8 Strategy (Behavioral) Design Pattern

The Strategy Design Pattern is a behavioral design pattern that defines a family of algorithms, encapsulates each one, and makes them interchangeable. This allows the algorithm to vary independently from the clients that use it.

Intent

• Enable a client to select an algorithm or behavior at runtime.
• Promote the Open/Closed Principle: New algorithms can be added without modifying existing code.

Key Components

1. Strategy Interface: Common interface for all supported algorithms.
2. Concrete Strategies: Implementations of the strategy interface, representing different algorithms or behaviors.
3. Context: Maintains a reference to a strategy object and delegates the behavior to the current strategy.

When to Use

• When multiple algorithms can be applied to solve a problem, and the decision of which algorithm to use is determined at runtime.
• To eliminate conditional statements (if-else or switch) for selecting behaviors.
• When you want to make algorithms easily interchangeable and independent of the client.