/**
* Checks if the specified item is no empty sequence.
*
* @param it item to be checked
* @param type expected type
* @return specified item
* @throws QueryException query exception
*/
protected Item checkNoEmpty(final Item it, final Type type) throws QueryException {
if (it != null) return it;
throw EMPTYFOUND_X.get(info, type);
}
/**
* Checks if the specified expression yields a string. Returns a value as token or throws an
* exception.
*
* @param ex expression to be evaluated
* @param qc query context
* @return token
* @throws QueryException query exception
*/
protected final byte[] toToken(final Expr ex, final QueryContext qc) throws QueryException {
final Item it = ex.atomItem(qc, info);
if (it == null) throw EMPTYFOUND_X.get(info, AtomType.STR);
return toToken(it);
}