source: gs3-extensions/solr/trunk/src/src/java/org/greenstone/gsdl3/service/SolrSearch.java@ 28967

package org.greenstone.gsdl3.service;


// Based on LuceneSearch, but not thoroughly tested

// Greenstone classes
import org.greenstone.gsdl3.util.*;
import org.greenstone.util.GlobalProperties;

// XML classes
import org.w3c.dom.Element; 
import org.w3c.dom.Document;
import org.w3c.dom.NodeList; 

import java.util.HashMap;
import java.util.ArrayList;
import java.util.Iterator;


import org.apache.solr.client.solrj.SolrQuery;
import org.apache.solr.client.solrj.SolrServer;
import org.apache.solr.client.solrj.SolrServerException;
import org.apache.solr.client.solrj.embedded.EmbeddedSolrServer;
import org.apache.solr.client.solrj.response.QueryResponse;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrDocumentList;
import org.apache.solr.common.params.ModifiableSolrParams;
import org.apache.solr.common.params.SolrParams;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.servlet.SolrRequestParsers;
import org.apache.solr.core.CoreContainer;
import org.apache.solr.core.SolrCore;

import java.io.File;
import java.util.Collection;


import org.apache.log4j.*;


public class SolrSearch extends LuceneSearch {

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.SolrSearch.class.getName());

    static protected CoreContainer solr_cores = null;
    protected HashMap solr_server;

    public SolrSearch()
    {
    solr_server = new HashMap();

    if (solr_cores == null) {
        // Share one CoreContainer across all sites/collections
        try { 
        
        String gsdl3_home = GlobalProperties.getGSDL3Home();
        String solr_ext_name = GlobalProperties.getProperty("gsdlext.solr.dirname","solr");
        
        String solr_home_str = GSFile.extHome(gsdl3_home,solr_ext_name);

        solr_cores = new CoreContainer(solr_home_str);
        }
        catch (Exception e) {
        e.printStackTrace();
        }
    }
    }
    

    // Overriding the cleanUp() method here, so as to parallel the structure of GS2SolrSearch 
    // which also calls shutdown() on its CoreContainer object in GS2SolrSearch.cleanUp().
    // However, this class has not yet been tested, so it's not certain that this method is 
    // required here.
    // Adjusted  to bring it up to speed with changes in GS2SolrSearch (for activate.pl) - not yet tested
    public void cleanUp() {
    super.cleanUp();
    
        // 1. clear the map keeping track of the solrcores' EmbeddedSolrServers in this collection
        solr_server.clear();

        // 2. Remove all SolrCores in the CoreContainer (solr_cores) that are specific to this collection
        String collection_core_name_prefix = getCollectionCoreNamePrefix();

        Collection<String> coreNames = solr_cores.getCoreNames();
        if(!coreNames.isEmpty()) {
            Iterator<String> coreIterator = coreNames.iterator();
            while(coreIterator.hasNext()) {

            String solrCoreName = coreIterator.next();      
            if(solrCoreName.startsWith(collection_core_name_prefix)) {

                logger.error("**** Removing collection-specific core: " + solrCoreName + " from CoreContainer");

                // CoreContainer.remove(String name): removes and returns registered core w/o decrementing it's reference count
                // http://lucene.apache.org/solr/api/index.html?org/apache/solr/core/CoreContainer.html
                SolrCore solr_core = solr_cores.remove(solrCoreName);
                while(!solr_core.isClosed()) {
                logger.error("@@@@@@ " + solrCoreName + " was not closed. Closing....");
                solr_core.close(); // http://lucene.apache.org/solr/api/org/apache/solr/core/SolrCore.html
                } 
                if(solr_core.isClosed()) {
                logger.error("@@@@@@ " + solrCoreName + " is closed.");
                }
                solr_core = null;
            }
            }
        }

