code: private String[] splitIntoPlusMinusPatterns(AmountFormatContext amountFormatContext, String pattern) {
          DecimalFormatSymbols decimalFormatSymbols = amountFormatContext.get(DecimalFormatSymbols.class);
          char patternSeparator = decimalFormatSymbols != null ? decimalFormatSymbols.getPatternSeparator() : SUBPATTERN_BOUNDARY;
          return pattern.split(String.valueOf(patternSeparator));
      }
docs: Split into (potential) plus, minus patterns