de.citec.lucene.SearchIndex.java Source code

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Here is the source code for de.citec.lucene.SearchIndex.java

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package de.citec.lucene;

import de.citec.util.Language;
import static de.citec.util.Language.DE;
import static de.citec.util.Language.EN;
import java.io.IOException;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.de.GermanAnalyzer;
import org.apache.lucene.analysis.en.EnglishAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopScoreDocCollector;
import org.apache.lucene.store.FSDirectory;

/**
 *
 * @author swalter
 */
public class SearchIndex {

    private Analyzer analyzer;
    private final IndexReader reader;
    private final IndexSearcher searcher;
    private final Language language;

    public SearchIndex(String pathToIndex, Language input_language) throws IOException {
        if (input_language.equals(DE))
            this.analyzer = new GermanAnalyzer();
        if (input_language.equals(EN))
            this.analyzer = new EnglishAnalyzer();
        this.language = input_language;
        this.reader = DirectoryReader.open(FSDirectory.open(Paths.get(pathToIndex)));
        this.searcher = new IndexSearcher(reader);

    }

    public Map<String, List<String>> runStrictSearch(List<String> terms, int top_k, boolean onlypersons)
            throws IOException {
        Set<String> cache = new HashSet<>();
        Map<String, List<String>> wikipedia_entries = new HashMap();
        try {

            //Generate Boolean query out of term
            BooleanQuery booleanQuery = new BooleanQuery();

            for (String term : terms) {
                booleanQuery.add(
                        new QueryParser("text", analyzer).parse("\"" + term.toLowerCase().replace(" ", "_") + "\""),
                        BooleanClause.Occur.SHOULD);
            }
            if (onlypersons) {
                booleanQuery.add(new QueryParser("persons", analyzer).parse("1"), BooleanClause.Occur.MUST);
                wikipedia_entries.putAll(runSearch(top_k, booleanQuery));
            } else {
                wikipedia_entries.putAll(runSearch(top_k, booleanQuery));
                booleanQuery.add(new QueryParser("persons", analyzer).parse("1"), BooleanClause.Occur.MUST);
                wikipedia_entries.putAll(runSearch(top_k, booleanQuery));
            }

        } catch (Exception e) {

        }

        return wikipedia_entries;
    }

    public Map<String, List<String>> runSearch(int top_k, BooleanQuery booleanQuery) throws IOException {
        int hitsPerPage = top_k;
        TopScoreDocCollector collector = TopScoreDocCollector.create(hitsPerPage);
        searcher.search(booleanQuery, collector);
        Map<String, List<String>> wikipedia_entries = new HashMap();
        ScoreDoc[] hits = collector.topDocs().scoreDocs;

        for (int i = 0; i < hits.length; ++i) {
            int docId = hits[i].doc;
            Document d = searcher.doc(docId);
            String artikelname = d.get("name");
            List<String> result = new ArrayList<>();
            result.add(artikelname);
            result.add(Float.toString(hits[i].score));
            wikipedia_entries.put(d.get("id"), result);
        }
        return wikipedia_entries;
    }

}