static void Main(string[] args)
{
// Option 1 : Using IObservable/IObserver pattern (.NET)
// Create those interfaces if not available in framework
var cart1 = new CartService();
var dataminingObserver = new DataMiningService();
var notificationObserver = new NotificationService();
dataminingObserver.Subscribe(cart1);
cart1.AddItem(new Product {
Name = "Bottle"
});
notificationObserver.Subscribe(cart1);
cart1.AddItem(new Product {
Name = "Cookies"
});
dataminingObserver.UnSubscribe();
cart1.AddItem(new Product {
Name = "Water"
});
cart1.Buy();
// Option 2 : Using EventHandler/Delegate
var cart2 = new CartService();
var reportingObserver = new ReportingService();
var deliveryObserver = new ReportingService();
cart2.ProductAdded += reportingObserver.HandleProductAdded;
cart2.AddItem(new Product {
Name = "Wine"
});
cart2.ProductAdded += deliveryObserver.HandleProductAdded;
cart2.AddItem(new Product {
Name = "Beer"
});
cart2.ProductAdded -= deliveryObserver.HandleProductAdded;
cart2.AddItem(new Product {
Name = "Cocktail"
});
cart2.Buy();
}
public void Subscribe(CartService provider)
{
cancellation = provider.Subscribe(this);
}