content: package org.apache.lucene.analysis.de;
  
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.
   */
  
  /* 
   * This algorithm is updated based on code located at:
   * http://members.unine.ch/jacques.savoy/clef/
   * 
   * Full copyright for that code follows:
   */
  
  /*
   * Copyright (c) 2005, Jacques Savoy
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without 
   * modification, are permitted provided that the following conditions are met:
   *
   * Redistributions of source code must retain the above copyright notice, this 
   * list of conditions and the following disclaimer. Redistributions in binary 
   * form must reproduce the above copyright notice, this list of conditions and
   * the following disclaimer in the documentation and/or other materials 
   * provided with the distribution. Neither the name of the author nor the names 
   * of its contributors may be used to endorse or promote products derived from 
   * this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  /**
   * Light Stemmer for German.
   * <p>
   * This stemmer implements the "UniNE" algorithm in:
   * <i>Light Stemming Approaches for the French, Portuguese, German and Hungarian Languages</i>
   * Jacques Savoy
   */
  public class GermanLightStemmer {
    
    public int stem(char s[], int len) {   
      for (int i = 0; i < len; i++)
        switch(s[i]) {
          case 'ä':
          case 'à':
          case 'á':
          case 'â': s[i] = 'a'; break;
          case 'ö':
          case 'ò':
          case 'ó':
          case 'ô': s[i] = 'o'; break;
          case 'ï':
          case 'ì':
          case 'í':
          case 'î': s[i] = 'i'; break;
          case 'ü': 
          case 'ù': 
          case 'ú':
          case 'û': s[i] = 'u'; break;
        }
      
      len = step1(s, len);
      return step2(s, len);
    }
    
    private boolean stEnding(char ch) {
      switch(ch) {
        case 'b':
        case 'd':
        case 'f':
        case 'g':
        case 'h':
        case 'k':
        case 'l':
        case 'm':
        case 'n':
        case 't': return true;
        default: return false;
      }
    }
    
    private int step1(char s[], int len) {
      if (len > 5 && s[len-3] == 'e' && s[len-2] == 'r' && s[len-1] == 'n')
        return len - 3;
      
      if (len > 4 && s[len-2] == 'e')
        switch(s[len-1]) {
          case 'm':
          case 'n':
          case 'r':
          case 's': return len - 2;
        }
      
      if (len > 3 && s[len-1] == 'e')
        return len - 1;
      
      if (len > 3 && s[len-1] == 's' && stEnding(s[len-2]))
        return len - 1;
      
      return len;
    }
    
    private int step2(char s[], int len) {
      if (len > 5 && s[len-3] == 'e' && s[len-2] == 's' && s[len-1] == 't')
        return len - 3;
      
      if (len > 4 && s[len-2] == 'e' && (s[len-1] == 'r' || s[len-1] == 'n'))
        return len - 2;
      
      if (len > 4 && s[len-2] == 's' && s[len-1] == 't' && stEnding(s[len-3]))
        return len - 2;
      
      return len;
    }
  }
  