org.elasticsearch.index.analysis.phonetic

Class Nysiis

java.lang.Object

org.elasticsearch.index.analysis.phonetic.Nysiis

All Implemented Interfaces:

org.apache.commons.codec.Encoder, org.apache.commons.codec.StringEncoder

public class Nysiis
extends Object
implements org.apache.commons.codec.StringEncoder

Taken from commons-codec trunk (unreleased yet) Encodes a string into a NYSIIS value. NYSIIS is an encoding used to relate similar names, but can also be used as a general purpose scheme to find word with similar phonemes.

NYSIIS features an accuracy increase of 2.7% over the traditional Soundex algorithm.

Algorithm description:

 1. Transcode first characters of name
   1a. MAC ->   MCC
   1b. KN  ->   NN
   1c. K   ->   C
   1d. PH  ->   FF
   1e. PF  ->   FF
   1f. SCH ->   SSS
 2. Transcode last characters of name
   2a. EE, IE          ->   Y
   2b. DT,RT,RD,NT,ND  ->   D
 3. First character of key = first character of name
 4. Transcode remaining characters by following these rules, incrementing by one character each time
   4a. EV  ->   AF  else A,E,I,O,U -> A
   4b. Q   ->   G
   4c. Z   ->   S
   4d. M   ->   N
   4e. KN  ->   N   else K -> C
   4f. SCH ->   SSS
   4g. PH  ->   FF
   4h. H   ->   If previous or next is nonvowel, previous
   4i. W   ->   If previous is vowel, previous
   4j. Add current to key if current != last key character
 5. If last character is S, remove it
 6. If last characters are AY, replace with Y
 7. If last character is A, remove it
 8. Collapse all strings of repeated characters
 9. Add original first character of name as first character of key
 

See Also:

NYSIIS on Wikipedia, NYSIIS on dropby.com

Constructor Summary

Constructors

Constructor and Description
Nysiis() Creates an instance of the Nysiis encoder with strict mode (original form), i.e.
Nysiis(boolean strict) Create an instance of the Nysiis encoder with the specified strict mode: true: encoded strings have a maximum length of 6 false: encoded strings may have arbitrary length

Method Summary

Methods

Modifier and Type	Method and Description
Object	encode(Object obj) Encodes an Object using the NYSIIS algorithm.
String	encode(String str) Encodes a String using the NYSIIS algorithm.
boolean	isStrict() Indicates the strict mode for this Nysiis encoder.
String	nysiis(String str) Retrieves the NYSIIS code for a given String object.

Methods inherited from class java.lang.Object

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

Constructor Detail

Nysiis

public Nysiis()

Creates an instance of the Nysiis encoder with strict mode (original form), i.e. encoded strings have a maximum length of 6.

Nysiis

public Nysiis(boolean strict)

Create an instance of the Nysiis encoder with the specified strict mode:

• true: encoded strings have a maximum length of 6
• false: encoded strings may have arbitrary length

Parameters:

strict - the strict mode

Method Detail

encode

public Object encode(Object obj)
              throws org.apache.commons.codec.EncoderException

Encodes an Object using the NYSIIS algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type String.

Specified by:

encode in interface org.apache.commons.codec.Encoder

Parameters:

obj - Object to encode

Returns:

An object (or a String) containing the NYSIIS code which corresponds to the given String.

Throws:

org.apache.commons.codec.EncoderException - if the parameter supplied is not of a String

IllegalArgumentException - if a character is not mapped

encode

public String encode(String str)

Encodes a String using the NYSIIS algorithm.

Specified by:

encode in interface org.apache.commons.codec.StringEncoder

Parameters:

str - A String object to encode

Returns:

A Nysiis code corresponding to the String supplied

Throws:

IllegalArgumentException - if a character is not mapped

isStrict

public boolean isStrict()

Indicates the strict mode for this Nysiis encoder.

Returns:

true if the encoder is configured for strict mode, false otherwise

nysiis

public String nysiis(String str)

Retrieves the NYSIIS code for a given String object.

Parameters:

str - String to encode using the NYSIIS algorithm

Returns:

A NYSIIS code for the String supplied