Package org.apache.commons.codec.language

Class Nysiis

java.lang.Object
org.apache.commons.codec.language.Nysiis
All Implemented Interfaces:
Encoder, StringEncoder
public class Nysiis extends Object implements StringEncoder
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 non-vowel, 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

This class is immutable and thread-safe.

Since:
1.7
See Also:

  • Constructor Summary

    Constructors
    Constructor
    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

    Modifier and Type
    Method
    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 Details

    • 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 Details

    • encode

      public Object encode(Object obj) throws 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 Encoder
      Parameters:
      obj - Object to encode
      Returns:
      An object (or a String) containing the NYSIIS code which corresponds to the given String.
      Throws:
      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 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