Order entity with state information

Order.java

class Order {  
  String id;
  Customer customer; 
  List<OrderItem> items;

  static enum GoodsDeliveryStatus {
    NOTHING_DONE,
    GOODS_RESERVED,
    GOODS_PICKED
  }  
  boolean paymentReceived = false;
  GoodsDeliveryStatus deliveryStatus = GoodsDeliveryStatus.NOTHING_DONE;
  boolean shipped = false;

  //...
}