code: @Override
  	public void addNode(Node n) {
  		if (nodeAccess.getCapacity() < getNodeIndex(nodePos) + NODE_SIZE)
  			nodeAccess.ensureCapacity(nodeAccess.getCapacity() + INITIAL_NODE_FILE_SIZE);
  		nodIdMapping.put(n.getId(), nodePos);
  		
  		long nodeIndex = getNodeIndex(nodePos);
  		
  		nodeAccess.setLong( nodeIndex      , n.getId() );
  		nodeAccess.setLong( nodeIndex + 8  ,    -1l    );
  		nodeAccess.setLong( nodeIndex + 16 ,    -1l    );
  		
  		nodeAccess.setLong( 0 , ++nodePos );
  		
  	}
docs: Add a new node into the graph.
  @param n the node that will be added.