Design Patterns in Modern C++: Reusable Approaches for Object-Oriented Software Design

© Dmitri Nesteruk 2018

Dmitri NesterukDesign Patterns in Modern C++https://doi.org/10.1007/978-1-4842-3603-1_21

21. State

Dmitri Nesteruk¹ 

(1)

St. Petersburg, Russia

 

I must confess: my behavior is governed by my state. If I didn’t get enough sleep, I’m going to be a bit tired. If I had a drink, I wouldn’t get behind the wheel. All of these are states and they govern my behavior: how I feel, and what I can and cannot do.

I can, of course, transition from one state to another. I can go get a coffee, and this will take me from sleepy to alert (I hope!). So we can think of coffee as a trigger that causes a transition of yours truly from sleepy to alert. Here, let me clumsily illustrate it for you:

1           coffee

2   sleepy --------> alert

So, the ...