Hi Shawn, thanks for the prompt reply! > On Nov 29, 2018, at 4:55 PM, Shawn Heisey <apa...@elyograg.org> wrote: > > On 11/29/2018 2:01 PM, Thomas L. Redman wrote: >> Hi! I am wanting to do nested facets/Grouping/Expand-Collapse using SolrJ, >> and I can find no API for that. I see I can add a pivot field, I guess to a >> query in general, but that doesn’t seem to work at all, I get an NPE. The >> documentation on SolrJ is sorely lacking, the documentation I have found is >> less than a readme. Are there any books that provided a good tretise on >> SolrJ specifically? Does SolrJ support these more advanced features? > > I don't have any specific details for that use case.
Check out page 498 of the PDF, that includes a brief but powerful discussion of the JSON Facet API. For just one example, I am interested in faceting a nominal field within a date range bucket. Example: I want to facet publication_date field into YEAR buckets, and within each YEAR bucket, facet on author to get the most prolific authors in that year, AND to also facet genre with the same bucket to find out how much scifi, adventure and so on was produced that year. From what I am seeing, beyond pivots(and pivots won’t support this specific use case), I don’t see this capability is supported by the SolrJ API, but this is a hugely powerful feature, and needs to be supported. Furthermore, I want to be able to support a vaste range of facets within a single query, perhaps including some collapse and expand, groupings and so on. > > If you share the code that gives you NPE, somebody might be able to help you > get it working. I haven’t looked in to this enough to drop it in somebody elses' lap at this point, I suspect I am not using the API correctly. And since this won’t allow what I want, I’m not too worried about it. > > The best place to find documentation for SolrJ is actually SolrJ itself -- > the javadocs. Much of that can be accessed pretty easily if you are using an > IDE to do your development. Here is a link to the top level of the SolrJ > javadocs: > > https://lucene.apache.org/solr/7_5_0/solr-solrj/index.html > <https://lucene.apache.org/solr/7_5_0/solr-solrj/index.html> The JavaDocs are limited. I surmise from tracing the code a bit though that I need to rely less on methods provided directly by SolrQuery, and add parameters using methods of the superclasses more frequently. Those superclass methods add simply key value pairs. Still not sure this will allow me the flexibility I need, particularly if the JSON Facet API is not supported. > > There's some documentation here, in the official reference guide: > > https://lucene.apache.org/solr/guide/7_5/using-solrj.html > <https://lucene.apache.org/solr/guide/7_5/using-solrj.html> This is an excellent document. It would be wonderful if a document of this caliber was provided solely for SolrJ in the form of a tutorial. The existing online tutorial says nothing about how to do anything beyond a simple query. I notice in this document most of the examples of how to issue queries, for example, use curl to issue query. Simply put, this is not a practical approach for the typical user. That being the case, people need to build real UIs around applications that hide the intricacies of the search API. I would rather not build my own API, since SolrJ is already in place, and seems quite powerful. I have been using it for a few years, but really just to do queries. I might be interested in contributing to such a document, provided it is sufficiently succinct. I find myself quite busy these days. But I think I would really have to ramp up my understanding of SolrJ to be of any use. Is there any such document in the works, or any interested parties? I am NOT a good writer, I would need somebody to review my work for both accuracy and grammar. Also, if the JSON API supported by SolrJ, or is there any plan to support?
