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Point Of Sale(POS) J2EE Application:

Point Of Sale(POS) J2EE Application Department : Computer Science Degree : Master Student : Woojin Choi ID : 0426367 (POS J2EE Application with JRun) < Master Degree Final Project >


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

Introduction of POS:

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

System Requirement:

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

Application Map:

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

Database Diagram:

Database Diagram

POS Components:

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, …

POS Workflow using J2EE design:

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

HTML / JSP / Servlet / EJB in POS:

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

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 Java 2 Enterprise Edition (J2EE)


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

POS Application with J2EE:

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 JSP 1.1 EJB 1.1 JNDI POS Application Work Flow Presentation : JSP Interface : Servlet Business Logic : EJB

Enterprise JavaBeans (EJB):

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

Entity Beans:

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, ...

Entity Beans:

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

Session Beans:

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

Session Beans:

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

Home / Remote Interface:

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

Packaging the Bean in a JAR File:

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

Deploy Tool:

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

EJB Conceptual Architecture:

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

Development Process EJB:

Development Process EJB CustomerHome.class Customer.class CustomerEJB.class ejb.xml EJB Devloper 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

POS Component Example:

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

POS Security Mechanism:

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 Login.jsp HTML JSP Servlet EJB Other Resources Authentication* Servlet Loginerror.jsp POS

POS Scheduler:

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.

Web.xml sample for scheduler:

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> <init-param> <param-name>logfile</param-name> <param-value>C:\JRun\3.0\servers\default\pos-app\scheduler-log\pos-scheduler.log</param-value> </init-param> <load-on-startup/> </servlet> Except those bold tags, developer can give any name or file

Schedule.ini Example:

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 * * * * http://localhost/pos/servlet/SchedulerForShoppingCart Scheduler runs this servlet every ten minutes

Supplementary Issues:

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

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