executable validation

gistfile1.php

  /**
   * Implements \Drupal\Core\Executable\ExecutableInterface::valdidate().
   */
  public function valdidate() {
    $violations = new \Symfony\Component\Validator\ConstraintViolationList();

    if ($definitions = $this->getContextDefinitions()) {
      foreach ($definitions as $key => $definition) {
        // Validate any set values.
        if (isset($this->context[$key])) {
          $typed_context = $this->context[$key]->getTypedContext();
          $violations->addAll($typed_context->validate());
        }
        // @todo: If no value is set, make sure any mapping is validated.
      }
    }
    return $violations;
  }