public async Task <Result <Exam> > GetAsync(ExamId identifier)
{
return(Maybe <Exam> .From(await _examsDbContext.Exams.SingleOrDefaultAsync(exam => exam.Id == identifier))
.ToResult(DomainErrors.BuildAggregateNotFound(nameof(Exam), identifier.Value)));
}
public static Result <ExamId> Create(long examId, IExamExistenceValidator examExistenceValidator)
{
return(Result.Create(() => examId > 0, DomainErrors.BuildInvalidIdentifier(examId))
.AndEnsure(() => examExistenceValidator.Exist(examId), DomainErrors.BuildAggregateNotFound("Exam", examId))
.OnSuccess(() => new ExamId(examId)));
}