abstract sclass DynSCP extends DynModule {

  transient SingleComponentPanel scp;

  transient ReliableSingleThread rstRevisualize2 = new(r revisualize2_impl);

  transient L<Runnable> afterVisualize2;

  static bool verbose;

  /*final*/ JComponent visualize() {

    scp = singleComponentPanel();

    scp.setComponent(visualize2());

    pcallFAll(afterVisualize2);

    ret scp;

  }

  void unvisualize() { scp = null; unvisualize2(); }

  JComponent visualize2() { null; }

  void unvisualize2() {} // overridable

  void revisualize2() {

    rstRevisualize2.trigger();

  }

  void revisualize2_impl() enter {

    //lock lock;

    if (scp == null) ret;

    JComponent c = visualize2();

    if (c != scp.getComponent()) {

      if (verbose) print("Setting component");

      scp.setComponent(c);

      pcallFAll(afterVisualize2);

    }

  }

  void setComponent(Component c) {

    if (scp != null) scp.setComponent(c);

  }

  // usually it'll be a JComponent

  JComponent getComponent() {

    ret scp == null ? null : (JComponent) scp.getComponent();

  }

  bool isShowing() { ret scp != null; }

  bool isShowing(Component c) { ret isComponentShowing(c); }

  void afterVisualize2(Runnable r) {

    afterVisualize2 = createOrAddToSyncList(afterVisualize2, r);

  }

}