private long hashTheBooking(Booking booking) {
String toHash = booking.getRoomName() + booking.getUserMail();
SimpleDateFormat ft = new SimpleDateFormat("HHddMMyyyy");
toHash += ft.format(booking.getDate());
toHash += ft.format(booking.getCreationDate());
toHash += booking.getSpectacle().getName();
toHash += booking.getTotalPrice();
return toHash.hashCode();
}
