+++ /dev/null
-package org.apache.lucene.analysis.ar;
-
-/**
- * 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.
- */
-
-import java.io.File;
-import java.io.IOException;
-import java.io.Reader;
-import java.util.Hashtable;
-import java.util.Set;
-
-import org.apache.lucene.analysis.Analyzer;
-import org.apache.lucene.analysis.LowerCaseFilter;
-import org.apache.lucene.analysis.CharArraySet;
-import org.apache.lucene.analysis.KeywordMarkerFilter;
-import org.apache.lucene.analysis.StopFilter;
-import org.apache.lucene.analysis.StopwordAnalyzerBase;
-import org.apache.lucene.analysis.TokenStream;
-import org.apache.lucene.analysis.Tokenizer;
-import org.apache.lucene.analysis.WordlistLoader;
-import org.apache.lucene.analysis.standard.StandardTokenizer;
-import org.apache.lucene.util.Version;
-
-/**
- * {@link Analyzer} for Arabic.
- * <p>
- * This analyzer implements light-stemming as specified by:
- * <i>
- * Light Stemming for Arabic Information Retrieval
- * </i>
- * http://www.mtholyoke.edu/~lballest/Pubs/arab_stem05.pdf
- * <p>
- * The analysis package contains three primary components:
- * <ul>
- * <li>{@link ArabicNormalizationFilter}: Arabic orthographic normalization.
- * <li>{@link ArabicStemFilter}: Arabic light stemming
- * <li>Arabic stop words file: a set of default Arabic stop words.
- * </ul>
- *
- */
-public final class ArabicAnalyzer extends StopwordAnalyzerBase {
-
- /**
- * File containing default Arabic stopwords.
- *
- * Default stopword list is from http://members.unine.ch/jacques.savoy/clef/index.html
- * The stopword list is BSD-Licensed.
- */
- public final static String DEFAULT_STOPWORD_FILE = "stopwords.txt";
-
- /**
- * The comment character in the stopwords file. All lines prefixed with this will be ignored
- * @deprecated use {@link WordlistLoader#getWordSet(File, String)} directly
- */
- // TODO make this private
- @Deprecated
- public static final String STOPWORDS_COMMENT = "#";
-
- /**
- * Returns an unmodifiable instance of the default stop-words set.
- * @return an unmodifiable instance of the default stop-words set.
- */
- public static Set<?> getDefaultStopSet(){
- return DefaultSetHolder.DEFAULT_STOP_SET;
- }
-
- /**
- * Atomically loads the DEFAULT_STOP_SET in a lazy fashion once the outer class
- * accesses the static final set the first time.;
- */
- private static class DefaultSetHolder {
- static final Set<?> DEFAULT_STOP_SET;
-
- static {
- try {
- DEFAULT_STOP_SET = loadStopwordSet(false, ArabicAnalyzer.class, DEFAULT_STOPWORD_FILE, STOPWORDS_COMMENT);
- } catch (IOException ex) {
- // default set should always be present as it is part of the
- // distribution (JAR)
- throw new RuntimeException("Unable to load default stopword set");
- }
- }
- }
-
- private final Set<?> stemExclusionSet;
-
- /**
- * Builds an analyzer with the default stop words: {@link #DEFAULT_STOPWORD_FILE}.
- */
- public ArabicAnalyzer(Version matchVersion) {
- this(matchVersion, DefaultSetHolder.DEFAULT_STOP_SET);
- }
-
- /**
- * Builds an analyzer with the given stop words
- *
- * @param matchVersion
- * lucene compatibility version
- * @param stopwords
- * a stopword set
- */
- public ArabicAnalyzer(Version matchVersion, Set<?> stopwords){
- this(matchVersion, stopwords, CharArraySet.EMPTY_SET);
- }
-
- /**
- * Builds an analyzer with the given stop word. If a none-empty stem exclusion set is
- * provided this analyzer will add a {@link KeywordMarkerFilter} before
- * {@link ArabicStemFilter}.
- *
- * @param matchVersion
- * lucene compatibility version
- * @param stopwords
- * a stopword set
- * @param stemExclusionSet
- * a set of terms not to be stemmed
- */
- public ArabicAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionSet){
- super(matchVersion, stopwords);
- this.stemExclusionSet = CharArraySet.unmodifiableSet(CharArraySet.copy(
- matchVersion, stemExclusionSet));
- }
-
- /**
- * Builds an analyzer with the given stop words.
- * @deprecated use {@link #ArabicAnalyzer(Version, Set)} instead
- */
- @Deprecated
- public ArabicAnalyzer( Version matchVersion, String... stopwords ) {
- this(matchVersion, StopFilter.makeStopSet(matchVersion, stopwords ));
- }
-
- /**
- * Builds an analyzer with the given stop words.
- * @deprecated use {@link #ArabicAnalyzer(Version, Set)} instead
- */
- @Deprecated
- public ArabicAnalyzer( Version matchVersion, Hashtable<?,?> stopwords ) {
- this(matchVersion, stopwords.keySet());
- }
-
- /**
- * Builds an analyzer with the given stop words. Lines can be commented out using {@link #STOPWORDS_COMMENT}
- * @deprecated use {@link #ArabicAnalyzer(Version, Set)} instead
- */
- @Deprecated
- public ArabicAnalyzer( Version matchVersion, File stopwords ) throws IOException {
- this(matchVersion, WordlistLoader.getWordSet( stopwords, STOPWORDS_COMMENT));
- }
-
- /**
- * Creates
- * {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
- * used to tokenize all the text in the provided {@link Reader}.
- *
- * @return {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
- * built from an {@link StandardTokenizer} filtered with
- * {@link LowerCaseFilter}, {@link StopFilter},
- * {@link ArabicNormalizationFilter}, {@link KeywordMarkerFilter}
- * if a stem exclusion set is provided and {@link ArabicStemFilter}.
- */
- @Override
- protected TokenStreamComponents createComponents(String fieldName,
- Reader reader) {
- final Tokenizer source = matchVersion.onOrAfter(Version.LUCENE_31) ?
- new StandardTokenizer(matchVersion, reader) : new ArabicLetterTokenizer(matchVersion, reader);
- TokenStream result = new LowerCaseFilter(matchVersion, source);
- // the order here is important: the stopword list is not normalized!
- result = new StopFilter( matchVersion, result, stopwords);
- // TODO maybe we should make ArabicNormalization filter also KeywordAttribute aware?!
- result = new ArabicNormalizationFilter(result);
- if(!stemExclusionSet.isEmpty()) {
- result = new KeywordMarkerFilter(result, stemExclusionSet);
- }
- return new TokenStreamComponents(source, new ArabicStemFilter(result));
- }
-}
-