code: void setRingAreaValid_(int path, boolean b_yes_no) {
  		int oldflags = getPathFlags_(path);
  		int flags = (oldflags | (int) PathFlags_.ringAreaValid)
  				- (int) PathFlags_.ringAreaValid;// clear the bit;
  		setPathFlags_(path, flags
  				| (b_yes_no ? (int) PathFlags_.ringAreaValid : 0));
  	}
docs: Sets exterior flag