Update repository pattern examples

Author: nemanjarogic

src/AdditionalPatterns/Repository/OrderManagement/Controllers/OrderController.cs

@@ -16,8 +16,8 @@ public OrderController(IOrderRepository orderRepository, IUnitOfWork unitOfWork)
 
     public Order Create(int id, string description, string deliveryAddress, decimal price)
     {
-        // ID is usually auto-genereated by database.
-        var newOrder = new Order()
+        // ID is usually auto-generated by database.
+        var newOrder = new Order
         {
             Id = id,
             Description = description,
@@ -34,6 +34,6 @@ public Order Create(int id, string description, string deliveryAddress, decimal
     public IEnumerable<Order> GetAll() =>
         _orderRepository.GetAll();
 
-    public Order GetTheMostExpensive() =>
+    public Order? GetTheMostExpensive() =>
         _orderRepository.GetTheMostExpensive();
 }

src/AdditionalPatterns/Repository/OrderManagement/Domain/Customer.cs

@@ -2,7 +2,6 @@
 
 public class Customer : Entity
 {
-    public string FirstName { get; set; }
-
-    public string LastName { get; set; }
-}
+    public string FirstName { get; set; } = string.Empty;
+    public string LastName { get; set; } = string.Empty;
+}

src/AdditionalPatterns/Repository/OrderManagement/Domain/Entity.cs

@@ -3,4 +3,4 @@
 public abstract class Entity
 {
     public int Id { get; set; }
-}
+}

src/AdditionalPatterns/Repository/OrderManagement/Domain/Order.cs

@@ -2,9 +2,7 @@
 
 public class Order : Entity
 {
-    public string Description { get; set; }
-
-    public string DeliveryAddress { get; set; }
-
+    public string Description { get; set; } = string.Empty;
+    public string DeliveryAddress { get; set; } = string.Empty;
     public decimal Price { get; set; }
-}
+}

src/AdditionalPatterns/Repository/OrderManagement/Infrastructure/Repositories/Contracts/ICustomerRepository.cs

@@ -4,4 +4,4 @@ namespace OrderManagement.Infrastructure.Repositories.Contracts;
 
 public interface ICustomerRepository : IRepository<Customer>
 {
-}
+}

src/AdditionalPatterns/Repository/OrderManagement/Infrastructure/Repositories/Contracts/IOrderRepository.cs

@@ -4,5 +4,5 @@ namespace OrderManagement.Infrastructure.Repositories.Contracts;
 
 public interface IOrderRepository : IRepository<Order>
 {
-    Order GetTheMostExpensive();
-}
+    Order? GetTheMostExpensive();
+}

src/AdditionalPatterns/Repository/OrderManagement/Infrastructure/Repositories/Contracts/IRepository.cs

@@ -1,18 +1,14 @@
-using System.Linq.Expressions;
-using OrderManagement.Domain;
+using OrderManagement.Domain;
+using System.Linq.Expressions;
 
 namespace OrderManagement.Infrastructure.Repositories.Contracts;
 
 public interface IRepository<T>
     where T : Entity
 {
     T Add(T entity);
-
     IEnumerable<T> GetAll();
-
     IEnumerable<T> Get(Expression<Func<T, bool>> predicate);
-
     T GetById(int id);
-
     void Delete(T entity);
-}
+}

src/AdditionalPatterns/Repository/OrderManagement/Infrastructure/Repositories/Contracts/IUnitOfWork.cs

@@ -3,4 +3,4 @@
 public interface IUnitOfWork
 {
     void Commit();
-}
+}

src/AdditionalPatterns/Repository/OrderManagement/Infrastructure/Repositories/OrderRepository.cs

@@ -10,8 +10,8 @@ public OrderRepository(OrderManagementContext context)
     {
     }
 
-    public Order GetTheMostExpensive() =>
+    public Order? GetTheMostExpensive() =>
         _context.Orders
             .OrderByDescending(order => order.Price)
             .FirstOrDefault();
-}
+}

src/AdditionalPatterns/Repository/OrderManagement/Infrastructure/Repositories/Repository.cs

@@ -24,9 +24,7 @@ protected Repository(OrderManagementContext context)
     }
 
     public virtual T Add(T entity) =>
-        _context
-            .Add(entity)
-            .Entity;
+        _context.Add(entity).Entity;
 
     public virtual IEnumerable<T> GetAll() =>
         _context.Set<T>().ToList();
@@ -37,8 +35,11 @@ public virtual IEnumerable<T> Get(Expression<Func<T, bool>> predicate) =>
             .Where(predicate)
             .ToList();
 
-    public virtual T GetById(int id) =>
-        _context.Find<T>(id);
+    public virtual T GetById(int id)
+    {
+        var entity = _context.Find<T>(id);
+        return entity ?? throw new ArgumentException($"Entity with {id} doesn't exists");
+    }
 
     public virtual void Delete(T entity) =>
         _context.Remove(entity);