Skip to main content

NotificationHandlerDelegate

Namespace: RA.Utilities.Dispatcher.Models

The NotificationHandlerDelegate delegates are what INotificationBehavior receives as its next parameter — invoking them runs the next stage of a single handler's notification pipeline.

📦 Type Definition​

/// <summary>Represents a delegate for handling notifications.</summary>
public delegate ValueTask<Result> NotificationHandlerDelegate();

/// <summary>Context-aware variant carrying the typed pipeline context.</summary>
public delegate ValueTask<Result> NotificationHandlerContextDelegate<TContext>(PipelineContext<TContext> context)
    where TContext : class, new();

🎯 Purpose​

When Publish fans out a notification to N handlers, each handler gets its own pipeline of INotificationBehavior<TNotification> instances. Each behavior's HandleAsync receives a delegate that invokes the next behavior — or the handler itself, innermost. The delegate returns ValueTask<Result>: the handler's result on success, or Result.Failure(...) on expected failure.

  • The non-generic NotificationHandlerDelegate is the plain pipeline step.
  • NotificationHandlerContextDelegate<TContext> is the context-aware step, used by the HandleAsync<TContext> overload.

🚀 Usage​

public class AuditBehavior<TNotification> : INotificationBehavior<TNotification>
    where TNotification : INotification
{
    public async ValueTask<Result> HandleAsync(
        TNotification notification, NotificationHandlerDelegate next, CancellationToken cancellationToken)
    {
        Result result = await next(); // runs the inner pipeline (or the handler)
        _auditLog.Record(typeof(TNotification).Name, result.IsSuccess);
        return result;
    }
}

🔗 Related​