edu.sdsc.scigraph.lucene.LuceneUtils.java Source code

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Here is the source code for edu.sdsc.scigraph.lucene.LuceneUtils.java

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/**
 * Copyright (C) 2014 The SciGraph authors
 *
 * Licensed 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.
 */
package edu.sdsc.scigraph.lucene;

import java.io.IOException;
import java.io.StringReader;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.StopAnalyzer;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.Query;
import org.apache.lucene.util.Version;

import com.google.common.base.Joiner;
import com.google.common.collect.Lists;

public class LuceneUtils {

    public static final String EXACT_SUFFIX = "_EXACT";

    /***
     * @return The current Lucene version in use across the application
     */
    public static Version getVersion() {
        return Version.LUCENE_36;
    }

    public static final Set<?> caseSensitiveStopSet;

    static {
        List<String> stopWords = Lists.newArrayList();
        for (Iterator<?> stopWord = StopAnalyzer.ENGLISH_STOP_WORDS_SET.iterator(); stopWord.hasNext();) {
            String word = new String((char[]) stopWord.next());
            stopWords.add(word);
            stopWords.add(Character.toUpperCase(word.charAt(0)) + word.substring(1).toLowerCase());
        }
        caseSensitiveStopSet = StopFilter.makeStopSet(getVersion(), stopWords, false);
    }

    public static boolean isStopword(String word) {
        for (Iterator<?> stopWord = StopAnalyzer.ENGLISH_STOP_WORDS_SET.iterator(); stopWord.hasNext();) {
            String stopword = new String((char[]) stopWord.next());
            if (stopword.equalsIgnoreCase(word)) {
                return true;
            }
        }
        return false;
    }

    public static boolean isAllStopwords(List<String> words) {
        for (String word : words) {
            if (!isStopword(word)) {
                return false;
            }
        }
        return true;
    }

    public static Query getBoostedQuery(QueryParser parser, String queryString, float boost) throws ParseException {
        Query query = parser.parse(queryString);
        query.setBoost(boost);
        return query;
    }

    public static String getTokenization(Analyzer analyzer, String term) {
        List<String> ret = getTokenization(analyzer, (CharSequence) term);
        return Joiner.on(", ").join(ret);
    }

    public static List<String> getTokenization(Analyzer analyzer, CharSequence term) {
        List<String> ret = Lists.newArrayList();

        try {
            TokenStream stream = analyzer.tokenStream("", new StringReader(term.toString()));
            CharTermAttribute token = stream.getAttribute(CharTermAttribute.class);
            stream.reset();
            while (stream.incrementToken()) {
                ret.add(token.toString());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return ret;
    }

}