Package org.apache.commons.text.similarity

Class IntersectionSimilarity<T>

java.lang.Object

org.apache.commons.text.similarity.IntersectionSimilarity<T>

Type Parameters:

T - the type of the elements extracted from the character sequence

All Implemented Interfaces:

SimilarityScore<IntersectionResult>

public class IntersectionSimilarity<T>
extends java.lang.Object
implements SimilarityScore<IntersectionResult>

Measures the intersection of two sets created from a pair of character sequences.

It is assumed that the type T correctly conforms to the requirements for storage within a Set or HashMap. Ideally the type is immutable and implements Object.equals(Object) and Object.hashCode().

Since:

1.7

See Also:

Set, HashMap

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	IntersectionSimilarity.BagCount	Mutable counter class for storing the count of elements.
private class	IntersectionSimilarity.TinyBag	A minimal implementation of a Bag that can store elements and a count.

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.function.Function<java.lang.CharSequence,java.util.Collection<T>>	converter	The converter used to create the elements from the characters.

Constructor Summary

Constructors

Constructor	Description
IntersectionSimilarity(java.util.function.Function<java.lang.CharSequence,java.util.Collection<T>> converter)	Create a new intersection similarity using the provided converter.

Method Summary

Modifier and Type	Method	Description
IntersectionResult	apply(java.lang.CharSequence left, java.lang.CharSequence right)	Calculates the intersection of two character sequences passed as input.
private static <T> int	getIntersection(java.util.Set<T> setA, java.util.Set<T> setB)	Compute the intersection between two sets.
private int	getIntersection(IntersectionSimilarity.TinyBag bagA, IntersectionSimilarity.TinyBag bagB)	Compute the intersection between two bags.
private IntersectionSimilarity.TinyBag	toBag(java.util.Collection<T> objects)	Convert the collection to a bag.

Methods inherited from class java.lang.Object

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

Field Detail

converter

private final java.util.function.Function<java.lang.CharSequence,java.util.Collection<T>> converter

The converter used to create the elements from the characters.

Constructor Detail

IntersectionSimilarity

public IntersectionSimilarity(java.util.function.Function<java.lang.CharSequence,java.util.Collection<T>> converter)

Create a new intersection similarity using the provided converter.

If the converter returns a Set then the intersection result will not include duplicates. Any other Collection is used to produce a result that will include duplicates in the intersect and union.

Parameters:

converter - the converter used to create the elements from the characters

Throws:

java.lang.IllegalArgumentException - if the converter is null

Method Detail

apply

public IntersectionResult apply(java.lang.CharSequence left,
                                java.lang.CharSequence right)

Calculates the intersection of two character sequences passed as input.

Specified by:

apply in interface SimilarityScore<T>

Parameters:

left - first character sequence

right - second character sequence

Returns:

The intersection result

Throws:

java.lang.IllegalArgumentException - if either input sequence is null

toBag

private IntersectionSimilarity.TinyBag toBag(java.util.Collection<T> objects)

Convert the collection to a bag. The bag will contain the count of each element in the collection.

Parameters:

objects - the objects

Returns:

The bag

getIntersection

private static <T> int getIntersection(java.util.Set<T> setA,
                                       java.util.Set<T> setB)

Compute the intersection between two sets. This is the count of all the elements that are within both sets.

Type Parameters:

T - the type of the elements in the set

Parameters:

setA - the set A

setB - the set B

Returns:

The intersection

getIntersection

private int getIntersection(IntersectionSimilarity.TinyBag bagA,
                            IntersectionSimilarity.TinyBag bagB)

Compute the intersection between two bags. This is the sum of the minimum count of each element that is within both sets.

Parameters:

bagA - the bag A

bagB - the bag B

Returns:

The intersection