public void addHole(EdgeRing holeER){
  holeER.setShell(this);
  LinearRing hole=holeER.getRing();
  if (holes == null)   holes=new ArrayList();
  holes.add(hole);
}

public void addHole ( EdgeRing holeER ) { holeER . setShell ( this ) ; LinearRing hole = holeER . getRing ( ) ; if ( holes == null ) holes = new ArrayList ( ) ; holes . add ( hole ) ; }
adds a hole to the polygon formed by this ring .
