OOP - lesson 6 | HackIndia Skills

OOP - lesson 6 | HackIndia Skills | HackIndia

Example

Small payment example

Here is a simple Dependency Inversion and Open/Closed example. Checkout uses the PaymentMethod interface. Adding NetBankingPayment later will not require changing Checkout.

interface PaymentMethod {
  boolean pay(int amountInRupees);
}

class UpiPayment implements PaymentMethod {
  public boolean pay(int amountInRupees) {
    System.out.println("Paid ₹" + amountInRupees + " using UPI");
    return true;
  }
}

class Checkout {
  private final PaymentMethod paymentMethod;

  Checkout(PaymentMethod paymentMethod) {
    this.paymentMethod = paymentMethod;
  }

  boolean placeOrder(int amountInRupees) {
    return paymentMethod.pay(amountInRupees);
  }
}

class Main {
  public static void main(String[] args) {
    Checkout checkout = new Checkout(new UpiPayment());
    checkout.placeOrder(499);
  }
}

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Small payment example

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