Passing complex JPA Entities to the controller with POJO

My team is coding an application that involves editing wikipedia-like pages. It is similar to the problem we have with registration:

A straightforward implementation gives something like

public static void doRegistration(User user) {
//...
}

The user parameter is a JPA Entity. The User model looks something like this:

@Entity
public class User extends Model {

//some other irrelevant fields

@OneToMany(cascade = CascadeType.ALL)
public Collection<Query> queries;

@OneToMany(cascade = CascadeType.ALL)
public Collection<Activity> activities;
//...

I have read here and there that this fails. Now, in Play!, what is the best course of action we can take? There must be some way to put all that data that has to go to the server in one object, that easily can be saved into the database.

EDIT: The reason this fails is because of the validation fail. It somehow says "incorrect value" when validating collection ob开发者_如何学Cjects. I was wondering if this can be avoided.

SOLUTION: Changing the Collection to List has resolved the issue. This is a bug that will be fixed in play 1.2 :)

Thanks beforehand

this works. To be more clear, you can define a controller method like the one you wrote:

public static void doRegistration(User user) {
//...
}

That's completely fine. Just map it to a POST route and use a #{form} to submit the object, like:

#{form id:'myId', action:@Application.doRegistration()}
   #{field user.id} 
   [...]
#{/form}

This works. You may have problems if you don't add all the field of the entity in the form (if some fields are not editable, either use hidden inputs or a NoBinding annotation as described here).

EDIT: on the OneToMany subject, the relation will be managed by the "Many" side. That side has to keep the id of the related entity as a hidden field (with a value of object.user.id). This will solve all related issues.

It doesn't fail. If you have a running transaction, the whole thing will be persisted. Just note that transactions are usually running within services, not controllers, so you should pass it from the controller to the service.