private Document getXmlResource(int aid) throws Exception {
	synchronized (BANNED) {
		CachedResource<Integer, Document> resource = getResourceCache().xml(aid, this::getResource).fetch(withPermit(fetchIfModified(), r -> {
			if (BANNED.get()) {
				throw new IllegalStateException("AniDB has already banned your IP. Please stop hitting AniDB for at least 24 hours.");
			}
			if (HARD_LIMIT.availablePermits() == 0) {
				log.warning("AniDB HTTP API daily limit has been exceeded. Processing will continue in 24 hours...");
				Cache.DISK_STORE.flush();
				TimeUnit.HOURS.sleep(24);
			}
			debug.finest(message("AniDB daily limit", HARD_LIMIT));
			HARD_LIMIT.acquirePermit();
			debug.finest(message("AniDB minutely limit", SOFT_LIMIT));
			SOFT_LIMIT.acquirePermit();
		})).expire(Cache.ONE_WEEK);

		// disable weekly expiration
		if ((BANNED.get() || HARD_LIMIT.availablePermits() < 100) && resource.available()) {
			log.config(message("AniDB cache expiration temporarily disabled due to heavy usage", aid, HARD_LIMIT));
			resource.expire(Cache.NEVER);
		}

		// retrieve resource
		Document dom = resource.get();

		// check for errors (e.g. <error>Banned</error>)
		String error = selectString("/error", dom);
		if (error != null && !error.isEmpty()) {
			// client error (cache expected response)
			if ("anime not found".equalsIgnoreCase(error)) {
				throw new LookupException(error, aid);
			}

			// server errors (do not cache unexpected response)
			resource.invalidate();

			if ("banned".equalsIgnoreCase(error)) {
				BANNED.set(true);
				throw new InvalidResponseException("AniDB has banned your IP due to excessive usage. Please try again in 24 hours or later.");
			}

			// unknown error
			throw new InvalidResponseException(error);
		}

		return dom;
	}
}