public void removePhoneNumber(TelephoneNumber telephoneNumber) { Enumeration keys = ((Hashtable) telephoneNumbers).keys(); while (keys.hasMoreElements()) { Object key = keys.nextElement(); TelephoneNumber potentialTelephoneNumber = (TelephoneNumber) telephoneNumbers.get(key); if (potentialTelephoneNumber.equals(telephoneNumber)) { telephoneNumbers.remove(key); potentialTelephoneNumber.setBeerConsumer(null); return; } } }