package org.apache.lucene.analysis.cjk;
/**
* 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 org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.util.Version;
import java.io.IOException;
import java.io.Reader;
import java.util.Set;
/**
* An {@link Analyzer} that tokenizes text with {@link CJKTokenizer} and
* filters with {@link StopFilter}
*
*/
public class CJKAnalyzer extends Analyzer {
//~ Static fields/initializers ---------------------------------------------
/**
* An array containing some common English words that are not usually
* useful for searching and some double-byte interpunctions.
*/
public final static String[] STOP_WORDS = {
"a", "and", "are", "as", "at", "be",
"but", "by", "for", "if", "in",
"into", "is", "it", "no", "not",
"of", "on", "or", "s", "such", "t",
"that", "the", "their", "then",
"there", "these", "they", "this",
"to", "was", "will", "with", "",
"www"
};
//~ Instance fields --------------------------------------------------------
/**
* stop word list
*/
private Set stopTable;
private final Version matchVersion;
//~ Constructors -----------------------------------------------------------
/**
* Builds an analyzer which removes words in {@link #STOP_WORDS}.
*
* @deprecated Use {@link #CJKAnalyzer(Version)} instead
*/
public CJKAnalyzer() {
this(Version.LUCENE_24);
}
/**
* Builds an analyzer which removes words in {@link #STOP_WORDS}.
*/
public CJKAnalyzer(Version matchVersion) {
stopTable = StopFilter.makeStopSet(STOP_WORDS);
this.matchVersion = matchVersion;
}
/**
* Builds an analyzer which removes words in the provided array.
*
* @param stopWords stop word array
* @deprecated Use {@link #CJKAnalyzer(Version, String[])} instead
*/
public CJKAnalyzer(String[] stopWords) {
this(Version.LUCENE_24, stopWords);
}
/**
* Builds an analyzer which removes words in the provided array.
*
* @param stopWords stop word array
*/
public CJKAnalyzer(Version matchVersion, String[] stopWords) {
stopTable = StopFilter.makeStopSet(stopWords);
this.matchVersion = matchVersion;
}
//~ Methods ----------------------------------------------------------------
/**
* Creates a {@link TokenStream} which tokenizes all the text in the provided {@link Reader}.
*
* @param fieldName lucene field name
* @param reader input {@link Reader}
* @return A {@link TokenStream} built from {@link CJKTokenizer}, filtered with
* {@link StopFilter}
*/
public final TokenStream tokenStream(String fieldName, Reader reader) {
return new StopFilter(StopFilter.getEnablePositionIncrementsVersionDefault(matchVersion),
new CJKTokenizer(reader), stopTable);
}
private class SavedStreams {
Tokenizer source;
TokenStream result;
};
/**
* Returns a (possibly reused) {@link TokenStream} which tokenizes all the text
* in the provided {@link Reader}.
*
* @param fieldName lucene field name
* @param reader Input {@link Reader}
* @return A {@link TokenStream} built from {@link CJKTokenizer}, filtered with
* {@link StopFilter}
*/
public final TokenStream reusableTokenStream(String fieldName, Reader reader) throws IOException {
/* tokenStream() is final, no back compat issue */
SavedStreams streams = (SavedStreams) getPreviousTokenStream();
if (streams == null) {
streams = new SavedStreams();
streams.source = new CJKTokenizer(reader);
streams.result = new StopFilter(StopFilter.getEnablePositionIncrementsVersionDefault(matchVersion),
streams.source, stopTable);
setPreviousTokenStream(streams);
} else {
streams.source.reset(reader);
}
return streams.result;
}
}