public org.jgraph.graph.CellView createView(GraphModel model, Object cell) {

    org.jgraph.graph.CellView view = null;
    if (model.isPort(cell)) view = new PortView(cell);
    else if (model.isEdge(cell)) view = createEdgeView(cell);
    else view = createVertexView(cell);
    return view;
  }