What is the proper way to throw an exception if a database query returns empty? I'm trying to use the .orElseThrow()
method but it won't compile :
Meeting meeting = meetingRepository.findByMeetingId(meetingId).orElseThrow(new MeetingDoesNotExistException(meetingId));
The compiler is saying :
"he method orElseThrow(Supplier) in the type Optional is not applicable for the arguments (MeetingRestController.MeetingDoesNotExistException)
Is it possible to do this with lambda expressions?
CrudRepository :
import java.util.Optional;
import org.springframework.data.repository.CrudRepository;
public interface MeetingRepository extends CrudRepository<Meeting, Long>{
Optional<Meeting> findByMeetingId(Long id);
}
Exception :
@ResponseStatus(HttpStatus.CONFLICT) // 409
class MeetingDoesNotExistException extends RuntimeException{
public MeetingDoesNotExistException(long meetingId){
super("Meeting " + meetingId + " does not exist.");
}
}
Try passing a lambda expression of type Supplier<MeetingDoesNotExistException>
:
Meeting meeting =
meetingRepository.findByMeetingId(meetingId)
.orElseThrow(() -> new MeetingDoesNotExistException(meetingId));