protected function initExtensions()
{
if (!$this->extensionsInitialized) {
foreach ($this->getExtensions() as $extension) {
$this->attributes = array_merge_recursive($this->attributes, $extension->getAttributes());
$this->nodes = array_merge_recursive($this->nodes, $extension->getNodes());
foreach ($extension->getSubscribers() as $subscriber) {
$this->dispatcher->addSubscriber($subscriber);
}
}
$this->extensionsInitialized = true;
}
}