domain-layer-expert

Rich domain models in Rust encapsulate business logic and validation rules within value objects and entities rather than using raw primitives. This approach prevents primitive obsession, enforces invariants at the type level, and makes domain constraints explicit in your code structure.

Value objects are domain-driven patterns that encapsulate invariants and validations for immutable concepts like money or email addresses. In Rust, implement them as structs with private fields, validation logic in constructors, and derived equality traits to ensure type safety and business rule enforcement.

Move business logic from services into entity methods that enforce domain rules directly. In Rust, define impl blocks on entities to encapsulate operations, validate state transitions, and emit domain events, keeping behavior co-located with the data it operates on.

Domain events capture significant business occurrences within your domain for downstream processing and event sourcing. Emit them from entities during state transitions to enable loose coupling, audit trails, and integration with other systems while maintaining clear separation of concerns.

Implement repository patterns or ports to abstract persistence behind interfaces. Keep domain entities and value objects free of database concerns, allowing them to focus on business rules while repositories handle serialization and storage, enabling testability and technology independence.

Yes. Rust's type system naturally enforces domain invariants through ownership, borrowing, and immutability. Value objects leverage these features to make invalid states unrepresentable, and entities use impl methods to guarantee business rules are maintained across state transitions.