package headfirst.singleton.chocolate;

public class ChocolateBoiler {
        private boolean empty;
        private boolean boiled;
        private static ChocolateBoiler uniqueInstance;

        private ChocolateBoiler() {
                empty = true;
                boiled = false;
        }

        public static ChocolateBoiler getInstance() {
                if (uniqueInstance == null) {
                        System.out.println("Creating unique instance of Chocolate Boiler");
                        uniqueInstance = new ChocolateBoiler();
                }
                System.out.println("Returning instance of Chocolate Boiler");
                return uniqueInstance;
        }

        public void fill() {
                if (isEmpty()) {
                        empty = false;
                        boiled = false;
                        // fill the boiler with a milk/chocolate mixture
                }
        }

        public void drain() {
                if (!isEmpty() && isBoiled()) {
                        // drain the boiled milk and chocolate
                        empty = true;
                }
        }

        public void boil() {
                if (!isEmpty() && !isBoiled()) {
                        // bring the contents to a boil
                        boiled = true;
                }
        }

        public boolean isEmpty() {
                return empty;
        }

        public boolean isBoiled() {
                return boiled;
        }
}