com.hazelcast.cardinality.impl.hyperloglog.impl

Interface HyperLogLogEncoder

All Superinterfaces:

DataSerializable, IdentifiedDataSerializable

All Known Implementing Classes:

DenseHyperLogLogEncoder, SparseHyperLogLogEncoder

public interface HyperLogLogEncoder
extends IdentifiedDataSerializable

Method Summary

Modifier and Type	Method and Description
boolean	add(long hash) Aggregates the hash value in the HyperLogLog registers, and returns a hint if the operation might have affected the cardinality, it is just a hint, and it relies to the respective implementation.
long	estimate() Computes a new estimate for the current status of the registers.
com.hazelcast.cardinality.impl.hyperloglog.impl.HyperLogLogEncoding	getEncodingType() Returns the encoding type of this instance; see: HyperLogLogEncoding
int	getMemoryFootprint() Returns the size in memory occupied (in bytes) for this implementation of HyperLogLog.
HyperLogLogEncoder	merge(HyperLogLogEncoder encoder) Merge the two HyperLogLog structures in one.

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.

Returns:

a cardinality estimation.

add

boolean add(long hash)

Aggregates the hash value in the HyperLogLog registers, and returns a hint if the operation might have affected the cardinality, it is just a hint, and it relies to the respective implementation.

Parameters:

hash - the value to aggregate

Returns:

boolean hint, if the latest operation might have affected the cardinality.

getMemoryFootprint

int getMemoryFootprint()

Returns the size in memory occupied (in bytes) for this implementation of HyperLogLog.

Returns:

the size in memory.

getEncodingType

com.hazelcast.cardinality.impl.hyperloglog.impl.HyperLogLogEncoding getEncodingType()

Returns the encoding type of this instance; see: HyperLogLogEncoding

Returns:

HyperLogLogEncoding

merge

HyperLogLogEncoder merge(HyperLogLogEncoder encoder)

Merge the two HyperLogLog structures in one. Estimations from both are taken into consideration and the unified estimate should be similar to the distinct union set of the two.

Parameters:

encoder - The second HLL to be merged into this one

Returns:

HyperLogLogEncoder the union