org.apache.lucene.search.spell

Class LuceneLevenshteinDistance

java.lang.Object

org.apache.lucene.search.spell.LuceneLevenshteinDistance

All Implemented Interfaces:

StringDistance

public final class LuceneLevenshteinDistance
extends java.lang.Object
implements StringDistance

Damerau-Levenshtein (optimal string alignment) implemented in a consistent way as Lucene's FuzzyTermsEnum with the transpositions option enabled. Notes:

• This metric treats full unicode codepoints as characters
• This metric scales raw edit distances into a floating point score based upon the shortest of the two terms
• Transpositions of two adjacent codepoints are treated as primitive edits.
• Edits are applied in parallel: for example, "ab" and "bca" have distance 3.

NOTE: this class is not particularly efficient. It is only intended for merging results from multiple DirectSpellCheckers.

Constructor Summary

Constructors

Constructor and Description
LuceneLevenshteinDistance() Creates a new comparator, mimicing the behavior of Lucene's internal edit distance.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object obj)
float	getDistance(java.lang.String target, java.lang.String other) Returns a float between 0 and 1 based on how similar the specified strings are to one another.

Methods inherited from class java.lang.Object

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

Constructor Detail

LuceneLevenshteinDistance

public LuceneLevenshteinDistance()

Creates a new comparator, mimicing the behavior of Lucene's internal edit distance.

Method Detail

getDistance

public float getDistance(java.lang.String target,
                         java.lang.String other)

Description copied from interface: StringDistance

Returns a float between 0 and 1 based on how similar the specified strings are to one another. Returning a value of 1 means the specified strings are identical and 0 means the string are maximally different.

Specified by:

getDistance in interface StringDistance

Parameters:

target - The first string.

other - The second string.

Returns:

a float between 0 and 1 based on how similar the specified strings are to one another.

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object