/*
* 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.no;
/*
* 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 Norwegian.
Parts of this stemmer is adapted from SwedishLightStemFilter, except
that while the Swedish one has a pre-defined rule set and a corresponding
corpus to validate against whereas the Norwegian one is hand crafted.
/**
* Light Stemmer for Norwegian.
* <p>
* Parts of this stemmer is adapted from SwedishLightStemFilter, except
* that while the Swedish one has a pre-defined rule set and a corresponding
* corpus to validate against whereas the Norwegian one is hand crafted.
*/
public class NorwegianLightStemmer {
Constant to remove Bokmål-specific endings /** Constant to remove Bokmål-specific endings */
public static final int BOKMAAL = 1;
Constant to remove Nynorsk-specific endings /** Constant to remove Nynorsk-specific endings */
public static final int NYNORSK = 2;
final boolean useBokmaal;
final boolean useNynorsk;
Creates a new NorwegianLightStemmer
Params:
/**
* Creates a new NorwegianLightStemmer
* @param flags set to {@link #BOKMAAL}, {@link #NYNORSK}, or both.
*/
public NorwegianLightStemmer(int flags) {
if (flags <= 0 || flags > BOKMAAL + NYNORSK) {
throw new IllegalArgumentException("invalid flags");
}
useBokmaal = (flags & BOKMAAL) != 0;
useNynorsk = (flags & NYNORSK) != 0;
}
public int stem(char s[], int len) {
// Remove posessive -s (bilens -> bilen) and continue checking
if (len > 4 && s[len-1] == 's')
len--;
// Remove common endings, single-pass
if (len > 7 &&
((endsWith(s, len, "heter") &&
useBokmaal) || // general ending (hemmelig-heter -> hemmelig)
(endsWith(s, len, "heten") &&
useBokmaal) || // general ending (hemmelig-heten -> hemmelig)
(endsWith(s, len, "heita") &&
useNynorsk))) // general ending (hemmeleg-heita -> hemmeleg)
return len - 5;
// Remove Nynorsk common endings, single-pass
if (len > 8 && useNynorsk &&
(endsWith(s, len, "heiter") || // general ending (hemmeleg-heiter -> hemmeleg)
endsWith(s, len, "leiken") || // general ending (trygg-leiken -> trygg)
endsWith(s, len, "leikar"))) // general ending (trygg-leikar -> trygg)
return len - 6;
if (len > 5 &&
(endsWith(s, len, "dom") || // general ending (kristen-dom -> kristen)
(endsWith(s, len, "het") &&
useBokmaal))) // general ending (hemmelig-het -> hemmelig)
return len - 3;
if (len > 6 && useNynorsk &&
(endsWith(s, len, "heit") || // general ending (hemmeleg-heit -> hemmeleg)
endsWith(s, len, "semd") || // general ending (verk-semd -> verk)
endsWith(s, len, "leik"))) // general ending (trygg-leik -> trygg)
return len - 4;
if (len > 7 &&
(endsWith(s, len, "elser") || // general ending (føl-elser -> føl)
endsWith(s, len, "elsen"))) // general ending (føl-elsen -> føl)
return len - 5;
if (len > 6 &&
((endsWith(s, len, "ende") &&
useBokmaal) || // (sov-ende -> sov)
(endsWith(s, len, "ande") &&
useNynorsk) || // (sov-ande -> sov)
endsWith(s, len, "else") || // general ending (føl-else -> føl)
(endsWith(s, len, "este") &&
useBokmaal) || // adj (fin-este -> fin)
(endsWith(s, len, "aste") &&
useNynorsk) || // adj (fin-aste -> fin)
(endsWith(s, len, "eren") &&
useBokmaal) || // masc
(endsWith(s, len, "aren") &&
useNynorsk))) // masc
return len - 4;
if (len > 5 &&
((endsWith(s, len, "ere") &&
useBokmaal) || // adj (fin-ere -> fin)
(endsWith(s, len, "are") &&
useNynorsk) || // adj (fin-are -> fin)
(endsWith(s, len, "est") &&
useBokmaal) || // adj (fin-est -> fin)
(endsWith(s, len, "ast") &&
useNynorsk) || // adj (fin-ast -> fin)
endsWith(s, len, "ene") || // masc/fem/neutr pl definite (hus-ene)
(endsWith(s, len, "ane") &&
useNynorsk))) // masc pl definite (gut-ane)
return len - 3;
if (len > 4 &&
(endsWith(s, len, "er") || // masc/fem indefinite
endsWith(s, len, "en") || // masc/fem definite
endsWith(s, len, "et") || // neutr definite
(endsWith(s, len, "ar") &&
useNynorsk) || // masc pl indefinite
(endsWith(s, len, "st") &&
useBokmaal) || // adj (billig-st -> billig)
endsWith(s, len, "te")))
return len - 2;
if (len > 3)
switch(s[len-1]) {
case 'a': // fem definite
case 'e': // to get correct stem for nouns ending in -e (kake -> kak, kaker -> kak)
case 'n':
return len - 1;
}
return len;
}
}