I'm currently using Struts2 in a project that is utilizing the Java Persistence API (JPA, specifically Hibernate) with container managed transactions (CMT). To access the Persistence layer, a layer was created using SLSBs as "service" objects which provide simple "<entity_type> get<entity_type>ById( int )" and "List<<entity_type>> get<entity_type>s()" type methods. The Struts2 Actions use these beans (by injection (provided by some interceptor, such as the EJB3 Plugin) or a JNDI lookup, it doesn't matter really) to get the instances of the entities.
Up until now, all of the properties of the entities that were being accessed to create the view were either eagerly fetched associations, or private members of the entity. Recently, I have the need to start using lazily fetched associations (self joins and the like), and need to find a way to extend the Persistence context through to the view generation. Although there isn't much need to explain, the error I am receiving is the following: ERROR [LazyInitializationException] failed to lazily initialize a collection of role: <private_member_name>, no session or session was closed I noticed recently that there was a "Full Hibernate" Plugin that supports injection of a Session (presumably into an Action?) and will close the Session after the view generation. This works fine for application managed persistence, but does not solve the issue of when using CMT (or at least to my knowledge). Searching the web for solutions to the problem resulted in a suggestion to create an interceptor (that runs after the Action, but before the view generation?) that does a JNDI lookup to create an EntityManager (extending the Persistence Context to the interceptor, I think). I'm not sure what this was supposed to resolve, but I have not tried this as 1) I'm not sure how to create such an interceptor and get it to "intercept" at the appropriate time, and 2) I don't think this would resolve anything, as I don't think this would really extend the Persistence Context through to the view generation. How are others resolving this issue and using lazy initialization? I have a few more ideas as last resorts, but I don't want to taint the responses, so I will hold onto them for now. Thanks, -Nate --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@struts.apache.org For additional commands, e-mail: user-h...@struts.apache.org
