*/
@Override
protected void _to(ObjectOutput out) throws IOException {
// subject term is guaranteed non-null
out.writeInt(subjectTerm);
RelationshipType rel = RelationshipType.fromString(relationship);
writeRelationship(out, rel);
writeInteger(out, objectTerm);
writeInteger(out, nestedSubject);
out.writeObject(nestedRelationship);
writeInteger(out, nestedObject);