Class Soundex
- java.lang.Object
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- org.apache.commons.codec.language.Soundex
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- All Implemented Interfaces:
Encoder
,StringEncoder
public class Soundex extends java.lang.Object implements StringEncoder
Encodes a string into a Soundex value. Soundex is an encoding used to relate similar names, but can also be used as a general purpose scheme to find word with similar phonemes. This class is thread-safe. Although not strictly immutable, themaxLength
field is not actually used.- Version:
- $Id: Soundex.java 1429868 2013-01-07 16:08:05Z ggregory $
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Field Summary
Fields Modifier and Type Field Description private int
maxLength
Deprecated.This feature is not needed since the encoding size must be constant.private char[]
soundexMapping
Every letter of the alphabet is "mapped" to a numerical value.static Soundex
US_ENGLISH
An instance of Soundex using the US_ENGLISH_MAPPING mapping.private static char[]
US_ENGLISH_MAPPING
This is a default mapping of the 26 letters used in US English.static java.lang.String
US_ENGLISH_MAPPING_STRING
This is a default mapping of the 26 letters used in US English.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description int
difference(java.lang.String s1, java.lang.String s2)
Encodes the Strings and returns the number of characters in the two encoded Strings that are the same.java.lang.Object
encode(java.lang.Object obj)
Encodes an Object using the soundex algorithm.java.lang.String
encode(java.lang.String str)
Encodes a String using the soundex algorithm.private char
getMappingCode(java.lang.String str, int index)
Used internally by the SoundEx algorithm.int
getMaxLength()
Deprecated.This feature is not needed since the encoding size must be constant.private char[]
getSoundexMapping()
Returns the soundex mapping.private char
map(char ch)
Maps the given upper-case character to its Soundex code.void
setMaxLength(int maxLength)
Deprecated.This feature is not needed since the encoding size must be constant.java.lang.String
soundex(java.lang.String str)
Retrieves the Soundex code for a given String object.
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Field Detail
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US_ENGLISH_MAPPING_STRING
public static final java.lang.String US_ENGLISH_MAPPING_STRING
This is a default mapping of the 26 letters used in US English. A value of0
for a letter position means do not encode.(This constant is provided as both an implementation convenience and to allow Javadoc to pick up the value for the constant values page.)
- See Also:
US_ENGLISH_MAPPING
, Constant Field Values
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US_ENGLISH_MAPPING
private static final char[] US_ENGLISH_MAPPING
This is a default mapping of the 26 letters used in US English. A value of0
for a letter position means do not encode.- See Also:
Soundex(char[])
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US_ENGLISH
public static final Soundex US_ENGLISH
An instance of Soundex using the US_ENGLISH_MAPPING mapping.- See Also:
US_ENGLISH_MAPPING
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maxLength
@Deprecated private int maxLength
Deprecated.This feature is not needed since the encoding size must be constant. Will be removed in 2.0.The maximum length of a Soundex code - Soundex codes are only four characters by definition.
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soundexMapping
private final char[] soundexMapping
Every letter of the alphabet is "mapped" to a numerical value. This char array holds the values to which each letter is mapped. This implementation contains a default map for US_ENGLISH
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Constructor Detail
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Soundex
public Soundex()
Creates an instance using US_ENGLISH_MAPPING- See Also:
Soundex(char[])
,US_ENGLISH_MAPPING
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Soundex
public Soundex(char[] mapping)
Creates a soundex instance using the given mapping. This constructor can be used to provide an internationalized mapping for a non-Western character set. Every letter of the alphabet is "mapped" to a numerical value. This char array holds the values to which each letter is mapped. This implementation contains a default map for US_ENGLISH- Parameters:
mapping
- Mapping array to use when finding the corresponding code for a given character
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Soundex
public Soundex(java.lang.String mapping)
Creates a refined soundex instance using a custom mapping. This constructor can be used to customize the mapping, and/or possibly provide an internationalized mapping for a non-Western character set.- Parameters:
mapping
- Mapping string to use when finding the corresponding code for a given character- Since:
- 1.4
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Method Detail
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difference
public int difference(java.lang.String s1, java.lang.String s2) throws EncoderException
Encodes the Strings and returns the number of characters in the two encoded Strings that are the same. This return value ranges from 0 through 4: 0 indicates little or no similarity, and 4 indicates strong similarity or identical values.- Parameters:
s1
- A String that will be encoded and compared.s2
- A String that will be encoded and compared.- Returns:
- The number of characters in the two encoded Strings that are the same from 0 to 4.
- Throws:
EncoderException
- if an error occurs encoding one of the strings- Since:
- 1.3
- See Also:
SoundexUtils.difference(StringEncoder,String,String)
, MS T-SQL DIFFERENCE
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encode
public java.lang.Object encode(java.lang.Object obj) throws EncoderException
Encodes an Object using the soundex 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 java.lang.String.- Specified by:
encode
in interfaceEncoder
- Parameters:
obj
- Object to encode- Returns:
- An object (or type java.lang.String) containing the soundex code which corresponds to the String supplied.
- Throws:
EncoderException
- if the parameter supplied is not of type java.lang.Stringjava.lang.IllegalArgumentException
- if a character is not mapped
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encode
public java.lang.String encode(java.lang.String str)
Encodes a String using the soundex algorithm.- Specified by:
encode
in interfaceStringEncoder
- Parameters:
str
- A String object to encode- Returns:
- A Soundex code corresponding to the String supplied
- Throws:
java.lang.IllegalArgumentException
- if a character is not mapped
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getMappingCode
private char getMappingCode(java.lang.String str, int index)
Used internally by the SoundEx algorithm. Consonants from the same code group separated by W or H are treated as one.- Parameters:
str
- the cleaned working string to encode (in upper case).index
- the character position to encode- Returns:
- Mapping code for a particular character
- Throws:
java.lang.IllegalArgumentException
- if the character is not mapped
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getMaxLength
@Deprecated public int getMaxLength()
Deprecated.This feature is not needed since the encoding size must be constant. Will be removed in 2.0.Returns the maxLength. Standard Soundex- Returns:
- int
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getSoundexMapping
private char[] getSoundexMapping()
Returns the soundex mapping.- Returns:
- soundexMapping.
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map
private char map(char ch)
Maps the given upper-case character to its Soundex code.- Parameters:
ch
- An upper-case character.- Returns:
- A Soundex code.
- Throws:
java.lang.IllegalArgumentException
- Thrown ifch
is not mapped.
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setMaxLength
@Deprecated public void setMaxLength(int maxLength)
Deprecated.This feature is not needed since the encoding size must be constant. Will be removed in 2.0.Sets the maxLength.- Parameters:
maxLength
- The maxLength to set
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soundex
public java.lang.String soundex(java.lang.String str)
Retrieves the Soundex code for a given String object.- Parameters:
str
- String to encode using the Soundex algorithm- Returns:
- A soundex code for the String supplied
- Throws:
java.lang.IllegalArgumentException
- if a character is not mapped
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