Interface INotificationHandler<TNotification>

Namespace

SimpleMediator

Assembly

SimpleMediator.dll

Processes a notification published by the mediator using Railway Oriented Programming.

public interface INotificationHandler<in TNotification> where TNotification : INotification

Type Parameters

TNotification

Notification type being handled.

Examples

public sealed class AuditReservationHandler : INotificationHandler<ReservationCreatedNotification>
{
    public async Task<Either<MediatorError, Unit>> Handle(ReservationCreatedNotification notification, CancellationToken cancellationToken)
    {
        var reservation = await _repository.FindAsync(notification.ReservationId, cancellationToken);
        if (reservation is null)
            return Left(MediatorErrors.NotFound("Reservation not found for audit"));

        await _auditLog.RecordAsync(notification.ReservationId, cancellationToken);
        return Right(Unit.Default);
    }
}

Remarks

Handlers run sequentially following the container resolution order. They must be idempotent and tolerate the presence of multiple consumers.

Handlers return LanguageExt.Either<L, R> to enable explicit error handling without exceptions. Return Right(Unit.Default) for success or Left(error) if the handler cannot process the notification. The first handler that returns Left will stop the notification propagation (fail-fast).

Methods

Handle(TNotification, CancellationToken)

Executes the logic associated with the received notification.

Task<Either<MediatorError, Unit>> Handle(TNotification notification, CancellationToken cancellationToken)

Parameters

notification TNotification

Event or signal to process.

cancellationToken CancellationToken

Token to cancel the operation when needed.

Returns

Task<Either<MediatorError, Unit>>

Either a MediatorError (Left) if the handler cannot process the notification, or LanguageExt.Unit (Right) on successful processing.

Remarks

Use static LanguageExt.Prelude to access Left and Right factory methods. If this handler returns Left, subsequent handlers will not be executed (fail-fast behavior).