//Immutable class pattern - Order checks its invariant data at construction, state changes must
//happen through methods not just property setters to ensure that the Order object is always
//in a valid state. Factory methods used because they have more flexibility than constructors
//with exception raising, virtual calls, etc
public static Order CreateNew(Customer customer, string address1, string address2,
string country, string phone, string stateAbbreviation, string zipCode, decimal taxRate)
{
Guard.ForNull(customer, "customer");
Guard.ForNullOrEmpty(address1, "address1");
Guard.ForNullOrEmpty(country, "country");
Guard.ForNullOrEmpty(phone, "phone");
Guard.ForNullOrEmpty(stateAbbreviation, "stateAbbreviation");
Guard.ForNullOrEmpty(zipCode, "zipCode");
Guard.ForNullOrEmpty(stateAbbreviation, "stateAbbreviation");
var foundState = States.GetByAbbreviation(stateAbbreviation);
Guard.ForNull(foundState, "stateAbbreviation", "Invalid state abbreviation");
Order order = CreateOrder(customer, taxRate);
order.Id = Guid.NewGuid();
order.State = SaveState.UnSaved;
order.OrderStatus = OrderStatus.Created;
//Double Dispatch pattern to create BillingAddress - Billing only has reference to an order ID
//imposing a traversal direction that is not bi-directional (not needed for this object)
//BillingAddress has its own Guard/invariant checks
order.BillingAddress = BillingAddress.Create(order, address1, address2, country, phone,
stateAbbreviation, zipCode);
//domain events added for any event sourcing needs - are published to consumers after save transaction completes
order.AddEvent(new OrderCreatedEvent(order));
return(order);
}
public static Order CreateExisting(Guid id, Customer customer, BillingAddress billing,
decimal taxRate, OrderStatus status)
{
Guard.ForNullOrEmpty(id, "id");
Guard.ForNull(billing, "billing");
Order order = CreateOrder(customer, taxRate);
order.Id = id;
order.State = SaveState.Saved;
order.OrderStatus = status;
order.BillingAddress = billing;
order.AddEvent(new OrderHydratedEvent(order));
return(order);
}
public static BillingAddress Create(Order order, string dtoAddress1, string dtoAddress2, string dtoCountry
, string dtoPhone, string dtoStateAbbreviation, string dtoZipCode)
{
//add guards
BillingAddress ba = new BillingAddress();
ba.Id = Guid.NewGuid();
ba.State = SaveState.UnSaved;
ba.Address1 = dtoAddress1;
ba.Address2 = dtoAddress2;
ba.Country = dtoCountry;
ba.Phone = dtoPhone;
ba.StateAbbreviation = dtoStateAbbreviation;
ba.ZipCode = dtoZipCode;
ba.OrderId = order.Id;
ba.AddEvent(new BillingAddressCreatedEvent(ba));
return(ba);
}
public BillingAddressCreatedEvent(BillingAddress billingAddress)
{
BillingAddress = billingAddress;
DateTimeEventOccurred = DateTime.Now;
}