private function getDefaultSearchProperty($field = self::DEFAULT_SEARCH_FIELD, $analyzer = null)
    {
        if (!isset($this->defaultMappingFields[$field])) {
            throw new \InvalidArgumentException("Unable to find field {$field}.");
        }

        $property = $field;

        if ($analyzer !== null) {
            if (!in_array($analyzer, $this->defaultMappingFields[$field])) {
                throw new \InvalidArgumentException("Unable to find analyzer {$analyzer} for field {$field}.");
            }

            $property = sprintf("%s.%s", $field, $analyzer);
        }

        return $property;
    }