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Point Of Sale(POS) J2EE Application. (POS J2EE Application with JRun). < Master Degree Final Project >. Department : Computer Science Degree : Master Student : Woojin Choi ID : 0426367. Topics. Introduction of POS Application System requirement Application Map Database Diagram
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Point Of Sale(POS) J2EE Application (POS J2EE Application with JRun) < Master Degree Final Project > Department : Computer Science Degree : Master Student : Woojin Choi ID : 0426367
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 • 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 • 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 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
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 • 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 JRun HTTP Server(HTML) JSPEngine JDBC <> HTTP Servlet Container DB HTTP on LAN EJB Container
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
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 • 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) • 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 • 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 • 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 • 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 • 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 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 • Includes: • Bean class • Remote interface • Home Interface • Deployment descriptor (ejb.xml) ShoppingListHome.class ShoppingList.class ShoppingListEJB.class ejb.xml
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
lookup(“Customer") create/find EJB Home Stub EJB Home Home Interface Home Interface getList( ) EJB Object Stub EJB Object EJB Class Remote Interface Remote Interface EJB Conceptual Architecture JNDI Server ƒ ‚ InitialContext „ EJB Server † … ‡ ˆ
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
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
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
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 • <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 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 • Physical Security Mechanism • Barcode scanner integration(physical) • Credit card process integration(physical) • Business data exchange using XML