This chapter describes how the Rational Unified Process is represented. We introduce the key concepts of workers, activities, artifacts, and workflows as well as other elements used in the process's description.
A process describes who is doing what, how, and when. The Rational Unified Process is represented using four primary modeling elements:
Workers: the who
Activities: the how
Artifacts: the what
Workflows: the when
The first three elements are shown in Figure 3-1, and Figure 3-5 shows a workflow.
The central concept in the process is that of a worker. A
defines the behavior and responsibilities of an individual or a
It's helpful to think of a worker as a "hat" that an individual can wear during the project. One person may wear many hats. This distinction is important because it is natural to think of a worker as the individual or the team, but in the Rational Unified Process the
The following are examples of workers:
An individual acting as a system analyst leads and coordinates requirements
An individual acting as a designer defines the responsibilities, operations, attributes, and relationships of one or more classes and determines how they should be adjusted to the implementation environment.
An individual acting as a test designer is responsible for the planning, design, implementation, and evaluation of tests, including generating the test plan and test model, implementing the test procedures, and evaluating test coverage, results, and effectiveness.
Note that workers are not individuals; instead, they describe how individuals should behave in the business and the responsibilities of each individual. Individual
 However, we often write, "The designer of class X does this" when,
strictlyspeaking, we should write, "The individual acting as the designer for class X does this."
In the example shown in Figure 3-2, one individual, Sylvia, can be a Worker: Use-Case Designer in the morning and act as a Worker: Design Reviewer in the afternoon. Paul and Mary are both Designers, although they are likely responsible for different classes or different design packages.
For each worker, a set of expected skills must be provided by the individual who is designated as the worker. Sylvia must understand how to design a use case and how to review a part of the design.
Workers are usually denoted in the process prefixed with the word Worker, as in Worker: Integration Tester. Appendix A lists all workers defined in the Rational Unified Process