So, I finally got back around to this (still no solution). What you’re describing isn’t really what I’m after. What I’d like to do is take an object (or array of objects) and a list of keys and have Cayenne basically do the same fetching it does with it’s pre-fetching code.
So when I use addPrefetch to a query, by default it will execute a fetch for each of the relationships. This allows me to decide at the application level what keys are important to me. So something like this: CayenneUtilities.batchFetch(myDataObjects, “toOne”, “toMany”). It would execute a query to find all the objects in “toOne” for all the objects in myDataObjects (and the same for “toMany”). Based on seeing how Cayenne executes the prefetch queries (at least with UNDEFINED_SEMANTICS), I bet it would be pretty straight forward. But I haven’t looked at the code enough and it might be above my pay grade. ;) The downside (I think) with the way WOnder implemented it is it just uses primary keys to find the objects (lots of ORs), so depending on your database you had to also specify the number of myDataObjects to process at once. -Lon On Tue, Jul 5, 2016 at 11:07 PM, Andrus Adamchik <and...@objectstyle.org> wrote: > IIRC in EOF this was "probabilistic", with framework trying to guess which > other objects' relationships to include in batch fetch. So we'd also need > to track some kind of "affinity" of root objects between each other. > > The first step would be to patch Cayenne to make > org.apache.cayenne.reflect.FaultFactory injectable (currently it is > created inside EntityResolver). Then come up with a custom FaultFactory and > an algorithm for tracking the affinity of faults between each other. And > make sure it doesn't leak memory :) > > Andrus > > > > On Jul 6, 2016, at 12:20 AM, Mike Kienenberger <mkien...@gmail.com> > wrote: > > > > That'd be something I'd get some use out of as well. > > > > On Tue, Jul 5, 2016 at 5:19 PM, Lon Varscsak <lon.varsc...@gmail.com> > wrote: > >> I know I’ve asked this before, but I need a batch fetch utility class, > to > >> trigger batch fetching of relationships. I know pre-fetching will do > this, > >> but usually when I need it is after the fetch (and I don’t want to > always > >> do it even when it’s not needed). > >> > >> Anyone have any pointers on how to go about implementing this? > >> > >> -Lon > >
