Ditch Switch! Use Strategy Pattern for Flexible Business Logic

✅ Why Use the Strategy Pattern Over Switch-Case?

1. Extensible & Open-Closed Principle (OCP) — Add new strategies without modifying existing code.
2. Encapsulation — Each behavior is isolated in a dedicated class.
3. Improved Readability — No more massive switch statements.
4. Easier Testing & Maintenance — Individual strategies can be tested independently.

🔥 In this guide, we’ll explore how to replace switch-case with the Strategy Pattern for a more scalable and flexible business logic implementation! 🚀

Ditch Switch! Use Strategy Pattern for Flexible Business Logic

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📝 The Problem: Switch-Case for Different Discount Types

public class DiscountService {
    public double applyDiscount(String type, double amount) {
        switch (type) {
            case "FESTIVAL":
                return amount * 0.9;  // 10% discount
            case "SEASONAL":
                return amount * 0.8;  // 20% discount
            case "NEW_USER":
                return amount * 0.95; // 5% discount
            default:
                return amount;
        }
    }
}

✔ Works, but violates Open/Closed Principle. ❌ New discounts require modifying the method.

✅ Solution: Use Strategy Pattern (Functional Interface)

import java.util.Map;
import java.util.function.Function;

public class DiscountService {
    private static final Map<String, Function<Double, Double>> DISCOUNT_MAP = Map.of(
        "FESTIVAL", amount -> amount * 0.9,
        "SEASONAL", amount -> amount * 0.8,
        "NEW_USER", amount -> amount * 0.95
    );

    public double applyDiscount(String type, double amount) {
        return DISCOUNT_MAP.getOrDefault(type, a -> a).apply(amount);
    }
}

✔ More Scalable — Add discounts without modifying the method. ✔ No More Switch! — Just look up the function in a Map. ✔ More Readable — Business logic is clear and declarative.

🔥 Use Maps and Functional Interfaces to replace switch-case! 🚀

Story List Categories:

• ***About Me & [List of Stories](https://medium.com/@saannjaay/lists)***
• Java — All things Java-related.
• Java Interview Playbook: Your Go-To Reading List — For interview preparation.
• JAVA-8 — Dedicated to Java 8 topics.
• Spring Boot & Spring — Focused on Spring and Spring Boot.
• Microservices Topics List — Covering various microservices to