Traceability Revisited

As discussed in earlier chapters, traceability is an important benefit of the Rational Unified Process (RUP) and the use case-driven development approach. Now that we have covered textual requirements all the way to the physical manifestation of the software, it is appropriate to revisit traceability and conclude with a concrete example to illustrate the concept of traceability across the entire UML model.

Figure 15-9 shows traceability graphically for the TransferServlet. It demonstrates clearly that we can easily justify the existence of the TransferServlet component based on the textual requirements by following the traceability chain from the requirements to the component. We can do so because the textual requirements directly lead to the use case in the use case model, which in turn results in the TransferFunds control object in the analysis model, and so on. We also benefit from knowing that should the requirements associated with the Transfer funds use case change, it will be relatively straightforward to identify the impacted pieces of software throughout the model.