Refactoring Domain Events so it is clear and differenciated versus Integration Events

src/Services/Ordering/Ordering.API/Application/DomainEventHandlers/OrderCreatedDomainEventHandler.cs

@@ -6,22 +6,22 @@ using Ordering.Domain.Events;
 using System;
 using System.Threading.Tasks;
 
-namespace Ordering.API.Application.EventHandlers
+namespace Ordering.API.Application.DomainEventHandlers
 {
-    public class OrderCreatedEventHandler : IAsyncNotificationHandler<OrderCreated>
+    public class OrderCreatedDomainEventHandler : IAsyncNotificationHandler<OrderCreatedDomainEvent>
     {
         private readonly ILoggerFactory _logger;
         private readonly IBuyerRepository<Buyer> _buyerRepository;
         private readonly IIdentityService _identityService;
 
-        public OrderCreatedEventHandler(ILoggerFactory logger, IBuyerRepository<Buyer> buyerRepository, IIdentityService identityService)
+        public OrderCreatedDomainEventHandler(ILoggerFactory logger, IBuyerRepository<Buyer> buyerRepository, IIdentityService identityService)
         {
             _buyerRepository = buyerRepository ?? throw new ArgumentNullException(nameof(buyerRepository));
             _identityService = identityService ?? throw new ArgumentNullException(nameof(identityService));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
         }
 
-        public async Task Handle(OrderCreated orderNotification)
+        public async Task Handle(OrderCreatedDomainEvent orderNotification)
         {
             var cardTypeId = orderNotification.CardTypeId != 0 ? orderNotification.CardTypeId : 1;
 
@@ -46,7 +46,7 @@ namespace Ordering.API.Application.EventHandlers
             await _buyerRepository.UnitOfWork
                 .SaveEntitiesAsync();
 
-            _logger.CreateLogger(nameof(OrderCreatedEventHandler)).LogTrace($"A new payment method has been successfully added for orderId: {orderNotification.Order.Id}.");
+            _logger.CreateLogger(nameof(OrderCreatedDomainEventHandler)).LogTrace($"A new payment method has been successfully added for orderId: {orderNotification.Order.Id}.");
 
         }
     }

src/Services/Ordering/Ordering.API/Application/DomainEventHandlers/PaymentMethodCheckedDomainEventHandler.cs

@@ -5,19 +5,19 @@ using Ordering.Domain.Events;
 using System;
 using System.Threading.Tasks;
 
-namespace Ordering.API.Application.EventHandlers
+namespace Ordering.API.Application.DomainEventHandlers
 {
-    public class PaymentMethodCheckedEventHandler : IAsyncNotificationHandler<PaymentMethodChecked>
+    public class PaymentMethodCheckedDomainEventHandler : IAsyncNotificationHandler<PaymentMethodCheckedDomainEvent>
     {
         private readonly IOrderRepository<Order> _orderRepository;
         private readonly ILoggerFactory _logger;
-        public PaymentMethodCheckedEventHandler(IOrderRepository<Order> orderRepository, ILoggerFactory logger)
+        public PaymentMethodCheckedDomainEventHandler(IOrderRepository<Order> orderRepository, ILoggerFactory logger)
         {
             _orderRepository = orderRepository ?? throw new ArgumentNullException(nameof(orderRepository));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
         }
 
-        public async Task Handle(PaymentMethodChecked paymentMethodNotification)
+        public async Task Handle(PaymentMethodCheckedDomainEvent paymentMethodNotification)
         {
             var orderToUpdate = await _orderRepository.GetAsync(paymentMethodNotification.OrderId);
             orderToUpdate.SetBuyerId(paymentMethodNotification.Buyer.Id);
@@ -26,7 +26,7 @@ namespace Ordering.API.Application.EventHandlers
             await _orderRepository.UnitOfWork
                 .SaveEntitiesAsync();
                                        
-            _logger.CreateLogger(nameof(PaymentMethodCheckedEventHandler))
+            _logger.CreateLogger(nameof(PaymentMethodCheckedDomainEventHandler))
                 .LogTrace($"Order with Id: {paymentMethodNotification.OrderId} has been successfully updated with a new payment method id: { paymentMethodNotification.Payment.Id }");
         }
     }

src/Services/Ordering/Ordering.API/Infrastructure/AutofacModules/MediatorModule.cs

