import javax.swing.Timer;

static void bindTimerToComponent(final Timer timer, JFrame f) {
  bindTimerToComponent(timer, f.getRootPane());
}

static void bindTimerToComponent(final Timer timer, JComponent c) {
  if (c.isShowing())
    timer.start();
  
  c.addAncestorListener(new AncestorListener {
    public void ancestorAdded(AncestorEvent event) {
      timer.start();
    }

    public void ancestorRemoved(AncestorEvent event) {
      timer.stop();
    }

    public void ancestorMoved(AncestorEvent event) {
    }
  });
}