Naive model implementation for Quora quesiton - http://www.quora.com/CakePHP/What-is-the-right-approach-to-consume-an-API-in-CakePHP

ecommerce-eg.php

<?php 
namespace Model;

class Product
{
  // etc...	
}

class Customer
{
	// etc...
}

class Order
{
	public function __construct(Customer $customer, array $products)
	{
		// etc...
	}
}