Metacat

/**

 *  '$RCSfile$'

 *  Copyright: 2000-2011 Regents of the University of California and the

 *              National Center for Ecological Analysis and Synthesis

 *

 *   '$Author: leinfelder $'

 *     '$Date: 2012-11-29 16:52:29 -0800 (Thu, 29 Nov 2012) $'

 *

 * 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.index;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.StringWriter;

import java.util.Collections;

import java.util.Comparator;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Properties;

import java.util.Set;

import javax.xml.parsers.ParserConfigurationException;

import org.apache.commons.io.FileUtils;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

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.dataone.service.exceptions.NotFound;

import org.dataone.service.exceptions.UnsupportedType;

import org.dataone.service.types.v1_1.QueryEngineDescription;

import org.dataone.service.types.v1_1.QueryField;

import org.xml.sax.SAXException;

import edu.ucsb.nceas.metacat.common.SolrServerFactory;

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

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

import edu.ucsb.nceas.metacat.properties.PropertyService;

import edu.ucsb.nceas.utilities.FileUtil;

/**

 * This class handles the request for getting the solr engine description.

 * @author tao

 *

 */

public class MetacatSolrEngineDescriptionHandler {

    private static final String UNKNOWN = "Unknown";

    private static final String DESCRIPTIONFILENAME= "solrQueryFieldDescriptions.properties";

    private static final String HTTPSOLRSERVERSCHEMAURLPATH="/admin/file/?contentType=text/xml;charset=utf-8&file=schema.xml";

    private static MetacatSolrEngineDescriptionHandler handler = null;

    private static Log logger = LogFactory.getLog(MetacatSolrEngineDescriptionHandler.class);

    private QueryEngineDescription qed = null;

    /**

     * Get an instance of the class.

     * @return

     */

    public static MetacatSolrEngineDescriptionHandler getInstance() throws Exception {

        if(handler == null) {

            handler = new MetacatSolrEngineDescriptionHandler();

        }

        return handler;

    }

    /**

     * Get the QueryEngineDescription

     * @return

     */

    public QueryEngineDescription getQueryEngineDescritpion() {

        return qed;

    }

    /*

     * Constructor

     */

    private MetacatSolrEngineDescriptionHandler() throws Exception {

       /*CoreContainer container = SolrServerFactory.getCoreContainer();

       if(container == null) {

           throw new Exception("MetacatSolrEngineDescriptionHandler - The Solr Server is not configured as an EmbeddedSolrServer and the EmbeddedSolrServer is the only SolrServer that the Metacat can provide the Query Engine Description.");

       }

       String coreName = SolrServerFactory.getCollectionName();

       if(container == null) {

           throw new Exception("MetacatSolrEngineDescriptionHandler - The collection name should not be null. Please check the value of the property \"solr.collectionName\" in the metacat.properties file.");

       }

       SolrCore core = container.getCore(coreName);

       if(core == null) {

           throw new Exception("MetacatSolrEngineDescriptionHandler - Metacat can't find the SolrCore for the given name - "+SolrServerFactory.getCollectionName());

       }*/

       init();

    }

    private void init() throws IOException, UnsupportedType, NotFound, ParserConfigurationException, SAXException {

        Map<String, String>fieldDescriptions = loadSchemaFieldDescriptions();

        qed = new QueryEngineDescription();

        qed.setName(EnabledQueryEngines.SOLRENGINE);

        //setSchemaVersionFromPropertiesFile(qed);

        setSolrVersion();

        //IndexSchema schema = core.getSchema();

        Map<String, SchemaField> fieldMap = SolrQueryServiceController.getInstance().getIndexSchemaFields();

        for (SchemaField schemaField : fieldMap.values()) {

            qed.addQueryField(createQueryFieldFromSchemaField(schemaField, fieldDescriptions));

        }

        Collections.sort(qed.getQueryFieldList(), new QueryFieldAlphaComparator());

    }

    /**

     * Based on org.apache.solr.handler.admin.SystemInfoHandler.getLuceneInfo()

     * @throws SAXException 

     * @throws IOException 

     * @throws ParserConfigurationException 

     * @throws NotFound 

     * @throws UnsupportedType 

     */

    private void setSolrVersion() throws UnsupportedType, NotFound, ParserConfigurationException, IOException, SAXException {

        qed.setQueryEngineVersion(SolrQueryServiceController.getInstance().getSolrSpecVersion());

    }

    private Map<String, String> loadSchemaFieldDescriptions() throws IOException {

        Map<String, String>fieldDescriptions = new HashMap<String, String>();

        Properties descriptionProperties = new Properties();

        String propertyFilePath = PropertyService.CONFIG_FILE_DIR + FileUtil.getFS() + DESCRIPTIONFILENAME;

        //System.out.println("the input strema is ================= "+propertyFilePath);

        descriptionProperties.load(new FileInputStream(new File(propertyFilePath)));

        Set<Object> names = descriptionProperties.keySet();

        for(Object nameObj : names) {

            String name = (String) nameObj;

            String description = (String) descriptionProperties.get(name);

            fieldDescriptions.put(name, description);

        }

        return fieldDescriptions;

    }

    private QueryField createQueryFieldFromSchemaField(SchemaField field,

                    Map<String, String> fieldDescriptions) {

                QueryField queryField = new QueryField();

                queryField.setName(field.getName());

                queryField.setType(field.getType().getTypeName());

                String description = fieldDescriptions.get(field.getName());

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

                    queryField.addDescription(description);

                }

                queryField.setSearchable(field.indexed());

                queryField.setReturnable(field.stored());

                queryField.setMultivalued(field.multiValued());

                queryField.setSortable(isSortable(field));

                return queryField;

            }

    private boolean isSortable(SchemaField field) {

                String type = field.getType().getTypeName();

                if ("int".equals(type) || "long".equals(type) || "float".equals(type)

                        || "double".equals(type)) {

                    return false;

                } else {

                    return true;

                }

    }

    private class QueryFieldAlphaComparator implements Comparator<QueryField> {

        public int compare(QueryField arg0, QueryField arg1) {

            String field1Name = arg0.getName();

            String field2Name = arg1.getName();

            return field1Name.compareToIgnoreCase(field2Name);

        }

    }

}