code: public StrTokenizer reset(final String input) {
          reset();
          if (input != null) {
              this.chars = input.toCharArray();
          } else {
              this.chars = null;
          }
          return this;
      }
docs: Reset this tokenizer, giving it a new input string to parse.
  In this manner you can re-use a tokenizer with the same settings
  on multiple input lines.
  
  @param input  the new string to tokenize, null sets no text to parse
  @return this, to enable chaining