È questo un esempio di Inversion of Control?

Question

Ho appena finito l'articolo di James Kovac su Inversion of Control and Dependency Injection e poi ho usato quello che ho imparato per creare il mio esempio IoC / DI di seguito.

Sono abbastanza soddisfatto di questo esempio poiché:

• soddisfa la testabilità aspetto di IoC in quanto istanzia i clienti passando sia un repository che un mockRepository
• anche il servizio di autorizzazione è disaccoppiato che ti consentirebbe ad es. scrivere un altro servizio di autorizzazione con regole diverse, quindi è possibile scambiarle facilmente in base ad altre condizioni

Tuttavia, guardando al progresso da qui, alcune cose sembrano strane:

• Sembra che non abbia un " container " . La mia classe cliente "sta fungendo da contenitore"? in questo senso?
• se dovessi portarlo su WPF, dove i Moduli (in termini di Prisma) rientrerebbero in questo esempio (ad es. AuthorizationService e Repository sarebbero moduli?)
• se dovessi portarlo su WPF, dove si inserirebbe MVVM ? Hanno parti di MVVM attraverso l'iniezione di dipendenza o MVVM è qualcosa di completamente separato.

Grazie per qualsiasi direzione tu possa fornire in merito.

NUOVO CODICE BASATO SUI COMMENTI:

using System;
using System.Linq;
using System.Collections.Generic;

namespace TestSimpleDependencyInjection1
{
    class Program
    {
        static void Main(string[] args)
        {
            AuthorizationService authorizationService = new AuthorizationService();

            //real example
            Repository repository = new Repository(authorizationService);
            for (int id = 1; id <= 3; id++)
            {
                Customer customer = repository.GetCustomer(id);
                customer.Display();
            }
            Console.WriteLine();

            //mock test example
            MockRepository mockRepository = new MockRepository(authorizationService);
            Customer mockCustomerAdministrator = repository.GetCustomer(1);
            Customer mockCustomerSalesperson = repository.GetCustomer(2);
            UnitTester.Assert("Administrators have access", mockCustomerAdministrator.GetAuthorizationMessage(), "Access Granted");
            UnitTester.Assert("Salespeople do not have access", mockCustomerAdministrator.GetAuthorizationMessage(), "Access Granted");

            Console.ReadLine();
        }
    }

    public static class UnitTester
    {
        public static void Assert(string title, string value, string expectedResult)
        {
            Console.WriteLine(value == expectedResult ? String.Format("{0}: test succeeded", title) : String.Format("{0}: TEST FAILED!", title));
        }
    }

    public class Customer
    {

        public int ID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public AccessGroup AccessGroup { get; set; }
        public AuthorizationService AuthorizationService { get; set; }

        public string GetAuthorizationMessage()
        {
            return this.AuthorizationService.GetAccessMessage(this);
        }

        public Customer()
        {

        }

        public void Display()
        {
            Console.WriteLine("Customer: {1}, {0} ({2}): {3}", this.FirstName, this.LastName, this.AccessGroup, this.GetAuthorizationMessage());
        }
    }

    public class AuthorizationService
    {
        public string GetAccessMessage(Customer customer)
        {
            return customer.AccessGroup == AccessGroup.Administrator ? "Access Granted" : "Access Denied";
        }
    }


    public class Repository : IRepository
    {
        private List<Customer> _customerSet = new List<Customer>();
        private AuthorizationService _authorizationService;

        public Repository(AuthorizationService authorizationService)
        {
            _authorizationService = authorizationService;
            _customerSet.Add(new Customer {AuthorizationService = _authorizationService, ID = 1, FirstName = "Jim", LastName = "Smith", AccessGroup = AccessGroup.Administrator });
            _customerSet.Add(new Customer {AuthorizationService = _authorizationService, ID = 2, FirstName = "John", LastName = "Johnson", AccessGroup = AccessGroup.Administrator });
            _customerSet.Add(new Customer {AuthorizationService = _authorizationService, ID = 3, FirstName = "Hank", LastName = "Rivers", AccessGroup = AccessGroup.Salesperson });
        }

        public Customer GetCustomer(int id)
        {
            return (from c in _customerSet
                    where c.ID == id
                    select c).SingleOrDefault();
        }
    }

    public class MockRepository : IRepository
    {
        private List<Customer> _customerSet = new List<Customer>();
        private AuthorizationService _authorizationService;

        public MockRepository(AuthorizationService authorizationService)
        {
            _authorizationService = authorizationService;
            _customerSet.Add(new Customer { AuthorizationService = _authorizationService, ID = 1, FirstName = "Test1AdministratorFirstName", LastName = "Test1AdministratorLastName", AccessGroup = AccessGroup.Administrator });
            _customerSet.Add(new Customer { AuthorizationService = _authorizationService, ID = 2, FirstName = "Test2SalespersonFirstName", LastName = "Test2SalesPersonLastName", AccessGroup = AccessGroup.Salesperson });
        }

        public Customer GetCustomer(int id)
        {
            return (from c in _customerSet
                            where c.ID == id
                            select c).SingleOrDefault();
        }

