lovinsstemmer.java

代码是一个分类器的实现,其中使用了部分weka的源代码。可以将项目导入eclipse运行

/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 * LovinsStemmer.java
 * Copyright (C) 2001 Eibe Frank
 *
 */

package weka.core.stemmers;

import weka.core.TechnicalInformation;
import weka.core.TechnicalInformation.Type;
import weka.core.TechnicalInformation.Field;
import weka.core.TechnicalInformationHandler;

import java.util.HashMap;

/**
 <!-- globalinfo-start -->
 * A stemmer based on the Lovins stemmer, described here:<br/>
 * <br/>
 * Julie Beth Lovins (1968). Development of a stemming algorithm. Mechanical Translation and Computational Linguistics. 11:22-31.
 * <p/>
 <!-- globalinfo-end -->
 * 
 <!-- technical-bibtex-start -->
 * BibTeX:
 * <pre>
 * &#64;article{Lovins1968,
 *    author = {Julie Beth Lovins},
 *    journal = {Mechanical Translation and Computational Linguistics},
 *    pages = {22-31},
 *    title = {Development of a stemming algorithm},
 *    volume = {11},
 *    year = {1968}
 * }
 * </pre>
 * <p/>
 <!-- technical-bibtex-end -->
 *
 * @author  Eibe Frank (eibe at cs dot waikato dot ac dot nz)
 * @version $Revision: 1.5 $
 */
public class LovinsStemmer 
  implements Stemmer, TechnicalInformationHandler {

  /** for serialization */
  static final long serialVersionUID = -6113024782588197L;
  
  /** Enters C version compatibility mode if set to true (emulates
    features of the original C implementation that are inconsistent
    with the algorithm as described in Lovins's paper) */
  private static boolean m_CompMode = false;

  /** The hash tables containing the list of endings. */
  private static HashMap m_l11 = null;
  private static HashMap m_l10 = null;
  private static HashMap m_l9 = null;
  private static HashMap m_l8 = null;
  private static HashMap m_l7 = null;
  private static HashMap m_l6 = null;
  private static HashMap m_l5 = null;
  private static HashMap m_l4 = null;
  private static HashMap m_l3 = null;
  private static HashMap m_l2 = null;
  private static HashMap m_l1 = null;

