@Override
public double compare(City record1, City record2) {
Double first = record1.getLongitude();
Double second = record2.getLongitude();
if (first == null || second == null) return 0d;
if (first < 0 || second < 0) {
first = Math.abs(first);
second = Math.abs(second);
}
return sim.calculate(first, second);
}
