/** * This model requires that a BeerConsumer be persisted prior to assigning him/her a telephone * number. This is because the BeerConsumer id is part of the composite primary key, and that key * is needed for the map that holds the telephone numbers. */ public void addTelephoneNumber(TelephoneNumber telephoneNumber) { telephoneNumber.setBeerConsumer(this); telephoneNumbers.put(telephoneNumber.buildPK(), telephoneNumber); }