--- /dev/null
+package org.apache.lucene.analysis.fa;
+
+/**
+ * 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.StopFilter;
+import org.apache.lucene.analysis.StopwordAnalyzerBase;
+import org.apache.lucene.analysis.CharReader;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.WordlistLoader;
+import org.apache.lucene.analysis.ar.ArabicLetterTokenizer;
+import org.apache.lucene.analysis.ar.ArabicNormalizationFilter;
+import org.apache.lucene.analysis.standard.StandardTokenizer;
+
+import org.apache.lucene.util.IOUtils;
+import org.apache.lucene.util.Version;
+
+/**
+ * {@link Analyzer} for Persian.
+ * <p>
+ * This Analyzer uses {@link ArabicLetterTokenizer} which implies tokenizing around
+ * zero-width non-joiner in addition to whitespace. Some persian-specific variant forms (such as farsi
+ * yeh and keheh) are standardized. "Stemming" is accomplished via stopwords.
+ * </p>
+ */
+public final class PersianAnalyzer extends StopwordAnalyzerBase {
+
+ /**
+ * File containing default Persian 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
+ */
+ 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, PersianAnalyzer.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");
+ }
+ }
+ }
+
+ /**
+ * Builds an analyzer with the default stop words:
+ * {@link #DEFAULT_STOPWORD_FILE}.
+ */
+ public PersianAnalyzer(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 PersianAnalyzer(Version matchVersion, Set<?> stopwords){
+ super(matchVersion, stopwords);
+ }
+
+ /**
+ * Builds an analyzer with the given stop words.
+ * @deprecated use {@link #PersianAnalyzer(Version, Set)} instead
+ */
+ @Deprecated
+ public PersianAnalyzer(Version matchVersion, String... stopwords) {
+ this(matchVersion, StopFilter.makeStopSet(matchVersion, stopwords));
+ }
+
+ /**
+ * Builds an analyzer with the given stop words.
+ * @deprecated use {@link #PersianAnalyzer(Version, Set)} instead
+ */
+ @Deprecated
+ public PersianAnalyzer(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 #PersianAnalyzer(Version, Set)} instead
+ */
+ @Deprecated
+ public PersianAnalyzer(Version matchVersion, File stopwords) throws IOException {
+ this(matchVersion, WordlistLoader.getWordSet(
+ IOUtils.getDecodingReader(stopwords, IOUtils.CHARSET_UTF_8),
+ STOPWORDS_COMMENT, matchVersion));
+ }
+
+ /**
+ * 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 a {@link StandardTokenizer} filtered with
+ * {@link LowerCaseFilter}, {@link ArabicNormalizationFilter},
+ * {@link PersianNormalizationFilter} and Persian Stop words
+ */
+ @Override
+ protected TokenStreamComponents createComponents(String fieldName,
+ Reader reader) {
+ final Tokenizer source;
+ if (matchVersion.onOrAfter(Version.LUCENE_31)) {
+ source = new StandardTokenizer(matchVersion, reader);
+ } else {
+ source = new ArabicLetterTokenizer(matchVersion, reader);
+ }
+ TokenStream result = new LowerCaseFilter(matchVersion, source);
+ result = new ArabicNormalizationFilter(result);
+ /* additional persian-specific normalization */
+ result = new PersianNormalizationFilter(result);
+ /*
+ * the order here is important: the stopword list is normalized with the
+ * above!
+ */
+ return new TokenStreamComponents(source, new StopFilter(matchVersion, result, stopwords));
+ }
+
+ /**
+ * Wraps the Reader with {@link PersianCharFilter}
+ */
+ @Override
+ protected Reader initReader(Reader reader) {
+ return matchVersion.onOrAfter(Version.LUCENE_31) ?
+ new PersianCharFilter(CharReader.get(reader)) :
+ reader;
+ }
+}
fnp / pylucene.git / blobdiff