1 package org.apache.lucene.analysis.el;
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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20 import java.io.IOException;
22 import org.apache.lucene.analysis.KeywordMarkerFilter; // for javadoc
23 import org.apache.lucene.analysis.TokenFilter;
24 import org.apache.lucene.analysis.TokenStream;
25 import org.apache.lucene.analysis.tokenattributes.KeywordAttribute;
26 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
29 * A {@link TokenFilter} that applies {@link GreekStemmer} to stem Greek
32 * To prevent terms from being stemmed use an instance of
33 * {@link KeywordMarkerFilter} or a custom {@link TokenFilter} that sets
34 * the {@link KeywordAttribute} before this {@link TokenStream}.
37 * NOTE: Input is expected to be casefolded for Greek (including folding of final
38 * sigma to sigma), and with diacritics removed. This can be achieved by using
39 * either {@link GreekLowerCaseFilter} or ICUFoldingFilter before GreekStemFilter.
40 * @lucene.experimental
42 public final class GreekStemFilter extends TokenFilter {
43 private final GreekStemmer stemmer = new GreekStemmer();
44 private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
45 private final KeywordAttribute keywordAttr = addAttribute(KeywordAttribute.class);
47 public GreekStemFilter(TokenStream input) {
52 public boolean incrementToken() throws IOException {
53 if (input.incrementToken()) {
54 if(!keywordAttr.isKeyword()) {
55 final int newlen = stemmer.stem(termAtt.buffer(), termAtt.length());
56 termAtt.setLength(newlen);