RelCollationImpl.java 文件源码

public int compareTo(@Nonnull RelMultipleTrait o) {
  final RelCollationImpl that = (RelCollationImpl) o;
  final UnmodifiableIterator<RelFieldCollation> iterator =
      that.fieldCollations.iterator();
  for (RelFieldCollation f : fieldCollations) {
    if (!iterator.hasNext()) {
      return 1;
    }
    final RelFieldCollation f2 = iterator.next();
    int c = Utilities.compare(f.getFieldIndex(), f2.getFieldIndex());
    if (c != 0) {
      return c;
    }
  }
  return iterator.hasNext() ? -1 : 0;
}