1. Point Of Sale(POS) J2EE Application
(POS J2EE Application with JRun)
< Master Degree Final Project >
Department : Computer Science
Degree : Master
Student : Woojin Choi
ID :

2. Topics Introduction of POS Application System requirement
Application Map
Database Diagram
POS Component
POS Workflow using J2EE Design
HTML / JSP / Servlet / EJB in POS
J2EE Introduction (J2EE – J2EE API)
POS Application with J2EE
Enterprise JavaBeans (EJB)
POS Component Example
POS Security Mechanism
POS Scheduler
Supplementary Issues

3. Introduction of POS POS : Point of Sale
Business topic : Web based application for a customer to check out the shopping easily and fast
Current Process : Customer comes in store -> Put the item to shopping cart -> Wait to check out -> Clerk help to check out
Problem : Customers need to wait for a long time even the item is simple
Solution : Put the clerk barcode scanning and checking out systems to each shopping lane and allow for a customer to check out the carts by himself
New system to solve the problem : POS J2EE Application
Benefits : Portable business solution / Integrated e-business / Save the customer’s time / Down the store cost

4. System Requirement Server side Operating System : Win NT 4.0 / Win2K
Web Server : IIS 4.0 / 5.0
Application Server : JRun 3.0.2
Database : MS SQL Server 7.0
Client side
Browser : IE4.0 or higher

5. (Display shoppling cart) Customized Error Pages Jrun Application Error
Application Map
Index.jsp
(Display shoppling cart)
Products.jsp
Add/Edit/Delete
Shopping list
Authentication
Servlet
Login.jsp
Checkout.jsp
Customized Error Pages
HTTP Error
Jrun Application Error
403.html
404.html
405.html
500.html
Loginerror.jsp
Loginerror.jsp
Logout.jsp
Scheduler

6. Database Diagram

7. POS Components Presentation Logic HTML JSP
Login.jsp, customers.jsp, customer_profile.jsp, …
Interface Logic (Data Modeling)
Servlet
EditCustomer.class, DeleteCustomer.class, AddShoppingList.class, …
Business Logic
EJB
Customer EJB, ShoppingList EJB, …

8. POS Workflow using J2EE design
Presentation : JSP
Interface : Servlet
Business Logic : EJB
Benefits : Presentation logic doesn’t implement business logics at all. Every business data is updated through EJB or Servlets. Especially Servlet is reponsible for data modeling for business logic as interface between presentation and business logic.
JSP
Servlet
EJB
Container
<> DB

9. HTML / JSP / Servlet / EJB in POS
JRun
HTTP Server(HTML)
JSP Engine
JDBC
<>
HTTP
Servlet
Container DB
HTTP on LAN
EJB
Container

10. Java 2 Enterprise Edition (J2EE)
Defines a standard for developing multi-tier applications
Vendors collaborate on standards and compete on implementation
All the pieces of the application are portable across platforms and servers
Simplifies application development
Developer focuses on application logic
J2EE server handles complexity of lower level services
Component
JSPs / Servlets / EJBs
API : Servlet / JSP / EJB / JDBC / JNDI / JavaMail / JMS / JTA

11. J2EE APIs Servlets Standard API extending and enhancing Web servers
Java Server Pages (JSP)
Standard API for creating dynamic content using static templates
Enterprise JavaBeans (EJB)
Standard server-side component model
Java Database Connectivity (JDBC)
JavaMail
Java Naming and Directory Interface (JNDI)
Java Message Service (JMS)
Java Transaction API (JTA)
*) POS system : Servlet / JSP / EJB / JNDI / JDBC

12. POS Application with J2EE
Provides complete implementation of J2EE
Servlets 2.2
JSP 1.1
EJB 1.1
JNDI
JMS
JDBC
JTA/JTS
JavaMail
POS Application
Servlet 2.2
POS Application Work Flow
Presentation : JSP
Interface : Servlet
Business Logic : EJB

13. Enterprise JavaBeans (EJB)
Server-side component model allowing developers to concentrate on business logic
EJB server handles complexity of lower level services
EJB API guarantees components to be portable across EJB Servers
Component life cycle
State management
Persistence
Multi-threading
Connection pooling
Transaction management
Security

14. Entity Beans
Used to
Represent a business entity (like a row in a database table)
Provide standard access and validation for business entities
Persistent (live beyond server lifetime)
Usually represent data in a database
Examples
Customer, Product, Employee, ...

