protected function load_filters($context) {
        $filters = filter_get_active_in_context($context);
        $this->textfilters[$context->id] = array();
        $this->stringfilters[$context->id] = array();
        foreach ($filters as $filtername => $localconfig) {
            $filter = $this->make_filter_object($filtername, $context, $localconfig);
            if (is_null($filter)) {
                continue;
            }
            $this->textfilters[$context->id][$filtername] = $filter;
            if (in_array($filtername, $this->stringfilternames)) {
                $this->stringfilters[$context->id][$filtername] = $filter;
            }
        }
    }