private JPanel setupRadio() {
    radioButtonPanel = new JPanel();
    radioButtonPanel.setLayout(new BoxLayout(radioButtonPanel, BoxLayout.PAGE_AXIS));
    radioButtonPanel.setPreferredSize(new Dimension(200,100));
    radioButtonPanel.setVisible(true);

    radioButtonSource = new JRadioButton("Source Hosts", true);
    radioButtonSource.setFont(font);
    radioButtonDestination = new JRadioButton("Destination Hosts",false);
    radioButtonDestination.setFont(font);
    radioButtons = new ButtonGroup();
    radioButtons.add(radioButtonSource);
    radioButtons.add(radioButtonDestination);
    radioButtonPanel.add(radioButtonSource);
    radioButtonPanel.add(radioButtonDestination);
    return radioButtonPanel;
  }