gate.creole.ir.lucene.LuceneSearch.java Source code

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Here is the source code for gate.creole.ir.lucene.LuceneSearch.java

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/*
 *  LuceneSearch.java
 *
 *  Copyright (c) 1995-2012, The University of Sheffield. See the file
 *  COPYRIGHT.txt in the software or at http://gate.ac.uk/gate/COPYRIGHT.txt
 *
 *  This file is part of GATE (see http://gate.ac.uk/), and is free
 *  software, licenced under the GNU Library General Public License,
 *  Version 2, June 1991 (in the distribution as file licence.html,
 *  and also available at http://gate.ac.uk/gate/licence.html).
 *
 *  Rosen Marinov, 19/Apr/2002
 *
 */

package gate.creole.ir.lucene;

import java.io.File;
import java.util.List;
import java.util.Vector;

import org.apache.lucene.analysis.SimpleAnalyzer;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.*;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

import gate.creole.ir.*;

/** This class represents Lucene implementation of serching in index. */
public class LuceneSearch implements Search {

    /** Default number of maximum results when no limit is specified
     * in a search method call 
     */
    private static int DEFAULTMAXRESULTS = 1000000;

    /** An instance of indexed corpus*/
    private IndexedCorpus indexedCorpus;

    /** Set the indexed corpus resource for searching. */
    @Override
    public void setCorpus(IndexedCorpus ic) {
        this.indexedCorpus = ic;
    }

    /** Search in corpus with this query. 
     * Result length is limited by DEFAULTMAXRESULTS */
    @Override
    public QueryResultList search(String query) throws IndexException, SearchException {
        return search(query, DEFAULTMAXRESULTS);
    }

    /** Search in corpus with this query.
     *  Size of the result list is limited. */
    @Override
    public QueryResultList search(String query, int limit) throws IndexException, SearchException {
        return search(query, limit, null);
    }

    /** Search in corpus with this query.
     *  In each QueryResult will be added values of theise fields.
     *  Result length is limited by DEFAULTMAXRESULTS. */
    @Override
    public QueryResultList search(String query, List<String> fieldNames) throws IndexException, SearchException {
        return search(query, DEFAULTMAXRESULTS, fieldNames);
    }

    /** Search in corpus with this query.
     *  In each QueryResult will be added values of these fields.
     *  Result length is limited. */
    @Override
    public QueryResultList search(String query, int limit, List<String> fieldNames)
            throws IndexException, SearchException {

        List<QueryResult> result = new Vector<QueryResult>();

        try {
            IndexSearcher searcher = new IndexSearcher(IndexReader
                    .open(FSDirectory.open(new File(indexedCorpus.getIndexDefinition().getIndexLocation())), true));
            QueryParser parser = new QueryParser(Version.LUCENE_30, "body", new SimpleAnalyzer(Version.LUCENE_30));
            Query luceneQuery = parser.parse(query);

            // JP was for lucene 2.2
            // Hits hits = searcher.search(luceneQuery);
            //int resultlength = hits.length();
            //if (limit>-1) {
            //  resultlength = Math.min(limit,resultlength);
            //}
            TopDocs topDocs = searcher.search(luceneQuery, limit);
            ScoreDoc[] hits = topDocs.scoreDocs;
            int resultlength = hits.length;

            Vector<Term> fieldValues = null;
            for (int i = 0; i < resultlength; i++) {

                if (fieldNames != null) {
                    fieldValues = new Vector<Term>();
                    for (int j = 0; j < fieldNames.size(); j++) {
                        fieldValues
                                .add(new Term(fieldNames.get(j), searcher.doc(hits[i].doc).get(fieldNames.get(j))));
                    }
                }

                result.add(new QueryResult(searcher.doc(hits[i].doc).get(LuceneIndexManager.DOCUMENT_ID),
                        hits[i].score, fieldValues));
            } // for (all search hints)

            searcher.close();

            return new QueryResultList(query, indexedCorpus, result);
        } catch (java.io.IOException ioe) {
            throw new IndexException(ioe.getMessage());
        } catch (org.apache.lucene.queryParser.ParseException pe) {
            throw new SearchException(pe.getMessage());
        }
    }
}