public static function getStringOperandsChoices()
    {
        $choices = array();

        $reflection = new \ReflectionClass(__CLASS__);
        foreach ($reflection->getConstants() as $name => $value) {
            if ('STRING_' === substr($name, 0, 7)) {
                $choices[$value] = strtolower(str_replace('STRING_', 'text.', $name));
            }
        }

        return array_flip($choices);
    }