isInternal() public method

An internal NodeData should never produce a Node object.
public isInternal ( ) : boolean
return boolean
 /**
  * Creates a node from the given NodeData container.
  *
  * If this factory has previously created a Node for the given $node and it's dimensions,
  * it will return the same node again.
  *
  * @param NodeData $nodeData
  * @param Context $context
  * @return NodeInterface
  * @throws NodeConfigurationException if a configured 'class' for a Node does not exist or does not inherit NodeInterface
  */
 public function createFromNodeData(NodeData $nodeData, Context $context)
 {
     if ($nodeData->isInternal()) {
         return null;
     }
     $internalNodeIdentifier = $nodeData->getIdentifier() . spl_object_hash($context);
     // In case there is a Node with an internal NodeData (because the NodeData was changed in the meantime) we need to flush it.
     if (isset($this->nodes[$internalNodeIdentifier]) && $this->nodes[$internalNodeIdentifier]->getNodeData()->isInternal()) {
         unset($this->nodes[$internalNodeIdentifier]);
     }
     if (!isset($this->nodes[$internalNodeIdentifier])) {
         // Warning: Alternative node implementations are considered internal for now, feature can change or be removed anytime. We want to be sure it works well and makes sense before declaring it public.
         $class = $nodeData->getNodeType()->getConfiguration('class') ?: $this->objectManager->getClassNameByObjectName(NodeInterface::class);
         if (!in_array($class, static::getNodeInterfaceImplementations($this->objectManager))) {
             throw new NodeConfigurationException('The configured implementation class name "' . $class . '" for NodeType "' . $nodeData->getNodeType() . '" does not inherit from ' . NodeInterface::class . '.', 1406884014);
         }
         $this->nodes[$internalNodeIdentifier] = new $class($nodeData, $context);
     }
     $node = $this->nodes[$internalNodeIdentifier];
     return $this->filterNodeByContext($node, $context);
 }