UML actors and requirements

Here's a simple but interesting quote from a "Use Case" book I was reading last night: 

"If the actor is not part of the system, then the requirements cannot be a part of the system."

This statement seems obvious, but reflecting on some of my own work I can see where I have occasionally strayed in this direction, and having reviewed the work of other people, I have often seen these types of requirements in requirements documentation.

In other news, my battle with assertions continues. The good news is that I think I'm finally getting comfortable with where to use them and where not to use them. I'll release some source code examples shortly where I have found assertions to be useful.

While I'm thinking about it, click here for a quick tip on how to enable assertions when compiling and running a Java program.