  static {

    m_l11 = new HashMap();
    m_l11.put("alistically", "B");
    m_l11.put("arizability", "A");
    m_l11.put("izationally", "B");
    m_l10 = new HashMap();
    m_l10.put("antialness", "A");
    m_l10.put("arisations", "A");
    m_l10.put("arizations", "A");
    m_l10.put("entialness", "A");
    m_l9 = new HashMap();
    m_l9.put("allically", "C");
    m_l9.put("antaneous", "A");
    m_l9.put("antiality", "A");
    m_l9.put("arisation", "A");
    m_l9.put("arization", "A");
    m_l9.put("ationally", "B");
    m_l9.put("ativeness", "A");
    m_l9.put("eableness", "E");
    m_l9.put("entations", "A");
    m_l9.put("entiality", "A");
    m_l9.put("entialize", "A");
    m_l9.put("entiation", "A");
    m_l9.put("ionalness", "A");
    m_l9.put("istically", "A");
    m_l9.put("itousness", "A");
    m_l9.put("izability", "A");
    m_l9.put("izational", "A");
    m_l8 = new HashMap();
    m_l8.put("ableness", "A");
    m_l8.put("arizable", "A");
    m_l8.put("entation", "A");
    m_l8.put("entially", "A");
    m_l8.put("eousness", "A");
    m_l8.put("ibleness", "A");
    m_l8.put("icalness", "A");
    m_l8.put("ionalism", "A");
    m_l8.put("ionality", "A");
    m_l8.put("ionalize", "A");
    m_l8.put("iousness", "A");
    m_l8.put("izations", "A");
    m_l8.put("lessness", "A");
    m_l7 = new HashMap();
    m_l7.put("ability", "A");
    m_l7.put("aically", "A");
    m_l7.put("alistic", "B");
    m_l7.put("alities", "A");
    m_l7.put("ariness", "E");
    m_l7.put("aristic", "A");
    m_l7.put("arizing", "A");
    m_l7.put("ateness", "A");
    m_l7.put("atingly", "A");
    m_l7.put("ational", "B");
    m_l7.put("atively", "A");
    m_l7.put("ativism", "A");
    m_l7.put("elihood", "E");
    m_l7.put("encible", "A");
    m_l7.put("entally", "A");
    m_l7.put("entials", "A");
    m_l7.put("entiate", "A");
    m_l7.put("entness", "A");
    m_l7.put("fulness", "A");
    m_l7.put("ibility", "A");
    m_l7.put("icalism", "A");
    m_l7.put("icalist", "A");
    m_l7.put("icality", "A");
    m_l7.put("icalize", "A");
    m_l7.put("ication", "G");
    m_l7.put("icianry", "A");
    m_l7.put("ination", "A");
    m_l7.put("ingness", "A");
    m_l7.put("ionally", "A");
    m_l7.put("isation", "A");
    m_l7.put("ishness", "A");
    m_l7.put("istical", "A");
    m_l7.put("iteness", "A");
    m_l7.put("iveness", "A");
    m_l7.put("ivistic", "A");
    m_l7.put("ivities", "A");
    m_l7.put("ization", "F");
    m_l7.put("izement", "A");
    m_l7.put("oidally", "A");
    m_l7.put("ousness", "A");
    m_l6 = new HashMap();
    m_l6.put("aceous", "A");
    m_l6.put("acious", "B");
    m_l6.put("action", "G");
    m_l6.put("alness", "A");
    m_l6.put("ancial", "A");
    m_l6.put("ancies", "A");
    m_l6.put("ancing", "B");
    m_l6.put("ariser", "A");
    m_l6.put("arized", "A");
    m_l6.put("arizer", "A");
    m_l6.put("atable", "A");
    m_l6.put("ations", "B");
    m_l6.put("atives", "A");
    m_l6.put("eature", "Z");
    m_l6.put("efully", "A");
    m_l6.put("encies", "A");
    m_l6.put("encing", "A");
    m_l6.put("ential", "A");
    m_l6.put("enting", "C");
    m_l6.put("entist", "A");
    m_l6.put("eously", "A");
    m_l6.put("ialist", "A");
    m_l6.put("iality", "A");
    m_l6.put("ialize", "A");
    m_l6.put("ically", "A");
    m_l6.put("icance", "A");
    m_l6.put("icians", "A");
    m_l6.put("icists", "A");
    m_l6.put("ifully", "A");
    m_l6.put("ionals", "A");
    m_l6.put("ionate", "D");
    m_l6.put("ioning", "A");
    m_l6.put("ionist", "A");
    m_l6.put("iously", "A");
    m_l6.put("istics", "A");
    m_l6.put("izable", "E");
    m_l6.put("lessly", "A");
    m_l6.put("nesses", "A");
    m_l6.put("oidism", "A");
    m_l5 = new HashMap();
    m_l5.put("acies", "A");
    m_l5.put("acity", "A");
    m_l5.put("aging", "B");
    m_l5.put("aical", "A");
    if (!m_CompMode) {
      m_l5.put("alist", "A");
    }
    m_l5.put("alism", "B");
    m_l5.put("ality", "A");
    m_l5.put("alize", "A");
    m_l5.put("allic", "b");
    m_l5.put("anced", "B");
    m_l5.put("ances", "B");
    m_l5.put("antic", "C");
    m_l5.put("arial", "A");
    m_l5.put("aries", "A");
    m_l5.put("arily", "A");
    m_l5.put("arity", "B");
    m_l5.put("arize", "A");
    m_l5.put("aroid", "A");
    m_l5.put("ately", "A");
    m_l5.put("ating", "I");
    m_l5.put("ation", "B");
    m_l5.put("ative", "A");
