public static async Task <Author> Create(User user, AuthorProfile authorProfile, IAuthorValidator authorValidator)
{
if (user == null)
{
throw new ArgumentNullException(nameof(user));
}
if (authorProfile == null)
{
throw new ArgumentNullException(nameof(authorProfile));
}
if (authorValidator == null)
{
throw new ArgumentNullException(nameof(authorValidator));
}
if (await authorValidator.Exists(user))
{
throw new InvalidOperationException("Only one author can be created per user.");
}
return(new Author(user, authorProfile));
}
private Author(User user, AuthorProfile authorProfile)
{
User = user;
AuthorProfile = authorProfile;
}