1 package org.apache.lucene.analysis.de;
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with
6 * this work for additional information regarding copyright ownership.
7 * The ASF licenses this file to You under the Apache License, Version 2.0
8 * (the "License"); you may not use this file except in compliance with
9 * the License. You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
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21 * This algorithm is updated based on code located at:
22 * http://members.unine.ch/jacques.savoy/clef/
24 * Full copyright for that code follows:
28 * Copyright (c) 2005, Jacques Savoy
29 * All rights reserved.
31 * Redistribution and use in source and binary forms, with or without
32 * modification, are permitted provided that the following conditions are met:
34 * Redistributions of source code must retain the above copyright notice, this
35 * list of conditions and the following disclaimer. Redistributions in binary
36 * form must reproduce the above copyright notice, this list of conditions and
37 * the following disclaimer in the documentation and/or other materials
38 * provided with the distribution. Neither the name of the author nor the names
39 * of its contributors may be used to endorse or promote products derived from
40 * this software without specific prior written permission.
42 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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49 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
50 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
51 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
52 * POSSIBILITY OF SUCH DAMAGE.
56 * Minimal Stemmer for German.
58 * This stemmer implements the following algorithm:
59 * <i>Morphologie et recherche d'information</i>
62 public class GermanMinimalStemmer {
64 public int stem(char s[], int len) {
68 for (int i = 0; i < len; i++)
70 case 'ä': s[i] = 'a'; break;
71 case 'ö': s[i] = 'o'; break;
72 case 'ü': s[i] = 'u'; break;
75 if (len > 6 && s[len-3] == 'n' && s[len-2] == 'e' && s[len-1] == 'n')
80 case 'n': if (s[len-2] == 'e') return len - 2; else break;
81 case 'e': if (s[len-2] == 's') return len - 2; else break;
82 case 's': if (s[len-2] == 'e') return len - 2; else break;
83 case 'r': if (s[len-2] == 'e') return len - 2; else break;
90 case 'r': return len - 1;