com.hazelcast.cardinality.impl.hyperloglog

Interface HyperLogLog

All Superinterfaces:

DataSerializable, IdentifiedDataSerializable

All Known Implementing Classes:

HyperLogLogImpl

public interface HyperLogLog
extends IdentifiedDataSerializable

HyperLogLog is a redundant and highly available distributed data-structure used for cardinality estimation purposes on unique items in significantly sized data cultures. HyperLogLog uses P^2 byte registers for storage and computation. HyperLogLog is an implementation of the two famous papers

• http://algo.inria.fr/flajolet/Publications/FlFuGaMe07.pdf
• http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/40671.pdf

Method Summary

Modifier and Type	Method and Description
void	add(long hash) Aggregates the hash in the HyperLogLog registers.
void	addAll(long[] hashes) Batch aggregation of hash values in the HyperLogLog registers.
long	estimate() Computes a new estimate for the current status of the registers.

Methods inherited from interface com.hazelcast.nio.serialization.IdentifiedDataSerializable

getFactoryId, getId

Methods inherited from interface com.hazelcast.nio.serialization.DataSerializable

readData, writeData

Method Detail

estimate

long estimate()

Computes a new estimate for the current status of the registers. If it was previously estimated and never invalidated, then a cached version is used.

Returns:

previously cached estimation or a newly computed one.

add

void add(long hash)

Aggregates the hash in the HyperLogLog registers.

Parameters:

hash - the value to aggregate

addAll

void addAll(long[] hashes)

Batch aggregation of hash values in the HyperLogLog registers.

Parameters:

hashes - the hash values array to aggregate