challenging “scoping” phase, in which agreement on the components of the vision must
be generated between the people or groups involved. In such a process, what’s in and
what’s out can be a key determinant of the success of the project, especially because this
effort is usually when initial estimates of costs are set forth.
Often, as the object-oriented expert, you join the project after the vision has been
articulated.Step 2: The Analysis Phase: Gathering Requirements ........................................
Some companies confuse the vision statement with the requirements. A strong vision is
necessary, but it is not sufficient. To move on to design, you must understand how the
product will be used and how it must perform. The goal of the analysis phase is to articu-
late and capture these requirements. The outcome of the analysis phase is the production
of a requirements document. The first section in the requirements document is the use-
case analysis.Use Cases........................................................................................................
The driving force in analysis, design, and implementation is the use cases. A use caseis
nothing more than a high-level description of how the product will be used. Use cases
drive not only the analysis, but they also drive the design, they help you determine the
classes, and they are especially important in testing the product.
Creating a robust and comprehensive set of use cases might be the single most important
task in analysis. It is here that you depend most heavily on your domain experts—those
experts having the most information about the business requirements you are trying to
capture.
Use cases pay little attention to the details of the user interface, and they pay no attention
to the internals of the system you are building. Rather, they should be focused on the
interactions that need to occur and those people and systems (called actors) that will
need to be working together to produce the desired results.
To summarize, the following are some definitions:- Use case—A description of how the software will be used
- Domain experts—People with expertise in the domain(area) of business for
which you are creating the product - Actor—Any person or system that interacts with the system you are developing
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