Untitled

public class OrderService {
    
    private final Database database;
    
    public OrderService(Database database) {
        this.database = database;
    }
    
    public void placeOrder(String customerId, String productId, int quantity) {
        try {
            validateOrderDetails(customerId, productId, quantity);
            Customer customer = findCustomerById(customerId);
            Product product = findProductById(productId);
            checkProductAvailability(product, quantity);
            createAndSaveOrder(customer, product, quantity);
            updateProductStock(product, quantity);
            System.out.println("Order placed successfully");
        } catch (OrderException e) {
            System.out.println(e.getMessage());
        }
    }
    
    private void validateOrderDetails(String customerId, String productId, int quantity) throws OrderException {
        if (customerId == null || productId == null || quantity <= 0) {
            throw new OrderException("Invalid order details");
        }
    }
    
    private Customer findCustomerById(String customerId) throws OrderException {
        Customer customer = database.findCustomerById(customerId);
        if (customer == null) {
            throw new OrderException("Customer not found");
        }
        return customer;
    }
    
    private Product findProductById(String productId) throws OrderException {
        Product product = database.findProductById(productId);
        if (product == null) {
            throw new OrderException("Product not found");
        }
        return product;
    }
    
    private void checkProductAvailability(Product product, int quantity) throws OrderException {
        if (product.getStock() < quantity) {
            throw new OrderException("Product not available");
        }
    }
    
    private void createAndSaveOrder(Customer customer, Product product, int quantity) {
        Order order = new Order(customer, product, quantity);
        database.saveOrder(order);
    }
    
    private void updateProductStock(Product product, int quantity) {
        product.setStock(product.getStock() - quantity);
        database.updateProduct(product);
    }
}

class OrderException extends Exception {
    public OrderException(String message) {
        super(message);
    }
}