15. Entity Beans Bean Managed Persistence (BMP)
Developer writes persistence code
Container Managed Persistence (CMP)
EJB properties are mapped to database columns
Persistence code automatically generated by EJB container
Implements javax.ejb.EntityBean

16. Session Beans Used to Manage processes and tasks
Model the workflow of Entity beans
Retrieve and update data that can't be adequately captured in an entity bean
No persistent state
Example
Order a product
Check out the shopping cart
Reservation

17. Session Beans Stateful Session Bean
Maintain a state between method invocations
Store properties as instance variables
Expose methods to manipulate properties
Stateless Session Bean
Do not retain information between method invocations
Each method is completely independent
Client passes needed information as parameters to the method
Participate in instance pooling
Greatest scalability
Many clients share limited number of instances
Implements javax.ejb.SessionBean

18. Home / Remote Interface
Home Interface
Defines methods to create (obtain), find, or remove a Bean Instance on behalf of the client
Extends javax.ejb.EJBHome
Remote Interface
Defines the bean's business methods
Extends javax.ejb.EJBObject

19. Packaging the Bean in a JAR File
Includes:
Bean class
Remote interface
Home Interface
Deployment descriptor
(ejb.xml)
ShoppingListHome.class
ShoppingList.class
ShoppingListEJB.class
ejb.xml

20. Deploy Tool
Deploy Tool(Macromedia KAWA, J2EE deploytool) generates stub classes and object classes
Deploy Tool uses jar file and generates necessary classes for EJB server
Stub classes
Downloaded to a client dynamically at run time
Used by client
Object classes
Implement all corresponding interfaces
Used by EJB server

21. EJB Conceptual Architecture
lookup(“Customer")
JNDI Server
EJB Home Stub
Home Interface ƒ
EJB Home
Home Interface ‚
InitialContext „
EJB Server
create/find
EJB Object Stub
Remote Interface †
EJB Object
Remote Interface …
getList( )
EJB Class ‡ ˆ

22. Development Process EJB
Developer
Home Interface
Remote Interface
EJB class
Support classes
Deployer (Deploy tool)
Packaging Interfaces, EJB class, and support classes
Deploy the packaged EJB (jar file)
Server
Implement EJB
EJB Servers
CustomerHome.class
EJB
Devloper
Customer.class
CustomerEJB.class
ejb.xml

23. POS Component Example
Add, remove, and display a customer shopping list
ShoppingListSession
Display
Index.jsp DB
Add Remove
AddShoppingList
RemoveShoppingList
ShoppingCart
Table
Select, update, delete shopping list from ShoppingCart table
Display all shopping list from EJB
Form action to add / remove shopping list
Implement get, add, remove shipping list methods
Capture the Shopping list id
Call bean method to be fit with each action

24. POS Security Mechanism
Form Based JRun application security based on J2EE
User / Group / Role
Protect entire application JSPs / Servlets / EJBs
*) DatabaseAthentication.java to verify user using DB
POS
Authentication*
Servlet
Login.jsp
HTML
JSP
Servlet
EJB
Other Resources
Loginerror.jsp

25. POS Scheduler
Jrun provides a Scheduler servlet to execute actions at specified times
Scheduler servlet : allaire.jrun.scheduler.CronService
Defines the servlet in web.xml
Application defines Schedule.ini for the service
Schedule.ini includes the rule and the requests to be scheduled
* If this service is used in application, this application is not potable because JRun added this service.

26. Web.xml sample for scheduler
<servlet> defines the service </servlet>
<servlet>
<servlet-name>POSScheduler</servlet-name>
<servlet-class>allaire.jrun.scheduler.CronService</servlet-class>
<display-name>POSScheduler</display-name>
<description>Scheduler for POS System</description>
<init-param>
<param-name>schedfile</param-name>
<param-value>C:\JRun\3.0\servers\default\pos-app\schedule.ini</param-value>
</init-param>
<param-name>logfile</param-name>
<param-value>C:\JRun\3.0\servers\default\pos-app\scheduler-log\pos-scheduler.log</param-value>
<load-on-startup/>
</servlet>
Except those bold tags, developer can give any name or file

27. Schedule.ini Example Schedule.ini is defined in web.xml
<init-param>
<param-name>schedfile</param-name>
<param-value>C:\JRun\3.0\servers\default\pos-app\schedule.ini</param-value>
</init-param>
Developer can use any file name on that
Schedule.ini example
# This is the ini file for JRun scheduler
# Scheduler checks the shopping cart table every ten minutes and updates the shopping cart status.
# If the shopping cart items are found to be older than 2hr, those will be deleted.
# Those items to be older than 2hr are supposed to be not in the cart or customer left the store without checkout.
0 0,10,20,30,40,50 * * * *
Scheduler runs this servlet every ten minutes

28. Supplementary Issues Physical Security Mechanism
Barcode scanner integration(physical)
Credit card process integration(physical)
Business data exchange using XML