Let's write code that demonstrates how to create a state machine based on the state diagram shown earlier in this chapter. Our state machine should cover the different states of a process and the transitions between them.
The State design pattern is usually implemented using a parent State class that contains the common functionality of all the states, and a number of concrete classes derived from State, where each derived class contains only the state-specific required functionality. In my opinion, these are implementation details. The State pattern focuses on implementing a state machine. The core parts of a state machine are the states and transitions between the states. It doesn't matter how those parts are implemented. ...
