code: private <T> T getCached(String prefix, String postfix, Class<T> cls) {
      return cls.cast(cache.get(prefix + '.' + postfix));
    }
docs: Get a value from the cache (to avoid repeated parsing)
  
  @param <T> Type
  @param prefix Tree name
  @param postfix Property name
  @param cls Class restriction
  @return Resulting value