4. Application Layer

Defines the context's public API (Application Services), Commands, and Flows.

Commands, Events, and DTOs

BoundedContext Checkout {
  Aggregate OrderAgg {
    CommandEvent PlaceOrderCommand { - OrderDTO details }
    DataTransferObject OrderDTO { String productId int quantity }
  }
}

Flows and Coordination

Model business processes or sagas.

BoundedContext Checkout {
  Application CheckoutApp {

    // Define the orchestration of a flow
    flow OrderFulfillment {
      command PlaceOrderCommand
      event OrderPlaced
      command BillCustomer
      event PaymentReceived
    }

    // Coordinate interaction between contexts (optional)
    coordination ShippingCoordination {
      inventoryCheck
      shippingRequest
    }
  }
}

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Recommended File Pattern

A single .cml file can contain everything, but it is common to structure it like this:

1. Strategic: At the beginning, Context Maps and Domain definitions.
2. Bounded Contexts: Empty or high-level definitions (BoundedContext A implements X {}).
3. Details: Then, detailed blocks for each Bounded Context (BoundedContext A { ... }) with their tactics.

The order is not strict, as CML resolves references by name globally within the file.