20230909.records.cs

using System;
using System.Text.RegularExpressions;
 
record ProductId
{
    public string URN { get; }
 
    private static readonly string URNPattern = @"^urn:ISBN:\d{1,5}-\d{1,7}-\d{1,7}-\d{1}$";
 
    public ProductId(string urn)
    {
        if (!IsValidURN(urn))
        {
            throw new ArgumentException("Invalid URN: ISBN format is not valid.", nameof(urn));
        }
 
        URN = urn;
    }
 
    private static bool IsValidURN(string urn)
    {
        return Regex.IsMatch(urn, URNPattern);
    }
}
 
class Program
{
    static void Main()
    {
        try
        {
            ProductId book = new ProductId("urn:ISBN:12345-6789101-2345678-9");
            Console.WriteLine($"URN: {book.URN}");
        }
        catch (ArgumentException ex)
        {
            Console.WriteLine(ex.Message);
        }
    }
}