: Acts as a middleman between business rules and the outside world. It uses (interfaces) and

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The book organizes software into three distinct logical "hexagons" to enforce separation of concerns: Domain Hexagon

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[ REST API / CLI ] --> ( Driving Adapter ) | v [ Driving Port ] | v +--------------------------+ | | | Core Domain Logic | | (Entities & Services) | | | +--------------------------+ | v [ Driven Port ] | v ( Driven Adapter ) | v [ Database / SMS ] The Domain Hexagon (The Core)

And finally, the using Spring Data JPA. Note the complete decoupling: the database entity is separate from our domain model.

The book bridges the gap between Hexagonal Architecture and DDD. It features: