/**
* Handle the subscribed event.
*
* @param GetGroupHeaderEvent $event The event.
*
* @return void
*/
public static function handle(GetGroupHeaderEvent $event)
{
if ($event->getValue() !== null) {
return;
}
$handler = new static();
$value = $handler->formatGroupHeader($event->getEnvironment(), $event->getModel(), $event->getGroupField(), $event->getGroupingMode(), $event->getGroupingLength());
if ($value !== null) {
$event->setValue($value);
}
}
