org.apache.commons.codec.language

Class ColognePhonetic

java.lang.Object

org.apache.commons.codec.language.ColognePhonetic

All Implemented Interfaces:

Encoder, StringEncoder

public class ColognePhonetic
extends Object
implements StringEncoder

Encodes a string into a Cologne Phonetic value.

Implements the Kölner Phonetik (Cologne Phonetic) algorithm issued by Hans Joachim Postel in 1969.

The Kölner Phonetik is a phonetic algorithm which is optimized for the German language. It is related to the well-known soundex algorithm.

Algorithm

• Step 1:

  After preprocessing (conversion to upper case, transcription of germanic umlauts, removal of non alphabetical characters) the letters of the supplied text are replaced by their phonetic code according to the following table.

  (Source: Wikipedia (de): Kölner Phonetik -- Buchstabencodes)

  Letter	Context	Code
  A, E, I, J, O, U, Y		0
  H		-
  B		1
  P	not before H
  D, T	not before C, S, Z	2
  F, V, W		3
  P	before H
  G, K, Q		4
  C	at onset before A, H, K, L, O, Q, R, U, X
  	before A, H, K, O, Q, U, X except after S, Z
  X	not after C, K, Q	48
  L		5
  M, N		6
  R		7
  S, Z		8
  C	after S, Z
  	at onset except before A, H, K, L, O, Q, R, U, X
  	not before A, H, K, O, Q, U, X
  D, T	before C, S, Z
  X	after C, K, Q

  Example:

  "Müller-Lüdenscheidt" => "MULLERLUDENSCHEIDT" => "6005507500206880022"

• Step 2:

  Collapse of all multiple consecutive code digits.

  Example:

  "6005507500206880022" => "6050750206802"

• Step 3:

  Removal of all codes "0" except at the beginning. This means that two or more identical consecutive digits can occur if they occur after removing the "0" digits.

  Example:

  "6050750206802" => "65752682"

This class is thread-safe.

Since:

1.5

See Also:

Wikipedia (de): Kölner Phonetik (in German)

Constructor Summary

Constructors

Constructor and Description
ColognePhonetic()

Method Summary

Modifier and Type	Method and Description
String	colognePhonetic(String text) Implements the Kölner Phonetik algorithm.
Object	encode(Object object) Encodes an "Object" and returns the encoded content as an Object.
String	encode(String text) Encodes a String and returns a String.
boolean	isEncodeEqual(String text1, String text2) Compares the first encoded string to the second encoded string.

Methods inherited from class java.lang.Object

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

Constructor Detail

ColognePhonetic

public ColognePhonetic()

Method Detail

colognePhonetic

public String colognePhonetic(String text)

Implements the Kölner Phonetik algorithm.

In contrast to the initial description of the algorithm, this implementation does the encoding in one pass.

Parameters:

text - The source text to encode

Returns:

the corresponding encoding according to the Kölner Phonetik algorithm

encode

public Object encode(Object object)
              throws EncoderException

Description copied from interface: Encoder

Encodes an "Object" and returns the encoded content as an Object. The Objects here may just be byte[] or Strings depending on the implementation used.

Specified by:

encode in interface Encoder

Parameters:

object - An object to encode

Returns:

An "encoded" Object

Throws:

EncoderException - An encoder exception is thrown if the encoder experiences a failure condition during the encoding process.

encode

public String encode(String text)

Description copied from interface: StringEncoder

Encodes a String and returns a String.

Specified by:

encode in interface StringEncoder

Parameters:

text - the String to encode

Returns:

the encoded String

isEncodeEqual

public boolean isEncodeEqual(String text1,
                             String text2)

Compares the first encoded string to the second encoded string.

Parameters:

text1 - source text to encode before testing for equality.

text2 - source text to encode before testing for equality.

Returns:

true if the encoding the first string equals the encoding of the second string, false otherwise