1.2 How to Model a J2EE Application

Modeling applications, whether J2EE or not, is largely a logical process. There are exceptions, for example places where you might wish to specify certain logic and you are constrained to use the natural language of the application, Java in the case of J2EE, or perhaps c# in a c#/.NET application, but these places are the exception rather than the rule.

The rule is - think logical. If you are a business modeler, it might not even occur to you to model the architecture. Good. But if you have used other generation tools you might think you need to add all sorts of things, such as interfaces, facades, transfer objects and the like. Banish these from your mind. They are no longer your problem.

You need to concern yourself with

• Modeling the processes you want the application to handle
• Modeling the services you need to call on from those processes
• Modeling the data structures needed to support the processes
• Modeling the connections to the table structures to access and modify common data

Often it is easier for an experienced systems analyst to start by modeling the persistent data structures, those which will form the tables. Business analysts will often prefer to start by modeling the processes. The choice is yours. Whichever you start with you will have to link the two up with dataviews and services and the chances are you will have to remodel many times during the design phase. This is not a bad thing and you should not worry about getting everything right first time. Regenerate your application frequently, take a look at what's coming out, prototype.

Before you can model anything there are the practicalities of setting up your project. This differs for each modeling tool and what follows is for RSA.

1. Think 'logical'. Don't worry about any implications of this being generated in J2EE or whether this has to accommodate a thousand users spread across the world.
2. Generate frequently. It doesn't take long to regenerate an application.

• How to set up a project
• How to add general application information
• How to model the table structure
• How to model the application data structures
• How to model services and operations
• How to model procedures and use cases
• How to generate the application
• What if it isn't in the box

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