HandlerRegistrations

Namespace: RA.Utilities.Dispatcher.Generated

HandlerRegistrations is the runtime-side queue that carries the compile-time registrations of your handlers and closed pipeline behaviors. You never call it directly — the source generator's module initializers enqueue into it, and AddMediator() drains it.

📦 Type Definition

public static class HandlerRegistrations
{
    public static void Add(Action<IServiceCollection> registration);
    internal static void ApplyAll(IServiceCollection services);
}

🎯 How It Works

1. At compile time, the package's source generator emits a module initializer per assembly containing IRequestHandler<,> / IRequestHandler<> / INotificationHandler<> implementations or closed behaviors. The initializer calls HandlerRegistrations.Add(...) with a callback that registers:
   • handlers under their interfaces and as themselves (concrete type, for the generated mediator's direct injection),
   • closed behaviors under their behavior interfaces.
2. At assembly load, the module initializer runs and queues the callback.
3. At startup, AddMediator() calls ApplyAll, applying every queued registration to the IServiceCollection in one pass.

The queue is thread-safe (a lock guards a snapshot on apply).

⏳ Lifetimes

Registration	Lifetime
IRequestHandler<TRequest, TResponse> → handler	Scoped
IRequestHandler<TRequest> → handler	Scoped
INotificationHandler<TNotification> → handler	Transient
Handler as its concrete type	Same as the interface registration
Closed behavior under its interface	Transient

🔗 Related

• Auto Registration — the discovery rules, diagnostics (DSAG001–DSAG005, DSAG010), and the assembly-loading guarantee.
• MediatorRegistrations — the sibling queue for the generated Mediator.