Blocking

Marks a function as blocking, indicating it should not be executed asynchronously.

Functions annotated with @Blocking will be executed synchronously, blocking the calling thread until completion. This is useful for operations that:

• Require immediate results

• Have external dependencies that don't support async execution

• Need to maintain thread-local context

• Must complete within the current transaction boundary

Use this annotation sparingly, as blocking operations can reduce system throughput and responsiveness. Prefer asynchronous processing when possible.

Example usage:

@AggregateRoot
class OrderAggregate {

    @OnCommand
    @Blocking
    fun processPayment(command: ProcessPaymentCommand): PaymentProcessed {
        // Synchronous payment processing that blocks until complete
        val result = paymentGateway.charge(command.amount)
        return PaymentProcessed(command.orderId, result.transactionId)
    }
}

See also