Lightweight NullObject/SpecialCase implementation

Nulls are awkward things in object-oriented programs because they defeat polymorphism, Martin Fowler

add more motivations

Suppose you have an interface defined like this

public interface IDataService
{
    bool IsConnected { get; }
    Task SendDataAsync();
    Task<int> PingAsync();
    //... methods
}

You may need to create a disconnected implementation used when the client is disconnected, and when the server is unresponsive.

 var disconnected = Null.Of<IDataService>()
                        .For(x => x.IsConnected).Returns(false)
                        .Create();
// disconnected.IsConnected == false

• Less code to write for Null Objects
• Easier to maintain (when the parent interface is altered)
• Less null-checks (if myobject!=null)
• No dynamic type-checking (the L of SOLID aka Liskov substitution principle)

TODO

• a new mocking framework
• a new library to build proxy classes
• somehting that will avoid NullReferenceException
• ...

But it has some advantages, and may help you sometimes