public Enumeration<? extends Principal> members(){
  Vector<Principal> v=new Vector<Principal>(1);
  v.addElement(this);
  return v.elements();
}

public Enumeration < ? extends Principal > members ( ) { Vector < Principal > v = new Vector < Principal > ( 1 ) ; v . addElement ( this ) ; return v . elements ( ) ; }
returns an enumeration which contains the subnet mask .
