1.2. Assigning Responsibilities

There are many possible activities and artifacts in introductory OOA/D, and a wealth of principles and guidelines. Suppose we must choose a single practical skill from all the topics discussed here—a “desert island” skill. What would it be?

Why? Because it is one activity that must be performed—either while drawing a UML diagram or programming—and it strongly influences the robustness, maintainability, and reusability of software components.

Of course, there are other necessary skills in OOA/D, but responsibility assignment is emphasized in this introduction because it tends to be a challenging skill to master, and yet vitally important. On a real project, a developer might not have the opportunity to perform any other analysis or design activities—the “rush to code” development process. Yet even in this situation, assigning responsibilities is inevitable.

Consequently, the design steps in this book emphasize principles of responsibility assignment.