1. Order Processing

2. Requirements An employee takes orders from customers
Each purchase may contain multiple products
System maintains customer information
System maintains product information
System keeps track of purchase orders

3. Use Cases Add/delete/update/view customers
Add/delete/update/view products
Take purchase orders
List/view purchase orders
Delete purchase orders
Update purchase orders

4. The Database - ERD Name Address Name Description Id Id Product
Customer 1 1
Price
Places
Is_for
PO Id N 1 N
Purchase Order
contains
Line_Item
Order_date
Total_Amount
Line#
Quantity

5. The Database - Schema customer customer_id name address purchase_order
po_id
Customer_id
order_date
Total_amount
line_item id
po_id
product_id
quantity
product
product_id
name
description
price

6. System Architecture Database Take purchase order Delete purchase order
OrderManagement
Take purchase order
Delete purchase order
Update purchase order
View purchase order
CustomerManagement
ProductManagement
Add customer
Delete customer
Update customer
View customer
Add product
Delete product
Update product
View product
Database

7. System Architecture
Each package is responsible for CRUD on a set of tightly related business entities
E.g., Customers, customer groups (VIP, etc), and customer credit card info as a package
Use cases are allocated to packages and each package contains related use cases
E.g., Add customer including his group and credit card info, update customer, delete customer, and query customer in CustomerManagemant
Each package has a Manager which takes cares of the business logic of the use cases.
E.g., OrderManager would check if an order contains more than the limit of the number of items or not.
A Design Pattern called Service Layer may be used to package managers’ operations as one class – ServiceLayer
OrderProcessing sample app employs this approach.

8. System Architecture
Each use case is mapped to a Presenter which is responsible for the presentation logic of the use case.
E.g., TakeOrderPresenter is responsible for creating a new purchase order and saving the order in the DB
Each Presenter may employ multiple Views each of which is a UI.
E.g., TakeOrderPresenter uses SelectCustomerView to select a customer for the order, SelectOrderItemsView to collect order items, finally ConfirmOrderView to display the order info to the user.

9. System Architecture Database entity OrderManagement Customer Product
PuchaseOrder
OrderItem
OrderManagerUI.java
takeOrder()
viewOrder()
updateOrder() db
deleteOrder()
CustomerDao
ProductDao
PuchaseOrderDao
OrderItemDao
MailOrderDatabase
PurchaseOrderManager
Depends on A B
Database

10. Architecture – Service Layer
OrderManagement
CustomerManagement
OrderManagerUI.java
ProductManagement
server
ServiceLayer (Façade)
PurchaseOrderManager
CustomerManager
ProductManager db
CustomerDao
PurchaseOrderDao
OrderItemDao
ProductDao
MailOrderDatabase
Database

11. Detailed Design: db & entity
Customer
Product
Purchase Order
Order Item
Customer_id
Name
Address
Product_id
Name
Description
Price
Po_id
Customer_id
Order_date
Po_id
Product_id
Quantity
CustomerDao
ProductDao
PurchaseOrderDao
OrderItemDao
Insert()
Delete()
Update()
getCustomerById()
getAllCustomers()
Insert()
Delete()
Update()
getProductById()
getAllProducts()
Insert()
Delete()
Update()
getPOById()
getAllPOs()
Insert()
Delete()
Update()
getItemByItemId()
getItemsByOrderId()
MailOrderDatabase
getConnection()
Close()

12. Detailed Design: Startup
AppController
Main()
HomeView.instance().display()
OrderManagement
HomeView
displayMenu()
Take Order
OrderManagerUI
takeOrderUI()
viewOrder()
View Order
CustomerManagement
AppContext
Static getInstance()
getDbConnection()
ProductManagement