org.basex.util
Class Levenshtein

java.lang.Object
  org.basex.util.Levenshtein

public final class Levenshtein
extends java.lang.Object

This class assembles methods for fuzzy token matching.

Author:

Workgroup DBIS, University of Konstanz 2005-08, ISC License, Christian Gruen

Constructor Summary

Levenshtein()
Constructor.

Method Summary

boolean	contains(byte[] tok, byte[] sub) Checks if the first token approximately contains the second fulltext term.
boolean	ftChar(byte ch) Checks if the specified character is a letter; special characters are converted to the standard ASCII charset.
int	ftNorm(int ch) Returns a lowercase ASCII character of the specified fulltext character.
int	ls(byte[] tok, int ts, int tl, byte[] sub, int k) Calculates a Levenshtein distance.
boolean	similar(byte[] tok, byte[] sub) Compares two character arrays for similarity.

Methods inherited from class java.lang.Object

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

Constructor Detail

Levenshtein

public Levenshtein()

Constructor.

Method Detail

similar

public boolean similar(byte[] tok,
                       byte[] sub)

Compares two character arrays for similarity.

Parameters:

tok - token to be compared

sub - second token to be compared

Returns:

true if the arrays are similar

ls

public int ls(byte[] tok,
              int ts,
              int tl,
              byte[] sub,
              int k)

Calculates a Levenshtein distance.

Parameters:

tok - token to be compared

ts - start position in token

tl - token length to be checked

sub - sub token to be compared

k - maximum number of accepted errors

Returns:

true if the arrays are similar

contains

public boolean contains(byte[] tok,
                        byte[] sub)

Checks if the first token approximately contains the second fulltext term.

Parameters:

tok - first token

sub - second token

Returns:

result of test

ftChar

public boolean ftChar(byte ch)

Checks if the specified character is a letter; special characters are converted to the standard ASCII charset. Note that this method does not support unicode characters.

Parameters:

ch - character to be converted

Returns:

converted character

ftNorm

public int ftNorm(int ch)

Returns a lowercase ASCII character of the specified fulltext character. Note that this method does not support unicode characters.

Parameters:

ch - character to be converted

Returns:

converted character