public void AddBook(Book book) { foreach (var item in _books) { if (item.Equals(book)) { throw new ArgumentException("Already exists"); } } _bookStorage.Add(book); }
public void AddBook(Book book) { _logger.Debug($"Try AddBook {book}"); foreach (var item in _books) { if (item.Equals(book)) { _logger.Error($"Book ISBN : {book.ISBN} Already exists"); throw new ArgumentException("Already exists"); } } _bookStorage.Add(book); _logger.Info($"Book ISBN : {book.ISBN} added"); }