IN THIS CHAPTER
Case Study: Virtual Realty Listing Service (VRLS)
Overview of Struts
Structure of the VRLS application
Review the notion of a web application.
Use the VRLS case study to discuss the requirements gathering and application design processes.
Provide an overview of the Struts framework and examine the inner workings of a Struts application in the context of VRLS.
Explain the reasons behind application design decisions.
Propose enhancements to the VRLS application.
As we mentioned in Chapter 1, web applications are client–server applications that use a browser as their client program. However, web applications are not limited to the interactions between browsers and servers. Server-side application components can operate as "clients", interacting with back-end data sources such as databases, web services, and legacy systems. In multi-tier web applications, every set of adjacent tiers represents a pairing of a client and a server, and every intermediate tier may act as either a client or a server, depending on which of its neighbors it is interacting with. For example, just as the browser connects to the web server to make a request, the application component executing on the web server may connect to a business logic layer, acting as a client for that layer's services.
In the last few chapters, we have covered both client-side techniques and server-side ...