@Override public void init(FilterConfig config) throws ServletException {
  try {
    expiry=Math.min(Math.max(MIN_EXPIRY,Long.parseLong(config.getInitParameter(CACHE_CONTROL))),MAX_EXPIRY);
  }
 catch (  NumberFormatException nfe) {
    LOGGER.warn("Failed to parse " + CACHE_CONTROL + " value.",nfe);
    expiry=null;
  }
}

@ Override public void init ( FilterConfig config ) throws ServletException { try { expiry = Math . min ( Math . max ( MIN_EXPIRY , Long . parseLong ( config . getInitParameter ( CACHE_CONTROL ) ) ) , MAX_EXPIRY ) ; } catch ( NumberFormatException nfe ) { LOGGER . warn ( "Failed to parse " + CACHE_CONTROL + " value." , nfe ) ; expiry = null ; } }
parse the cache - control configuration parameter as a long integer , and set the filter expiry value , modulo the minimum and maximum expiry constraints . if the configuration parameter is not present , or not a valid long integer value , then no cache - control headers will be applied by the filter .
