Section 2.6. Looking Ahead...

2.6. Looking Ahead...

As this application matures, the various pieces get pushed into different tiers. Instead of the servlet creating the CarBeans out of thin air, it will pass the request to an EJB. The EJB will eventually get the information out of a database. But for now we completed the first step toward a fully realized J2EE application.

If you are familiar with agile development methodologies, you know that having one working application in the hand is worth two that are still stuck in development. Even though the UI is just the tip of the iceberg in terms of the entire application, having this much in place is a huge milestone.

Nothing makes an application seem more real than a working set of screens, even if (as is the case here) it has nothing of substance behind the façade. It allows the user to see the program far more clearly and persuasively than index cards, white board drawings, or cocktail napkins. From the developer's perspective, it gives a clear idea of what blanks still need to be filled in (persistence, business logic, etc.).

Perhaps most importantly, it allows the UI to have the longest usage cycle. By the time the application is fully implemented, you and the users will have spent enough time working with the UI that all the usability and look-and-feel issues will have been long since been hammered out. As one of our customers said, "Because I was working with the screens from the very beginning, by the time the final application was delivered, I felt like I was already an expert."