dannyrusnok / chain.of.responsibility.example Goto Github PK

using System.Threading.Tasks;

namespace Chain.Of.Responsibility.Example.Chain.Pattern
{
    public abstract class Handler<T>
    {
        private IHandler<T> Next { get; set; }

        public virtual **async Task** Handle(T request)
        {
            Next?.Handle(request);
           
        }

        public IHandler<T> SetNext(IHandler<T> next)
        {
            Next = next;
            return Next;
        }
    }
}


and this is UsernameRequiredValidationHandler

using System;
using System.Threading.Tasks;

namespace Chain.Of.Responsibility.Example.Chain.Pattern
{
    public class UsernameRequiredValidationHandler : Handler<User>, IHandler<User>
    {
        public override **async Task** Handle(User user)
        {
            if (string.IsNullOrWhiteSpace(user.Username))
            {
                throw new Exception("Username is required.");
            }
            base.Handle(user);
        }
    }
}

using System;
using System.ComponentModel.DataAnnotations;
using System.Threading.Tasks;

namespace Chain.Of.Responsibility.Example.Chain.Pattern
{
    public class PasswordRequiredValidationHandler : Handler<User>, IHandler<User>
    {
        public override **async Task** Handle(User user)
        {
          
            if (string.IsNullOrWhiteSpace(user.Password))
            {
                throw new Exception("Password is required.");
            }

             base.Handle(user);
        }
    }
}

and this is OnlyAdultValidationHandler

using System;
using System.Threading.Tasks;

namespace Chain.Of.Responsibility.Example.Chain.Pattern
{
    public class OnlyAdultValidationHandler : Handler<User>, IHandler<User>
    {
        public override async Task Handle(User user)
        {
            throw new Exception();
            if (user.BirthDate.Year > DateTime.Now.Year - 18)
            {
                throw new Exception("Age under 18 is not allowed.");
            }

            base.Handle(user);
        }
    }
}

public class ChainPatternRegistrationProcessor
    {
        public async Task Register(User user)
        {
            try
            {
                var handler = new UsernameRequiredValidationHandler();
                handler.SetNext(new PasswordRequiredValidationHandler())
                    .SetNext(new OnlyAdultValidationHandler());

                await handler.Handle(user);
                Console.WriteLine("");
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
        }
    }

can we catch this error in Register class?