protected String encodeBody(){
  String retval=Integer.toString(expires);
  if (!parameters.isEmpty()) {
    retval+=SEMICOLON + parameters.encode();
  }
  return retval;
}

protected String encodeBody ( ) { String retval = Integer . toString ( expires ) ; if ( ! parameters . isEmpty ( ) ) { retval += SEMICOLON + parameters . encode ( ) ; } return retval ; }
encode the header content into a string .
