package com.github.jsonldjava.rdf2go;
import java.util.Map;
import org.ontoware.aifbcommons.collection.ClosableIterator;
import org.ontoware.rdf2go.model.Model;
import org.ontoware.rdf2go.model.ModelSet;
import org.ontoware.rdf2go.model.Statement;
import org.ontoware.rdf2go.model.node.DatatypeLiteral;
import org.ontoware.rdf2go.model.node.LanguageTagLiteral;
import org.ontoware.rdf2go.model.node.Literal;
import org.ontoware.rdf2go.model.node.Node;
import org.ontoware.rdf2go.model.node.Resource;
import org.ontoware.rdf2go.model.node.URI;
import com.github.jsonldjava.core.JsonLdError;
import com.github.jsonldjava.core.JsonLdError.Error;
import com.github.jsonldjava.core.RDFDataset;
import com.github.jsonldjava.core.RDFParser;
/**
* Implementation of {@link RDFParser} which serializes the contents of a
* {@link ModelSet} or {@link Model} into a JSON-LD document.
*
* @author Ismael Rivera
*/
public class RDF2GoRDFParser implements RDFParser {
private void importModel(RDFDataset result, Model model) {
// add prefixes/namespaces
final Map<String, String> nsPrefixMap = model.getNamespaces();
for (final String prefix : nsPrefixMap.keySet()) {
result.setNamespace(prefix, nsPrefixMap.get(prefix));
}
// add all statements from model
final URI context = model.getContextURI();
final ClosableIterator<Statement> statements = model.iterator();
while (statements.hasNext()) {
handleStatement(result, statements.next(), context);
}
statements.close();
}
private void importModelSet(RDFDataset result, ModelSet modelSet, URI... contexts) {
final ClosableIterator<Model> models = modelSet.getModels();
while (models.hasNext()) {
importModel(result, models.next());
}
models.close();
}
private void handleStatement(RDFDataset result, Statement statement, URI context) {
final Resource subject = statement.getSubject();
final URI predicate = statement.getPredicate();
final Node object = statement.getObject();
if (object instanceof DatatypeLiteral) {
final DatatypeLiteral literal = (DatatypeLiteral) object;
addStatement(result, context, subject, predicate, literal.getValue(),
literal.getDatatype());
} else if (object instanceof LanguageTagLiteral) {
final LanguageTagLiteral literal = (LanguageTagLiteral) object;
addStatement(result, context, subject, predicate, literal.getValue(),
literal.getLanguageTag());
} else if (object instanceof Literal) {
final Literal literal = (Literal) object;
addStatement(result, context, subject, predicate, literal.getValue());
} else {
addStatement(result, context, subject, predicate, object.asURI());
}
}
private void addStatement(RDFDataset result, URI context, Resource subject, URI predicate,
URI object) {
if (context == null) {
result.addTriple(subject.toString(), predicate.toString(), object.toString());
} else {
result.addQuad(subject.toString(), predicate.toString(), object.toString(),
context.toString());
}
}
private void addStatement(RDFDataset result, URI context, Resource subject, URI predicate,
String value) {
if (context == null) {
result.addTriple(subject.toString(), predicate.toString(), value, null, null);
} else {
result.addQuad(subject.toString(), predicate.toString(), value, null, null,
context.toString());
}
}
private void addStatement(RDFDataset result, URI context, Resource subject, URI predicate,
String value, URI datatype) {
if (context == null) {
result.addTriple(subject.toString(), predicate.toString(), value, datatype.toString(),
null);
} else {
result.addQuad(subject.toString(), predicate.toString(), value, datatype.toString(),
null, context.toString());
}
}
private void addStatement(RDFDataset result, URI context, Resource subject, URI predicate,
String value, String language) {
if (context == null) {
result.addTriple(subject.toString(), predicate.toString(), value, null, language);
} else {
result.addQuad(subject.toString(), predicate.toString(), value, null, language,
context.toString());
}
}
@Override
public RDFDataset parse(Object input) throws JsonLdError {
final RDFDataset result = new RDFDataset();
// empty dataset if no input given
if (input == null) {
return result;
}
if (input instanceof ModelSet) {
importModelSet(result, (ModelSet) input);
} else if (input instanceof Model) {
importModel(result, (Model) input);
} else {
throw new JsonLdError(Error.INVALID_INPUT,
"RDF2Go parser expects a Model or ModelSet object as input");
}
return result;
}
}