Summary


Business events and business use cases allow us to carve out a cohesive piece of the work for further modeling and study. By first understanding the effect each of the adjacent systems has on the work, we can come to understand the optimal product to build for that work. We arrive at the product scope by understanding the work in its context, not by presupposing that there will be a user and a computer, or by slavishly following the existing technology.

In some situations, you may not have any idea of the product scope. For example, suppose you are specifying business requirements so that an external supplier or outsourcer can come back to you and describe the product it can supply. To do so, you would write a scenario and then the requirements for each of the business use cases. The supplier would, in turn, determine which parts of those business use cases it can deliver as product use cases.

By using business events to partition the work, you take an external view of the work. You do not rely on how it happens to be partitioned internally at the moment or on someone's idea of how it might be partitioned in the future. Instead, you partition according to the most important view of the work: how the outside world (often your customers) sees it. Figure 4.14 is an overview of this kind of partitioning.

Figure 4.14.

The flow of requirements gathering. The response to each business eventthe business use caseis examined and an appropriate product determined. The analysts write the requirements for each product use case.


The idea of deriving the use cases from the business events means your requirements are grouped according to how the work responds to the business event. As a consequence, all of the response is part of the business use case, regardless of where in the work it happens to be partitioned at the moment. The result is a natural partitioning of the work. The actors are chosen as an outcome of this partitioning, with the end result being a work area and eventually a product that are more responsive to the outside world.




Mastering the Requirements Process
Mastering the Requirements Process (2nd Edition)
ISBN: 0321419499
EAN: 2147483647
Year: 2006
Pages: 371

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