Package org.apache.datasketches.tuple

Class CompactSketch<S extends Summary>

java.lang.Object

org.apache.datasketches.tuple.Sketch<S>

org.apache.datasketches.tuple.CompactSketch<S>

Type Parameters:

S - type of Summary

public class CompactSketch<S extends Summary>
extends Sketch<S>

CompactSketches are never created directly. They are created as a result of the compact() method of an UpdatableSketch or as a result of the getResult() method of a set operation like Union, Intersection or AnotB. CompactSketch consists of a compact list (i.e. no intervening spaces) of hash values, corresponding list of Summaries, and a value for theta. The lists may or may not be ordered. CompactSketch is read-only.

Field Summary

Fields inherited from class org.apache.datasketches.tuple.Sketch

PREAMBLE_LONGS

Method Summary

Modifier and Type	Method	Description
CompactSketch<S>	compact()	Converts this sketch to a CompactSketch on the Java heap.
int	getCountLessThanThetaLong(long thetaLong)	Gets the number of hash values less than the given theta expressed as a long.
int	getRetainedEntries()
SketchIterator<S>	iterator()	Returns a SketchIterator
byte[]	toByteArray()	This is to serialize an instance to a byte array.

Methods inherited from class org.apache.datasketches.tuple.Sketch

getEstimate, getEstimate, getLowerBound, getLowerBound, getTheta, getThetaLong, getUpperBound, getUpperBound, isEmpty, isEstimationMode, toString

Methods inherited from class java.lang.Object

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

Method Details

compact

public CompactSketch<S> compact()

Description copied from class: Sketch

Converts this sketch to a CompactSketch on the Java heap.

If this sketch is already in compact form this operation returns this.

Specified by:

compact in class Sketch<S extends Summary>

Returns:

this sketch as a CompactSketch on the Java heap.

getRetainedEntries

public int getRetainedEntries()

Specified by:

getRetainedEntries in class Sketch<S extends Summary>

Returns:

number of retained entries

getCountLessThanThetaLong

public int getCountLessThanThetaLong(long thetaLong)

Description copied from class: Sketch

Gets the number of hash values less than the given theta expressed as a long.

Specified by:

getCountLessThanThetaLong in class Sketch<S extends Summary>

Parameters:

thetaLong - the given theta as a long between zero and Long.MAX_VALUE.

Returns:

the number of hash values less than the given thetaLong.

toByteArray

public byte[] toByteArray()

Description copied from class: Sketch

This is to serialize an instance to a byte array.

Specified by:

toByteArray in class Sketch<S extends Summary>

Returns:

serialized representation of the sketch

iterator

public SketchIterator<S> iterator()

Description copied from class: Sketch

Returns a SketchIterator

Specified by:

iterator in class Sketch<S extends Summary>

Returns:

a SketchIterator