/**
* Extract RML Mapping object from a RML file written with Turtle syntax.
*
* <p>Important : The R2RML vocabulary also includes the following R2RML classes, which represent
* various R2RML mapping constructs. Using these classes is optional in a mapping graph. The
* applicable class of a resource can always be inferred from its properties. Consequently, in
* order to identify each triple type, a rule will be used to extract the applicable class of a
* resource.
*
* @param fileToRMLFile
* @return
* @throws InvalidR2RMLSyntaxException
* @throws InvalidR2RMLStructureException
* @throws R2RMLDataError
* @throws IOException
* @throws RDFParseException
* @throws RepositoryException
*/
public static RMLMapping extractRMLMapping(String fileToRMLFile)
throws InvalidR2RMLStructureException, InvalidR2RMLSyntaxException, R2RMLDataError,
RepositoryException, RDFParseException, IOException {
// Load RDF data from R2RML Mapping document
SesameDataSet r2rmlMappingGraph = new SesameDataSet();
// RML document is a a URI
if (!RMLEngine.isLocalFile(fileToRMLFile)) {
HttpURLConnection con = (HttpURLConnection) new URL(fileToRMLFile).openConnection();
con.setRequestMethod("HEAD");
if (con.getResponseCode() == HttpURLConnection.HTTP_OK)
r2rmlMappingGraph.addURI(fileToRMLFile, RDFFormat.TURTLE);
}
// RML document is a a local file
else {
// r2rmlMappingGraph.addFile(fileToRMLFile, RDFFormat.TURTLE);
r2rmlMappingGraph.loadDataFromFile(fileToRMLFile, RDFFormat.TURTLE);
}
log.debug(
"[RMLMappingFactory:extractRMLMapping] Number of R2RML triples in file "
+ fileToRMLFile
+ " : "
+ r2rmlMappingGraph.getSize());
// Transform RDF with replacement shortcuts
replaceShortcuts(r2rmlMappingGraph);
// Run few tests to help user in its RDF syntax
launchPreChecks(r2rmlMappingGraph);
// Construct R2RML Mapping object
Map<Resource, TriplesMap> triplesMapResources = extractTripleMapResources(r2rmlMappingGraph);
log.debug(
"[RMLMappingFactory:extractRMLMapping] Number of RML triples with "
+ " type "
+ R2RMLTerm.TRIPLES_MAP_CLASS
+ " in file "
+ fileToRMLFile
+ " : "
+ triplesMapResources.size());
// Fill each triplesMap object
for (Resource triplesMapResource : triplesMapResources.keySet()) // Extract each triplesMap
{
extractTriplesMap(r2rmlMappingGraph, triplesMapResource, triplesMapResources);
}
// Generate RMLMapping object
RMLMapping result = new RMLMapping(triplesMapResources.values());
return result;
}
