Visual Modeling with Rational Rose 2002 and UML

Complexity and Sequence Diagrams

Every time i teach a class, the question “How complex can a sequence diagram be?” is always asked. The answer I always give is “Keep them simple.” The beauty of these diagrams is their simplicity—it is very easy to see the objects, the object interactions, the messages between the objects, and the functionality captured by the scenario.

The next question is usually “What do I do about conditional logic?” (all the if, then, else logic that exists in the real world). Here, you again have a very subjective answer. If the logic is simple, involving only a few messages, I usually add the logic to one diagram and use notes and scripts to communicate the choices to be made. On the other hand, if the if, then, else logic ...