soundex.java

CRM源码This file describes some issues that should be implemented in future and how it should be imple

/*
 * Copyright 2006-2007 Queplix Corp.
 *
 * Licensed under the Queplix Public License, Version 1.1.1 (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.queplix.com/solutions/commercial-open-source/queplix-public-license/
 *
 * 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 com.queplix.core.utils;

/**
 * Encodes words using the soundex phonetic algorithm.
 */
public class Soundex {

 // Private Fields
 // ----------------
 
   /**
   * Length of code to build.
   */
 private static int LengthInt = 4;


   /**
   * Soundex code table.
   */
 private final static int[] SoundexInts = createArray();

 // Public Methods
 // --------------

 /**
  * Returns the soundex code for the specified word.
  * @param string The word to encode.
  */
 public static String getSoundex(String word){	 
	 return encode(word);
 } 

 /**
  * Returns the soundex code for the specified word.
  * @param string The word to encode.
  * @param int The Length of code to build.
  */
 public static String getSoundex(String word, int length){	 
	 if(length > 0) LengthInt = length;
	 return encode(word);
 } 

   /**
   * Returns the soundex code for the specified word.
   * @param string The word to encode.
   */
 private final static String encode(String word) {
   word = word.trim();
   word = reduce(word);
   int wordLength = word.length(); //original word size
   int sofar = 0; //how many codes have been created
   int max = LengthInt - 1; //max codes to create (less the first char)
   if (LengthInt < 0) //if NO_MAX
     max = wordLength; //wordLength was the max possible size.
   int code = 0; 
   StringBuffer buf = new StringBuffer(max);
   buf.append(Character.toLowerCase(word.charAt(0)));
   for (int i = 1;(i < wordLength) && (sofar < max); i++) {
     code = getCode(word.charAt(i));
     if (code > 0) {
       buf.append(code);
       sofar++;
       }
     }
   if (LengthInt > 0) {
     for (;sofar < max; sofar++)
       buf.append('0');
     }
   return buf.toString().toUpperCase();
   }


 // Private Methods
 // -----------------

 /**
  * Returns the Soundex code for the specified character.
  * @param ch Should be between A-Z or a-z
  * @return -1 if the character has no phonetic code.
  */
private final static int getCode(char ch) {
  int arrayidx = -1;
  if (('a' <= ch) && (ch <= 'z'))
    arrayidx = (int)ch - (int)'a';
  else if (('A' <= ch) && (ch <= 'Z'))
    arrayidx = (int)ch - (int)'A';
  if ((arrayidx >= 0) && (arrayidx < SoundexInts.length))
    return SoundexInts[arrayidx];
  else
    return -1;
  }

   /**
   * Creates the Soundex code table.
   */
 private final static int[] createArray() {
   return new int[] {
     -1, //a 
      1, //b
      2, //c 
      3, //d
     -1, //e 
      1, //f
      2, //g 
     -1, //h
     -1, //i 
      2, //j
      2, //k
      4, //l
      5, //m
      5, //n
     -1, //o
      1, //p
      2, //q
      6, //r
      2, //s
      3, //t
     -1, //u
      1, //v
     -1, //w
      2, //x
     -1, //y
      2  //z
     };
   }

   /**
   * Removes adjacent sounds.
   */
 private final static String reduce(String word) {
   int len = word.length();
   StringBuffer buf = new StringBuffer(len);
   char ch = word.charAt(0);
   int currentCode = getCode(ch);
   buf.append(ch);
   int lastCode = currentCode;
   for (int i = 1; i < len; i++) {
     ch = word.charAt(i);
     currentCode = getCode(ch);
     if ((currentCode != lastCode) && (currentCode >= 0)) {
       buf.append(ch);
       lastCode = currentCode;
       }
     }
   return buf.toString();
   }


 }//Soundex