How can I generate 100 random number of nodes from the whole graph Gephi Toolkit?

I'm working on a project and I'm using Gephi toolkit.I need to generate 100 random number of nodes from the whole graph.

public void script() {
        //Init a project - and therefore a workspace
        ProjectController pc = Lookup.getDefault().lookup(ProjectController.class);
        pc.newProject();
        Workspace workspace = pc.getCurrentWorkspace();
 GraphModel graphModel = Lookup.getDefault().lookup(GraphController.class).getGraphModel();
        PreviewModel model = Lookup.getDefault().lookup(PreviewController.class).getModel();
        ImportController importController = Lookup.getDefault().lookup(ImportController.class);
        FilterController filterController = Lookup.getDefault().lookup(FilterController.class);
        AppearanceController appearanceController = Lookup.getDefault().lookup(AppearanceController.class);
        AppearanceModel appearanceModel = appearanceController.getModel();

        //Import file       
        Container container;
        try {
           // File file = new File(getClass().getResource("/org/gephi/toolkit/demos/polblogs.gml").toURI());
           File file = new File(getClass().getResource("/org/gephi/toolkit/demos/Book3.csv").toURI()); 
           container = importController.importFile(file);
            container.getLoader().setEdgeDefault(EdgeDirectionDefault.DIRECTED);   //Force DIRECTED
        } catch (Exception ex) {
            ex.printStackTrace();
            return;
        }

        //Append imported data to GraphAPI
        importController.process(container, new DefaultProcessor(), workspace);


        //See if graph is well imported
        DirectedGraph graph = graphModel.getDirectedGraph();
        System.out.println("Nodes: " + graph.getNodeCount());
        System.out.println("Edges: " + graph.getEdgeCount());

This code returns number of nodes and edges..but I can't find a function to extract a subset of nodes randomly...I need to print out number of nodes not all the nodes because i'm working on Genetic algorithm and i'm needing to generate initial population...please any idea.