public boolean deleteOwner(Principal caller,Principal owner) throws NotOwnerException, LastOwnerException {
  if (!ownerList.contains(caller))   throw new NotOwnerException();
  if (!ownerList.contains(owner)) {
    return false;
  }
 else {
    if (ownerList.size() == 1)     throw new LastOwnerException();
    ownerList.removeElement(owner);
    return true;
  }
}

public boolean deleteOwner ( Principal caller , Principal owner ) throws NotOwnerException , LastOwnerException { if ( ! ownerList . contains ( caller ) ) throw new NotOwnerException ( ) ; if ( ! ownerList . contains ( owner ) ) { return false ; } else { if ( ownerList . size ( ) == 1 ) throw new LastOwnerException ( ) ; ownerList . removeElement ( owner ) ; return true ; } }
deletes an owner . if this is the last owner in the acl , an exception is raised . < p > the caller principal must be an owner of the acl in order to invoke this method .
