Lesson 14: Capstone: order system architecture
Without design, a real order system collapses into one giant class where every change is scary: pricing, email, and database tangled together. In this capstone we combine the course's ideas — single responsibility, injected contracts, an async repository, events, and value objects — into one small o
A well-designed system is like a restaurant kitchen on a busy night: each station has one job, orders pass through one fixed window, and a bell rings when a dish is ready.
- Capstone: order system architecture
- One small design that visibly combines records, injected async contracts, and events from across the course.
- constructor injection
- The service receives its dependencies as contracts through the constructor — whoever assembles the system picks the implementations, not the service itself.
- domain event
- The service announces that a fact happened — 'an order was placed' — and subscribers react without the service knowing them.