private void childInv(Node r){
  Edge e;
  Node s;
  for (int noa=0; (e=r.getChild(noa)) != null; noa++) {
    s=e.getTarget();
    s.setVisible(false);
    childInv(s);
  }
}

private void childInv ( Node r ) { Edge e ; Node s ; for ( int noa = 0 ; ( e = r . getChild ( noa ) ) != null ; noa ++ ) { s = e . getTarget ( ) ; s . setVisible ( false ) ; childInv ( s ) ; } }
recursively goes through the tree and sets all the children to invisible , not the parent though .
