Update entities to implement generic ICommandProcessor.

Anthony Sneed · Anthony Sneed · commit 96f3c735f3b9 · 2022-01-31T07:00:17.000-06:00
diff --git a/reference-architecture/CustomerService/Domain/CustomerAggregate/CommandHandlers/CustomerCommandHandler.cs b/reference-architecture/CustomerService/Domain/CustomerAggregate/CommandHandlers/CustomerCommandHandler.cs
@@ -1,9 +1,7 @@
-using System.Linq;
 using System.Threading.Tasks;
 using AutoMapper;
 using Common.Integration.Events;
 using CustomerService.Domain.CustomerAggregate.Commands;
-using CustomerService.Domain.CustomerAggregate.Events;
 using CustomerService.Repositories;
 using EventDriven.DDD.Abstractions.Commands;
 using EventDriven.EventBus.Abstractions;
@@ -38,11 +36,9 @@ public async Task<CommandResult<Customer>> Handle(CreateCustomer command)
         {
             // Process command
             _logger.LogInformation("Handling command: {CommandName}", nameof(CreateCustomer));
-            var events = command.Entity.Process(command);
+            var domainEvent = command.Entity.Process(command);
             
             // Apply events
-            var domainEvent = events.OfType<CustomerCreated>().SingleOrDefault();
-            if (domainEvent == null) return new CommandResult<Customer>(CommandOutcome.NotHandled);
             command.Entity.Apply(domainEvent);
             
             // Persist entity
diff --git a/reference-architecture/CustomerService/Domain/CustomerAggregate/Customer.cs b/reference-architecture/CustomerService/Domain/CustomerAggregate/Customer.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using CustomerService.Domain.CustomerAggregate.Commands;
 using CustomerService.Domain.CustomerAggregate.Events;
 using EventDriven.DDD.Abstractions.Commands;
@@ -10,19 +9,16 @@ namespace CustomerService.Domain.CustomerAggregate
 {
     public class Customer : 
         Entity,
-        ICommandProcessor<CreateCustomer>,
+        ICommandProcessor<CreateCustomer, CustomerCreated>,
         IEventApplier<CustomerCreated>
     {
         public string FirstName { get; set; }
         public string LastName { get; set; }
         public Address ShippingAddress { get; set; }
 
-        public IEnumerable<IDomainEvent> Process(CreateCustomer command)
+        public CustomerCreated Process(CreateCustomer command)
             // To process command, return one or more domain events
-            => new List<IDomainEvent>
-            {
-                new CustomerCreated(command.Entity)
-            };
+            => new(command.Entity);
 
         public void Apply(CustomerCreated domainEvent) =>
             // Set Id
diff --git a/reference-architecture/OrderService/Domain/OrderAggregate/CommandHandlers/OrderCommandHandler.cs b/reference-architecture/OrderService/Domain/OrderAggregate/CommandHandlers/OrderCommandHandler.cs
@@ -1,9 +1,7 @@
-using System.Linq;
 using System.Threading.Tasks;
 using EventDriven.DDD.Abstractions.Commands;
 using Microsoft.Extensions.Logging;
 using OrderService.Domain.OrderAggregate.Commands;
-using OrderService.Domain.OrderAggregate.Events;
 using OrderService.Repositories;
 
 namespace OrderService.Domain.OrderAggregate.CommandHandlers
@@ -30,11 +28,9 @@ public async Task<CommandResult<Order>> Handle(CreateOrder command)
         {
             // Process command
             _logger.LogInformation("Handling command: {CommandName}", nameof(CreateOrder));
-            var events = command.Entity.Process(command);
+            var domainEvent = command.Entity.Process(command);
             
             // Apply events
-            var domainEvent = events.OfType<OrderCreated>().SingleOrDefault();
-            if (domainEvent == null) return new CommandResult<Order>(CommandOutcome.NotHandled);
             command.Entity.Apply(domainEvent);
             
             // Persist entity
@@ -74,11 +70,9 @@ public async Task<CommandResult<Order>> Handle(ShipOrder command)
             _logger.LogInformation("Handling command: {CommandName}", nameof(ShipOrder));
             var entity = await _repository.GetOrder(command.EntityId);
             if (entity == null) return new CommandResult<Order>(CommandOutcome.NotFound);
-            var events = entity.Process(command);
+            var domainEvent = entity.Process(command);
             
