protected static void handleETagFor(RestxRequest req, RestxResponse resp, Iterable<Entry<String, String>> entries) {
Hasher hasher = Hashing.sha1().newHasher();
for (Entry<String, String> entry : entries) {
hasher.putString(entry.getKey(), Charsets.UTF_8).putString(entry.getValue(), Charsets.UTF_8);
}
new ETag(hasher.hash().toString(), CacheControl.MUST_REVALIDATE).handleIn(req, resp);
}