public void addBook(Book book, ReplySystem replySystem) {
    if (!replySystem.equals(null)) {
      if (book.isInStore() == false) {
        if (books.contains(book) == false) {
          books.add(book);
        }
      } else {
        books.add(book);
      }
      for (Reply reply : replySystem.getReplies()) {

        boolean condition =
            (reply.getBook().getAuthor().equals(book.getAuthor()))
                && ((reply.getBook().getName().equals(book.getName())))
                && ((reply.getBook().getPrice() == book.getPrice()))
                && ((reply.getBook().getDateOfPublication().get(Calendar.YEAR))
                    == (book.getDateOfPublication().get(Calendar.YEAR)))
                && ((reply.getBook().getDateOfPublication().get(Calendar.MONTH))
                    == (book.getDateOfPublication().get(Calendar.MONTH)))
                && ((reply.getBook().getDateOfPublication().get(Calendar.DATE))
                    == (book.getDateOfPublication().get(Calendar.DATE)))
                && (book.isInStore());
        if (condition) {

          reply.setExecuted(true);
          ;
        }
      }
    }
  }