protected function getFacetParameters() {
        $facetParameters = [];
        $facetParameters['facet'] = 'true';
        $facetParameters['facet.mincount'] = $this->getMinCount();
        $facetParameters['facet.limit'] = $this->getLimit();
        $facetParameters['facet.field'] = $this->getFields();

        foreach ($this->getAdditionalParameters() as $additionalParameterKey => $additionalParameterValue) {
            $facetParameters[$additionalParameterKey] = $additionalParameterValue;
        }

        if ($facetParameters['json.facet']) {
            $facetParameters['json.facet'] = json_encode($facetParameters['json.facet']);
        }

        $facetParameters = $this->applySorting($facetParameters);
        return $facetParameters;
    }