Firstly my apologies if I should have been able to work this out from the documentation but I've been staring at the problem with no progress too long so I'd appreciate any help.

I have a simple one-to-many relationship and I have two requirements:

1. That the getter for the many side returns the results in a particular order. This I can do with a <set sort="myCustomComparator">.

2. That I can get the index of the child in it's collection. This I can do with <list><index column="index"></list>.

However I really want to combine the two requirements. I.e. I want Hibernate to order my children by the custom comparator and write the correct values to an index field in the table so that I can retrieve the index with a child.getIndex() option method call.

I assume this isn't really what the various one-to-many collection options are all about but could anyone suggest the best way to do it? Should I use callbacks to write the index value of the list onSave()?

Thanks,
Matt.

Hibernate appropriately sets the index value for list elements based on their position within the List (a List be definition is ordered). So when persisting the many side of the association, just make sure the List is sorted based upon your comparison requirements.

Then, when you hydrate the object graph to include this List, Hibernate will make sure the list elements are ordered by the index property.

So based on what you said, it seems like just an additional step prior to persisting the owner of the List association to make sure it is appropriately sorted.

Thanks, that cleared up my confusion and all is fixed now.

Matt.