Dispatcher API

Ice.Object Interface

For historical reasons, the Dispatcher abstraction does not correspond to a Dispatcher interface in C#. We use instead the interface Ice.Object as the base interface for dispatchers.

Object is a interface that provides the default implementation for the pseudo Slice interface Object:

C#

namespace Ice;

[SliceTypeId("::Ice::Object")]
public interface Object
{
    public ValueTask<OutgoingResponse> dispatchAsync(IncomingRequest request)
    {
        ...  
    }
    ...
}

The implementation of dispatch on Ice.Object dispatches an incoming request to the 4 operations defined on Object: ice_id, ice_ids, ice_isA, and ice_ping. It throws OperationNotExistException for any other operation.

This implementation is immaterial: in practice, a dispatcher is any C# class that implements Ice.Objectand reimplements dispatch. This dispatcher may (but does not need to) implement the 4 operations defined on Object.

Servants

In C#, a servant is a concrete class that implements the Dispatcher abstraction by itself, without delegating to some other object. In other words, a servant is a “terminal dispatcher”. A servant should generally handle the 4 operations defined on the pseudo-Slice interface Object.

The most common type of C# servants are classes that implement skeleton classes generated by the Slice compiler. These generated skeleton classes reimplement dispatch by:

unmarshaling input parameters
calling the pure virtual member function whose name matches the operation name carried by the request (you implement this pure virtual function in the servant class)
creating a response from the return value and out parameters returned by this function

They also implement or reimplement the 4 operations defined on Object.