I have been reading various posts on this topic. The most significant being: http://www.hibernate.org/124.html

I was wondering is there some pattern or design to allow lazy instantiation failover? Such as from the UI.

The very simplest would be have a configuration such that you could catch LazyInstantiationException and then take the suspect object and lock it to a newly created session.

One example I have of this is using the DisplayTag TagLib. If I don't preload the entire bean list that I pass to the UI it will throw an exception if I try to do an XML export etc. To work around this I have only found 2 solutions. The first is to preload every attribute of each bean at the DAO level when I retrieve them. This is obvously not a great solution. The second is to call a specific method in my DAO to preload specific attributes of the beans. This also is not the best since I have to anticipate what attributes will be accessed.

Another solution that I am considering is to somehow intercept the 'LazyInstantiationException' and have the framework auto associate the object with a new or current session. I am not sure how to approach this exactly and would welcome comments.

Thanks

Troy McKinnon

No takers on this?

I would really appreciate some direction on this one.

Troy

This has been discussed many times, search the forum.

I had search the forum, and unless I missed something I didn't see any definitive answers to my question.

From what I read you basically HAVE to preload everything you plan on using.. so you need knowledge of what the user will do before they do it.

I didn't see anything particular to optimizing this preloading by allow some type of callback or after the fact rebinding of an element if Exception was thrown.

Thanks

I prefer the eager fetching, described in chapter 7 of HIA.
In short: when your are constructing HQL query or Criteria, you can specify eager fetching for some lazy associations that you are going to use with:
left join fetch in HQL query or Criteria.setFetchMode with FetchMode.EAGER.

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Leonid