public Element addElementToRegistry(Element element,boolean filter){
  if (element == null)   return (this);
  setFilterState(filter);
  addElementToRegistry(Integer.toString(element.hashCode()),element);
  return (this);
}

public Element addElementToRegistry ( Element element , boolean filter ) { if ( element == null ) return ( this ) ; setFilterState ( filter ) ; addElementToRegistry ( Integer . toString ( element . hashCode ( ) ) , element ) ; return ( this ) ; }
registers an element in the head element list
