Design Patterns Java™ Workbook

State (Chapter 22)

SOLUTION 22.1

As the state machine shows, when the door is open, a click will take the door to the StayOpen state, and a second click will start the door closing.

SOLUTION 22.2

Your code should look something like: public void complete() { if (state == OPENING) { setState(OPEN); } else if (state == CLOSING) { setState(CLOSED); } } public void timeout() { setState(CLOSING); }

SOLUTION 22.3

The code for status() relies on the state's class name and will report, for example, the status of an open door as "DoorOpen", instead of "Open". You can, of course, trim off the "Door" prefix, if you like.

SOLUTION 22.4

Your code should look something like: package com.oozinoz.carousel; public class DoorClosing extends DoorState { public ...