private void nextStream() throws IOException {
  if (in != null) {
    in.close();
  }
  if (e.hasMoreElements()) {
    in=e.nextElement();
    if (in == null) {
      throw new NullPointerException("element is null");
    }
  }
 else {
    in=null;
  }
}

private void nextStream ( ) throws IOException { if ( in != null ) { in . close ( ) ; } if ( e . hasMoreElements ( ) ) { in = e . nextElement ( ) ; if ( in == null ) { throw new NullPointerException ( "element is null" ) ; } } else { in = null ; } }
sets up the next inputstream or leaves it alone if there are none left .
