code: public void invalidate(Envelope envelope) {
  		List<String> keys = index.getOverlappingKeys(envelope);
  		if (CacheIndexService.ALL_KEYS == keys) {
  			log.debug("clear all keys from cache");
  			clear();
  		} else {
  			log.debug("invalidate keys {}", keys);
  			for (String key : keys) {
  				remove(key);
  			}
  		}
  	}
docs: Invalidate all entries which (may) overlap with the given geometry.
  
  @param envelope envelope to test