source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/service/LuceneSearch.java@ 25763

package org.greenstone.gsdl3.service;

// Greenstone classes
import java.io.File;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;

import org.apache.log4j.Logger;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.greenstone.gsdl3.util.GSFile;
import org.greenstone.gsdl3.util.GSXML;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

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

    protected static final String INDEX_ELEM = "index";

    protected ArrayList<String> index_ids;

    public LuceneSearch()
    {
        index_ids = new ArrayList<String>();
    }

    public boolean configure(Element info, Element extra_info)
    {
        if (!super.configure(info, extra_info))
        {
            return false;
        }

        default_index = "idx";

        // cache index info read from config file
        Element index_list = (Element) GSXML.getChildByTagName(this.config_info, INDEX_ELEM + GSXML.LIST_MODIFIER);
        if (index_list != null)
        {
            NodeList indexes = index_list.getElementsByTagName(INDEX_ELEM);
            int len = indexes.getLength();
            // now add even if there is only one
            for (int i = 0; i < len; i++)
            {
                Element index = (Element) indexes.item(i);
                index_ids.add(index.getAttribute(GSXML.NAME_ATT));
            }
        }
        else
        {
            // there is only one index, so we assume the default
            index_ids.add(this.default_index);
        }

        return true;
    }

    protected void getIndexData(ArrayList<String> index_ids, ArrayList<String> index_names, String lang)
    {
        // copying exercise for index_ids, 
        for (int i = 0; i < this.index_ids.size(); i++)
        {
            index_ids.add(this.index_ids.get(i));
        }

        // But need to work out display name from scratch as this uses
        // the 'lang' parameter

        Element index_list = (Element) GSXML.getChildByTagName(this.config_info, INDEX_ELEM + GSXML.LIST_MODIFIER);
        if (index_list != null)
        {
            NodeList indexes = index_list.getElementsByTagName(INDEX_ELEM);
            int len = indexes.getLength();
            // now add even if there is only one
            for (int i = 0; i < len; i++)
            {
                Element index = (Element) indexes.item(i);
                index_names.add(GSXML.getDisplayText(index, GSXML.DISPLAY_TEXT_NAME, lang, "en"));

            }
        }
        else
        {
            // there is only one index, so we assume the default
            index_names.add("default index");
        }
    }

    protected void initResultElement(Element result, Element doc_node_list, Element metadata_list)
    {
        // Create a new (empty) result message
        result.setAttribute(GSXML.FROM_ATT, QUERY_SERVICE);
        result.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);
        result.appendChild(doc_node_list);
        result.appendChild(metadata_list);
    }

    protected boolean hasParamList(Element request, Element metadata_list)
    {
        // Get the parameters of the request
        Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
        if (param_list == null)
        {
            logger.error("TextQuery request had no paramList.");
            GSXML.addMetadata(this.doc, metadata_list, "numDocsMatched", "0");
            return false; // signal that an empty result should be return
        }

        return true;
    }

    protected boolean hasQueryString(Element param_list, Element metadata_list)
    {
        // Process the request parameters to make sure a query has been specified
        HashMap<String, Serializable> params = GSXML.extractParams(param_list, false);
        String query_string = (String) params.get(QUERY_PARAM);

        if (query_string == null || query_string.equals(""))
        {
            logger.error("TextQuery request had no query string.");
            GSXML.addMetadata(this.doc, metadata_list, "numDocsMatched", "0");
            return false; // signal that an empty result should be return
        }

        return true;
    }

    /** Process a text query - implemented by concrete subclasses */
    protected Element processTextQuery(Element request)
    {
        Element result = this.doc.createElement(GSXML.RESPONSE_ELEM);
        Element doc_node_list = this.doc.createElement(GSXML.DOC_NODE_ELEM + GSXML.LIST_MODIFIER);
        Element metadata_list = this.doc.createElement(GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER);
        initResultElement(result, doc_node_list, metadata_list);

        if (!hasParamList(request, metadata_list))
        {
            return result;
        }

        Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
        if (!hasQueryString(param_list, metadata_list))
        {
            return result;
        }

        HashMap<String, Serializable> params = GSXML.extractParams(param_list, false);
        String query_string = (String) params.get(QUERY_PARAM);

        // Get the index
        String index = (String) params.get(INDEX_PARAM);
        if (index == null || index.equals(""))
        {
            index = this.default_index; // assume the default
        }

        try
        {
            String index_dir = GSFile.collectionIndexDir(this.site_home, this.cluster_name);
            index_dir += File.separator + index;
            Directory index_dir_dir = FSDirectory.open(new File(index_dir));
            IndexSearcher searcher = new IndexSearcher(index_dir_dir);

            Term term = new Term("content", query_string);

            Query query = new TermQuery(term);

            TopDocs hits = searcher.search(query, Integer.MAX_VALUE);

            GSXML.addMetadata(this.doc, metadata_list, "numDocsMatched", "" + hits.scoreDocs.length);

            IndexReader reader = searcher.getIndexReader();

            for (int i = 0; i < hits.scoreDocs.length; i++)
            {
                int lucene_doc_num = hits.scoreDocs[i].doc;
                org.apache.lucene.document.Document luc_doc = reader.document(lucene_doc_num);
                String node_id = luc_doc.get("nodeID");
                Element node = this.doc.createElement(GSXML.DOC_NODE_ELEM);
                node.setAttribute(GSXML.NODE_ID_ATT, node_id);
                doc_node_list.appendChild(node);
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

        return result;
    }
}