code: public boolean allPlaced(IRingSet rs) {
          for (int i = 0; i < rs.getAtomContainerCount(); i++) {
              if (!((IRing) rs.getAtomContainer(i)).getFlag(CDKConstants.ISPLACED)) {
                  return false;
              }
          }
          return true;
      }
docs: True if coordinates have been assigned to all atoms in all rings.
  
  @param   rs  The ringset to be checked
  @return  True if coordinates have been assigned to all atoms in all rings.