// -expires in cached response
// the expires value gives us a very easy hint when the cache is stale
// sometimes, the expires date is set to the past to prevent that a page is cached
// we use that information to see if we should index it
final Date expires = responseHeader.expires();
if (expires != null && expires.before(new Date(GenericFormatter.correctedUTCTime()))) {
return "Stale_(Expired)";
}
// -lastModified in cached response
// this information is too weak to use it to prevent indexing