Let’s start by jotting down an outline specification for the Depot application. We’ll look at the high-level use cases and sketch out the flow through the web pages. We’ll also try working out what data the application needs with the understanding that our initial guesses will likely be wrong.
Use cases
A use case is simply a statement about how some entity uses a system. Depot’s use cases are simple . We start off by identifying two different roles or actors: the buyer and the seller.
Depot’s use cases are simple (some would say tragically so). We start off by identifying two different roles or actors: the buyer and the seller.
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The buyer uses Depot to browse the products we have to sell, select some to purchase, and supply the information needed to create an order.
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The seller uses Depot to maintain a list of products to sell, determine the orders that are awaiting shipment, and mark orders as shipped.
For now, that’s all the detail we need. We could go into excruciating detail about what it means to maintain products and what constitutes an order ready to ship, but we can save that for later. If some details aren’t obvious, we’ll explore them soon enough as we reveal successive iterations of our work to the customer.
Speaking of getting feedback, let’s get some right now. Let’s make sure our initial approximate use cases are on the mark by asking our users. Assuming the use cases pass muster, we’ll figure out how the application will work from the perspectives of its various users.
Page flow
We always like to have at least a general sense of what the main pages in our applications will be and how users will navigate among them. This early in the development, these page flows will likely be incomplete, but they can still help us focus on what needs doing and clarify how actions will be sequenced.
Some folks like to use Photoshop, Word, or HTML to mock up web application page flows. For this course, we will be using illustrations.
The first sketch of the buyer flow is shown in the following figure.
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