UML Distilled: A Brief Guide to the Standard Object Modeling Language, Third Edition

Chapter 10. State Machine Diagrams

State machine diagrams are a familiar technique to describe the behavior of a system. Various forms of state diagrams have been around since the 1960s and the earliest object-oriented techniques adopted them to show behavior. In object-oriented approaches, you draw a state machine diagram for a single class to show the lifetime behavior of a single object.

Whenever people write about state machines, the examples are inevitably cruise controls or vending machines. As I’m a little bored with them, I decided to use a controller for a secret panel in a Gothic castle. In this castle, I want to keep my valuables in a safe that’s hard to find. So to reveal the lock to the safe, I have to remove a strategic candle ...