    }

    public interface IRepository
    {
        Customer GetCustomer(int id);
    }

    public enum AccessGroup
    {
        Administrator,
        Salesperson
    }
}

E SU RICHIESTA, ECCO IL CODICE ORIGINALE:

using System;
using System.Collections.Generic;

namespace TestSimpleDependencyInjection1
{
    class Program
    {
        static void Main(string[] args)
        {
            AuthorizationService authorizationService = new AuthorizationService();

            //real example
            Repository repository = new Repository();
            for (int id = 1; id <= 3; id++)
            {
                Customer customer = new Customer(id, authorizationService, repository);
                customer.Display();
            }
            Console.WriteLine();

            //mock test example
            MockRepository mockRepository = new MockRepository();
            Customer mockCustomerAdministrator = new Customer(1, authorizationService, mockRepository);
            Customer mockCustomerSalesperson = new Customer(2, authorizationService, mockRepository);
            UnitTester.Assert("Administrators have access", mockCustomerAdministrator.GetAuthorizationMessage(), "Access Granted");
            UnitTester.Assert("Salespeople do not have access", mockCustomerAdministrator.GetAuthorizationMessage(), "Access Granted");

            Console.ReadLine();
        }
    }

    public static class UnitTester
    {
        public static void Assert(string title, string value, string expectedResult)
        {
            Console.WriteLine(value == expectedResult ? String.Format("{0}: test succeeded", title) : String.Format("{0}: TEST FAILED!", title));
        }
    }

    public class Customer
    {
        private AuthorizationService authorizationService;
        private IRepository repository;

        public int ID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public AccessGroup AccessGroup { get; set; }

        public string GetAuthorizationMessage()
        {
            return authorizationService.GetAccessMessage(this);
        }

        public Customer(int id, AuthorizationService authorizationService, IRepository repository)
        {
            this.authorizationService = authorizationService;
            this.repository = repository;

            CustomerDB customerDB = repository.GetCustomerDB(id);
            this.ID = customerDB.ID;
            this.FirstName = customerDB.FirstName;
            this.LastName = customerDB.LastName;
            this.AccessGroup = customerDB.AccessGroup;
        }

        public void Display()
        {
            Console.WriteLine("Customer: {1}, {0} ({2}): {3}", this.FirstName, this.LastName, this.AccessGroup, this.GetAuthorizationMessage());
        }
    }

    public class AuthorizationService
    {
        public string GetAccessMessage(Customer customer)
        {
            return customer.AccessGroup == AccessGroup.Administrator ? "Access Granted" : "Access Denied";
        }
    }


    public class Repository : IRepository
    {
        private List<CustomerDB> _customerDBSet = new List<CustomerDB>();

        public Repository()
        {
            _customerDBSet.Add(new CustomerDB { ID = 1, FirstName = "Jim", LastName = "Smith", AccessGroup = AccessGroup.Administrator });
            _customerDBSet.Add(new CustomerDB { ID = 2, FirstName = "John", LastName = "Johnson", AccessGroup = AccessGroup.Administrator });
            _customerDBSet.Add(new CustomerDB { ID = 3, FirstName = "Hank", LastName = "Rivers", AccessGroup = AccessGroup.Salesperson });
        }

        public CustomerDB GetCustomerDB(int id)
        {
            CustomerDB customerDBchosen = null;
            //this should be done with LINQ (couldn't get it CustomerDB to implement IEnumerable correctly)
            foreach (CustomerDB customerDB in _customerDBSet)
            {
                if (customerDB.ID == id)
                {
                    customerDBchosen = customerDB;
                    break;
                }
            }
            return customerDBchosen;
        }
    }

    public class MockRepository : IRepository
    {
        public CustomerDB GetCustomerDB(int id)
        {
            switch (id)
            {
                case 1:
                    return new CustomerDB { ID = 1, FirstName = "Test1AdministratorFirstName", LastName = "Test1AdministratorLastName", AccessGroup = AccessGroup.Administrator };
                case 2:
                    return new CustomerDB { ID = 2, FirstName = "Test2SalespersonFirstName", LastName = "Test2SalesPersonLastName", AccessGroup = AccessGroup.Salesperson };
                default:
                    return null;
            }
        }
    }

    public interface IRepository
    {
        CustomerDB GetCustomerDB(int id);
    }

    public class CustomerDB
    {
        public int ID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public AccessGroup AccessGroup { get; set; }
    }

    public enum AccessGroup
    {
        Administrator,
        Salesperson
    }
}

Answer 1

Il tuo codice viola il principale responsabile in modo piuttosto serio.

http://en.wikipedia.org/wiki/Single_responsibility_principle

L'oggetto Cliente non deve caricarsi da un repository, il repository deve caricare l'oggetto Customer e restituirlo al chiamante.

Mi aspetterei qualcosa di più simile a:

Customer customer = repository.GetCustomer(3);

Answer 2

l'utilizzo delle istruzioni Switch nella maggior parte dei casi viola SRP. Fai controlla questo per modi per eliminare le istruzioni switch nel tuo codice. La sfida & amp; la bellezza di scrivere un codice liberamente accoppiato è eliminare se, se non altro & amp; istruzioni switch.