/**
Fetch the next future {@link Visit} (if any), along with a listing of all
associated {@link Rsvp} responses.
*/
public ResponsePage execute() throws AppException {
VisitDAO dao = new VisitDAO();
//might not be any future visit (possibly-null)
Visit nextVisit = dao.fetchNextFutureVisit();
addToRequest(NEXT_VISIT, nextVisit);
if ( nextVisit != null ) {
RsvpDAO rsvpDAO = new RsvpDAO();
addToRequest(ITEMS_FOR_LISTING, rsvpDAO.list(nextVisit.getId()));