How to bind BeanItemContainer to Combobox - spring

Question

I have BeanItemContainer, which i load from database via jdbc:
BeanItemContainer myBeans = new BeanItemContainer<>(MyBean.class, mybeanDao.findAll());
and this is how i attach it to combobox:
Combobox combo = new Combobox();
combobox.setContainerDataSource(myBeans);
So far, so good. I received what i want, but for now i have a problem -
How do i get actual id that has been selected? This must be synchronized (id selected in combobox is actual entry in database).
I have no idea, how to solve this problem
Please help
P.S MyBean class
public class MyBean {
private Long id;
private String field1;
*** getters /setters ***
and toString() {} method
}

Answer 1

Here is the code:
#Theme("mytheme")
public class MyUI extends UI {
#Override
protected void init(VaadinRequest vaadinRequest) {
final VerticalLayout layout = new VerticalLayout();
layout.setMargin(true);
layout.setSpacing(true);
setContent(layout);
BeanItemContainer myBeans = new BeanItemContainer<>(MyBean.class, getBeans());
ComboBox combo = new ComboBox();
combo.setContainerDataSource(myBeans);
combo.setItemCaptionMode(AbstractSelect.ItemCaptionMode.PROPERTY);
combo.setItemCaptionPropertyId("field");
combo.addValueChangeListener(new Property.ValueChangeListener() {
#Override
public void valueChange(Property.ValueChangeEvent event) {
MyBean bean = (MyBean) combo.getValue();
Notification notif = new Notification("Selected Bean Id: "+bean.getId(), Notification.Type.TRAY_NOTIFICATION);
notif.setPosition(Position.TOP_CENTER);
notif.show(Page.getCurrent());
}
});
layout.addComponent(combo);
}
#WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
#VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
public static class MyUIServlet extends VaadinServlet {
}
public class MyBean {
private Long id;
private String field;
public MyBean(Long id, String field) {
this.id = id;
this.field = field;
}
public Long getId() {
return id;
}
public String getField() {
return field;
}
}
public ArrayList<MyBean> getBeans() {
ArrayList<MyBean> beans = new ArrayList<>();
MyBean bean = new MyBean(1l, "Vikrant");
beans.add(bean);
bean = new MyBean(2l, "Rampal");
beans.add(bean);
bean = new MyBean(3l, "viky");
beans.add(bean);
return beans;
}
}

Answer 2

If I understood the question correctly combo.getValue() should give you the MyBean instance relative to the current selection (or null if no item is selected)