What is the best way to re-attach a detached entity?

[smokingapipe]

I have an object called customer. I'm using Seam, and an EntityManager is injected, and a customer object is successful injected. I try to merge the customer back like this:

entityManager.merge(customer);

but that does not work, because after that, I do:

if(! entityManager.contains(customer)) log.severe("Oh no it did not work");

Of course, it logs that the entityManager does not contain the customer.

What is the best way to re-attach a detached entity?

Should I do:

customer = entityManager.find(Customer.class, customer.getId());

?

That seems like it would re-attach, but surely there is some method within EntityManager to re-attach a detached entity without doing a find on it?

[smokingapipe]

Or the other option would be to remove and persist:

entityManager.remove(customer);
entityManager.persist(customer);

but that seems like it would not be a good solution. Surely this is something that comes up in nearly every Seam application, but I can't find any good suggestions on how to handle this.

[wolfc]

Please try:

customer = entityManager.merge(customer);

[smokingapipe]

That's what I did, but after I do the merge, I do:

if(! entityManager.contains(customer)) {
log.severe("the entity manager is broken");
}

and of course, that log entry shows up. Does this make any sense?

[aidan_b5]

I may be wrong but is this not to do with transactions?

try

entityManager.flush()

after you've done the merge but before you query the db

[taras1984]

I think Wolfc is right.
You have to try:

customer2 = entityManager.merge(customer);

not

entityManager.merge(customer);

I think customer2 is merged entity when customer after those codes remains detached.