2.3 Thinking About the Use Case and Page Flow

After creating an application workspace, you might begin the development process by doing some use case modeling to capture and communicate end-user requirements for the system to be built. Figure 2-3 shows a simple diagram created the use case diagrammer, one of a number of built-in UML diagramming tools. The diagram represents the simple technician management system that your managers are asking you to build. It consists of two related use cases: "Search for Technician by Name" and "Update Technician Profile." Using diagram annotations, you can capture particular requirements about what end users might need to see on the screens that will implement the use case. For example, you might note that managers want to see product names and technician expertise levels while browsing the search results.

Figure 2-3 Use Case Diagram for a Simple Technician Management System

By modeling the use cases, you begin to understand the kinds of user interface pages that will be required to implement end-user requirements. As shown in Figure 2-4, using the JSF page flow diagrammer, you can create a skeleton page flow for the system. Since the page flow is related to the user interface, this work happens in the context of the ViewController project in the workspace.

Using the Component Palette, you drop pages and named navigation rules to connect them. You should be able to implement the requirements using the combination of a searchtechnicians page and an updateprofile page. After using the searchtechnicians page to find the technician to update, the manager will proceed to updateprofile page to modify that technician's profile. After saving the changes, she'll return back to the searchtechnicians page. The navigation lines on the page diagram reflect this flow. The warning symbols you see are no reason for alarm. They indicate that you still have to create the page that the page icon represents. You'll see that in a later step of the walkthrough.

Figure 2-4 Skeleton JSF Page Flow Diagram in the ViewController Project

Note: JDeveloper supports the ability to do "UI first" development to mock up web page displays using unbound UI components, and then bind them to data later. However, in this walkthrough you'll be following a more traditional bottom up approach that is most similar to the way traditional 4GL tools attack the problem. Both styles of development are possible, or you can develop simultaneously and meet in the middle.