[OJB-developers] ObjectCache and IdentityFactory

[Florian B. <bf...@fl...>]

Hi!

I'm currently investigating how to improve the object cache and how to
create a "factory" for Identity objects.

The object cache already stores identities and objects in a HashMap, but
unfortunately you cannot retrieve the key of a value from a HashMap
reasonably. The idea is now to create a "DoubleHashMap" that maps keys to
values and values to keys in an efficient way using SoftReferences.
Additionally the map could implement things like throwing out gc'd entries
and rehashing in a separate thread, so adding objects to the Map would not
lead to a long processing time if the map decides that rehashing is needed.

Over the last week I've been looking around if there are any implementations
of this concept in the net but found nothing. Then I wrote a little
prototype to get a better feeling for the requirements and complexity of
such a class, but I am not really satisfied with it and it still needs a lot
of work until it is stable enough to be used in OJB.

Now the questions:

- Do you think this approach is valid and is it worth to pursue it

- Does anybody know of an implementation of this concept (I known the
jakarta project has a somewhat related class, but it is a DoubleTreeMap and
we do not need the overhead of sorting the objects).

- Does anybody know of junit tests for Map classes I could use for testing
this implementation

- What else do you think would be needed for such a class

If you have any comments or flames on this, don't hestitate to write a
message, I'd appreciate any comment.

best regards,
Florian