package com.github.jsonldjava.sesame;
import java.util.Set;
import org.openrdf.model.BNode;
import org.openrdf.model.Graph;
import org.openrdf.model.Literal;
import org.openrdf.model.Model;
import org.openrdf.model.Namespace;
import org.openrdf.model.Resource;
import org.openrdf.model.Statement;
import org.openrdf.model.URI;
import org.openrdf.model.Value;
import org.openrdf.model.vocabulary.RDF;
import org.openrdf.model.vocabulary.XMLSchema;
import com.github.jsonldjava.core.JsonLdError;
import com.github.jsonldjava.core.RDFDataset;
public class SesameRDFParser implements com.github.jsonldjava.core.RDFParser {
public void setPrefix(RDFDataset result, String fullUri, String prefix) {
result.setNamespace(fullUri, prefix);
}
public void handleStatement(RDFDataset result, Statement nextStatement) {
// TODO: from a basic look at the code it seems some of these could be
// null
// null values for IRIs will probably break things further down the line
// and i'm not sure yet if this should be something handled later on, or
// something that should be checked here
final String subject = getResourceValue(nextStatement.getSubject());
final String predicate = getResourceValue(nextStatement.getPredicate());
final Value object = nextStatement.getObject();
final String graphName = getResourceValue(nextStatement.getContext());
if (object instanceof Literal) {
final Literal literal = (Literal) object;
final String value = literal.getLabel();
final String language = literal.getLanguage();
String datatype = getResourceValue(literal.getDatatype());
// In RDF-1.1, Language Literals internally have the datatype
// rdf:langString
if (language != null && datatype == null) {
datatype = RDF.LANGSTRING.stringValue();
}
// In RDF-1.1, RDF-1.0 Plain Literals are now Typed Literals with
// type xsd:String
if (language == null && datatype == null) {
datatype = XMLSchema.STRING.stringValue();
}
result.addQuad(subject, predicate, value, datatype, language, graphName);
} else {
result.addQuad(subject, predicate, getResourceValue((Resource) object), graphName);
}
}
private String getResourceValue(Resource subject) {
if (subject == null) {
return null;
} else if (subject instanceof URI) {
return subject.stringValue();
} else if (subject instanceof BNode) {
return "_:" + subject.stringValue();
}
throw new IllegalStateException("Did not recognise resource type: "
+ subject.getClass().getName());
}
@Override
public RDFDataset parse(Object input) throws JsonLdError {
final RDFDataset result = new RDFDataset();
if (input instanceof Statement) {
handleStatement(result, (Statement) input);
} else if (input instanceof Graph) {
if (input instanceof Model) {
final Set<Namespace> namespaces = ((Model) input).getNamespaces();
for (final Namespace nextNs : namespaces) {
result.setNamespace(nextNs.getName(), nextNs.getPrefix());
}
}
for (final Statement nextStatement : (Graph) input) {
handleStatement(result, nextStatement);
}
}
return result;
}
}