According to dspace-api's Constants.java, items are type 2 and they
use a unique ID field of `id` instead of `owningItem`. There is no
need to check the bundleName for item types.
Also, I decided to use the main Solr query for item IDs because the
filter query parameter (fq) stores results in the filterCache and
can be quite expensive with cores storing tens of millions of docu-
ments (we currently have 149 million docs!). It makes sense to use
the filter query parameter to reduce the result set returned by the
main Solr query.
This whole business with negative query ranges is confusing as hell
and I'll definitely forget it in the future. In DSpace's Solr term-
inology a "download" is a view to some bitstream that lives in the
ORIGINAL bundle. This is where bitstreams that are uploaded during
the item submission process go, versus generated thumbnails, etc.
Alan Orth