@Override
public MGraph createMGraph(UriRef name) throws
UnsupportedOperationException, EntityAlreadyExistsException {
initialize();
if (uriRef2MGraphMap.containsKey(name)) {
throw new EntityAlreadyExistsException(name);
}
FileMGraph mGraph = new FileMGraph(name, parser, serializer);
uriRef2MGraphMap.put(name, mGraph);
writeDataFile();
return mGraph;