com.sk89q.worldedit.util.function

Class LevenshteinDistance

java.lang.Object

com.sk89q.worldedit.util.function.LevenshteinDistance

All Implemented Interfaces:

com.google.common.base.Function<String,Integer>

public class LevenshteinDistance
extends Object
implements com.google.common.base.Function<String,Integer>

Provides a Levenshtein distance between a given string and each string that this function is applied to.

Field Summary

Fields

Modifier and Type	Field and Description
static Pattern	STANDARD_CHARS

Constructor Summary

Constructors

Constructor and Description
LevenshteinDistance(String baseString, boolean caseSensitive) Create a new instance.
LevenshteinDistance(String baseString, boolean caseSensitive, Pattern replacePattern) Create a new instance.

Method Summary

Modifier and Type	Method and Description
Integer	apply(String input)
static int	distance(String s, String t) Find the Levenshtein distance between two Strings.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.google.common.base.Function

equals

Field Detail

STANDARD_CHARS

public static final Pattern STANDARD_CHARS

Constructor Detail

LevenshteinDistance

public LevenshteinDistance(String baseString,
                           boolean caseSensitive)

Create a new instance.

Parameters:

baseString - the string to compare to

caseSensitive - true to make case sensitive comparisons

LevenshteinDistance

public LevenshteinDistance(String baseString,
                           boolean caseSensitive,
                           @Nullable
                           Pattern replacePattern)

Create a new instance.

Parameters:

baseString - the string to compare to

caseSensitive - true to make case sensitive comparisons

replacePattern - pattern to match characters to be removed in both the input and test strings (may be null)

Method Detail

apply

@Nullable
public Integer apply(String input)

Specified by:

apply in interface com.google.common.base.Function<String,Integer>

distance

public static int distance(String s,
                           String t)

Find the Levenshtein distance between two Strings.

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

The previous implementation of the Levenshtein distance algorithm was from http://www.merriampark.com/ld.htm

Chas Emerick has written an implementation in Java, which avoids an OutOfMemoryError which can occur when my Java implementation is used with very large strings.
This implementation of the Levenshtein distance algorithm is from http://www.merriampark.com/ldjava.htm

 distance(null, *)             = IllegalArgumentException
 distance(*, null)             = IllegalArgumentException
 distance("","")               = 0
 distance("","a")              = 1
 distance("aaapppp", "")       = 7
 distance("frog", "fog")       = 1
 distance("fly", "ant")        = 3
 distance("elephant", "hippo") = 7
 distance("hippo", "elephant") = 7
 distance("hippo", "zzzzzzzz") = 8
 distance("hello", "hallo")    = 1
 

Parameters:

s - the first String, must not be null

t - the second String, must not be null

Returns:

result distance

Throws:

IllegalArgumentException - if either String input null