public void setHost(String host) throws ParseException { if (sentBy == null)
public void setHost(Host host) { if (sentBy == null) {
	public void setHost(String host) throws ParseException {		if (sentBy == null)			sentBy = new HostPort();		try {			Host h = new Host(host);			sentBy.setHost(h);		} catch (Exception e) {			throw new NullPointerException(" host parameter is null");		}	}