package org.apache.lucene.analysis.hu;
/**
* 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.
*/
/*
* 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 Hungarian.
* <p>
* This stemmer implements the "UniNE" algorithm in:
* <i>Light Stemming Approaches for the French, Portuguese, German and Hungarian Languages</i>
* Jacques Savoy
*/
public class HungarianLightStemmer {
public int stem(char s[], int len) {
for (int i = 0; i < len; i++)
switch(s[i]) {
case 'á': s[i] = 'a'; break;
case 'ë':
case 'é': s[i] = 'e'; break;
case 'í': s[i] = 'i'; break;
case 'ó':
case 'ő':
case 'õ':
case 'ö': s[i] = 'o'; break;
case 'ú':
case 'ű':
case 'ũ':
case 'û':
case 'ü': s[i] = 'u'; break;
}
len = removeCase(s, len);
len = removePossessive(s, len);
len = removePlural(s, len);
return normalize(s, len);
}
private int removeCase(char s[], int len) {
if (len > 6 && endsWith(s, len, "kent"))
return len - 4;
if (len > 5) {
if (endsWith(s, len, "nak") ||
endsWith(s, len, "nek") ||
endsWith(s, len, "val") ||
endsWith(s, len, "vel") ||
endsWith(s, len, "ert") ||
endsWith(s, len, "rol") ||
endsWith(s, len, "ban") ||
endsWith(s, len, "ben") ||
endsWith(s, len, "bol") ||
endsWith(s, len, "nal") ||
endsWith(s, len, "nel") ||
endsWith(s, len, "hoz") ||
endsWith(s, len, "hez") ||
endsWith(s, len, "tol"))
return len - 3;
if (endsWith(s, len, "al") || endsWith(s, len, "el")) {
if (!isVowel(s[len-3]) && s[len-3] == s[len-4])
return len - 3;
}
}
if (len > 4) {
if (endsWith(s, len, "at") ||
endsWith(s, len, "et") ||
endsWith(s, len, "ot") ||
endsWith(s, len, "va") ||
endsWith(s, len, "ve") ||
endsWith(s, len, "ra") ||
endsWith(s, len, "re") ||
endsWith(s, len, "ba") ||
endsWith(s, len, "be") ||
endsWith(s, len, "ul") ||
endsWith(s, len, "ig"))
return len - 2;
if ((endsWith(s, len, "on") || endsWith(s, len, "en")) && !isVowel(s[len-3]))
return len - 2;
switch(s[len-1]) {
case 't':
case 'n': return len - 1;
case 'a':
case 'e': if (s[len-2] == s[len-3] && !isVowel(s[len-2])) return len - 2;
}
}
return len;
}
private int removePossessive(char s[], int len) {
if (len > 6) {
if (!isVowel(s[len-5]) &&
(endsWith(s, len, "atok") ||
endsWith(s, len, "otok") ||
endsWith(s, len, "etek")))
return len - 4;
if (endsWith(s, len, "itek") || endsWith(s, len, "itok"))
return len - 4;
}
if (len > 5) {
if (!isVowel(s[len-4]) &&
(endsWith(s, len, "unk") ||
endsWith(s, len, "tok") ||
endsWith(s, len, "tek")))
return len - 3;
if (isVowel(s[len-4]) && endsWith(s, len, "juk"))
return len - 3;
if (endsWith(s, len, "ink"))
return len - 3;
}
if (len > 4) {
if (!isVowel(s[len-3]) &&
(endsWith(s, len, "am") ||
endsWith(s, len, "em") ||
endsWith(s, len, "om") ||
endsWith(s, len, "ad") ||
endsWith(s, len, "ed") ||
endsWith(s, len, "od") ||
endsWith(s, len, "uk")))
return len - 2;
if (isVowel(s[len-3]) &&
(endsWith(s, len, "nk") ||
endsWith(s, len, "ja") ||
endsWith(s, len, "je")))
return len - 2;
if (endsWith(s, len, "im") ||
endsWith(s, len, "id") ||
endsWith(s, len, "ik"))
return len - 2;
}
if (len > 3)
switch(s[len-1]) {
case 'a':
case 'e': if (!isVowel(s[len-2])) return len - 1; break;
case 'm':
case 'd': if (isVowel(s[len-2])) return len - 1; break;
case 'i': return len - 1;
}
return len;
}
private int removePlural(char s[], int len) {
if (len > 3 && s[len-1] == 'k')
switch(s[len-2]) {
case 'a':
case 'o':
case 'e': if (len > 4) return len - 2; /* intentional fallthru */
default: return len - 1;
}
return len;
}
private int normalize(char s[], int len) {
if (len > 3)
switch(s[len-1]) {
case 'a':
case 'e':
case 'i':
case 'o': return len - 1;
}
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;
}
}
}