public ICommandResult <ShoppingCart, IDomainEvent> Execute(AddItemToShoppingCart command)
{
var context = CommandExecutionContext.Create(this, ApplyEventRouter);
var isNew = Id == null;
if (isNew)
{
var shoppingCartCreated = new ShoppingCartCreated(command.Id);
context = context.ApplyEvent(shoppingCartCreated);
}
var itemAddedToShoppingCart = new ItemAddedToShoppingCart(command.Id, command.Item);
context = context.ApplyEvent(itemAddedToShoppingCart);
return(context.Result);
}
public ShoppingCartCommandResult Handle(AddItemToShoppingCart command)
{
var result = new ShoppingCartCommandResult(this).WithEventRouter(EventRouter);
var isNew = Id == null;
if (isNew)
{
var shoppingCartCreated = new ShoppingCartCreated(command.Id);
result = result.ApplyEvent(shoppingCartCreated);
}
var itemAddedToShoppingCart = new ItemAddedToShoppingCart(command.Id, command.Item);
result = result.ApplyEvent(itemAddedToShoppingCart);
return(result);
}
public void RoundTripTest()
{
var shoppingCartId = Guid.NewGuid(); // This could come from a sequence, or could be the customer's ID.
// Execute the first command.
var initialState = new ShoppingCart();
var command1 = new AddItemToShoppingCart(shoppingCartId, "First Item");
var result1 = initialState.Handle(command1);
// Check the updated aggregate root state.
Assert.That(result1.AggregateRoot.Id, Is.EqualTo(shoppingCartId));
Assert.That(result1.AggregateRoot.Items, Has.Count.EqualTo(1));
Assert.That(result1.AggregateRoot.Items[0], Is.EqualTo("First Item"));
// We expect that two events were be applied.
Assert.That(result1.AppliedEvents, Has.Count.EqualTo(2));
Assert.That(result1.AppliedEvents[0], Is.TypeOf <ShoppingCartCreated>());
Assert.That(result1.AppliedEvents[1], Is.TypeOf <ItemAddedToShoppingCart>());
// Execute the second command to the result of the first command.
var command2 = new AddItemToShoppingCart(shoppingCartId, "Second Item");
var result2 = result1.AggregateRoot.Handle(command2);
// Check the updated aggregate root state.
Assert.That(result2.AggregateRoot.Id, Is.EqualTo(shoppingCartId));
Assert.That(result2.AggregateRoot.Items, Has.Count.EqualTo(2));
Assert.That(result2.AggregateRoot.Items[0], Is.EqualTo("First Item"));
Assert.That(result2.AggregateRoot.Items[1], Is.EqualTo("Second Item"));
// We expect that one event was applied.
Assert.That(result2.AppliedEvents, Has.Count.EqualTo(1));
Assert.That(result2.AppliedEvents[0], Is.TypeOf <ItemAddedToShoppingCart>());
// The aggregate event log is the sum total of all events from both commands.
// Simulate loading from the event log.
var eventLog = result1.AppliedEvents.Concat(result2.AppliedEvents);
var loadedAggregate = ShoppingCart.EventRouter.Apply(new ShoppingCart(), eventLog);
// Check the loaded aggregate root state.
Assert.That(loadedAggregate.Id, Is.EqualTo(shoppingCartId));
Assert.That(loadedAggregate.Items, Has.Count.EqualTo(2));
Assert.That(loadedAggregate.Items[0], Is.EqualTo("First Item"));
Assert.That(loadedAggregate.Items[1], Is.EqualTo("Second Item"));
}
public async Task PersistedRoundTripTest()
{
var shoppingCartId = Guid.NewGuid(); // This could come from a sequence, or could be the customer's ID.
// Execute the first command.
var initialState = new ShoppingCart();
var command1 = new AddItemToShoppingCart(shoppingCartId, "First Item");
var result1 = initialState.Execute(command1);
// Execute the second command to the result of the first command.
var command2 = new AddItemToShoppingCart(shoppingCartId, "Second Item");
var result2 = result1.NewState.Execute(command2);
Assert.That(result2.NewState.Id.HasValue, "Expected ShoppingCart ID to be set");
var eventsToPersist = result1.AppliedEvents.Concat(result2.AppliedEvents).ToList();
var serializer = CreateJsonSerializer(initialState.EventNameMap);
var repository = new EventStoreEventsRepository(EventStoreConnection, serializer);
var streamName = $"shoppingCart-{result2.NewState.Id.Value}";
var nextEventVersion = await repository.SaveEventsAsync(streamName, ExpectedVersion.NoStream, eventsToPersist);
var expectedNextEventVersion = eventsToPersist.Count - 1;
Assert.That(nextEventVersion, Is.EqualTo(expectedNextEventVersion));
var eventsFromPersistence = (await repository.LoadEventsAsync <IDomainEvent>(streamName));
var loadedAggregate = ShoppingCart.FromEvents(eventsFromPersistence);
// Check the loaded aggregate root state.
Assert.That(loadedAggregate.Id, Is.EqualTo(shoppingCartId));
Assert.That(loadedAggregate.Items, Has.Count.EqualTo(2));
Assert.That(loadedAggregate.Items[0], Is.EqualTo("First Item"));
Assert.That(loadedAggregate.Items[1], Is.EqualTo("Second Item"));
}
