Payment strategy pattern in LLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Payment Strategy Pattern?

It is a design pattern that lets you choose different payment methods at runtime without changing the code that uses them. It helps keep payment logic separate and flexible.

beginner

Why use the Payment Strategy Pattern in system design?

It allows adding new payment methods easily, supports multiple payment options, and keeps the code clean by separating payment logic from business logic.

intermediate

Name the main components of the Payment Strategy Pattern.

1. Strategy Interface: defines payment method behavior.<br>2. Concrete Strategies: implement specific payment methods (e.g., credit card, PayPal).<br>3. Context: uses a strategy to perform payment.

intermediate

How does the Context class interact with payment strategies?

The Context holds a reference to a payment strategy and calls its payment method. It can switch strategies at runtime to support different payment options.

beginner

Give a real-life example of the Payment Strategy Pattern.

An online store lets customers pay by credit card, PayPal, or gift card. Each payment method is a strategy. The store’s checkout system (context) uses the chosen strategy to process payment.

What does the Payment Strategy Pattern help you do?

A Store payment data in a database

B Switch payment methods without changing client code

C Encrypt payment information

D Generate invoices automatically

The pattern allows switching payment methods easily without modifying the client code.

Which component defines the payment method interface in the Payment Strategy Pattern?

A Context

B Concrete Strategy

C Strategy Interface

D Payment Gateway

The Strategy Interface defines the methods that all payment strategies must implement.

In the Payment Strategy Pattern, where is the payment method chosen?

A In the Context class at runtime

B Inside the Concrete Strategy

C Hardcoded in the client code

D In the database schema

The Context class holds and uses the chosen payment strategy at runtime.

Which of these is NOT a benefit of using the Payment Strategy Pattern?

A Easier to add new payment methods

B Improves code maintainability

C Supports multiple payment options

D Automatically detects fraud

Fraud detection is not handled by the Payment Strategy Pattern.

What role does the Concrete Strategy play?

A Implements a specific payment method

B Manages user sessions

C Defines the payment interface

D Handles database connections

Concrete Strategies implement specific payment methods like credit card or PayPal.

Explain how the Payment Strategy Pattern improves flexibility in a payment system.

Think about how changing payment methods affects code.

Describe the roles of Context, Strategy Interface, and Concrete Strategies in the Payment Strategy Pattern.

Focus on how these parts work together.