eu.morfeoproject.fast.catalogue.ontologies.OntologyFetcher.java Source code

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Here is the source code for eu.morfeoproject.fast.catalogue.ontologies.OntologyFetcher.java

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/**
 * Copyright (c) 2008-2011, FAST Consortium
 * 
 * This file is part of FAST Platform.
 * 
 * FAST Platform is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * FAST Platform 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 Affero General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with FAST Platform. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Info about members and contributors of the FAST Consortium
 * is available at http://fast.morfeo-project.eu
 *
 **/
package eu.morfeoproject.fast.catalogue.ontologies;

import java.io.InputStream;
import java.net.URL;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.HttpResponse;
import org.ontoware.aifbcommons.collection.ClosableIterator;
import org.ontoware.rdf2go.RDF2Go;
import org.ontoware.rdf2go.model.Model;
import org.ontoware.rdf2go.model.Statement;
import org.ontoware.rdf2go.model.Syntax;
import org.ontoware.rdf2go.model.node.URI;
import org.ontoware.rdf2go.model.node.Variable;
import org.ontoware.rdf2go.vocabulary.OWL;
import org.ontoware.rdf2go.vocabulary.RDF;

import eu.morfeoproject.fast.catalogue.ontologies.DefaultOntologies.Ontology;
import eu.morfeoproject.fast.catalogue.ontologies.DefaultOntologies.PublicOntology;
import eu.morfeoproject.fast.catalogue.util.URLInputSource;

public class OntologyFetcher {

    private static final Log log = LogFactory.getLog(OntologyFetcher.class);

    private static final Syntax[] syntaxList = { Syntax.Ntriples, Syntax.RdfXml, Syntax.Turtle };

    public static Ontology fetch(URL url) {
        if (log.isInfoEnabled())
            log.info("fetching " + url + "...");
        for (Syntax syntax : syntaxList) {
            try {
                URLInputSource source = new URLInputSource(url, syntax.getMimeType());
                HttpResponse response = source.getHttpResponse();
                String contentType = response.getFirstHeader("Content-Type").getValue();
                if (contentType.startsWith(syntax.getMimeType())) {
                    InputStream in = response.getEntity().getContent();
                    if (in != null) {
                        URI oUri = getOntologyUri(in, syntax);
                        if (oUri != null) {
                            return new PublicOntology(oUri, url.toString(), syntax, false);
                        }
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
                log.error("Error while fetching " + url + "[Accept: " + syntax.getMimeType() + "]");
            }
        }
        return null;
    }

    private static URI getOntologyUri(InputStream in, Syntax syntax) {
        try {
            Model model = RDF2Go.getModelFactory().createModel();
            model.open();
            model.readFrom(in, syntax);
            ClosableIterator<Statement> cIt = model.findStatements(Variable.ANY, RDF.type, OWL.Ontology);
            URI oUri = cIt.hasNext() ? cIt.next().getSubject().asURI() : null;
            cIt.close();
            model.close();
            return oUri;
        } catch (Exception e) {
            log.error(e.getLocalizedMessage(), e);
        }
        return null;
    }
}