Auditar entrada e saída de um usuário no sistema

public class LoggerListener implements HttpSessionAttributeListener {
	private HttpSessionBindingEvent evt;
	
	private void logarEntrada() {
		HttpSession session = evt.getSession();
		try {
			Logger logBEAN = new Logger();
			LoggerDAO logDAO = new LoggerDAO();		
			logBEAN.setUserid(this.evt.getValue().toString());
			logBEAN.setDtentrada(new Timestamp(System.currentTimeMillis()));
			logBEAN.setIp("teste");
			logDAO.login(logBEAN);
			session.setAttribute("_LOGGER", logBEAN);
		} catch (Exception e) {
			System.out.println("------------------------------------------------");
			System.out.println("ERRO ao fazer o logger (index.jsp): "+ e.getMessage());
			System.out.println("------------------------------------------------");
		}	
	}
	private void logarSaida() {
		try {
			Logger bean = (Logger) this.evt.getValue();
			bean.setDtsaida(new Timestamp(System.currentTimeMillis()));
			LoggerDAO dao = new LoggerDAO();
			dao.logout(bean);
		} catch (Exception e) {
			System.out.println("------------------------------------------------");
			System.out.println("ERRO (LoggerListner.java): "+ e.getMessage() );
			System.out.println("------------------------------------------------");
		}		
	}
	public void attributeAdded(HttpSessionBindingEvent evt) {
		this.evt = evt;
		if ("j_username".equals(evt.getName())) {
			this.logarEntrada();
		}		
	}

	public void attributeRemoved(HttpSessionBindingEvent evt) {
		this.evt = evt;
		if ("_LOGGER".equals(evt.getName())) {
			this.logarSaida();
		}
	}

	public void attributeReplaced(HttpSessionBindingEvent evt) {
		this.evt = evt;
		if ("j_username".equals(evt.getName())) {
			this.logarSaida();
			this.logarEntrada();
		}		
	}
}