Thibau/datalift-datacubeviz

/*
 * Copyright / LIRMM 2013
 * Contributor(s) : T. Colas, T. Marmin
 *
 * Contact: thibaut.marmin@etud.univ-montp2.fr
 * Contact: thibaud.colas@etud.univ-montp2.fr
 *
 * This software is governed by the CeCILL license under French law and
 * abiding by the rules of distribution of free software. You can use,
 * modify and/or redistribute the software under the terms of the CeCILL
 * license as circulated by CEA, CNRS and INRIA at the following URL
 * "http://www.cecill.info".
 *
 * As a counterpart to the access to the source code and rights to copy,
 * modify and redistribute granted by the license, users are provided only
 * with a limited warranty and the software's author, the holder of the
 * economic rights, and the successive licensors have only limited
 * liability.
 *
 * In this respect, the user's attention is drawn to the risks associated
 * with loading, using, modifying and/or developing or reproducing the
 * software by the user in light of its specific status of free software,
 * that may mean that it is complicated to manipulate, and that also
 * therefore means that it is reserved for developers and experienced
 * professionals having in-depth computer knowledge. Users are therefore
 * encouraged to load and test the software's suitability as regards their
 * requirements in conditions enabling the security of their systems and/or
 * data to be ensured and, more generally, to use and operate it in the
 * same conditions as regards security.
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL license and that you accept its terms.
 */

package org.datalift.datacubeviz;

import static org.openrdf.query.QueryLanguage.SPARQL;

import org.datalift.fwk.project.Source;
import org.datalift.fwk.project.SparqlSource;
import org.datalift.fwk.project.TransformedRdfSource;
import org.openrdf.model.impl.URIImpl;
import org.openrdf.query.TupleQuery;
import org.openrdf.query.TupleQueryResult;
import org.openrdf.query.resultio.TupleQueryResultFormat;
import org.openrdf.repository.Repository;
import org.openrdf.repository.RepositoryConnection;
import org.openrdf.repository.http.HTTPRepository;

/**
 * A module to visualize Datacube (RDF) data in the Datalift Platform.
 * 
 * @author T. Colas, T. Marmin
 * @version 260213
 */
public class DatacubeVizModel extends ModuleModel {

    // -------------------------------------------------------------------------
    // Instance members
    // -------------------------------------------------------------------------

    public static URIImpl DATACUBE_NS = new URIImpl(
            "http://purl.org/linked-data/cube#");
    public static URIImpl DATACUBE_DATASET_NS = new URIImpl(DATACUBE_NS
            + "DataSet");

    // -------------------------------------------------------------------------
    // Constructors
    // -------------------------------------------------------------------------

    /**
     * Creates a new DatacubeVizModel instance.
     * 
     * @param name
     *            Name of the module.
     */
    public DatacubeVizModel(String name) {
        super(name);
    }

    // -------------------------------------------------------------------------
    // Sources management.
    // -------------------------------------------------------------------------

    /**
     * Checks if a given {@link Source} contains valid Datacube-structured data.
     * 
     * @param src
     *            The source to check.
     * @return True if src is {@link TransformedRdfSource} or
     *         {@link SparqlSource}.
     */
    public boolean isValidSource(Source src) {
        // detect if src is a valid source to be used by the module
        // A valid source is an instance of TransformedRdfSource witch contains
        // a qb:Dataset
        try {
            if (src instanceof TransformedRdfSource) {
                TransformedRdfSource rdf = (TransformedRdfSource) src;
                LOG.debug("Source {} is candidate", rdf.getTitle());

                RepositoryConnection cnx = INTERNAL_REPO.newConnection();
                LOG.debug("Connexion to internal repo OK");
                TupleQuery q = cnx.prepareTupleQuery(
                        SPARQL,
                        "SELECT DISTINCT ?s WHERE { GRAPH <"
                                + rdf.getTargetGraph() + "> { ?s a <"
                                + DATACUBE_DATASET_NS + "> . } }");
                LOG.debug("Query ready, evaluate... -> {}", q.toString());
                TupleQueryResult rs = q.evaluate();
                LOG.debug("OK");
                if (rs.hasNext())
                    return true;
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            LOG.fatal("BAD THING APPEND");
            e.printStackTrace();
        }
        return false;
    }

    public TupleQueryResult getDatasets(Source src) {
        TupleQueryResult rs = null;
        if (src instanceof TransformedRdfSource) {
            try {
                TransformedRdfSource rdf = (TransformedRdfSource) src;
                HTTPRepository repo = (HTTPRepository) INTERNAL_REPO
                        .getNativeRepository();
                repo.setPreferredTupleQueryResultFormat(TupleQueryResultFormat.JSON);

                RepositoryConnection cnx = repo.getConnection();

                LOG.debug("Connexion to internal repo OK");
                TupleQuery q;
                q = cnx.prepareTupleQuery(
                        SPARQL,
                        "SELECT DISTINCT ?uri ?title WHERE {   GRAPH <"
                                + rdf.getTargetGraph()
                                + ">  {   ?uri a <"
                                + DATACUBE_DATASET_NS
                                + "> .    ?uri <http://www.w3.org/2000/01/rdf-schema#label> ?title . }  }");
                LOG.debug("Query ready, evaluate... -> {}", q.toString());
                rs = q.evaluate();
                LOG.debug("OK");
            } catch (Exception e) {
                // TODO Auto-generated catch block
                LOG.fatal("BAD THING APPEND");
                e.printStackTrace();
            }
        }
        return rs;
    }
}