        // 3. if there are no more solr cores in Greenstone, then solr_cores will be empty, null the CoreContainer
        // All going well, this will happen when we're ant stopping the Greenstone server and the last Solr collection
        // is being deactivated
        Collection<String> coreNamesRemaining = solr_cores.getCoreNames();
        if(coreNamesRemaining.isEmpty()) {
            logger.error("**** CoreContainer contains 0 solrCores. Shutting down...");

            solr_cores.shutdown(); // wouldn't do anything anyway for 0 cores I think
            solr_cores = null;
        } 
        else { // else part is just for debugging
            Iterator coreIterator = coreNamesRemaining.iterator();
            while(coreIterator.hasNext()) {
            logger.error("**** Core: " + coreIterator.next() + " still exists in CoreContainer");
            }
        }
    
    }

    
    // adjusted configure to bring it up to speed with changes in GS2SolrSearch (for activate.pl) - not yet tested
    public boolean configure(Element info, Element extra_info) {
        boolean success = super.configure(info, extra_info);
    
        // 1. Make the CoreContainer reload solr.xml
        // This is particularly needed for when activate.pl is executed during
        // a running GS3 server. At that point, the solr collection is reactivated and 
        // we need to tell Greenstone that the solr index has changed. This requires
        // the CoreContainer to reload the solr.xml file, and it all works again.

        solr_server.clear(); // clear the map of solr cores for this collection added to the map upon querying
        
        // Reload the updated solr.xml into the CoreContainer
        // (Doing a solr_cores.shutdown() first doesn't seem to be required)
        try {   
            String solr_home_str = solr_cores.getSolrHome();
            File solr_home = new File(solr_home_str);
            File solr_xml = new File( solr_home,"solr.xml" );
            
            solr_cores.load(solr_home_str,solr_xml);            
        } catch (Exception e) {
            logger.error("Exception in SolrSearch.configure(): " + e.getMessage());
            e.printStackTrace();
            return false;
        }

    // initialize required number of SolrCores based on values
    // in 'index_ids' that are set by LuceneSearch::configure()

    String core_name_prefix = getCollectionCoreNamePrefix();

    for (int i=0; i<index_ids.size(); i++) {

        String idx_name = (String)index_ids.get(i);
        String core_name = core_name_prefix + "-" + idx_name;

        EmbeddedSolrServer solr_core
        = new EmbeddedSolrServer(solr_cores,core_name); 

        solr_server.put(core_name,solr_core);
    }

    return success;
    }
    
    protected void getIndexData(ArrayList index_ids, ArrayList index_names, String lang) 
    {
    }

    /** Process a text query - implemented by concrete subclasses */
    protected Element processTextQuery(Element request) {

      Document result_doc = XMLConverter.newDOM();
    Element result = result_doc.createElement(GSXML.RESPONSE_ELEM);
    Element doc_node_list = result_doc.createElement(GSXML.DOC_NODE_ELEM+GSXML.LIST_MODIFIER);
    Element metadata_list = result_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 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 {

        ModifiableSolrParams solrParams = new ModifiableSolrParams();
        solrParams.set("q", query_string);
        //solrParams.set("start", start);
        //solrParams.set("rows", nbDocuments);

        String core_name = getCollectionCoreNamePrefix() + "-" + index;

        EmbeddedSolrServer solr_core = (EmbeddedSolrServer)solr_server.get(core_name);

        QueryResponse solrResponse = solr_core.query(solrParams);

        SolrDocumentList hits = solrResponse.getResults();

        if (hits != null) {
        // or should this be docs.getNumFound() ??
        GSXML.addMetadata(metadata_list, "numDocsMatched", ""+hits.size());

        System.err.println(hits.getNumFound() + " documents found, "
                   + hits.size() + " returned : ");

        for (int i = 0; i < hits.size(); i++) {
            SolrDocument solr_doc = hits.get(i);

            String node_id = (String)solr_doc.get("docOID");
            Element node = result_doc.createElement(GSXML.DOC_NODE_ELEM);
            node.setAttribute(GSXML.NODE_ID_ATT, node_id);
            doc_node_list.appendChild(node);

            System.out.println("\t" + solr_doc.toString());
        }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    
    return result;
        
    }

    protected String getCollectionCoreNamePrefix() {
        String site_name = this.router.getSiteName();
        String coll_name = this.cluster_name;
        String collection_core_name_prefix = site_name + "-" + coll_name;
        return collection_core_name_prefix;
    }
    
}