code: public synchronized void invalidateBucket(String bucket) {
      PrefixKey key = new PrefixKey(bucket, "");
  
      getPrefixSubMap(itemMap, key).clear();
      getPrefixSubMap(prefixMap, key).clear();
    }
docs: Invalidates all cached items and lists associated with the given bucket.
  
  @param bucket the bucket to invalidate. This must not be null.