Question

I have a C# project in which I use the Memento/Command pattern to implement Undo/Redo functionality. The application is a WPF application that uses StructureMap for IOC, has extensive unit tests and makes use of mocking via interfaces using RhinoMocks.

In my code I have an Operation class which represents all undoable operations, and I also have an IRepositoryWriter interface through which all writes to the database are routed.

I am wondering what is the best way to enforce the policy that only Operation and its derived classes should be able to use IRepositoryWriter.

The obvious way to achieve this would be to make IRepositoryWriter a protected, nested interface of Operation.

Advantages: only Operation and derived classes have access to IRepositoryWriter.

Disadvantages: no longer can be used with StructureMap or Unit Tested.

What are some other solutions to this? The policy doesn’t need to be strictly enforced – just enough to give a hint to someone else working on the codebase would be enough.

Answer 1

The policy doesn’t need to be strictly enforced – just enough to give a hint to someone else working on the codebase would be enough

/// <summary>
///    blah blah, what this interface is for
/// </summary>
/// <remarks>
///   This interface should only be implemented by inheritors of Operation.
/// </remarks>
public interface IRepositoryWriter{}

Just stating the obvious solution for you. 😉