Implementing Custom Validations with Java and Spring Boot

Published on January 15, 2024 · 12 min read

In this article, we'll explore the process of building a scalable e-commerce platform using a modern technology stack. We'll cover the key architectural decisions, the technologies used, and the challenges faced during development. This platform is designed to handle a large number of users and transactions while maintaining high performance and reliability.

Architecture Overview

The platform follows a microservices architecture, where different functionalities are separated into independent services. This approach allows for better scalability, maintainability, and fault isolation. The core services include: User Service, Product Service, Order Service, Payment Service, and Notification Service. Each service is responsible for a specific aspect of the platform and communicates with other services through APIs.

Technology Stack

The technology stack chosen for this project includes: React for the front-end, Node.js with Express for the back-end services, PostgreSQL for the database, AWS for cloud infrastructure, and Docker for containerization. This combination provides a robust and scalable foundation for the platform.

Example Java Code

Below is an example of a Java class that implements a simple e-commerce product service:

/**
 * A simple product service implementation for our e-commerce platform.
 */
public class ProductService {
    private final ProductRepository repository;
    private final CacheService cacheService;

    public ProductService(ProductRepository repository, CacheService cacheService) {
        this.repository = repository;
        this.cacheService = cacheService;
    }

    /**
     * Retrieves a product by its ID.
     * First checks the cache, then falls back to the database.
     */
    public Product getProductById(Long id) {
        // Try to get from cache first
        String cacheKey = "product:" + id;
        Product product = cacheService.get(cacheKey, Product.class);

        if (product == null) {
            // Not in cache, get from database
            product = repository.findById(id)
                .orElseThrow(() -> new ProductNotFoundException("Product not found with id: " + id));

            // Store in cache for future requests
            cacheService.put(cacheKey, product, 3600); // Cache for 1 hour
        }

        return product;
    }

    /**
     * Creates a new product in the system.
     */
    public Product createProduct(Product product) {
        // Validate product data
        validateProduct(product);

        // Save to database
        Product savedProduct = repository.save(product);

        // Invalidate any relevant caches
        cacheService.invalidate("products:list");

        return savedProduct;
    }

    private void validateProduct(Product product) {
        if (product.getName() == null || product.getName().trim().isEmpty()) {
            throw new IllegalArgumentException("Product name cannot be empty");
        }

        if (product.getPrice() == null || product.getPrice().compareTo(BigDecimal.ZERO) <= 0) {
            throw new IllegalArgumentException("Product price must be greater than zero");
        }
    }
}

Challenges and Solutions

During the development of this platform, we faced several challenges, including managing inter-service communication, ensuring data consistency across services, and optimizing performance for high traffic. We addressed these challenges by implementing asynchronous communication using message queues, employing database transactions for data consistency, and utilizing caching mechanisms to improve performance.

Conclusion

Building a scalable e-commerce platform requires careful planning and the use of appropriate technologies. The microservices architecture, combined with a modern technology stack, provides a solid foundation for handling the demands of a large user base. By addressing challenges proactively and implementing best practices, we can create a platform that is both scalable and reliable.