, List<Tag> tags, List<Long> bucketCounts) Constructs a new DistributionAggregation with the optional bucketCounts.
List<Long>	getBucketCounts() A Distribution may optionally contain a histogram of the values in the population.
long	getCount() The number of values in the population.
double	getMean() The arithmetic mean of the values in the population.
DistributionAggregation.Range	getRange() The range of the population values.
double	getSum() The sum of the values in the population.
List<Tag>	getTags() Tags associated with this DistributionAggregation.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static final DistributionAggregation create(long count,
                                                   double mean,
                                                   double sum,
                                                   DistributionAggregation.Range range,
                                                   List<Tag> tags)

Constructs a new DistributionAggregation.

create

public static final DistributionAggregation create(long count,
                                                   double mean,
                                                   double sum,
                                                   DistributionAggregation.Range range,
                                                   List<Tag> tags,
                                                   List<Long> bucketCounts)

Constructs a new DistributionAggregation with the optional bucketCounts.

getTags

public final List<Tag> getTags()

Tags associated with this DistributionAggregation.

Note: The returned list is unmodifiable, attempts to update it will throw an UnsupportedOperationException.

getCount

public long getCount()

The number of values in the population. Must be non-negative.

getMean

public double getMean()

The arithmetic mean of the values in the population. If getCount() is zero then this value must also be zero.

getSum

public double getSum()

The sum of the values in the population. If getCount() is zero then this values must also be zero.

getRange

public DistributionAggregation.Range getRange()

The range of the population values. If getCount() is zero then this returned range is implementation-dependent.

getBucketCounts

@Nullable
public List<Long> getBucketCounts()

A Distribution may optionally contain a histogram of the values in the population. The histogram is given in getBucketCounts() as counts of values that fall into one of a sequence of non-overlapping buckets, described by DistributionAggregationDescriptor.getBucketBoundaries(). The sum of the values in getBucketCounts() must equal the value in getCount().

Bucket counts are given in order under the numbering scheme described above (the underflow bucket has number 0; the finite buckets, if any, have numbers 1 through N-2; the overflow bucket has number N-1).

The size of getBucketCounts() must be no greater than N as defined in DistributionAggregationDescriptor.getBucketBoundaries().

Any suffix of trailing buckets containing only zero may be omitted.

getBucketCounts() will return null iff the associated DistributionAggregationDescriptor.getBucketBoundaries() returns null.