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Layered Architecture

category: Architecture
tags: layered, mvc, java, design-patterns, kubernetes

Main Topic 1

Layered Architecture (also known as n-tier) divides the system into layers with well-defined responsibilities, such as presentation, business, and data access layers.

Subtopic A: What It Is

• Vertical separation of concerns
• Common layers: UI, Business Logic, Persistence
• Components communicate only with adjacent layers

Subtopic B: Why Use It

• Modularity – Separation makes code easier to understand and maintain
• Reusability – Each layer can evolve independently
• Testability – Unit testing becomes easier

Subtopic C: When To Use It

• Traditional enterprise applications
• Systems with clearly separated concerns
• Long-term maintainability needed

Main Topic 2

Code Example (Java Spring Boot)

// Service layer
@Service
public class UserService {
    @Autowired
    private UserRepository repository;

    public User getUser(Long id) {
        return repository.findById(id).orElse(null);
    }
}

Infra Example (Kubernetes)

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service
spec:
  replicas: 1
  selector:
    matchLabels:
      app: user-service
  template:
    metadata:
      labels:
        app: user-service
    spec:
      containers:
      - name: user-service
        image: myregistry/user-service:latest

Key Concepts Summary

• Logical layers for structure
• Encourages best practices in OOP and separation of concerns
• Can be deployed as a monolith or microservices

Best Practices / Tips

1. Avoid business logic in the controller layer
2. Use DTOs to pass data between layers
3. Follow SOLID principles

Common Issues / Troubleshooting

Problem 1: Tight coupling between layers

• Cause: Poor abstraction
• Solution: Use interfaces and clean boundaries

Problem 2: Inefficiency in data mapping

• Cause: Overuse of models between layers
• Solution: Use data transfer objects (DTOs)

References / Further Reading

• https://en.wikipedia.org/wiki/Multitier_architecture
• https://spring.io/guides/gs/accessing-data-jpa/

Last updated: 2025-08-26 20:00 UTC