Dart-Liskov-substitution

readme.md

Dart-Liskov-substitution

Created with <3 with dartpad.dev.

main.dart

// Liskov substitution principle
void main() {
  PayPalProcessor payPalProcessor = PayPalProcessor();
  VisaPaymentProcessor visaProcessor = VisaPaymentProcessor();

  // Here the checkout function don't now which service it is using to process the payment.
  // THe underlying implementation is hidden from the checkout function.
  //
  // I can add more function to the payment processor and can extend it's functionality.
  checkout(payPalProcessor, 230);
  checkout(visaProcessor, 250);
}

void checkout(PaymentProcessor processor, double amount) {
  processor.processPayment(amount);
}

class PaymentProcessor {
  void processPayment(amount) {
    print('PaymentProcessor - completed');
  }
}

class PayPalProcessor extends PaymentProcessor {
  @override
  void processPayment(amount) {
    print('PayPalProcessor - completed');
  }
}

class VisaPaymentProcessor extends PaymentProcessor {
  @override
  void processPayment(amount) {
    print('VisaPaymentProcessor - completed');
  }
}