hexagonal-architecture

Hexagonal architecture is a structural pattern that isolates domain logic from infrastructure by defining ports and adapters. It enforces clean architecture by ensuring dependencies point inward, keeping use-case layers framework-agnostic and highly testable.

To structure code for the ports and adapters pattern, use decision trees for class placement to assign logic to the domain or infrastructure. Define clear boundaries for ports, ensuring outward-facing adapters interact with external systems without leaking dependencies inward.

Verify framework-agnostic domain logic by checking that dependencies flow strictly inwards. Use a comprehensive checklist to confirm infrastructure concerns have not leaked into the domain, ensuring use cases remain independent of specific frameworks or platforms.

Dependency injection enforces inward dependency direction by providing infrastructure implementations through defined ports. This mechanism prevents direct dependencies on external tools, ensuring the application core remains isolated and testable.

Common pitfalls in domain-driven design with hexagonal architecture include letting infrastructure leak into the domain layer and improperly defining boundaries. Avoid these by applying decision trees for port creation and verifying layer responsibilities.

Hexagonal architecture may not suit applications with minimal domain logic or simple CRUD operations, as the overhead of defining ports and adapters outweighs benefits. It is best for complex domains requiring strict separation of concerns and high maintainability.