The Strategy Pattern is a behavioral design pattern that allows a class to change its behavior at runtime by switching between different algorithms or strategies. Instead of implementing multiple behaviors inside a class, it delegates the responsibility to separate strategy classes.
- Encapsulates algorithms 🏗️ into interchangeable objects.
- Promotes the Open/Closed Principle 📜 (open for extension, closed for modification).
- Reduces code duplication ✂️ by separating concerns.
- When you need multiple variations of an algorithm (e.g., different sorting methods).
- When a class has many conditional statements that choose behaviors.
- When you want to dynamically switch behaviors at runtime.
- Context: The main class that delegates work to a strategy.
- Strategy Interface: Defines a common interface for all strategies.
- Concrete Strategies: Implement different variations of an algorithm.
A payment system where users can select different payment methods (Credit Card, PayPal, Bitcoin) at runtime.
🔗 Related Patterns:
- State Pattern 🏛️ (focuses on object states rather than interchangeable algorithms)
- Decorator Pattern 🎨 (adds behavior dynamically without modifying existing code)
🔗 Example Code: See Implementation