private void drawDotsAndConnections(IFigure contents, DirectedGraph graph){ 
     for (int i = 0; i < graph.nodes.size(); i++) { 
         Node node = graph.nodes.getNode(i); 
         drawNode(contents, node); 
     } 
     for (int i = 0; i < graph.edges.size(); i++) { 
         Edge edge = graph.edges.getEdge(i); 
         drawEdge(contents, edge); 
     }   
 } 
 
 
 private void drawNode(IFigure contents, Node node){ 
   Dot dotFigure = new Dot(); 
   node.data = dotFigure; 
   int xPos = node.x; 
   int yPos = node.y;   
   contents.add(dotFigure); 
   contents.setConstraint(dotFigure, new Rectangle(xPos,yPos,-1,-1)); 
 } 
 
 
 private void drawEdge(IFigure contents, Edge edge){ 
     PolylineConnection wireFigure = new PolylineConnection(); 
  //edge.source is the Node to the left of this edge 
     EllipseAnchor sourceAnchor = new EllipseAnchor((Dot)edge.source.data); 

  //edge.target is the Node to the right of this edge 
  EllipseAnchor targetAnchor = new EllipseAnchor((Dot)edge.target.data); 
     wireFigure.setSourceAnchor(sourceAnchor); 
     wireFigure.setTargetAnchor(targetAnchor); 
     contents.add(wireFigure);      
 }