public class MyRadioButtonGroup extends AbstractRadioButtonGroup<Integer> {

  private Integer myOldValue;

  public class RadioButton1 extends AbstractRadioButton {
    @Override
    protected Object getConfiguredRadioValue() {
      return Integer.valueOf(1);
    }
  }

  public class RadioButton2 extends AbstractRadioButton {
    @Override
    protected Object getConfiguredRadioValue() {
      return Integer.valueOf(2);
    }
  }

  @Override
  protected void execChangedValue() throws ProcessingException {
    super.execChangedValue();

    if(myOldValue > getValue()) {
      // do something
    }

    // last line of code for this method
    myOldValue = getValue();
  }
}