@ModelAttribute: Interactions between 'referenceData' and 'formBackingObject'

[samspot]

I'm trying to convert our most complicated spring 2 controller to spring 3 with annotations. This controller has a ton of reference data, and some of it needs a loaded model to do its thing.

The issue I'm having is that once a referenceData style method includes the model as a parameter, the method for that model is no longer called.

Here are some snippets:

    // reference data
    @ModelAttribute("packages")
    public List<StretchPackage> getPackages(@ModelAttribute("eventModelObj") EventModel model){
        return packageDao.getForUser(model.getClientId());
    }
    
    // form backing object
    // This is invoked when getPackages does NOT have the model passed to it
    // If i remove it from getPackages(), or rename it to @ModelAttribute("eventModelObj111") it is invoked
    @ModelAttribute("eventModelObj")
    public EventModel formBackingObject(HttpServletRequest request){
        EventModel model = new EventModel();
        // do lots of stuff
        return model;
    }

I'm pretty sure I'm not doing this the right way, but the documentation is light on information. Is it possible to have a 'referenceData' method use the form backing object? If so, how?

[samspot]

I figured out what was wrong... I was missing an annotation at the class level:

@Controller
@SessionAttributes("eventModelObj")
public class EventEditorController {

Adding the @SessionAttributes annotation causes it to work as expected.