code: public Dater setClock(String clock) {
  		String tip = "clock format must HH:mm:ss";
  		checkArgument(checkNotNull(clock).length() == 8, tip);
  		List<String> pieces = Splitter.on(":").splitToList(clock);
  		checkArgument(pieces.size() == 3, tip);
  		return setClock(Ints.tryParse(pieces.get(0)), Ints.tryParse(pieces.get(1)), Ints.tryParse(pieces.get(2)));
  	}
docs: Sets the hour, minute, second to the delegate date, format is {@link DateStyle#CLOCK}
  
  @see #setClock(int, int, int)
  @see DateStyle#CLOCK
  @param clock
  @return