private String getPatternAsFixedString(Class<?> aTargetClass){
    String result = null;
    if ( BigDecimal.class == aTargetClass || Decimal.class == aTargetClass ) {
      result = "_1_ is not in the expected format/range : '_2_'";
    }
    else if ( Integer.class == aTargetClass ) {
      result = "_1_ is not an integer : '_2_'";
    }
    else if ( hirondelle.web4j.model.DateTime.class == aTargetClass ) {
      result = "_1_ is not in the expected date format 'YYYYMMDD' : '_2_'";
    }
    else if ( SafeText.class == aTargetClass ) {
      result = "_1_ contains unpermitted character(s).";
    }
    else if ( TimeZone.class == aTargetClass ) {
      result = "_1_ is not a valid Time Zone identifier: '_2_'";
    }
    else if ( Locale.class == aTargetClass ) {
      result = "_1_ is not a valid Locale identifier: '_2_'";
    }
    else {
      throw new AssertionError("Unexpected case for target base class: " + aTargetClass);
    }
    return result;
  }