Design a object oriented class for a vending machine?

Question

class VendingMachine
    - boolean takeMoney(Money money);
    //Here item will contain type & quantity, no smart search required 
    //say user need half litere Coke.
    - Item pickItem(Item item); 
    - boolean isAvilable(Item item)
    - Double askForAmount(Input input);
    - Double valiDateAndReturnBalance(Money money);
class Money
    -CurrencyType type;
    -Double amount  
class MoneyValidator
    - boolean validate(Money amount);
class Item
    -ItemType type;
    -Double quantity
    -String barcode; // May be anything else to identify it
class Input
    - CommandType type;
    - Double quantity
    - ItemType type;
class display
    - void updateDisplay(String instructions)
class KeyPad
    - Input readUserInput(Key key);
class Key
    -KeyType type
    -Double value

enum CurrencyType
enum ItemType
enum KeyType
enum CommandType