Package org.apache.commons.text.similarity

Class DamerauLevenshteinDistance

java.lang.Object

org.apache.commons.text.similarity.DamerauLevenshteinDistance

All Implemented Interfaces:

BiFunction<CharSequence,CharSequence,Integer>, EditDistance<Integer>, ObjectSimilarityScore<CharSequence,Integer>, SimilarityScore<Integer>

public class DamerauLevenshteinDistance
extends Object
implements EditDistance<Integer>

An algorithm for measuring the difference between two character sequences using the Damerau-Levenshtein Distance.

This is the number of changes needed to change one sequence into another, where each change is a single character modification (deletion, insertion, substitution, or transposition of two adjacent characters).

Since:

1.15.0

See Also:

• Damerau-Levenshtein Distance on Wikipedia

Constructor Summary

Constructors

Constructor	Description
DamerauLevenshteinDistance()	Constructs a default instance that uses a version of the algorithm that does not use a threshold parameter.
DamerauLevenshteinDistance(Integer threshold)	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
Integer	apply(CharSequence left, CharSequence right)	Computes the Damerau-Levenshtein distance between two Strings.
<E> Integer	apply(SimilarityInput<E> left, SimilarityInput<E> right)	Computes the Damerau-Levenshtein distance between two inputs.
Integer	getThreshold()	Gets the distance threshold.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.function.BiFunction

andThen

Constructor Details

DamerauLevenshteinDistance

public DamerauLevenshteinDistance()

Constructs a default instance that uses a version of the algorithm that does not use a threshold parameter.

DamerauLevenshteinDistance

public DamerauLevenshteinDistance(Integer threshold)

Constructs a new instance. If the threshold is not null, distance calculations will be limited to a maximum length. If the threshold is null, the unlimited version of the algorithm will be used.

Parameters:

threshold - If this is null then distances calculations will not be limited. This may not be negative.

Method Details

apply

public Integer apply(CharSequence left,
 CharSequence right)

Computes the Damerau-Levenshtein distance between two Strings.

A higher score indicates a greater distance.

Specified by:

apply in interface BiFunction<CharSequence,CharSequence,Integer>

Specified by:

apply in interface ObjectSimilarityScore<CharSequence,Integer>

Specified by:

apply in interface SimilarityScore<Integer>

Parameters:

left - the first input, must not be null.

right - the second input, must not be null.

Returns:

result distance, or -1 if threshold is exceeded.

Throws:

IllegalArgumentException - if either String input null.

apply

public <E> Integer apply(SimilarityInput<E> left,
 SimilarityInput<E> right)

Computes the Damerau-Levenshtein distance between two inputs.

A higher score indicates a greater distance.

Type Parameters:

E - The type of similarity score unit.

Parameters:

left - the first input, must not be null.

right - the second input, must not be null.

Returns:

result distance, or -1 if threshold is exceeded.

Throws:

IllegalArgumentException - if either String input null.

Since:

1.13.0

getThreshold

public Integer getThreshold()

Gets the distance threshold.

Returns:

The distance threshold.