@@ -3,7 +3,7 @@ using Autofac.Core;
 using MediatR;
 using Microsoft.eShopOnContainers.Services.Ordering.API.Application.Commands;
 using Microsoft.eShopOnContainers.Services.Ordering.API.Application.Decorators;
-using Ordering.API.Application.EventHandlers;
+using Ordering.API.Application.DomainEventHandlers;
 using Ordering.Domain.Events;
 using System.Collections.Generic;
 using System.Linq;
@@ -24,7 +24,7 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.API.Infrastructure.Autof
                     .Select(i => new KeyedService("IAsyncRequestHandler", i)));
             
             builder
-                .RegisterAssemblyTypes(typeof(OrderCreatedEventHandler).GetTypeInfo().Assembly)
+                .RegisterAssemblyTypes(typeof(OrderCreatedDomainEventHandler).GetTypeInfo().Assembly)
                 .Where(t => t.IsClosedTypeOf(typeof(IAsyncNotificationHandler<>)))
                 .AsImplementedInterfaces();           
 

src/Services/Ordering/Ordering.Domain/AggregatesModel/BuyerAggregate/Buyer.cs

@@ -33,7 +33,7 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Domain.AggregatesModel.B
 
             if (existingPayment != null)
             {
-                AddEvent(new PaymentMethodChecked(this, existingPayment, orderId));
+                AddDomainEvent(new PaymentMethodCheckedDomainEvent(this, existingPayment, orderId));
                 return existingPayment;
             }
             else
@@ -41,7 +41,7 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Domain.AggregatesModel.B
                 var payment = new PaymentMethod(cardTypeId, alias, cardNumber, securityNumber, cardHolderName, expiration);
 
                 _paymentMethods.Add(payment);
-                AddEvent(new PaymentMethodChecked(this, payment, orderId));
+                AddDomainEvent(new PaymentMethodCheckedDomainEvent(this, payment, orderId));
                 return payment;
             }
         }       

src/Services/Ordering/Ordering.Domain/AggregatesModel/OrderAggregate/Order.cs

@@ -51,7 +51,10 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Domain.AggregatesModel.O
             _orderStatusId = OrderStatus.InProcess.Id;
             _orderDate = DateTime.UtcNow;
             Address = address;
-            AddCreatedOrderEvent(cardTypeId, cardNumber,
+
+            // Add the OrderCreatedEvent to the domain events collection 
+            // to be raised/dispatched when comitting changes into the Database [ After DbContext.SaveChanges() ]
+            AddOrderCreatedDomainEvent(cardTypeId, cardNumber,
                 cardSecurityNumber, cardHolderName, cardExpiration);
         }
 
@@ -93,14 +96,14 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Domain.AggregatesModel.O
             _buyerId = id;
         }
 
-        private void AddCreatedOrderEvent(int cardTypeId, string cardNumber,
+        private void AddOrderCreatedDomainEvent(int cardTypeId, string cardNumber,
                 string cardSecurityNumber, string cardHolderName, DateTime cardExpiration)
         {
-            var @orderCreatedEvent = new OrderCreated(
+            var orderCreatedDomainEvent = new OrderCreatedDomainEvent(
                 this, cardTypeId, cardNumber, cardSecurityNumber,
                 cardHolderName, cardExpiration);
 
-            AddEvent(@orderCreatedEvent);
+            AddDomainEvent(orderCreatedDomainEvent);
         }
     }
 }

src/Services/Ordering/Ordering.Domain/Events/OrderCreatedDomainEvent.cs

@@ -9,7 +9,7 @@ namespace Ordering.Domain.Events
     /// <summary>
     /// Event used when an order is created
     /// </summary>
-    public class OrderCreated
+    public class OrderCreatedDomainEvent
         : IAsyncNotification
     {
         public int CardTypeId { get; private set; }
@@ -19,7 +19,7 @@ namespace Ordering.Domain.Events
         public DateTime CardExpiration { get; private set; }
         public Order Order { get; private set; }
 
