1 package org.apache.lucene.analysis.fi;
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,
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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.
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32 * modification, are permitted provided that the following conditions are met:
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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 Finnish.
60 * This stemmer implements the algorithm described in:
61 * <i>Report on CLEF-2003 Monolingual Tracks</i>
64 public class FinnishLightStemmer {
66 public int stem(char s[], int len) {
70 for (int i = 0; i < len; i++)
73 case 'å': s[i] = 'a'; break;
74 case 'ö': s[i] = 'o'; break;
85 private int step1(char s[], int len) {
87 if (endsWith(s, len, "kin"))
88 return step1(s, len-3);
89 if (endsWith(s, len, "ko"))
90 return step1(s, len-2);
94 if (endsWith(s, len, "dellinen"))
96 if (endsWith(s, len, "dellisuus"))
102 private int step2(char s[], int len) {
104 if (endsWith(s, len, "lla")
105 || endsWith(s, len, "tse")
106 || endsWith(s, len, "sti"))
109 if (endsWith(s, len, "ni"))
112 if (endsWith(s, len, "aa"))
113 return len-1; // aa -> a
119 private int step3(char s[], int len) {
121 if (endsWith(s, len, "nnen")) {
126 if (endsWith(s, len, "ntena")) {
131 if (endsWith(s, len, "tten"))
134 if (endsWith(s, len, "eiden"))
139 if (endsWith(s, len, "neen")
140 || endsWith(s, len, "niin")
141 || endsWith(s, len, "seen")
142 || endsWith(s, len, "teen")
143 || endsWith(s, len, "inen"))
146 if (s[len-3] == 'h' && isVowel(s[len-2]) && s[len-1] == 'n')
149 if (endsWith(s, len, "den")) {
154 if (endsWith(s, len, "ksen")) {
159 if (endsWith(s, len, "ssa")
160 || endsWith(s, len, "sta")
161 || endsWith(s, len, "lla")
162 || endsWith(s, len, "lta")
163 || endsWith(s, len, "tta")
164 || endsWith(s, len, "ksi")
165 || endsWith(s, len, "lle"))
170 if (endsWith(s, len, "na")
171 || endsWith(s, len, "ne"))
174 if (endsWith(s, len, "nei"))
179 if (endsWith(s, len, "ja")
180 || endsWith(s, len, "ta"))
186 if (s[len-1] == 'n' && isVowel(s[len-2]))
196 private int norm1(char s[], int len) {
197 if (len > 5 && endsWith(s, len, "hde")) {
204 if (endsWith(s, len, "ei") || endsWith(s, len, "at"))
215 case 'i': return len-1;
221 private int norm2(char s[], int len) {
235 for (int i = 1; i < len; i++) {
237 (ch == 'k' || ch == 'p' || ch == 't'))
238 len = delete(s, i--, len);
248 private boolean isVowel(char ch) {
255 case 'y': return true;
256 default: return false;