Data-Centric Applications with Vaadin 8

Implementing a service class

As mentioned before, we need to add some transaction and session handling code in order to use mapper classes. This can be done in service classes. A service class is simply a class that performs some kind of business logic (in contrast, a mapper class performs persistence-only logic). The following is an example of a class that encapsulates session handling in order to avoid coupling the UI with MyBatis-related logic:

public class MessageService {    public static List<Message> findAll() {        try (SqlSession session =             MyBatisService.getSqlSessionFactory().openSession()) {            MessageMapper mapper =              session.getMapper(MessageMapper.class);            return mapper.findAll();        }    }    public static void save(Message message) {        try (SqlSession ...