📑 Table of Contents

1. [📋 Executive Summary](#-executive-summary) 1. **[Design Patterns](#design-patterns)**

🎯 Main Topics Covered

1. Executive Summary

📋 Executive Summary

Document: Object-Oriented Design Patterns
Type: Technical Documentation
Reading Time: ~20 min
Last Updated: December 2025

📊 Quick Stats

🎯 Main Patterns Covered

Creational Patterns (5):

1. Singleton — Ensure single instance
2. Factory Method — Object creation interface
3. Abstract Factory — Family of objects
4. Builder — Complex object construction
5. Prototype — Clone existing objects

Structural Patterns (7):

1. Adapter — Interface compatibility
2. Bridge — Separate abstraction from implementation
3. Composite — Tree structures
4. Decorator — Dynamic behavior addition
5. Facade — Simplified interface
6. Flyweight — Share common state
7. Proxy — Control access

Behavioral Patterns (11):

1. Chain of Responsibility — Request handling chain
2. Command — Encapsulate requests
3. Iterator — Sequential access
4. Mediator — Centralized communication
5. Memento — State snapshots
6. Observer — Event notification
7. State — Object state behavior
8. Strategy — Interchangeable algorithms
9. Template Method — Algorithm skeleton
10. Visitor — Operations on elements
11. Interpreter — Language grammar

💡 What You’ll Learn

• Recognize when and why to apply each design pattern
• Understand the problem each pattern solves
• Implement patterns in object-oriented languages
• Identify anti-patterns and code smells
• Refactor legacy code using design patterns
• Balance pattern usage (avoid over-engineering)
• Communicate design decisions using pattern vocabulary
• Apply patterns in real-world system architecture

📚 Prerequisites

• Solid OOP fundamentals (classes, inheritance, polymorphism, encapsulation)
• Experience with at least one OOP language (Java/C++/Python/C#)
• Understanding of interfaces and abstract classes
• Basic UML diagram reading skills
• Familiarity with software design principles (SOLID)

👥 Target Audience

✅ Software Engineers — Writing maintainable, scalable code
✅ Interview Candidates — Preparing for system design interviews
✅ Tech Leads — Establishing team coding standards
✅ Architects — Designing large-scale systems
✅ Code Reviewers — Identifying improvement opportunities

🎓 Learning Path

Beginner → Start with Singleton, Factory, Observer, Strategy (most common)
Intermediate → Add Decorator, Adapter, Template Method, Command
Advanced → Master Composite, Flyweight, Visitor, Interpreter

🔑 Key Principle

“Design patterns are solutions to recurring problems in software design.”
They provide a shared vocabulary and proven approaches, but should be applied judiciously—not forced into every situation.

Design Patterns

Concepts, examples, and anti-patterns.