Hexagonal.md

Hexagonal (Ports & Adapters) Architecture

Proposed by Alistair Cockburn, focuses on creating systems independent from external interfaces.

Components:

• Core Application (Domain): Business logic and domain rules.
• Ports: Interfaces defining communication channels to/from the Core.
• Adapters: Concrete implementations of ports.

Structure:

Adapters ↔ Ports ↔ Core (Application Domain)

Pros:

• Highly testable due to clean separation.
• Easily replaceable external integrations.

Cons:

• Requires significant discipline in keeping ports/adapters clean.
• High initial overhead.

When to use:

• Microservices architecture.
• Systems with multiple external dependencies (DB, APIs, messaging).# 3. Clean Architecture

Clean Architecture emphasizes decoupling, independence of frameworks, testability, and maintainability. Developed by Robert C. Martin (Uncle Bob).

Layers:

• Entities: Core business objects.
• Use Cases (Application): Contains application logic; interacts with Entities.
• Interface Adapters: Controllers, Presenters, Gateways. Converts data between Use Cases and external layers.
• Frameworks & Drivers: External layer (e.g., web, database, UI frameworks).

Structure (Inner layers don't depend on outer layers):

Entities ← Use Cases ← Interface Adapters ← Frameworks & Drivers

Pros:

• Excellent maintainability and testability.
• Highly decoupled design.

Cons:

• May seem overly abstract and complicated for smaller projects.
• High initial setup complexity.

When to use:

• Enterprise-scale applications.
• Projects needing long-term maintenance and evolution.