0 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 #US_ENGLISH_MAPPING */ public static final String US_ENGLISH_MAPPING_STRING = "01230120022455012623010202"; /** * 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 Soundex#Soundex(char[])
*/
public static final char[] US_ENGLISH_MAPPING = US_ENGLISH_MAPPING_STRING.toCharArray();
// BEGIN android-note
// Removed @see reference to SoundexUtils below, since the class isn't
// public.
// END android-note
/**
* 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.
*
* @param s1
* A String that will be encoded and compared.
* @param s2
* A String that will be encoded and compared.
* @return The number of characters in the two encoded Strings that are the same from 0 to 4.
*
* @see MS
* T-SQL DIFFERENCE
*
* @throws EncoderException
* if an error occurs encoding one of the strings
* @since 1.3
*/
public int difference(String s1, String s2) throws EncoderException {
return SoundexUtils.difference(this, s1, s2);
}
/**
* The maximum length of a Soundex code - Soundex codes are only four characters by definition.
*
* @deprecated This feature is not needed since the encoding size must be constant. Will be removed in 2.0.
*/
private int maxLength = 4;
/**
* 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
*/
private char[] soundexMapping;
/**
* Creates an instance using US_ENGLISH_MAPPING
*
* @see Soundex#Soundex(char[])
* @see Soundex#US_ENGLISH_MAPPING
*/
public Soundex() {
this(US_ENGLISH_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
*
* @param mapping
* Mapping array to use when finding the corresponding code for a given character
*/
public Soundex(char[] mapping) {
this.setSoundexMapping(mapping);
}
/**
* 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.
*
* @param pObject
* Object to encode
* @return 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.String
* @throws IllegalArgumentException
* if a character is not mapped
*/
public Object encode(Object pObject) throws EncoderException {
if (!(pObject instanceof String)) {
throw new EncoderException("Parameter supplied to Soundex encode is not of type java.lang.String");
}
return soundex((String) pObject);
}
/**
* Encodes a String using the soundex algorithm.
*
* @param pString
* A String object to encode
* @return A Soundex code corresponding to the String supplied
* @throws IllegalArgumentException
* if a character is not mapped
*/
public String encode(String pString) {
return soundex(pString);
}
/**
* Used internally by the SoundEx algorithm.
*
* Consonants from the same code group separated by W or H are treated as one.
*
* @param str
* the cleaned working string to encode (in upper case).
* @param index
* the character position to encode
* @return Mapping code for a particular character
* @throws IllegalArgumentException
* if the character is not mapped
*/
private char getMappingCode(String str, int index) {
char mappedChar = this.map(str.charAt(index));
// HW rule check
if (index > 1 && mappedChar != '0') {
char hwChar = str.charAt(index - 1);
if ('H' == hwChar || 'W' == hwChar) {
char preHWChar = str.charAt(index - 2);
char firstCode = this.map(preHWChar);
if (firstCode == mappedChar || 'H' == preHWChar || 'W' == preHWChar) {
return 0;
}
}
}
return mappedChar;
}
/**
* Returns the maxLength. Standard Soundex
*
* @deprecated This feature is not needed since the encoding size must be constant. Will be removed in 2.0.
* @return int
*/
public int getMaxLength() {
return this.maxLength;
}
/**
* Returns the soundex mapping.
*
* @return soundexMapping.
*/
private char[] getSoundexMapping() {
return this.soundexMapping;
}
/**
* Maps the given upper-case character to it's Soudex code.
*
* @param ch
* An upper-case character.
* @return A Soundex code.
* @throws IllegalArgumentException
* Thrown if ch is not mapped.
*/
private char map(char ch) {
int index = ch - 'A';
if (index < 0 || index >= this.getSoundexMapping().length) {
throw new IllegalArgumentException("The character is not mapped: " + ch);
}
return this.getSoundexMapping()[index];
}
/**
* Sets the maxLength.
*
* @deprecated This feature is not needed since the encoding size must be constant. Will be removed in 2.0.
* @param maxLength
* The maxLength to set
*/
public void setMaxLength(int maxLength) {
this.maxLength = maxLength;
}
/**
* Sets the soundexMapping.
*
* @param soundexMapping
* The soundexMapping to set.
*/
private void setSoundexMapping(char[] soundexMapping) {
this.soundexMapping = soundexMapping;
}
/**
* Retreives the Soundex code for a given String object.
*
* @param str
* String to encode using the Soundex algorithm
* @return A soundex code for the String supplied
* @throws IllegalArgumentException
* if a character is not mapped
*/
public String soundex(String str) {
if (str == null) {
return null;
}
str = SoundexUtils.clean(str);
if (str.length() == 0) {
return str;
}
char out[] = {'0', '0', '0', '0'};
char last, mapped;
int incount = 1, count = 1;
out[0] = str.charAt(0);
last = getMappingCode(str, 0);
while ((incount < str.length()) && (count < out.length)) {
mapped = getMappingCode(str, incount++);
if (mapped != 0) {
if ((mapped != '0') && (mapped != last)) {
out[count++] = mapped;
}
last = mapped;
}
}
return new String(out);
}
}