ComplexDataConstraintValidator.php

<?php

namespace Drupal\Core\Validation\Plugin\Validation\Constraint;

use Drupal\Core\TypedData\ComplexDataInterface;
use Drupal\Core\TypedData\TypedDataInterface;
use Drupal\Core\TypedData\Validation\TypedDataAwareValidatorTrait;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Symfony\Component\Validator\Exception\UnexpectedTypeException;

/**
 * Validates complex data.
 */
class ComplexDataConstraintValidator extends ConstraintValidator {
    use TypedDataAwareValidatorTrait;
    
    /**
     * {@inheritdoc}
     */
    public function validate($data, Constraint $constraint) {
        // If un-wrapped data has been passed, fetch the typed data object first.
        if (!$data instanceof TypedDataInterface) {
            $data = $this->getTypedData();
        }
        if (!$data instanceof ComplexDataInterface) {
            throw new UnexpectedTypeException($data, 'ComplexData');
        }
        foreach ($constraint->properties as $name => $constraints) {
            $this->context
                ->getValidator()
                ->inContext($this->context)
                ->validate($data->get($name), $constraints, NULL, FALSE);
        }
    }

}