code: public static final Function<String,String> matchAndExtract(final String regex, final int group) {
          return new MatchAndExtract(regex, group);
      }
docs: <p>
  Matches the entire target String against the specified regular expression and extracts
  the specified group from it (as specified by <tt>java.util.regex.Matcher</tt>.
  </p>
  <p>
  Regular expressions must conform to the <tt>java.util.regex.Pattern</tt> format.
  </p>
  
  @param regex the regular expression to match against
  @param group the group number to be extracted
  @return the substring matching the group number