عرض عملي: تحويل Shop إلى منافذ ومحوّلات (ports and adapters)

خطوة بخطوة

1. Start from the layered Shop: OrderService imports JpaOrderRepository and a Stripe client.
2. Create the orders domain package; move Order as a plain class without JPA annotations.
3. Define outbound ports OrderRepository and PaymentGateway in the domain; add the inbound port PlaceOrderUseCase.
4. Write adapters: a JPA adapter with a separate OrderEntity and mapper, and a payment adapter.
5. Planned mistake: put @Entity back on the domain Order "to save a mapper". Add an ArchUnit test that fails on jakarta.persistence imports in the domain; remove the annotation and keep the mapper.
6. Swap in a fake payment adapter; the domain tests still pass untouched.