/** returns true if old triples from r were removed */
public static boolean setUniqueObject(
Model r, Resource subject, Resource predicate, RDFNode object) throws ModelException {
Model old = r.find(subject, predicate, null);
SetOperations.subtract(r, old);
Statement stmt = get1(old);
if (subject == null && stmt != null) subject = stmt.subject();
if (predicate == null && stmt != null) predicate = stmt.predicate();
r.add(r.getNodeFactory().createStatement(subject, predicate, object));
return !old.isEmpty();
}
/** Returns the first triple of the model */
public static Statement get1(Model m) throws ModelException {
if (m == null || m.isEmpty()) return null;
// if(m.size() > 1)
// throw new RuntimeException("Model contains more than one triple");
return (Statement) m.elements().nextElement();
}