static int[] findMinMaxLengthsInSymbols(String[] symbols) {
    int min = Integer.MAX_VALUE;
    int max = 0;
    for (String symbol : symbols) {
      int len = symbol.length();
      // some SENTINEL values can be empty strings, the month at index 12 or the weekday at index 0
      if(len == 0)
        continue;
      min = Math.min(min, len);
      max = Math.max(max, len);
    }
    return new int[]{min, max};
  }
@Test
  public void emptyStringValuesShouldBeIgnoredByFindMinMaxLengthsInSymbols() {
    String[] symbols = new String[]{"aaa", ""};
    int[] results = CharSequenceToRegexMapper.findMinMaxLengthsInSymbols(symbols);
    assertEquals(3, results[0]);
    assertEquals(3, results[1]);
  }