When the customer enters into the xPetStore web site, he can:

• Sign into the site
• Sign off from the site
• Browses the catalog
• Updates its shopping cart
• Places its order. Then he will receive an email notification
• Manages its account

xPetstore will provide 2 implementations:

The EJB implementation:
The business layer is implemented with:

• EntityBean and CMP 2.0 for business objects
• a SessionBean to manages the application logic
• MessageDriverBean for asynchronous processing (sending email, processing customer orders)

• The View implemeented with JSP and Sitemesh
• The Model and Controller implemented with Struts.

The Servlet implementation:
The business layer is implemented with Plain JavaBean Object using Hibernate as persistence framework.

The web layers is implemented using the Model-View-Controller design pattern:

• The View implemeented with Velocity and Sitemesh
• The Model and Controller implemented with Webwork. All the business logic is implemented at this level.