public function defaultSearchFilters()
    {
        $filters = array();

        foreach ($this->searchableFields() as $name => $spec) {
            if (empty($spec['filter'])) {
                /** @skipUpgrade */
                $filters[$name] = 'PartialMatchFilter';
            } elseif ($spec['filter'] instanceof SearchFilter) {
                $filters[$name] = $spec['filter'];
            } else {
                $filters[$name] = Injector::inst()->create($spec['filter'], $name);
            }
        }

        return $filters;
    }