de.unihildesheim.iw.lucene.analyzer.GermanAnalyzer.java Source code

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Here is the source code for de.unihildesheim.iw.lucene.analyzer.GermanAnalyzer.java

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/*
 * Copyright (C) 2014 Jens Bertram <code@jens-bertram.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.unihildesheim.iw.lucene.analyzer;

import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.core.LowerCaseFilter;
import org.apache.lucene.analysis.core.StopFilter;
import org.apache.lucene.analysis.de.GermanLightStemFilter;
import org.apache.lucene.analysis.de.GermanNormalizationFilter;
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.analysis.standard.StandardTokenizer;
import org.apache.lucene.analysis.util.CharArraySet;
import org.apache.lucene.analysis.util.StopwordAnalyzerBase;
import org.jetbrains.annotations.Nullable;

/**
 * @author Jens Bertram
 */
public final class GermanAnalyzer extends StopwordAnalyzerBase {

    /**
     * Builds an analyzer without any stop words.
     */
    public GermanAnalyzer() {
        // empty
    }

    /**
     * Builds an analyzer with the given stop words.
     *
     * @param newStopwords stop words
     */
    public GermanAnalyzer(@Nullable final CharArraySet newStopwords) {
        super(newStopwords);
    }

    /**
     * This configuration must match with the configuration used for the index!
     *
     * @param fieldName Document field
     * @return Token stream
     */
    @SuppressWarnings("resource")
    @Override
    protected TokenStreamComponents createComponents(final String fieldName) {
        final Tokenizer source = new StandardTokenizer();
        TokenStream result = new StandardFilter(source);
        result = new LowerCaseFilter(result);
        result = new StopFilter(result, getStopwordSet());
        result = new GermanNormalizationFilter(result);
        result = new GermanLightStemFilter(result);
        return new TokenStreamComponents(source, result);
    }
}