Class ColognePhonetic
java.lang.Object
org.apache.commons.codec.language.ColognePhonetic
- All Implemented Interfaces:
Encoder
,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
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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:
"M
üller-L
üdenscheidt" => "MULLERLUDENSCHEIDT" => "6005507500206880022"
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Step 2:
Collapse of all multiple consecutive code digits.Example:
"6005507500206880022" => "6050750206802"
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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:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescription(package private) static class
This class is not thread-safe; the fieldColognePhonetic.CologneBuffer.length
is mutable.private class
private class
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final char[]
private static final char[]
private static final char[]
private static final char
private static final char[]
private static final char[]
private static final char[]
private static final char[]
private static final char[]
private static final char[]
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate static boolean
arrayContains
(char[] arr, char key) colognePhonetic
(String text) Implements the Kölner Phonetik algorithm.Encodes an "Object" and returns the encoded content as an Object.Encodes a String and returns a String.boolean
isEncodeEqual
(String text1, String text2) Compares the first encoded string to the second encoded string.private char[]
preprocess
(String text) Converts the string to upper case and replaces Germanic umlaut characters The following characters are mapped: capital A, umlaut mark capital U, umlaut mark capital O, umlaut mark small sharp s, German
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Field Details
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AEIJOUY
private static final char[] AEIJOUY -
CSZ
private static final char[] CSZ -
FPVW
private static final char[] FPVW -
GKQ
private static final char[] GKQ -
CKQ
private static final char[] CKQ -
AHKLOQRUX
private static final char[] AHKLOQRUX -
SZ
private static final char[] SZ -
AHKOQUX
private static final char[] AHKOQUX -
DTX
private static final char[] DTX -
CHAR_IGNORE
private static final char CHAR_IGNORE- See Also:
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Constructor Details
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ColognePhonetic
public ColognePhonetic()
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Method Details
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arrayContains
private static boolean arrayContains(char[] arr, char key) -
colognePhonetic
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
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encode
Description copied from interface:Encoder
Encodes an "Object" and returns the encoded content as an Object. The Objects here may just bebyte[]
orString
s depending on the implementation used.- Specified by:
encode
in interfaceEncoder
- 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.
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encode
Description copied from interface:StringEncoder
Encodes a String and returns a String.- Specified by:
encode
in interfaceStringEncoder
- Parameters:
text
- the String to encode- Returns:
- the encoded String
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isEncodeEqual
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
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preprocess
Converts the string to upper case and replaces Germanic umlaut characters The following characters are mapped:- capital A, umlaut mark
- capital U, umlaut mark
- capital O, umlaut mark
- small sharp s, German
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