Object Relational Mapping (ORM) using NHibernate - Part 7 of 8 Completing the Ecommerce Example

using System;
using Iesi.Collections.Generic;

namespace ECommerceSystem.Domain
{
    public class PaymentApprovedOrder
    {
        public PaymentApprovedOrder()
        {
            PaidOrderItems = new HashedSet<Item>();
        }
        public PaymentApprovedOrder(Order order,Payment pay)
        {
            PaidOrderItems = new HashedSet<Item>();
            CurrentOrder = order;

            // SET ONE END OF ASSOCIATION

            OrderPayment = pay;

            // SET OTHER END OF ASSOCIATION

            pay.PaidOrder = this;  

            foreach (Item item in order.OrderItems)
            {
                //ORDER ITEMS FLAGGED HERE TO SHOW PAYMENT IS COMPLETE
                //UPDATES TO DB AUTOGENERATED BY Nhibernate
                if (item.IsOrdered == false)
                    item.IsOrdered = true;

                //SET THE ORDER ITEMS 
                // THE ORDER USED IN PAYMENTAPPROVEDORDER HERE
                //CONTAINS ORDERITEMS
                AddPaidItem(item);
            }
            // Set the Customer BIDEIRECTIONAL ASSOCIATION
            order.OrderedByCustomer.AddPaidOrder(this);
        }

        public virtual long PaymentApprovedOrderId { get; set; }

        public virtual Order CurrentOrder { get; set; }

        // NOTE: BIDIRECTIONAL ASSOCIATION WITH "PAYMENT"

        public virtual Payment OrderPayment { get; set; }

        //NOTE: BIDIRECTIONAL ONE-TO-MANY ASSOCIATION WITH ITEM

        public virtual ISet<Item> PaidOrderItems { get; set; }

        //NOTE: BIDIRECTIONAL MANY-TO-ONE ASSOCIATION WITH CUSTOMER

        public virtual Customer PaidByCustomer { get; set;}

        public virtual void AddPaidItem(Item item)
        {
            //SET THE REFERENCE FOR PAYMENTAPPROVEDORDER
            //IN ITEM OBJECT TO THIS (THE PAYMENT APPROVED
            //ORDER INSTANCE TO WHICH THE item IS ADDED")

            // THIS IS FIRST END OF THE
            // ONE-TO-MANY ASSOCIATION - THE "ONE" END

            item.PaidOrder = this;

            //ADD "item" TO THE SET PaidOrderItems
            //OTHER END OF ASSOCIATION - THE "MANY" END

            PaidOrderItems.Add(item);
            
        }

    }
}