protected Product buildProduct(String category, String title, String upc) {
   Product product = new Product();
   product.setCategory(category);
   product.setTitle(title);
   product.setUpc(upc);
   return product;
 }
 protected boolean containsUpc(Collection<Product> products, String upc) {
   for (Product product : products) {
     if (upc.equals(product.getUpc())) {
       return true;
     }
   }
   return false;
 }
 protected Product buildProduct(String category) {
   Product product = new Product();
   product.setCategory(category);
   return product;
 }