code: @Override
      public boolean canParse(final String threshold) {
          if (threshold == null || threshold.isEmpty()) {
              return false;
          }
          switch (threshold.charAt(0)) {
          case '+':
          case '-':
              return !(threshold.startsWith("-inf") || threshold.startsWith("+inf"));
          default:
              return Character.isDigit(threshold.charAt(0));
          }
      }
docs: Method canParse.
  @param threshold String
  @return boolean