             // Apply events
-            var domainEvent = events.OfType<OrderShipped>().SingleOrDefault();
-            if (domainEvent == null) return new CommandResult<Order>(CommandOutcome.NotHandled);
             entity.Apply(domainEvent);
             
             try
@@ -100,11 +94,9 @@ public async Task<CommandResult<Order>> Handle(CancelOrder command)
             _logger.LogInformation("Handling command: {CommandName}", nameof(CancelOrder));
             var entity = await _repository.GetOrder(command.EntityId);
             if (entity == null) return new CommandResult<Order>(CommandOutcome.NotFound);
-            var events = entity.Process(command);
+            var domainEvent = entity.Process(command);
             
             // Apply events
-            var domainEvent = events.OfType<OrderCancelled>().SingleOrDefault();
-            if (domainEvent == null) return new CommandResult<Order>(CommandOutcome.NotHandled);
             entity.Apply(domainEvent);
             
             try
diff --git a/reference-architecture/OrderService/Domain/OrderAggregate/Order.cs b/reference-architecture/OrderService/Domain/OrderAggregate/Order.cs
@@ -10,11 +10,11 @@ namespace OrderService.Domain.OrderAggregate
 {
     public class Order : 
         Entity,
-        ICommandProcessor<CreateOrder>,
+        ICommandProcessor<CreateOrder, OrderCreated>,
         IEventApplier<OrderCreated>,
-        ICommandProcessor<ShipOrder>,
+        ICommandProcessor<ShipOrder, OrderShipped>,
         IEventApplier<OrderShipped>,
-        ICommandProcessor<CancelOrder>,
+        ICommandProcessor<CancelOrder, OrderCancelled>,
         IEventApplier<OrderCancelled>
     {
         public Guid CustomerId { get; set; }
@@ -23,23 +23,17 @@ public class Order :
         public Address ShippingAddress { get; set; }
         public OrderState OrderState { get; set; }
 
-        public IEnumerable<IDomainEvent> Process(CreateOrder command)
+        public OrderCreated Process(CreateOrder command)
             // To process command, return one or more domain events
-            => new List<IDomainEvent>
-            {
-                new OrderCreated(command.Entity)
-            };
+            => new(command.Entity);
 
         public void Apply(OrderCreated domainEvent) =>
             // Set Id
             Id = domainEvent.EntityId != default(Guid) ? domainEvent.EntityId : Guid.NewGuid();
 
-        public IEnumerable<IDomainEvent> Process(ShipOrder command)
+        public OrderShipped Process(ShipOrder command)
             // To process command, return one or more domain events
-            => new List<IDomainEvent>
-            {
-                new OrderShipped(command.EntityId, command.ETag)
-            };
+            => new OrderShipped(command.EntityId, command.ETag);
 
         public void Apply(OrderShipped domainEvent)
         {
@@ -48,12 +42,9 @@ public void Apply(OrderShipped domainEvent)
             ETag = domainEvent.ETag;
         }
 
-        public IEnumerable<IDomainEvent> Process(CancelOrder command)
+        public OrderCancelled Process(CancelOrder command)
             // To process command, return one or more domain events
-            => new List<IDomainEvent>
-            {
-                new OrderCancelled(command.EntityId, command.ETag)
-            };
+            => new(command.EntityId, command.ETag);
 
         public void Apply(OrderCancelled domainEvent)
         {
diff --git a/test/EventDriven.CQRS.Tests/CustomerCommandControllerTests.cs b/test/EventDriven.CQRS.Tests/CustomerCommandControllerTests.cs
@@ -6,6 +6,7 @@
 using CustomerService.DTO.Write;
 using CustomerService.Mapping;
 using EventDriven.CQRS.Tests.Fakes;
+using EventDriven.EventBus.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging.Abstractions;
 using Xunit;
@@ -27,7 +28,7 @@ public async Task Create_Adds_Customer()
         {
             // Arrange
             var handler = new CustomerCommandHandler(
-                new FakeCustomerRepository(), new FakeEventBus(),
+                new FakeCustomerRepository(), new FakeEventBus(new EventBusOptions()),
                 _mapper, new NullLogger<CustomerCommandHandler>());
             var controller = new CustomerCommandController(handler, _mapper);
             
@@ -37,29 +38,29 @@ public async Task Create_Adds_Customer()
             // Assert
             var createdResult = Assert.IsType<CreatedResult>(actionResult);
             var value = (Customer)createdResult.Value;
-            Assert.Equal(Customers.Customer1.Id, value.Id);
-            Assert.NotEqual(default(Guid).ToString(), value.ETag);
+            Assert.Equal(Customers.Customer1.Id, value?.Id);
+            Assert.NotEqual(default(Guid).ToString(), value?.ETag);
         }
         
