public boolean isMember(Principal p){
  if ((p.hashCode() & super.hashCode()) == p.hashCode())   return true;
 else   return false;
}

public boolean isMember ( Principal p ) { if ( ( p . hashCode ( ) & super . hashCode ( ) ) == p . hashCode ( ) ) return true ; else return false ; }
returns true if the passed principal is a member of the group .
