@Override public boolean is_tail(){
  Collection<BrdItem> contact_list=get_normal_contacts();
  if (contact_list.size() <= 1) {
    return true;
  }
  Iterator<BrdItem> iter=contact_list.iterator();
  BrdItem curr_contact_item=iter.next();
  int first_contact_first_layer=curr_contact_item.first_layer();
  int first_contact_last_layer=curr_contact_item.last_layer();
  while (iter.hasNext()) {
    curr_contact_item=iter.next();
    if (curr_contact_item.first_layer() != first_contact_first_layer || curr_contact_item.last_layer() != first_contact_last_layer) {
      return false;
    }
  }
  return true;
}

@ Override public boolean is_tail ( ) { Collection < BrdItem > contact_list = get_normal_contacts ( ) ; if ( contact_list . size ( ) <= 1 ) { return true ; } Iterator < BrdItem > iter = contact_list . iterator ( ) ; BrdItem curr_contact_item = iter . next ( ) ; int first_contact_first_layer = curr_contact_item . first_layer ( ) ; int first_contact_last_layer = curr_contact_item . last_layer ( ) ; while ( iter . hasNext ( ) ) { curr_contact_item = iter . next ( ) ; if ( curr_contact_item . first_layer ( ) != first_contact_first_layer || curr_contact_item . last_layer ( ) != first_contact_last_layer ) { return false ; } } return true ; }
checks , if the via has contacts on at most 1 layer .
