java - Can Hibernate return a collection of result objects OTHER than a List?

Question

Does the Hibernate API support object result sets in the form of a collection other than a List?

For example, I have process that runs hundreds of thousands of iterations in order to create some data for a client. This process uses records from a Value table (for example) in order to create this output for each iteration.

With a List I would have to iterate through the entire list in order to find a certain value, which is expensive. I'd like to be able to return a TreeMap and specify a key programmatically so I can search the collection for the specific value I need. Can Hibernate do this for me?

Answer 1

If I understand correctly, you load a bunch of data from the database to memory and then use them locally by looking for certain objects in that list.

If this is the case, I see 2 options.

1. Dont load all the data, but for each iteration access the database with a query returning only the specific record that you need. This will make more database queries, so it will probably bu slower, but with much less memory consumption. This solution could easily be improved by adding cache, so that most used values will be gotten fast. It will of course need some performance measurement, but I usually favor a naive solution with good caching, as the cache can implemented as a cross-concern and be very transparent to the programmer.
2. If you really want to load all your data in memory (which is actually a form of caching), the time to transform your data from a list to a TreeMap (or any other efficient structure) will probably be small compared to the full processing. So you could do the data transformation yourself.

As I said, in the general case, I would favor a solution with caching ...