title: Draw a PolylineConnection between existing Nodes on a FigureCanvas
body: <p>I am having list of nodes to be drawn.Here Node means <code>RectangleFigure</code>. So, all these nodes are plotted first on canvas(<code>FigureCanvas</code>)
  Then I have a map maintained having dependency relations between nodes drawn earlier.
  In the map, keys are the nodes and values are nothing but a list of nodes maintained.</p>
  
  <p>e.g.  There are 3 nodes, [ClassA, ClassB, InterfaceC]</p>
  
  <p>I have them drawn on a canvas.
  And my map is like below:
  [ClassA=[ClassB], ClassB=[InterfaceC]]
  So, it means <code>ClassA extends ClassB</code> and <code>ClassB implements InterfaceC</code>.</p>
  
  <p>Now, I want to draw <code>PolylineConnection</code> in between the nodes drawn already ,using the map maintained.
  So, how can I proceed for this?</p>
  
  <p>Any pointers are really appreciated, Thanks in advance!</p>