/*
 * 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.hu;


/* 
 * 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.

This stemmer implements the "UniNE" algorithm in: Light Stemming Approaches for the French, Portuguese, German and Hungarian Languages Jacques Savoy

/** * 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; } @SuppressWarnings("fallthrough") 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; } } }