Metacat

/**

 *  Copyright: 2013 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat.common.query;

import java.io.IOException;

import java.io.InputStream;

import java.io.StringWriter;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.Set;

import javax.xml.parsers.ParserConfigurationException;

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.SolrDocumentList;

import org.apache.solr.common.params.SolrParams;

import org.apache.solr.common.util.XML;

import org.apache.solr.core.CoreContainer;

import org.apache.solr.core.SolrCore;

import org.apache.solr.schema.IndexSchema;

import org.apache.solr.schema.SchemaField;

import org.apache.solr.servlet.SolrRequestParsers;

import org.dataone.service.exceptions.NotFound;

import org.dataone.service.exceptions.NotImplemented;

import org.dataone.service.exceptions.UnsupportedType;

import org.dataone.service.types.v1.Identifier;

import org.dataone.service.types.v1.Subject;

import org.xml.sax.SAXException;

import edu.ucsb.nceas.metacat.common.query.SolrQueryResponseTransformer;

/**

 *The query service of the embedded solr server.

 * @author tao

 *

 */

public class EmbeddedSolrQueryService extends SolrQueryService {

    private EmbeddedSolrServer solrServer = null;

    private CoreContainer coreContainer = null;

    private String collectionName = null;

    private SolrCore solrCore = null;

    /**

     * Constructor.

     * @param solrServer

     * @param solrCore

     * @throws NotFound 

     */

    public EmbeddedSolrQueryService(EmbeddedSolrServer solrServer, CoreContainer coreContainer, String collectionName) throws NotFound {

        if(solrServer == null) {

            throw new NullPointerException("EmbeddedSolrQueryService.constructor - the EmbeddedSolrServer parameter can't be null.");

        }

        if(coreContainer == null) {

            throw new NullPointerException("EmbeddedSolrQueryService.constructor - the CoreContainer parameter can't be null.");

        }

        if(collectionName == null || collectionName.trim().equals("")) {

            throw new NullPointerException("EmbeddedSolrQueryService.constructor - the name of Collection parameter can't be null or empty.");

        }

        this.solrServer = solrServer;

        this.coreContainer = coreContainer;

        this.collectionName = collectionName;

        this.solrCore = this.coreContainer.getCore(collectionName);

        if(solrCore == null) {

            throw new NotFound("0000","EmbeddedSolrQueryService.constructor - There is no SolrCore named "+collectionName+".");

        }

        schema = solrCore.getSchema();

        fieldMap = schema.getFields();

    }

    /**

     * Query the Solr server with specified query and user's identity. If the Subjects

     * is null, there will be no access rules for the query. This is the for the http solr server.

     * @param query the query string

     * @param subjects the user's identity which sent the query

     * @return the response

     * @throws Exception

     */

    /*public InputStream query(String query, Set<Subject>subjects) throws Exception {

        throw new NotImplemented("0000", "EmbeddSolrQueryService - the method of  query(String query, Set<Subject>subjects) is not for the EmbeddedSolrServer. We donot need to implemente it");

    }*/

    /**

     * Query the Solr server with specified query and user's identity. If the Subjects

     * is null, there will be no access rules for the query. This is for the embedded solr server.

     * @param query the query params. 

     * @param subjects the user's identity which sent the query

     * @return the response

     * @throws SAXException 

     * @throws IOException 

     * @throws ParserConfigurationException 

     * @throws SolrServerException 

     * @throws UnsupportedType 

     * @throws Exception

     */

    public  InputStream query(SolrParams query, Set<Subject>subjects) throws ParserConfigurationException, IOException, SAXException, SolrServerException, UnsupportedType {

        InputStream inputStream = null;

        String wt = query.get(WT);

        query = appendAccessFilterParams(query, subjects);

        SolrQueryResponseTransformer solrTransformer = new SolrQueryResponseTransformer(solrCore);

        // handle normal and skin-based queries

        if (isSupportedWT(wt)) {

            // just handle as normal solr query

            //reload the core before query. Only after reloading the core, the query result can reflect the change made in metacat-index module.

            coreContainer.reload(collectionName);

            QueryResponse response = solrServer.query(query);

            inputStream = solrTransformer.transformResults(query, response, wt);

        } else {

            throw new UnsupportedType("0000","EmbeddSolrQueryService.query - the wt type "+wt+" in the solr query is not supported");

        }

        return inputStream;

    }

    /**

     * Get the fields map of the index schema

     * @return the fields map (the field name is the key and the SchemaField is the value).

     */

    public  Map<String, SchemaField> getIndexSchemaFields() {

        return fieldMap;

    }

    /**

     * Get the list of the valid field name (moved the fields names of the CopyFieldTarget).

     * @return

     */

    public List<String> getValidSchemaField() {

        return super.getValidSchemaFields();

    }

    /**

     * Get the version of the solr server.

     * @return

     */

    public String getSolrServerVersion() {

        if( solrSpecVersion !=null ) {

            return solrSpecVersion;

        } else {

            Package p = SolrCore.class.getPackage();

            StringWriter tmp = new StringWriter();

            solrSpecVersion = p.getSpecificationVersion();

            if (null != solrSpecVersion) {

                try {

                    XML.escapeCharData(solrSpecVersion, tmp);

                    solrSpecVersion = tmp.toString();

                } catch (IOException e) {

                    e.printStackTrace();

                }

            }

            if (solrSpecVersion == null || solrSpecVersion.trim().equals("")) {

                solrSpecVersion = UNKNOWN;

            } 

            return solrSpecVersion;

        }

    }

    /**

     * If there is a solr doc for the given id.

     * @param id - the specified id.

     * @return true if there is a solr doc for this id.

     */

    public boolean hasSolrDoc(Identifier id) throws ParserConfigurationException, SolrServerException, IOException, SAXException{

    	boolean hasIt = false;

    	if(id != null && id.getValue() != null && !id.getValue().trim().equals("") ) {

    		SolrParams query = buildIdQuery(id.getValue());

    		coreContainer.reload(collectionName);

            QueryResponse response = solrServer.query(query);

            hasIt = hasResult(response);

    	}

    	return hasIt;

    }

    /**

     * Build a query for decide if the solr server has the id.

     * @param id

     * @return the query

     */

    public static SolrParams buildIdQuery(String id) {

    	    String query = "select?q=id:"+id;

    		query = query.replaceAll("\\+", "%2B");

            SolrParams solrParams = SolrRequestParsers.parseQueryString(query);

            return solrParams;

    }

    /**

     * Determine if the response has any solr documents.

     * @param response

     * @return true if it has at least one solr document;

     */

    public static boolean hasResult(QueryResponse response) {

    	boolean hasResult = false;

    	if(response != null) {

    		SolrDocumentList list = response.getResults();

    		if(list != null && list.getNumFound() >0) {

    			hasResult = true;

    		}

    	}

    	return hasResult;

    }

}