public static void addStock(String uid, String id, int amount) {
    	if(checkUserExistance(uid))
    	{
    	stocks = UserControl.getUserStock(uid);
        if (stocks.containsKey(id)) {
            stocks.put(id, stocks.get(id) + amount);
        } else {
            stocks.put(id, amount);
        }       
        try {
        	
        	Stock currentStock = StockControl.queryStock(id);
            System.out.println(currentStock);
        	UserStorageAccess xmlAccessor = new UserStorageAccess();
			xmlAccessor.addStock(uid,currentStock .getPrice()*amount,stocks);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    	}
    }