    m_l5.put("ators", "A");
    m_l5.put("atory", "A");
    m_l5.put("ature", "E");
    m_l5.put("early", "Y");
    m_l5.put("ehood", "A");
    m_l5.put("eless", "A");
    if (!m_CompMode) {
      m_l5.put("elily", "A");
    } else {
      m_l5.put("elity", "A");
    }
    m_l5.put("ement", "A");
    m_l5.put("enced", "A");
    m_l5.put("ences", "A");
    m_l5.put("eness", "E");
    m_l5.put("ening", "E");
    m_l5.put("ental", "A");
    m_l5.put("ented", "C");
    m_l5.put("ently", "A");
    m_l5.put("fully", "A");
    m_l5.put("ially", "A");
    m_l5.put("icant", "A");
    m_l5.put("ician", "A");
    m_l5.put("icide", "A");
    m_l5.put("icism", "A");
    m_l5.put("icist", "A");
    m_l5.put("icity", "A");
    m_l5.put("idine", "I");
    m_l5.put("iedly", "A");
    m_l5.put("ihood", "A");
    m_l5.put("inate", "A");
    m_l5.put("iness", "A");
    m_l5.put("ingly", "B");
    m_l5.put("inism", "J");
    m_l5.put("inity", "c");
    m_l5.put("ional", "A");
    m_l5.put("ioned", "A");
    m_l5.put("ished", "A");
    m_l5.put("istic", "A");
    m_l5.put("ities", "A");
    m_l5.put("itous", "A");
    m_l5.put("ively", "A");
    m_l5.put("ivity", "A");
    m_l5.put("izers", "F");
    m_l5.put("izing", "F");
    m_l5.put("oidal", "A");
    m_l5.put("oides", "A");
    m_l5.put("otide", "A");
    m_l5.put("ously", "A");
    m_l4 = new HashMap();
    m_l4.put("able", "A");
    m_l4.put("ably", "A");
    m_l4.put("ages", "B");
    m_l4.put("ally", "B");
    m_l4.put("ance", "B");
    m_l4.put("ancy", "B");
    m_l4.put("ants", "B");
    m_l4.put("aric", "A");
    m_l4.put("arly", "K");
    m_l4.put("ated", "I");
    m_l4.put("ates", "A");
    m_l4.put("atic", "B");
    m_l4.put("ator", "A");
    m_l4.put("ealy", "Y");
    m_l4.put("edly", "E");
    m_l4.put("eful", "A");
    m_l4.put("eity", "A");
    m_l4.put("ence", "A");
    m_l4.put("ency", "A");
    m_l4.put("ened", "E");
    m_l4.put("enly", "E");
    m_l4.put("eous", "A");
    m_l4.put("hood", "A");
    m_l4.put("ials", "A");
    m_l4.put("ians", "A");
    m_l4.put("ible", "A");
    m_l4.put("ibly", "A");
    m_l4.put("ical", "A");
    m_l4.put("ides", "L");
    m_l4.put("iers", "A");
    m_l4.put("iful", "A");
    m_l4.put("ines", "M");
    m_l4.put("ings", "N");
    m_l4.put("ions", "B");
    m_l4.put("ious", "A");
    m_l4.put("isms", "B");
    m_l4.put("ists", "A");
    m_l4.put("itic", "H");
    m_l4.put("ized", "F");
    m_l4.put("izer", "F");
    m_l4.put("less", "A");
    m_l4.put("lily", "A");
    m_l4.put("ness", "A");
    m_l4.put("ogen", "A");
    m_l4.put("ward", "A");
    m_l4.put("wise", "A");
    m_l4.put("ying", "B");
    m_l4.put("yish", "A");
    m_l3 = new HashMap();
    m_l3.put("acy", "A");
    m_l3.put("age", "B");
    m_l3.put("aic", "A");
    m_l3.put("als", "b");
    m_l3.put("ant", "B");
    m_l3.put("ars", "O");
    m_l3.put("ary", "F");
    m_l3.put("ata", "A");
    m_l3.put("ate", "A");
    m_l3.put("eal", "Y");
    m_l3.put("ear", "Y");
    m_l3.put("ely", "E");
    m_l3.put("ene", "E");
    m_l3.put("ent", "C");
    m_l3.put("ery", "E");
    m_l3.put("ese", "A");
    m_l3.put("ful", "A");
    m_l3.put("ial", "A");
    m_l3.put("ian", "A");
    m_l3.put("ics", "A");
    m_l3.put("ide", "L");
    m_l3.put("ied", "A");
    m_l3.put("ier", "A");
    m_l3.put("ies", "P");
    m_l3.put("ily", "A");
    m_l3.put("ine", "M");
    m_l3.put("ing", "N");
    m_l3.put("ion", "Q");
    m_l3.put("ish", "C");
    m_l3.put("ism", "B");
    m_l3.put("ist", "A");
    m_l3.put("ite", "a");
    m_l3.put("ity", "A");
    m_l3.put("ium", "A");
    m_l3.put("ive", "A");
    m_l3.put("ize", "F");
    m_l3.put("oid", "A");
    m_l3.put("one", "R");
    m_l3.put("ous", "A");
    m_l2 = new HashMap();
    m_l2.put("ae", "A"); 
    m_l2.put("al", "b");
    m_l2.put("ar", "X");
    m_l2.put("as", "B");
    m_l2.put("ed", "E");
    m_l2.put("en", "F");
    m_l2.put("es", "E");
    m_l2.put("ia", "A");
    m_l2.put("ic", "A");
    m_l2.put("is", "A");
    m_l2.put("ly", "B");
    m_l2.put("on", "S");
    m_l2.put("or", "T");
    m_l2.put("um", "U");
    m_l2.put("us", "V");
    m_l2.put("yl", "R");
    m_l2.put("s\'", "A");
    m_l2.put("\'s", "A");
    m_l1 = new HashMap();
    m_l1.put("a", "A");
    m_l1.put("e", "A");
    m_l1.put("i", "A");
    m_l1.put("o", "A");
    m_l1.put("s", "W");
    m_l1.put("y", "B");	
  }

