class UnprocessableHttpEntityException

class UnprocessableHttpEntityException extends HttpException {
    use DependencySerializationTrait;
    
    /**
     * The constraint violations associated with this exception.
     *
     * @var \Drupal\Core\Entity\EntityConstraintViolationListInterface
     */
    protected $violations;
    
    /**
     * UnprocessableHttpEntityException constructor.
     *
     * @param \Exception|null $previous
     *   The pervious error, if any, associated with the request.
     * @param array $headers
     *   The headers associated with the request.
     * @param int $code
     *   The HTTP status code associated with the request. Defaults to zero.
     */
    public function __construct(\Exception $previous = NULL, array $headers = [], $code = 0) {
        parent::__construct(422, "Unprocessable Entity: validation failed.", $previous, $headers, $code);
    }
    
    /**
     * Gets the constraint violations associated with this exception.
     *
     * @return \Drupal\Core\Entity\EntityConstraintViolationListInterface
     *   The constraint violations.
     */
    public function getViolations() {
        return $this->violations;
    }
    
    /**
     * Sets the constraint violations associated with this exception.
     *
     * @param \Drupal\Core\Entity\EntityConstraintViolationListInterface $violations
     *   The constraint violations.
     */
    public function setViolations(EntityConstraintViolationListInterface $violations) {
        $this->violations = $violations;
    }

}