| /* |
| * 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. |
| */ |
| package org.apache.lucene.analysis.fi; |
| |
| |
| /* |
| * 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. |
| */ |
| |
| import static org.apache.lucene.analysis.util.StemmerUtil.*; |
| |
| /** |
| * Light Stemmer for Finnish. |
| * <p> |
| * This stemmer implements the algorithm described in: |
| * <i>Report on CLEF-2003 Monolingual Tracks</i> |
| * Jacques Savoy |
| */ |
| public class FinnishLightStemmer { |
| |
| public int stem(char s[], int len) { |
| if (len < 4) |
| return len; |
| |
| for (int i = 0; i < len; i++) |
| switch(s[i]) { |
| case 'ä': |
| case 'å': s[i] = 'a'; break; |
| case 'ö': s[i] = 'o'; break; |
| } |
| |
| len = step1(s, len); |
| len = step2(s, len); |
| len = step3(s, len); |
| len = norm1(s, len); |
| len = norm2(s, len); |
| return len; |
| } |
| |
| private int step1(char s[], int len) { |
| if (len > 8) { |
| if (endsWith(s, len, "kin")) |
| return step1(s, len-3); |
| if (endsWith(s, len, "ko")) |
| return step1(s, len-2); |
| } |
| |
| if (len > 11) { |
| if (endsWith(s, len, "dellinen")) |
| return len-8; |
| if (endsWith(s, len, "dellisuus")) |
| return len-9; |
| } |
| return len; |
| } |
| |
| private int step2(char s[], int len) { |
| if (len > 5) { |
| if (endsWith(s, len, "lla") |
| || endsWith(s, len, "tse") |
| || endsWith(s, len, "sti")) |
| return len-3; |
| |
| if (endsWith(s, len, "ni")) |
| return len-2; |
| |
| if (endsWith(s, len, "aa")) |
| return len-1; // aa -> a |
| } |
| |
| return len; |
| } |
| |
| private int step3(char s[], int len) { |
| if (len > 8) { |
| if (endsWith(s, len, "nnen")) { |
| s[len-4] = 's'; |
| return len-3; |
| } |
| |
| if (endsWith(s, len, "ntena")) { |
| s[len-5] = 's'; |
| return len-4; |
| } |
| |
| if (endsWith(s, len, "tten")) |
| return len-4; |
| |
| if (endsWith(s, len, "eiden")) |
| return len-5; |
| } |
| |
| if (len > 6) { |
| if (endsWith(s, len, "neen") |
| || endsWith(s, len, "niin") |
| || endsWith(s, len, "seen") |
| || endsWith(s, len, "teen") |
| || endsWith(s, len, "inen")) |
| return len-4; |
| |
| if (s[len-3] == 'h' && isVowel(s[len-2]) && s[len-1] == 'n') |
| return len-3; |
| |
| if (endsWith(s, len, "den")) { |
| s[len-3] = 's'; |
| return len-2; |
| } |
| |
| if (endsWith(s, len, "ksen")) { |
| s[len-4] = 's'; |
| return len-3; |
| } |
| |
| if (endsWith(s, len, "ssa") |
| || endsWith(s, len, "sta") |
| || endsWith(s, len, "lla") |
| || endsWith(s, len, "lta") |
| || endsWith(s, len, "tta") |
| || endsWith(s, len, "ksi") |
| || endsWith(s, len, "lle")) |
| return len-3; |
| } |
| |
| if (len > 5) { |
| if (endsWith(s, len, "na") |
| || endsWith(s, len, "ne")) |
| return len-2; |
| |
| if (endsWith(s, len, "nei")) |
| return len-3; |
| } |
| |
| if (len > 4) { |
| if (endsWith(s, len, "ja") |
| || endsWith(s, len, "ta")) |
| return len-2; |
| |
| if (s[len-1] == 'a') |
| return len-1; |
| |
| if (s[len-1] == 'n' && isVowel(s[len-2])) |
| return len-2; |
| |
| if (s[len-1] == 'n') |
| return len-1; |
| } |
| |
| return len; |
| } |
| |
| private int norm1(char s[], int len) { |
| if (len > 5 && endsWith(s, len, "hde")) { |
| s[len-3] = 'k'; |
| s[len-2] = 's'; |
| s[len-1] = 'i'; |
| } |
| |
| if (len > 4) { |
| if (endsWith(s, len, "ei") || endsWith(s, len, "at")) |
| return len-2; |
| } |
| |
| if (len > 3) |
| switch(s[len-1]) { |
| case 't': |
| case 's': |
| case 'j': |
| case 'e': |
| case 'a': |
| case 'i': return len-1; |
| } |
| |
| return len; |
| } |
| |
| private int norm2(char s[], int len) { |
| if (len > 8) { |
| if (s[len-1] == 'e' |
| || s[len-1] == 'o' |
| || s[len-1] == 'u') |
| len--; |
| } |
| |
| if (len > 4) { |
| if (s[len-1] == 'i') |
| len--; |
| |
| if (len > 4) { |
| char ch = s[0]; |
| for (int i = 1; i < len; i++) { |
| if (s[i] == ch && |
| (ch == 'k' || ch == 'p' || ch == 't')) |
| len = delete(s, i--, len); |
| else |
| ch = s[i]; |
| } |
| } |
| } |
| |
| return len; |
| } |
| |
| private boolean isVowel(char ch) { |
| switch(ch) { |
| case 'a': |
| case 'e': |
| case 'i': |
| case 'o': |
| case 'u': |
| case 'y': return true; |
| default: return false; |
| } |
| } |
| } |