-        public OrderCreated(Order order,
+        public OrderCreatedDomainEvent(Order order,
             int cardTypeId, string cardNumber, 
             string cardSecurityNumber, string cardHolderName, 
             DateTime cardExpiration)

src/Services/Ordering/Ordering.Domain/Events/PaymentMethodCheckedDomainEvent.cs

@@ -6,14 +6,14 @@ using System.Text;
 
 namespace Ordering.Domain.Events
 {
-    public class PaymentMethodChecked
+    public class PaymentMethodCheckedDomainEvent
         : IAsyncNotification
     {
         public Buyer Buyer { get; private set; }
         public PaymentMethod Payment { get; private set; }
         public int OrderId { get; private set; }
 
-        public PaymentMethodChecked(Buyer buyer, PaymentMethod payment, int orderId)
+        public PaymentMethodCheckedDomainEvent(Buyer buyer, PaymentMethod payment, int orderId)
         {
             Buyer = buyer;
             Payment = payment;

src/Services/Ordering/Ordering.Domain/SeedWork/Entity.cs

@@ -10,7 +10,7 @@
         int? _requestedHashCode;
         int _Id;
 
-        private List<IAsyncNotification> _events;
+        private List<IAsyncNotification> _domainEvents;
 
         public virtual  int Id 
         {
@@ -24,17 +24,17 @@
             }
         }
 
-        public List<IAsyncNotification> Events => _events;        
+        public List<IAsyncNotification> DomainEvents => _domainEvents;        
-        public void AddEvent(IAsyncNotification eventItem)
+        public void AddDomainEvent(IAsyncNotification eventItem)
         {
-            _events = _events ?? new List<IAsyncNotification>();
+            _domainEvents = _domainEvents ?? new List<IAsyncNotification>();
-            _events.Add(eventItem);
+            _domainEvents.Add(eventItem);
         }
 
-        public void RemoveEvent(IAsyncNotification eventItem)
+        public void RemoveDomainEvent(IAsyncNotification eventItem)
         {
-            if (_events is null) return;
+            if (_domainEvents is null) return;
-            _events.Remove(eventItem);
+            _domainEvents.Remove(eventItem);
         }
 
         public bool IsTransient()

src/Services/Ordering/Ordering.Infrastructure/MediatorExtension.cs

@@ -10,9 +10,9 @@ namespace Ordering.Infrastructure
     {
         public static async Task RaiseDomainEventsAsync(this IMediator mediator, OrderingContext ctx)
         {
-            var domainEntities = ctx.ChangeTracker.Entries<Entity>().Where(x => x.Entity.Events != null && x.Entity.Events.Any());
+            var domainEntities = ctx.ChangeTracker.Entries<Entity>().Where(x => x.Entity.DomainEvents != null && x.Entity.DomainEvents.Any());
-            var domainEvents = domainEntities.SelectMany(x => x.Entity.Events).ToList();
+            var domainEvents = domainEntities.SelectMany(x => x.Entity.DomainEvents).ToList();
-            domainEntities.ToList().ForEach(entity => entity.Entity.Events.Clear());
+            domainEntities.ToList().ForEach(entity => entity.Entity.DomainEvents.Clear());
 
             var tasks = domainEvents
                 .Select(async (domainEvent) => {

src/Services/Ordering/Ordering.Infrastructure/OrderingContext.cs

@@ -74,7 +74,7 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Infrastructure
 
             buyerConfiguration.HasKey(b => b.Id);
 
-            buyerConfiguration.Ignore(b => b.Events);
+            buyerConfiguration.Ignore(b => b.DomainEvents);
 
             buyerConfiguration.Property(b => b.Id)
                 .ForSqlServerUseSequenceHiLo("buyerseq", DEFAULT_SCHEMA);
@@ -102,7 +102,7 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Infrastructure
 
             paymentConfiguration.HasKey(b => b.Id);
 
-            paymentConfiguration.Ignore(b => b.Events);
+            paymentConfiguration.Ignore(b => b.DomainEvents);
 
             paymentConfiguration.Property(b => b.Id)
                 .ForSqlServerUseSequenceHiLo("paymentseq", DEFAULT_SCHEMA);
@@ -139,7 +139,7 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Infrastructure
 
             orderConfiguration.HasKey(o => o.Id);
 
