Cloning UnitOfWorkQueryValueHolder omitting instantiation

Question

I am using toplink essential with weaving. I have a class
@Entity
class Target {
@Entity
class Source {
@ManyToOne
Target target;
@ManyToMany
Set<Target> targets;
Assume I load an instance of Source via an EntityManager em
Source s = em.find(Sourcre.class, ...);
Now I want to clone s without loading the instances of Target it refers to via s.target or s.targets
Since I am using weaving, this s will have an UnitOfWorkQueryValueHolder s._toplink_target taking care of lazy initialization of s.target. When cloning s, I have to "clone" this value holder either by using
sClone._toplink_target = new ValueHolder(s._toplink_target.getValue());
or may be by
cClone._toplink_target = s._toplink_target.clone();
I am not sure that the second method would be correct though. The first works. But both methods seem to enforce instantitaion of the original value holder - at least the instance t of Target being referred to by s is loaded into the EntityManager.
Is there a way to clone s without having to load t into the Entity Manager?
I have the same problem with the ManyToMany relation s.targets, which is represented by an IndirectSet. Is there a way to "clone" those indirect sets without having to load the elements referred by them into the EntityManager?
Thanks for any help coming forward, Thomas.

Answer 1

Creating the new ValueHolder() or a new ArraySet() with the old value is probably the best way to clone to a reference or a collection that is lazy. If you are making a deep clone then you may also clone the targets objects and would need to instantiate the relationship anyway.
If you really don't want to instantiate the relationship then it is more involved. Calling clone() on the value holder seems like it would work, what issue did you encounter? To clone an IndirectSet you could create a new IndirectSet(), and call setValueHolder() on the new set with a clone of the existing indirect set's value holder.
Another option would be to create your own ValueHolderWrapper which implements the ValueHolderInterface and takes another ValueHolderInterface and in its getValue() it would call the nested value holder's getValue(), setValue would set its local value.