source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/service/GS2LuceneSearch.java@ 25855

/*
 *    GS2LuceneSearch.java
 *    Copyright (C) 2006 New Zealand Digital Library, http://www.nzdl.org
 *
 *    This program is free software; you can redistribute it and/or modify
 *   the Free Software Foundation; either version 2 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, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package org.greenstone.gsdl3.service;

// Greenstone classes
import java.io.File;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Vector;

import org.apache.log4j.Logger;
import org.greenstone.LuceneWrapper3.GS2LuceneQuery;
import org.greenstone.LuceneWrapper3.LuceneQueryResult;
import org.greenstone.gsdl3.util.GSFile;
import org.greenstone.gsdl3.util.GSXML;
import org.w3c.dom.Element;

public class GS2LuceneSearch extends SharedSoleneGS2FieldSearch
{
    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.GS2LuceneSearch.class.getName());

    private GS2LuceneQuery lucene_src = null;

    public GS2LuceneSearch()
    {
        this.lucene_src = new GS2LuceneQuery();
    }

    public void cleanUp()
    {
        super.cleanUp();
        this.lucene_src.cleanUp();
    }

    /** methods to handle actually doing the query */

    /** do any initialisation of the query object */
    protected boolean setUpQueryer(HashMap params)
    {
        String indexdir = GSFile.collectionBaseDir(this.site_home, this.cluster_name) + File.separatorChar + "index" + File.separatorChar;

        String index = "didx";
        String physical_index_language_name = null;
        String physical_sub_index_name = null;
        int maxdocs = 100;
        int hits_per_page = 20;
        int start_page = 1;
        // set up the query params
        Set entries = params.entrySet();
        Iterator i = entries.iterator();
        while (i.hasNext())
        {
            Map.Entry m = (Map.Entry) i.next();
            String name = (String) m.getKey();
            String value = (String) m.getValue();

            if (name.equals(MAXDOCS_PARAM) && !value.equals(""))
            {
                maxdocs = Integer.parseInt(value);
            }
            else if (name.equals(HITS_PER_PAGE_PARAM))
            {
                hits_per_page = Integer.parseInt(value);
            }
            else if (name.equals(START_PAGE_PARAM))
            {
                start_page = Integer.parseInt(value);

            }
            else if (name.equals(MATCH_PARAM))
            {
                if (value.equals(MATCH_PARAM_ALL))
                {
                    this.lucene_src.setDefaultConjunctionOperator("AND");
                }
                else
                {
                    this.lucene_src.setDefaultConjunctionOperator("OR");
                }
            }
            else if (name.equals(RANK_PARAM))
            {
                if (value.equals(RANK_PARAM_RANK_VALUE))
                {
                    value = null;
                }
                this.lucene_src.setSortField(value);
            }
            else if (name.equals(LEVEL_PARAM))
            {
                if (value.toUpperCase().equals("SEC"))
                {
                    index = "sidx";
                }
                else
                {
                    index = "didx";
                }
            }
            else if (name.equals(INDEX_SUBCOLLECTION_PARAM))
            {
                physical_sub_index_name = value;
            }
            else if (name.equals(INDEX_LANGUAGE_PARAM))
            {
                physical_index_language_name = value;
            } // ignore any others
        }
        // set up start and end results if necessary
        int start_results = 1;
        if (start_page != 1)
        {
            start_results = ((start_page - 1) * hits_per_page) + 1;
        }
        int end_results = hits_per_page * start_page;
        this.lucene_src.setStartResults(start_results);
        this.lucene_src.setEndResults(end_results);

        if (index.equals("sidx") || index.equals("didx"))
        {
            if (physical_sub_index_name != null)
            {
                index += physical_sub_index_name;
            }
            if (physical_index_language_name != null)
            {
                index += physical_index_language_name;
            }
        }

        this.lucene_src.setIndexDir(indexdir + index);
        this.lucene_src.initialise();
        return true;
    }

    /** do the query */
    protected Object runQuery(String query)
    {
        try
        {
            LuceneQueryResult lqr = this.lucene_src.runQuery(query);
            return lqr;
        }
        catch (Exception e)
        {
            logger.error("Exception happened in runQuery(): ", e);
        }

        return null;
    }

    /** get the total number of docs that match */
    protected long numDocsMatched(Object query_result)
    {
        return ((LuceneQueryResult) query_result).getTotalDocs();
    }

    /** get the list of doc ids */
    protected String[] getDocIDs(Object query_result)
    {
        Vector docs = ((LuceneQueryResult) query_result).getDocs();
        String[] doc_nums = new String[docs.size()];
        for (int d = 0; d < docs.size(); d++)
        {
            String doc_num = ((LuceneQueryResult.DocInfo) docs.elementAt(d)).id_;
            doc_nums[d] = doc_num;
        }
        return doc_nums;
    }

    /** get the list of doc ranks */
    protected String[] getDocRanks(Object query_result)
    {
        Vector docs = ((LuceneQueryResult) query_result).getDocs();
        String[] doc_ranks = new String[docs.size()];
        for (int d = 0; d < docs.size(); d++)
        {
            doc_ranks[d] = Float.toString(((LuceneQueryResult.DocInfo) docs.elementAt(d)).rank_);
        }
        return doc_ranks;
    }

    /** add in term info if available */
    protected boolean addTermInfo(Element term_list, HashMap params, Object query_result)
    {
        String query_level = (String) params.get(LEVEL_PARAM); // the current query level

        Vector terms = ((LuceneQueryResult) query_result).getTerms();
        for (int t = 0; t < terms.size(); t++)
        {
            LuceneQueryResult.TermInfo term_info = (LuceneQueryResult.TermInfo) terms.get(t);

            Element term_elem = this.doc.createElement(GSXML.TERM_ELEM);
            term_elem.setAttribute(GSXML.NAME_ATT, term_info.term_);
            term_elem.setAttribute(FREQ_ATT, "" + term_info.term_freq_);
            term_elem.setAttribute(NUM_DOCS_MATCH_ATT, "" + term_info.match_docs_);
            term_elem.setAttribute(FIELD_ATT, term_info.field_);
            term_list.appendChild(term_elem);
        }

        Vector stopwords = ((LuceneQueryResult) query_result).getStopWords();
        for (int t = 0; t < stopwords.size(); t++)
        {
            String stopword = (String) stopwords.get(t);

            Element stopword_elem = this.doc.createElement(GSXML.STOPWORD_ELEM);
            stopword_elem.setAttribute(GSXML.NAME_ATT, stopword);
            term_list.appendChild(stopword_elem);
        }

        return true;
    }
}