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
17 * limitations under the License.
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"
43 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
44 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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47 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
48 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 * Light Stemmer for German.
58 * This stemmer implements the "UniNE" algorithm in:
59 * <i>Light Stemming Approaches for the French, Portuguese, German and Hungarian Languages</i>
62 public class GermanLightStemmer {
64 public int stem(char s[], int len) {
65 for (int i = 0; i < len; i++)
70 case 'â': s[i] = 'a'; break;
74 case 'ô': s[i] = 'o'; break;
78 case 'î': s[i] = 'i'; break;
82 case 'û': s[i] = 'u'; break;
89 private boolean stEnding(char ch) {
100 case 't': return true;
101 default: return false;
105 private int step1(char s[], int len) {
106 if (len > 5 && s[len-3] == 'e' && s[len-2] == 'r' && s[len-1] == 'n')
109 if (len > 4 && s[len-2] == 'e')
114 case 's': return len - 2;
117 if (len > 3 && s[len-1] == 'e')
120 if (len > 3 && s[len-1] == 's' && stEnding(s[len-2]))
126 private int step2(char s[], int len) {
127 if (len > 5 && s[len-3] == 'e' && s[len-2] == 's' && s[len-1] == 't')
130 if (len > 4 && s[len-2] == 'e' && (s[len-1] == 'r' || s[len-1] == 'n'))
133 if (len > 4 && s[len-2] == 's' && s[len-1] == 't' && stEnding(s[len-3]))