-            orderConfiguration.Ignore(b => b.Events);
+            orderConfiguration.Ignore(b => b.DomainEvents);
 
             orderConfiguration.Property(o => o.Id)
                 .ForSqlServerUseSequenceHiLo("orderseq", DEFAULT_SCHEMA);
@@ -176,7 +176,7 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Infrastructure
 
             orderItemConfiguration.HasKey(o => o.Id);
 
-            orderItemConfiguration.Ignore(b => b.Events);
+            orderItemConfiguration.Ignore(b => b.DomainEvents);
 
             orderItemConfiguration.Property(o => o.Id)
                 .ForSqlServerUseSequenceHiLo("orderitemseq");
@@ -238,6 +238,8 @@ namespace Microsoft.eShopOnContainers.Services.Ordering.Infrastructure
         public async Task<int> SaveEntitiesAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
             var result = await base.SaveChangesAsync();
+
+            // Dispatch the Domain Events collection right after saving/commiting data into the database
             await _mediator.RaiseDomainEventsAsync(this);
             return result;
         }        

test/Services/UnitTest/Ordering/Domain/BuyerAggregateTest.cs

@@ -122,6 +122,6 @@ public class BuyerAggregateTest
         fakeBuyer.AddPaymentMethod(cardTypeId, alias, cardNumber, cardSecurityNumber, cardHolderName, cardExpiration, orderId);
 
         //Assert
-        Assert.Equal(fakeBuyer.Events.Count, expectedResult);
+        Assert.Equal(fakeBuyer.DomainEvents.Count, expectedResult);
     }
 }

test/Services/UnitTest/Ordering/Domain/OrderAggregateTest.cs

@@ -112,7 +112,7 @@ public class OrderAggregateTest
         var fakeOrder = new Order(new Address(street, city, state, country, zipcode), cardTypeId, cardNumber, cardSecurityNumber, cardHolderName, cardExpiration);
 
         //Assert
-        Assert.Equal(fakeOrder.Events.Count, expectedResult);
+        Assert.Equal(fakeOrder.DomainEvents.Count, expectedResult);
     }
 
     [Fact]
@@ -133,9 +133,9 @@ public class OrderAggregateTest
 
         //Act 
         var fakeOrder = new Order(new Address(street, city, state, country, zipcode), cardTypeId, cardNumber, cardSecurityNumber, cardHolderName, cardExpiration);
-        fakeOrder.AddEvent(new OrderCreated(fakeOrder,cardTypeId,cardNumber,cardSecurityNumber,cardHolderName,cardExpiration));
+        fakeOrder.AddDomainEvent(new OrderCreatedDomainEvent(fakeOrder,cardTypeId,cardNumber,cardSecurityNumber,cardHolderName,cardExpiration));
         //Assert
-        Assert.Equal(fakeOrder.Events.Count, expectedResult);
+        Assert.Equal(fakeOrder.DomainEvents.Count, expectedResult);
     }
 
     [Fact]
@@ -153,13 +153,13 @@ public class OrderAggregateTest
         var cardHolderName = "FakeName";
         var cardExpiration = DateTime.Now.AddYears(1);
         var fakeOrder = new Order(new Address(street, city, state, country, zipcode), cardTypeId, cardNumber, cardSecurityNumber, cardHolderName, cardExpiration);
-        var @fakeEvent = new OrderCreated(fakeOrder, cardTypeId, cardNumber, cardSecurityNumber, cardHolderName, cardExpiration);
+        var @fakeEvent = new OrderCreatedDomainEvent(fakeOrder, cardTypeId, cardNumber, cardSecurityNumber, cardHolderName, cardExpiration);
         var expectedResult = 1;
 
         //Act         
-        fakeOrder.AddEvent(@fakeEvent);
+        fakeOrder.AddDomainEvent(@fakeEvent);
-        fakeOrder.RemoveEvent(@fakeEvent);
+        fakeOrder.RemoveDomainEvent(@fakeEvent);
         //Assert
-        Assert.Equal(fakeOrder.Events.Count, expectedResult);
+        Assert.Equal(fakeOrder.DomainEvents.Count, expectedResult);
     }
 }