Adapter Design Pattern with Spring Boot

Overview

This project demonstrates the Adapter Design Pattern using a Spring Boot application. The example focuses on integrating multiple payment gateways (e.g., PayPal, Stripe, Razorpay, Google Pay) through a unified adapter, making the application more maintainable, scalable and adaptable to future changes.

Key Features

• Unified Integration: A single adapter interface to interact with multiple payment gateways
• Scalability: Easily add new payment gateways without modifying the core business logic
• Maintainability: Centralized logic reduces redundancy and improves code organization
• Real-World Example: Suitable for e-commerce platforms handling diverse payment options

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Technologies Used

• Java
• Spring Boot
• Maven
• REST APIs

Design Pattern: Adapter

Problem

Each payment gateway provides its own API, resulting in scattered, repetitive, and hard-to-maintain integration code.

Solution

The Adapter Design Pattern bridges these differences by providing a unified interface for all payment gateways, allowing the application to communicate seamlessly with them.

How It Works

1. Adapter Interface: Defines the contract for all payment gateways
2. Concrete Adapters: Implement the interface and encapsulate the logic specific to each gateway
3. Payment Service: Calls the appropriate adapter based on the gateway specified by the client

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API Documentation

Endpoints

1. Process Payment

   • URL: /api/v1/payment/process
   • Method: POST
   • Headers:

     Content-Type: application/json
     

   • Request Body (JSON):

     {
         "amount": 100.50,
         "gateway": "paypal"
     }

   • Response (JSON):

     {
         "success": true,
         "transactionId": 1234567890
     }

2. Supported Gateways:

   • paypal
   • stripe
   • gpay

Example Workflow

1. Client Request
   The client specifies the amount and gateway in the JSON request.

2. Adapter Selection
   The PaymentService dynamically selects the appropriate adapter based on the gateway.

3. Payment Processing
   The selected adapter processes the payment and returns a success response along with a transaction ID.

How to Run

1. Clone the repository:

   git clone https://github.com/18-RAJAT/Spring-Adapter-Integration-Design.git

2. Navigate to the project directory:

   cd Spring-Adapter-Integration-Design

3. Build the project:

   mvn clean install

4. Run the application:

   mvn spring-boot:run

Sample Test Cases

PayPal Payment

Request:

{
    "amount": 150.75,
    "gateway": "paypal"
}

Response:

{
    "success": true,
    "transactionId": 1234567890
}

Stripe Payment

Request:

{
    "amount": 99.99,
    "gateway": "stripe"
}

Response:

{
    "success": true,
    "transactionId": 987654321
}

Unsupported Gateway

Request:

{
    "amount": 200.00,
    "gateway": "unknown"
}

Response:

{
    "timestamp": "2024-12-13T17:00:00.123+00:00",
    "status": 400,
    "error": "Bad Request",
    "message": "Unsupported payment gateway: unknown",
    "path": "/api/v1/payment/process"
}

Future Enhancements

Add More Gateways

• Integrate more payment providers like Razorpay or Square

Error Handling

• Improve error messages and add logging for failed transactions

Security Enhancements

• Use secure tokens or API keys for communication with payment gateways