/**
  * Create a new node inside a graph
  * @param SimpleGraph $oGraph
  * @param string $sId The unique identifier of this node inside the graph
  */
 public function __construct(SimpleGraph $oGraph, $sId)
 {
     parent::__construct($sId);
     $this->aIncomingEdges = array();
     $this->aOutgoingEdges = array();
     $oGraph->_AddNode($this);
 }