RTS Questionnaire · Question 33 of 52 · file: answers/q33.html
Have you worked with SOLID principles and common object-oriented design patterns?
SOLIDDesign PatternsOOP
✅ Yes — SOLID and classic design patterns are the foundation of my code and architectural decisions.
🧪 Interactive proof: this answer has its own page with a live SOLID refactor workflow, the same class before and after, and the pattern catalogue as data — open the Q33 SOLID proof →
Technical detail
- 🅂 Single Responsibility — one reason to change per class; controllers translate HTTP, handlers orchestrate use cases, domain objects hold invariants, adapters talk to infrastructure.
- 🅾️ Open/Closed — new behaviour by extension: strategy and specification implementations, plugin-style handlers registered by DI, or new implementations of an interface rather than
if/elsechains in existing classes. - 🅻 Liskov Substitution — contracts that hold for every implementation: no surprising exceptions, no strengthened preconditions, consistent return semantics — enforced by interface-driven testing.
- 🅸 Interface Segregation — small, purpose-specific interfaces (read vs. write ports) so clients depend only on what they use; avoids the "god interface" repositories.
- 🅳 Dependency Inversion — high-level policy depends on abstractions; infrastructure is injected (EF Core, messaging, HTTP clients, clock, cache) which makes the domain testable and the deployment target swappable.
🧩 Patterns I apply regularly: factory, builder, strategy, adapter, decorator, facade, mediator, observer/domain events, template method, singleton (carefully, via container), specification, CQRS and saga for distributed workflows. ☕ In Java/Spring and 🟪 .NET the same vocabulary transfers directly, which keeps designs consistent across stacks.
🧾 CV evidence: CV header explicitly lists 'SOLID Principles' and 'Understanding of SOA, design patterns and principles'; Java/JEE design pattern and architectural mechanism competencies; 2025 CV highlight 'Secure APIs', 'Multi-stack delivery'.