| /* |
| * Copyright 2001-2004 The Apache Software Foundation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.commons.codec.language; |
| |
| import org.apache.commons.codec.EncoderException; |
| import org.apache.commons.codec.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. |
| * |
| * @author Apache Software Foundation |
| * @version $Id: Soundex.java,v 1.26 2004/07/07 23:15:24 ggregory Exp $ |
| */ |
| public class Soundex implements StringEncoder { |
| |
| /** |
| * An instance of Soundex using the US_ENGLISH_MAPPING mapping. |
| * |
| * @see #US_ENGLISH_MAPPING |
| */ |
| public static final Soundex US_ENGLISH = new Soundex(); |
| |
| /** |
| * This is a default mapping of the 26 letters used in US English. A value of <code>0</code> for a letter position |
| * means do not encode. |
| * <p> |
| * (This constant is provided as both an implementation convenience and to allow Javadoc to pick |
| * up the value for the constant values page.) |
| * </p> |
| * |
| * @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 of <code>0</code> 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 <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts_de-dz_8co5.asp"> MS |
| * T-SQL DIFFERENCE </a> |
| * |
| * @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 <code>ch</code> 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); |
| } |
| |
| } |