I have done a lot of experimentation at the moment and I am using CDI dependency injection now for a simple wicket project. It is based on the code at utils.wamblee.org (wicket/inject).
The issue I am running into is the following. I am creating a detachable entity object which is simply a detachable model that safes the primary key in onDetach() + sets the object to null. It loads the object from persistent storage using entityManager.find(class, key) in the get() method (if not yet initialized). The detachable model is constructed using an entity manager obtained using CDI. However, in the following scenario, things go wrong: (1) edit an entity in a form, (2) click ok, (3) browser back. What happens is that I get a NullPointerException in EntityManagerWrapper on line 314 on glassfish v3. What is actually happening here is that the detachable model is being serialized but the EntityManagerWrapper (the contextual that delegates to the actual entitymanager to use) has transient fields which become null after deserialization. The EntityManagerWrapper is declared Serializable but in fact it isn't. Now, I have to do two things. First I have to report an issue on glassfish v3. I think the entity manager wrapper should be truly serializable and not just declared serializable. Second, I need to work around this problem. The solution I am thinking of is to use a simple utility that provides a truly serializable entity manager that delegates to an entity manager obtained using CDI. That would solve the problem with the detachable. However, there is one more issue which is the injection setup in the application. I still need the injection at component instantiation to allow use of injected objects in the constructor. But I still have a question whether it would be required to also use a IComponentOnBeforeRenderListener to do an additional injection in the onBeforeRender() method. The only reason I would need to do this is when pages in wicket are serialized as well. Do I need to take page serialization into account? Is there also a callback in wicket to listen for component serialization and deserialization?