  /**
   * Returns a string describing the stemmer
   * @return a description suitable for
   *         displaying in the explorer/experimenter gui
   */
  public String globalInfo() {
    return 
        "A stemmer based on the Lovins stemmer, described here:\n\n"
      + getTechnicalInformation().toString();
  }

  /**
   * Returns an instance of a TechnicalInformation object, containing 
   * detailed information about the technical background of this class,
   * e.g., paper reference or book this class is based on.
   * 
   * @return the technical information about this class
   */
  public TechnicalInformation getTechnicalInformation() {
    TechnicalInformation 	result;
    
    result = new TechnicalInformation(Type.ARTICLE);
    result.setValue(Field.AUTHOR, "Julie Beth Lovins");
    result.setValue(Field.YEAR, "1968");
    result.setValue(Field.TITLE, "Development of a stemming algorithm");
    result.setValue(Field.JOURNAL, "Mechanical Translation and Computational Linguistics");
    result.setValue(Field.VOLUME, "11");
    result.setValue(Field.PAGES, "22-31");

    return result;
  }

  /**
   * Finds and removes ending from given word.
   * 
   * @param word	the word to work on
   * @return 		the processed word
   */
  private String removeEnding(String word) {

    int length = word.length();
    int el = 11;

    while (el > 0) {
      if (length - el > 1) {
        String ending = word.substring(length - el);
        String conditionCode = null;
        switch (el) {
          case 11: conditionCode = (String)m_l11.get(ending);
                   break;
          case 10: conditionCode = (String)m_l10.get(ending);
                   break; 
          case 9: conditionCode = (String)m_l9.get(ending);
                  break;
          case 8: conditionCode = (String)m_l8.get(ending);
                  break;   
          case 7: conditionCode = (String)m_l7.get(ending);
                  break;   
          case 6: conditionCode = (String)m_l6.get(ending);
                  break;   
          case 5: conditionCode = (String)m_l5.get(ending);
                  break;   
          case 4: conditionCode = (String)m_l4.get(ending);
                  break;   
          case 3: conditionCode = (String)m_l3.get(ending);
                  break;   
          case 2: conditionCode = (String)m_l2.get(ending);
                  break;   
          case 1: conditionCode = (String)m_l1.get(ending);
                  break;   
          default:
        }
        if (conditionCode != null) {
          switch (conditionCode.charAt(0)) {
            case 'A':
              return word.substring(0, length - el);
            case 'B':
              if (length - el > 2) {
                return word.substring(0, length - el);
              }
              break;
            case 'C':
              if (length - el > 3) {
                return word.substring(0, length - el);
              }
              break;
            case 'D':
              if (length - el > 4) {
                return word.substring(0, length - el);
              }
              break;
            case 'E':
              if (word.charAt(length - el - 1) != 'e') {
                return word.substring(0, length - el);
              }
              break;
            case 'F':
              if ((length - el > 2) &&
                  (word.charAt(length - el - 1) != 'e')) {
                return word.substring(0, length - el);
                  }