1 package org.apache.lucene.analysis.ru;
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
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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
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40 * this software without specific prior written permission.
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55 import static org.apache.lucene.analysis.util.StemmerUtil.*;
58 * Light Stemmer for Russian.
60 * This stemmer implements the following algorithm:
61 * <i>Indexing and Searching Strategies for the Russian Language.</i>
62 * Ljiljana Dolamic and Jacques Savoy.
64 public class RussianLightStemmer {
66 public int stem(char s[], int len) {
67 len = removeCase(s, len);
68 return normalize(s, len);
71 private int normalize(char s[], int len) {
75 case 'и': return len - 1;
76 case 'н': if (s[len-2] == 'н') return len - 1;
81 private int removeCase(char s[], int len) {
83 (endsWith(s, len, "иями") ||
84 endsWith(s, len, "оями")))
88 (endsWith(s, len, "иям") ||
89 endsWith(s, len, "иях") ||
90 endsWith(s, len, "оях") ||
91 endsWith(s, len, "ями") ||
92 endsWith(s, len, "оям") ||
93 endsWith(s, len, "оьв") ||
94 endsWith(s, len, "ами") ||
95 endsWith(s, len, "его") ||
96 endsWith(s, len, "ему") ||
97 endsWith(s, len, "ери") ||
98 endsWith(s, len, "ими") ||
99 endsWith(s, len, "ого") ||
100 endsWith(s, len, "ому") ||
101 endsWith(s, len, "ыми") ||
102 endsWith(s, len, "оев")))
106 (endsWith(s, len, "ая") ||
107 endsWith(s, len, "яя") ||
108 endsWith(s, len, "ях") ||
109 endsWith(s, len, "юю") ||
110 endsWith(s, len, "ах") ||
111 endsWith(s, len, "ею") ||
112 endsWith(s, len, "их") ||
113 endsWith(s, len, "ия") ||
114 endsWith(s, len, "ию") ||
115 endsWith(s, len, "ьв") ||
116 endsWith(s, len, "ою") ||
117 endsWith(s, len, "ую") ||
118 endsWith(s, len, "ям") ||
119 endsWith(s, len, "ых") ||
120 endsWith(s, len, "ея") ||
121 endsWith(s, len, "ам") ||
122 endsWith(s, len, "ем") ||
123 endsWith(s, len, "ей") ||
124 endsWith(s, len, "ём") ||
125 endsWith(s, len, "ев") ||
126 endsWith(s, len, "ий") ||
127 endsWith(s, len, "им") ||
128 endsWith(s, len, "ое") ||
129 endsWith(s, len, "ой") ||
130 endsWith(s, len, "ом") ||
131 endsWith(s, len, "ов") ||
132 endsWith(s, len, "ые") ||
133 endsWith(s, len, "ый") ||
134 endsWith(s, len, "ым") ||
135 endsWith(s, len, "ми")))
148 case 'ь': return len - 1;