Design Pattern | Strategy Pattern
What Is the Strategy Pattern?
- Strategy means strategy. In programming, it is often easier to understand as an algorithm.
- Programs are written to solve problems. To solve a problem, a specific algorithm is implemented. The Strategy pattern is a way to quietly replace the part that implements the algorithm.
- It allows a system to be changed and extended flexibly.
- It lets the user(Client) choose a suitable Strategy and execute logic with it.
- In GoF design patterns, it is classified as a behavioral design pattern.
Example Program
The example is a rock-paper-scissors program. It includes a strategy that chooses a hand randomly and a strategy that only chooses rock.
Class Diagram
The example defines a Hand class for rock-paper-scissors hands, a Strategy interface for choosing hands and learning from results, concrete strategies, and a player class that delegates hand selection to its strategy.
Advantages
Algorithms can be replaced without changing the client. Related algorithms can be encapsulated behind a common interface, making it easy to add new strategies or switch behavior at runtime.