Redraw Graph on JUNG

Question

I build a graph using JUNG (Java Universal Network/Graph Framework) with the following code:

g = new SparseMultigraph<BusStop, Travel>();

//add some Vertex and Edges

Layout<String, String> layout1 = new CircleLayout(g);
layout1.setSize(new Dimension(300,300)); // sets the initial size of the layout space

VisualizationViewer vv = new VisualizationViewer(layout1);
vv.setPreferredSize(new Dimension(350,350)); //Sets the viewing area size

Transformer<BusStop,Paint> vertexPaint = new Transformer<BusStop,Paint>() {
    public Paint transform(BusStop b) {
        return Color.GREEN;
    }
};

Transformer<BusStop,Shape> vertexShape = new Transformer<BusStop,Shape>() {
    public Shape transform(BusStop b) {
        return new Rectangle(-20, -10, 40, 20);
    }
};

vv.getRenderContext().setVertexFillPaintTransformer(vertexPaint);
vv.getRenderContext().setVertexShapeTransformer(vertexShape);
vv.getRenderContext().setVertexLabelTransformer(new ToStringLabeller());
vv.getRenderer().getVertexLabelRenderer().setPosition(Position.CNTR);

GraphViewerForm = new edu.uci.ics.jung.visualization.GraphZoomScrollPane(vv);

Now, I want to add more vertices and edges to the graph.. how can I do this? What instructions should I run for the graph to be redrawn? Thanks!

Answer 1

If you are looking for redrawing the graph after user interaction, you have to add an EditingModalGraphMouse to your VisualizationViewer

    EditingModalGraphMouse gm = new EditingModalGraphMouse(vv.getRenderContext(), 
             vertexFactory, edgeFactory); 
    vv.setGraphMouse(gm);

the constructor must be fed with vertexFactory and edgeFactory objects derived from

Factory<E> and Factory<V>

whose job is to create a new instance of edge/vertices class via the create() method

Factory <BusStop> vertexFactory = new Factory<BusStop>() {
            public BusStop create() {
                return new BusStop();
            }
        };

same for the edgeFactory

Answer 2

After adding edges and vertices to the graph, you must call vv.repaint() to draw the changes.

Answer 3

If you want to add vertices and edges:

//add some Vertex and Edges
g.addVertex((BusStop)obj1);
g.addVertex((BusStop)obj2);
g.addEdge((Travel) trv1, obj1, obj2);

For example see how addVertex and addEdge is being used in SimpleGraphView.java