package org.apache.lucene.analysis.br;
/**
* 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.HashSet;
import java.util.Map;
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.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.WordlistLoader;
import org.apache.lucene.analysis.standard.StandardAnalyzer; // for javadoc
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.analysis.standard.StandardTokenizer;
import org.apache.lucene.util.Version;
/**
* {@link Analyzer} for Brazilian Portuguese language.
* <p>
* Supports an external list of stopwords (words that
* will not be indexed at all) and an external list of exclusions (words that will
* not be stemmed, but indexed).
* </p>
*
* <p><b>NOTE</b>: This class uses the same {@link Version}
* dependent settings as {@link StandardAnalyzer}.</p>
*/
public final class BrazilianAnalyzer extends Analyzer {
/**
* List of typical Brazilian Portuguese stopwords.
*/
public final static String[] BRAZILIAN_STOP_WORDS = {
"a","ainda","alem","ambas","ambos","antes",
"ao","aonde","aos","apos","aquele","aqueles",
"as","assim","com","como","contra","contudo",
"cuja","cujas","cujo","cujos","da","das","de",
"dela","dele","deles","demais","depois","desde",
"desta","deste","dispoe","dispoem","diversa",
"diversas","diversos","do","dos","durante","e",
"ela","elas","ele","eles","em","entao","entre",
"essa","essas","esse","esses","esta","estas",
"este","estes","ha","isso","isto","logo","mais",
"mas","mediante","menos","mesma","mesmas","mesmo",
"mesmos","na","nas","nao","nas","nem","nesse","neste",
"nos","o","os","ou","outra","outras","outro","outros",
"pelas","pelas","pelo","pelos","perante","pois","por",
"porque","portanto","proprio","propios","quais","qual",
"qualquer","quando","quanto","que","quem","quer","se",
"seja","sem","sendo","seu","seus","sob","sobre","sua",
"suas","tal","tambem","teu","teus","toda","todas","todo",
"todos","tua","tuas","tudo","um","uma","umas","uns"};
/**
* Contains the stopwords used with the {@link StopFilter}.
*/
private Set stoptable = new HashSet();
/**
* Contains words that should be indexed but not stemmed.
*/
private Set excltable = new HashSet();
private final Version matchVersion;
/**
* Builds an analyzer with the default stop words ({@link #BRAZILIAN_STOP_WORDS}).
*
* @deprecated Use {@link #BrazilianAnalyzer(Version)} instead
*/
public BrazilianAnalyzer() {
this(Version.LUCENE_23);
}
/**
* Builds an analyzer with the default stop words ({@link #BRAZILIAN_STOP_WORDS}).
*/
public BrazilianAnalyzer(Version matchVersion) {
stoptable = StopFilter.makeStopSet( BRAZILIAN_STOP_WORDS );
this.matchVersion = matchVersion;
}
/**
* Builds an analyzer with the given stop words.
*
* @deprecated Use {@link #BrazilianAnalyzer(Version, String[])} instead
*/
public BrazilianAnalyzer( String[] stopwords ) {
this(Version.LUCENE_23, stopwords);
}
/**
* Builds an analyzer with the given stop words.
*/
public BrazilianAnalyzer( Version matchVersion, String[] stopwords ) {
stoptable = StopFilter.makeStopSet( stopwords );
this.matchVersion = matchVersion;
}
/**
* Builds an analyzer with the given stop words.
*
* @deprecated Use {@link #BrazilianAnalyzer(Version, Map)} instead
*/
public BrazilianAnalyzer( Map stopwords ) {
this(Version.LUCENE_23, stopwords);
}
/**
* Builds an analyzer with the given stop words.
*/
public BrazilianAnalyzer( Version matchVersion, Map stopwords ) {
stoptable = new HashSet(stopwords.keySet());
this.matchVersion = matchVersion;
}
/**
* Builds an analyzer with the given stop words.
* @deprecated Use {@link #BrazilianAnalyzer(Version, File)} instead
*/
public BrazilianAnalyzer( File stopwords ) throws IOException {
this(Version.LUCENE_23, stopwords);
}
/**
* Builds an analyzer with the given stop words.
*/
public BrazilianAnalyzer( Version matchVersion, File stopwords ) throws IOException {
stoptable = WordlistLoader.getWordSet( stopwords );
this.matchVersion = matchVersion;
}
/**
* Builds an exclusionlist from an array of Strings.
*/
public void setStemExclusionTable( String[] exclusionlist ) {
excltable = StopFilter.makeStopSet( exclusionlist );
setPreviousTokenStream(null); // force a new stemmer to be created
}
/**
* Builds an exclusionlist from a {@link Map}.
*/
public void setStemExclusionTable( Map exclusionlist ) {
excltable = new HashSet(exclusionlist.keySet());
setPreviousTokenStream(null); // force a new stemmer to be created
}
/**
* Builds an exclusionlist from the words contained in the given file.
*/
public void setStemExclusionTable( File exclusionlist ) throws IOException {
excltable = WordlistLoader.getWordSet( exclusionlist );
setPreviousTokenStream(null); // force a new stemmer to be created
}
/**
* Creates a {@link TokenStream} which tokenizes all the text in the provided {@link Reader}.
*
* @return A {@link TokenStream} built from a {@link StandardTokenizer} filtered with
* {@link LowerCaseFilter}, {@link StandardFilter}, {@link StopFilter}, and
* {@link BrazilianStemFilter}.
*/
public final TokenStream tokenStream(String fieldName, Reader reader) {
TokenStream result = new StandardTokenizer( matchVersion, reader );
result = new LowerCaseFilter( result );
result = new StandardFilter( result );
result = new StopFilter( StopFilter.getEnablePositionIncrementsVersionDefault(matchVersion),
result, stoptable );
result = new BrazilianStemFilter( result, excltable );
return result;
}
private class SavedStreams {
Tokenizer source;
TokenStream result;
};
/**
* Returns a (possibly reused) {@link TokenStream} which tokenizes all the text
* in the provided {@link Reader}.
*
* @return A {@link TokenStream} built from a {@link StandardTokenizer} filtered with
* {@link LowerCaseFilter}, {@link StandardFilter}, {@link StopFilter}, and
* {@link BrazilianStemFilter}.
*/
public TokenStream reusableTokenStream(String fieldName, Reader reader)
throws IOException {
SavedStreams streams = (SavedStreams) getPreviousTokenStream();
if (streams == null) {
streams = new SavedStreams();
streams.source = new StandardTokenizer(matchVersion, reader);
streams.result = new LowerCaseFilter(streams.source);
streams.result = new StandardFilter(streams.result);
streams.result = new StopFilter(StopFilter.getEnablePositionIncrementsVersionDefault(matchVersion),
streams.result, stoptable);
streams.result = new BrazilianStemFilter(streams.result, excltable);
setPreviousTokenStream(streams);
} else {
streams.source.reset(reader);
}
return streams.result;
}
}