(Oracle) J2EE Design Patterns.pdf

Using J2EE Design Patterns

Introduction

May 2002

OTN developers have implemented the Virtual Shopping Mall (VSM), a sample application that

demonstrates design patterns for building J2EE applications. A software design pattern describes an

approach to solving a recurring programming problem or performing a task. The design patterns

discussed in this article can improve the performance of J2EE applications over the Internet or an

intranet, and make them more flexible and easier to maintain.

Documents

Download

About the VSM Sample Application (HTML)

l The VSM sample

application

download (JAR file,

553 KB) includes

installation

instructions and

complete source

code.

l View the source

code online.

l View an online

demo of the VSM in

action.

Design Patterns in the VSM (HTML)

The following links provide background information that will

help you understand this sample application.

l J2EE Design Patterns

l EJB Design Patterns

Simplifying J2EE and EJB Development with BC4J

http://otn.oracle.com/sample_code/tech/java/ejb_corba/vsm/htdocs/vsmhome.html (1 of 2) [17.9.2002 17:13:05]

Using J2EE Design Patterns

http://otn.oracle.com/sample_code/tech/java/ejb_corba/vsm/htdocs/vsmhome.html (2 of 2) [17.9.2002 17:13:05]

About The VSM Sample Application

Using J2EE Design Patterns

About the VSM Sample Application

The Virtual Shopping Mall (VSM) sample application enables vendors to set up online shops, customers to browse through the

shops, and a system administrator to approve and reject requests for new shops and maintain lists of shop categories.

l About VSM User Roles

l Database Schema

l Conclusion

About VSM Users

The application identifies three types of users—Mall Administrator, Shop Owner and Mall Customer—each with different

privileges.

Mall Administrator The Mall Administrator is the superuser and has complete control over all the activities that can be

performed. The application notifies the administrator of all shop creation requests, and the

adminstrator can then approve or reject them. The administrator also manages the list of available

product categories. The administrator can also view and delete entries in the guestbook.

Shop Owner Any user can submit a shop creation request through the application. When the request is approved by

the Mall Administrator, the requester is notified, and from there on is given the role of Shop Owner.

The Shop Owner is responsible for setting up the shop and maintaining it. The job involves managing

the sub-categories of the items in the shop. Also, the shop owner can add or remove items from his

shop. The Shop Owner can view different reports that give details of the sales and orders specific to

his shop. The Shop Owner can also decide to close shop and remove it from the mall.

Mall Customer A Mall Customer can browse through the shops and choose products to place in a virtual shopping

cart. The shopping cart details can be viewed and items can be removed from the cart. To proceed

with the purchase, the customer is prompted to login. Also, the customer can modify personal profile

information (such as phone number and shipping address) stored by the application. The customer can

also view the status of any previous orders, and cancel any order that has not been shipped yet.

The following use-case diagram shows how each type of user interacts with the VSM application.

http://otn.oracle.com/sample_code/tech/java/ejb_corba/vsm/htdocs/vsmdemo.html (1 of 4) [17.9.2002 17:13:26]

About The VSM Sample Application

http://otn.oracle.com/sample_code/tech/java/ejb_corba/vsm/htdocs/vsmdemo.html (2 of 4) [17.9.2002 17:13:26]

About The VSM Sample Application

Database Schema

The figure below shows the database schema for the VSM application.

Conclusion

The Virtual Shopping Mall (VSM) sample application shows how design patterns can simplify enterprise development tasks, and

demonstrates approaches you can use to implement common J2EE design patterns. If you're interested in other approaches, you can

visit OTN to learn how Oracle's J2EE-compliant Business Components for Java (BC4J) framework provides off-the-shelf

implementations of numerous design patterns you would otherwise have to code by hand. The article Simplifying J2EE and EJB

Development with BC4J provides more information.

http://otn.oracle.com/sample_code/tech/java/ejb_corba/vsm/htdocs/vsmdemo.html (3 of 4) [17.9.2002 17:13:26]

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