         [Fact]
         public async Task Update_Updates_Customer()
         {
             // Arrange
             var handler = new CustomerCommandHandler(
-                new FakeCustomerRepository(), new FakeEventBus(), 
+                new FakeCustomerRepository(), new FakeEventBus(new EventBusOptions()), 
                 _mapper, new NullLogger<CustomerCommandHandler>());
             var controller = new CustomerCommandController(handler, _mapper);
             var customer = (await controller.Create(Customers.Customer1) as CreatedResult)?.Value as Customer;
-            customer.ShippingAddress.City = "Los Angeles";
+            customer!.ShippingAddress.City = "Los Angeles";
             
             // Act
             var actionResult = await controller.Update(customer);
             
             // Assert
             var objectResult = Assert.IsType<OkObjectResult>(actionResult);
             var value = (Customer)objectResult.Value;
-            Assert.Equal(customer.Id, value.Id);
-            Assert.NotEqual(customer.ETag, value.ETag);
+            Assert.Equal(customer.Id, value?.Id);
+            Assert.NotEqual(customer.ETag, value?.ETag);
         }
 
         [Fact]
@@ -68,13 +69,13 @@ public async Task Remove_Removes_Customer()
             // Arrange
             var repository = new FakeCustomerRepository();
             var handler = new CustomerCommandHandler(
-                repository, new FakeEventBus(),
+                repository, new FakeEventBus(new EventBusOptions()),
                 _mapper, new NullLogger<CustomerCommandHandler>());
             var controller = new CustomerCommandController(handler, _mapper);
             var customer = (await controller.Create(Customers.Customer1) as CreatedResult)?.Value as Customer;
             
             // Act
-            var actionResult = await controller.Remove(customer.Id);
+            var actionResult = await controller.Remove(customer!.Id);
             
             // Assert
             Assert.IsType<NoContentResult>(actionResult);
diff --git a/test/EventDriven.CQRS.Tests/CustomerQueryControllerTests.cs b/test/EventDriven.CQRS.Tests/CustomerQueryControllerTests.cs
@@ -6,6 +6,7 @@
 using CustomerService.DTO.Read;
 using CustomerService.Mapping;
 using EventDriven.CQRS.Tests.Fakes;
+using EventDriven.EventBus.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging.Abstractions;
 using Xunit;
@@ -27,7 +28,7 @@ public async Task Get_Retrieves_Customers()
         {
             // Arrange
             var repository = new FakeCustomerRepository();
-            var handler = new CustomerCommandHandler(repository, new FakeEventBus(),
+            var handler = new CustomerCommandHandler(repository, new FakeEventBus(new EventBusOptions()),
                 _mapper, new NullLogger<CustomerCommandHandler>());
             var commandController = new CustomerCommandController(handler, _mapper);
             await commandController.Create(Customers.Customer1);
@@ -52,7 +53,7 @@ public async Task Get_Retrieves_Customer_By_Id()
         {
             // Arrange
             var repository = new FakeCustomerRepository();
-            var handler = new CustomerCommandHandler(repository, new FakeEventBus(),
+            var handler = new CustomerCommandHandler(repository, new FakeEventBus(new EventBusOptions()),
                 _mapper, new NullLogger<CustomerCommandHandler>());
             var commandController = new CustomerCommandController(handler, _mapper);
             await commandController.Create(Customers.Customer1);
diff --git a/test/EventDriven.CQRS.Tests/Fakes/FakeEventBus.cs b/test/EventDriven.CQRS.Tests/Fakes/FakeEventBus.cs
@@ -1,9 +1,14 @@
 using System.Threading.Tasks;
+using EventDriven.EventBus.Abstractions;
 
 namespace EventDriven.CQRS.Tests.Fakes
 {
     public class FakeEventBus : EventBus.Abstractions.EventBus
     {
+        public FakeEventBus(EventBusOptions eventBusOptions) : base(eventBusOptions)
+        {
+        }
+
         public override Task PublishAsync<TIntegrationEvent>(
             TIntegrationEvent @event,
             string topic = null,

Original file line number	Diff line number	Diff line change
`@@ -1,9 +1,14 @@`
`1`	`1`	`using System.Threading.Tasks;`
	`2`	`+using EventDriven.EventBus.Abstractions;`
`2`	`3`
`3`	`4`	`namespace EventDriven.CQRS.Tests.Fakes`
`4`	`5`	`{`
`5`	`6`	`public class FakeEventBus : EventBus.Abstractions.EventBus`
`6`	`7`	`{`
	`8`	`+ public FakeEventBus(EventBusOptions eventBusOptions) : base(eventBusOptions)`
	`9`	`+ {`
	`10`	`+ }`
	`11`	`+`
`7`	`12`	`public override Task PublishAsync<TIntegrationEvent>(`
`8`	`13`	`TIntegrationEvent @event,`
`9`	`14`	`string topic = null,`