code: public void init(Converter converter, Converter convAlternate, Converter convCheckmark)
      {
          super.init(converter, convAlternate);
          m_convCheckmark = convCheckmark;
      }
docs: Initialize this converter.
  @param converter The next converter in the converter chain.
  @param convCheckmark The converter to check the state of (if true, use the alternate converter).
  @param converterAlt The converter to use if the checkmark is true.