Thanks Dan!
I'll give it a try when I am back at the office.
Regars,
Minto
PS. Regarding code formatting I prefer my own formatting (me being
stubborn ;-) which is consistent over my isis and not isis projects. But
thanks for the tip anyways. To reduce boilerplate (getters and setters)
I mostly use Lombok.
Op 22-9-2012 9:05, Dan Haywood schreef:
> Aha! Have found the problem. It's a good one.
>
> The problem was that DataNucleus didn't seem to have replaced the Parent's
> ArrayList with its own RDBMS-aware equivalent:
>
> @Persistent(mappedBy="parent")
> private final List<Child> children = new ArrayList<Child>();
>
> And the reason for that is "final".
>
> So, instead, this should read:
>
> @Persistent(mappedBy="parent")
> private List<Child> children = new ArrayList<Child>();
>
>
> Fixing this then discovered a second issue. JDO/DataNucleus gives us
> persistence-by-reachability. In the addChild() method, you had:
>
> public void addChild( @Named("Name") String name ) {
> final Child child = newTransientInstance(Child.class);
> child.setName(name);
> addToChildren(child);
> persist(child);
> }
>
> However, attaching the child to the parent will cause it to be persisted,
> and then calling persist() once again makes Isis throw an exception. So, I
> changed the code to:
>
> public void addChild( @Named("Name") String name ) {
> final Child child = newTransientInstance(Child.class);
> child.setName(name);
> addToChildren(child);
> persistIfNotAlready(child);
> }
>
> and it worked.
>
> This might indicate a slight inconsistency in the OS implementations. Not
> sure yet whether that's an issue or not. One (simple) solution is to
> change the semantics of persist() to be persistIfNotAlready()... that
> happens to be closer to JDO's semantics, and I don't think would break any
> other design assumptions in Isis.
>
> Anyway, you should be good to go.
>
> Cheers
> Dan
>
> PS: looking at your code, you might want to check out the CoffeeBytes
> plugin along with the Eclipse templates, both on the Isis website [1].
>
>
> [1]http://incubator.apache.org/isis/ide-support.html
>
--
ir. ing. Minto van der Sluis
Software innovator / renovator
Xup BV
Mobiel: +31 (0) 626 014541
