What is the DRY Principle (Don't Repeat Yourself)?

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Need:

  • In software development, repeating the same code or logic multiple times can lead to code that is harder to maintain, error-prone, and difficult to update.
  • The DRY Principle aims to address this issue by promoting reusable and maintainable code.

What is the DRY Principle?

  • The DRY (Don’t Repeat Yourself) Principle is a software development concept that encourages reducing duplication of code or logic by abstracting and reusing common functionality.
  • Instead of writing the same piece of code multiple times, DRY encourages writing it once and reusing it wherever necessary.

Why is the DRY Principle Important?

  • Improves Maintainability:

By reducing redundancy, you ensure that changes made to a particular piece of logic only need to be updated in one place, making the code easier to maintain and modify. * Reduces Errors:

When code is repeated, it increases the chance of introducing errors or inconsistencies. DRY helps minimize this risk by centralizing common functionality. * Enhances Code Readability:

DRY helps in writing clean, concise, and organized code, which improves readability and makes the code easier to understand.

Example of DRY in Action:

Without DRY:

public class OrderService {
    public void calculateOrderTotal() {
        double tax = 0.18;  // tax calculation logic
        double discount = 0.10;  // discount logic
        // More repeated logic
    }

public void printOrderDetails() {
double tax = 0.18; // tax calculation logic (repeated)
double discount = 0.10; // discount logic (repeated)
// More repeated logic
}


}

With DRY:

public class OrderService {
    private double calculateTax() {
        return 0.18;  // tax logic centralized
    }

private double calculateDiscount() {
return 0.10; // discount logic centralized
}

public void calculateOrderTotal() {
double tax = calculateTax();
double discount = calculateDiscount();
// Use these values
}

public void printOrderDetails() {
double tax = calculateTax();
double discount = calculateDiscount();
// Use these values
}


}

Summary:

The DRY Principle promotes the practice of reducing code duplication by abstracting common logic into reusable components or methods. This makes code more maintainable, reduces errors, and improves readability. By following DRY, developers can write cleaner, more efficient, and easier-to-maintain code.