public function __construct(ClassTargetIdentity $class, $fieldName)
 {
     parent::__construct($class->getClassName(), null, $fieldName);
     $this->class = $class;
 }
 public function __construct(ClassTargetIdentity $class, $objectId)
 {
     parent::__construct($class->getClassName(), $objectId);
     $this->class = $class;
 }