How do I implement the Strategy Pattern in Java?

How do I implement the Strategy Pattern in Java?

The Strategy Pattern allows you to define a family of algorithms, encapsulate each one, and make them interchangeable. In Java, you can implement it using interfaces and classes.

Can you give me a code example?

Sure! Here's a simple example:

// Strategy interface
interface Strategy {
    int doOperation(int num1, int num2);
}

// Concrete strategies
class AddOperation implements Strategy {
    public int doOperation(int num1, int num2) {
        return num1 + num2;
    }
}

class SubtractOperation implements Strategy {
    public int doOperation(int num1, int num2) {
        return num1 - num2;
    }
}
}

// Context class
class Context {
    private Strategy strategy;

    public Context(Strategy strategy) {
        this.strategy = strategy;
    }

    public int executeStrategy(int num1, int num2) {
        return strategy.doOperation(num1, num2);
    }
}

// Usage
public class StrategyPatternDemo {
    public static void main(String[] args) {
        Context context = new Context(new AddOperation());
        System.out.println("10 + 5 = " + context.executeStrategy(10, 5));

        context = new Context(new SubtractOperation());
        System.out.println("10 - 5 = " + context.executeStrategy(10, 5));
    }
}

What are the benefits of using the Strategy Pattern?

The Strategy Pattern promotes flexibility and reusability. It allows you to change algorithms at runtime and adhere to the Open/Closed Principle, making your code easier to maintain.