org.apache.datasketches.theta

Class Intersection

java.lang.Object

org.apache.datasketches.theta.SetOperation

org.apache.datasketches.theta.Intersection

public abstract class Intersection
extends SetOperation

The API for intersection operations

Author:

Lee Rhodes

Constructor Summary

Constructors

Constructor and Description
Intersection()

Method Summary

Modifier and Type	Method and Description
Family	getFamily() Gets the Family of this SetOperation
abstract CompactSketch	getResult() Gets the result of this operation as an ordered CompactSketch on the Java heap.
abstract CompactSketch	getResult(boolean dstOrdered, org.apache.datasketches.memory.WritableMemory dstMem) Gets the result of this operation as a CompactSketch of the chosen form.
abstract boolean	hasResult() Returns true if there is an intersection result available
CompactSketch	intersect(Sketch a, Sketch b) Perform intersect set operation on the two given sketch arguments and return the result as an ordered CompactSketch on the heap.
abstract CompactSketch	intersect(Sketch a, Sketch b, boolean dstOrdered, org.apache.datasketches.memory.WritableMemory dstMem) Perform intersect set operation on the two given sketches and return the result as a CompactSketch.
abstract void	reset() Resets this Intersection.
abstract byte[]	toByteArray() Serialize this intersection to a byte array form.
abstract void	update(Sketch sketchIn) Intersect the given sketch with the internal state.

Methods inherited from class org.apache.datasketches.theta.SetOperation

builder, getMaxIntersectionBytes, getMaxUnionBytes, heapify, heapify, isSameResource, wrap, wrap, wrap, wrap

Methods inherited from class java.lang.Object

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

Constructor Detail

Intersection

public Intersection()

Method Detail

getFamily

public Family getFamily()

Description copied from class: SetOperation

Gets the Family of this SetOperation

Specified by:

getFamily in class SetOperation

Returns:

the Family of this SetOperation

getResult

public abstract CompactSketch getResult(boolean dstOrdered,
                                        org.apache.datasketches.memory.WritableMemory dstMem)

Gets the result of this operation as a CompactSketch of the chosen form. The update method must have been called at least once, otherwise an exception will be thrown. This is because a virgin Intersection object represents the Universal Set, which has an infinite number of values.

Note that presenting an intersection with an empty or null sketch sets the internal state of the intersection to empty = true, and current count = 0. This is consistent with the mathematical definition of the intersection of any set with the null set is always null.

Parameters:

dstOrdered - See Destination Ordered

dstMem - See Destination Memory.

Returns:

the result of this operation as a CompactSketch of the chosen form

getResult

public abstract CompactSketch getResult()

Gets the result of this operation as an ordered CompactSketch on the Java heap. The update method must have been called at least once.

Returns:

the result of this operation as an ordered CompactSketch on the Java heap

hasResult

public abstract boolean hasResult()

Returns true if there is an intersection result available

Returns:

true if there is an intersection result available

reset

public abstract void reset()

Resets this Intersection. The seed remains intact, otherwise reverts to the Universal Set, theta of 1.0 and empty = false.

toByteArray

public abstract byte[] toByteArray()

Serialize this intersection to a byte array form.

Returns:

byte array of this intersection

update

public abstract void update(Sketch sketchIn)

Intersect the given sketch with the internal state. This method can be repeatedly called. If the given sketch is null the internal state becomes the empty sketch. Theta will become the minimum of thetas seen so far.

Parameters:

sketchIn - the given sketch

intersect

public CompactSketch intersect(Sketch a,
                               Sketch b)

Perform intersect set operation on the two given sketch arguments and return the result as an ordered CompactSketch on the heap.

Parameters:

a - The first sketch argument

b - The second sketch argument

Returns:

an ordered CompactSketch on the heap

intersect

public abstract CompactSketch intersect(Sketch a,
                                        Sketch b,
                                        boolean dstOrdered,
                                        org.apache.datasketches.memory.WritableMemory dstMem)

Perform intersect set operation on the two given sketches and return the result as a CompactSketch.

Parameters:

a - The first sketch argument

b - The second sketch argument

dstOrdered - See Destination Ordered.

dstMem - See Destination Memory.

Returns:

the result as a CompactSketch.