amazon: added order id

Author: kousiknath

src/com/lld/amazon/Main.java

@@ -59,6 +59,7 @@ private static void test1(PricingService pricingService, OrderService orderServi
 
         Payment payment = orderService.pay(order);
         System.out.println("Payment status: " + payment.getPaymentStatus());
+        System.out.println("Order placed with order id: " + order.getId());
     }
 
     private static Product getProduct1(PricingService pricingService) throws PricingException {

src/com/lld/amazon/model/Order.java

@@ -2,19 +2,26 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.UUID;
 
 public class Order {
+    private final String id;
     private List<QuantifiedCartOrOrder> orders;
     // Each item in the order can have its own delivery ETA
     private List<OrderItemDelivery> orderItemDeliveries;
     private Payment payment;
 
     public Order(List<QuantifiedCartOrOrder> orders, List<OrderItemDelivery> orderItemDeliveries, Payment payment) {
+        this.id = UUID.randomUUID().toString();
         this.orders = orders;
         this.orderItemDeliveries = orderItemDeliveries;
         this.payment = payment;
     }
 
+    public String getId() {
+        return id;
+    }
+
     public Money getOrderTotal() {
         return this.payment.getTotalAmount();
     }

src/com/lld/amazon/service/impl/OrderServiceImpl.java

@@ -41,6 +41,7 @@ public Payment pay(Order order) {
         // Order service should talk to payment service here
         // Depending on the result, mark success or failure
         order.getPayment().markPaymentSuccess();
+        // Update order state here through state machine mechanism
         return order.getPayment();
     }
 }