class Diesel extends FuelType {
    public static FuelType getInstance(){
        return instance;
    }

    public String toString(){
        return "Diesel";
    }

        // Return the mean amount of fuel to be delivered for this
        // particular fuel type.
    protected long meanAmount(){
        return 200L;
    }

        // Prevent arbitrary construction.
    protected Diesel(){
    }

    private static final FuelType instance = new Diesel();
}