new ChainedTransformer<Edge, Paint>(
new Transformer[] { new ConstantTransformer<Paint>(
Color.GREEN) }));
vv.getRenderContext().setEdgeStrokeTransformer(
new ConstantTransformer(new BasicStroke(2.5f)));
vv.getRenderer().setEdgeLabelRenderer(new BasicEdgeLabelRenderer());
vv.setBackground(Color.white);
// add a listener for ToolTips
vv.setVertexToolTipTransformer(new ToStringLabeller());