DeletedWorkspaceConstraintValidator.php

<?php

namespace Drupal\workspaces\Plugin\Validation\Constraint;

use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
use Drupal\workspaces\WorkspaceAssociationInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

/**
 * Checks if data still exists for a deleted workspace ID.
 */
class DeletedWorkspaceConstraintValidator extends ConstraintValidator implements ContainerInjectionInterface {
    
    /**
     * The workspace association service.
     *
     * @var \Drupal\workspaces\WorkspaceAssociationInterface
     */
    protected $workspaceAssociation;
    
    /**
     * Creates a new DeletedWorkspaceConstraintValidator instance.
     *
     * @param \Drupal\workspaces\WorkspaceAssociationInterface $workspace_association
     *   The workspace association service.
     */
    public function __construct(WorkspaceAssociationInterface $workspace_association) {
        $this->workspaceAssociation = $workspace_association;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('workspaces.association'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function validate($value, Constraint $constraint) {
        
        /** @var \Drupal\Core\Field\FieldItemListInterface $value */
        // This constraint applies only to newly created workspace entities.
        if (!isset($value) || !$value->getEntity()
            ->isNew()) {
            return;
        }
        if ($this->workspaceAssociation
            ->getTrackedEntities($value->getEntity()
            ->id())) {
            $this->context
                ->addViolation($constraint->message);
        }
    }

}