JPA, EntityManager and RMI

Question

Hello,
in my client server application, I want to get a DAO from the server to add or update a business object.
My problem is that the DAO must have a property with the EntityManager so he can do his job, this EntityManager
is not serializable, so RMI throw a NotSerializableException, but when I set the property tansient, the EntityManager
will be null after serialize the DAO to the client.
How can I solve that problem?
Thanks.

Answer 1

teramor1 wrote:
Thank you! I undestand, the domain objects are not attached and therefor not JPA managed, when some changes are made to the objects.
When I take a Service Interface and take the implementation from the Rmi Server, so I can call update(...) the ServiceImplementation must have a property to a DAO and the DAO to an EntityManager, but the EntityManager is not serializable.
How can I detach the ServicImplementation from the DAO and/or the EntityManager so the Client gets the ServiceImplementation and can call the update(...) method and this method can do his job on the dao and the dao can do his job on the EntityManager?Assuming i understand your usage of the word "Service" (and i'm not sure i do), the client will never get an instance of the Service implementation. the Service implementation never leaves the server. a client gets a handle to the Service interface through some sort of jndi lookup. it then invokes remote methods on this Service which may return entity objects. then only things that travel between the client and server are the entity objects themselves.