Hi Thomas, I recently added a first pass at JSON faceting support to SolrJ. The main classes are "JsonQueryRequest" and "DirectJsonQueryRequest" and live in the package "org.apache.solr.client.solrj.request.json" (https://github.com/apache/lucene-solr/tree/master/solr/solrj/src/java/org/apache/solr/client/solrj/request/json). I've also added examples of how to use this code on the "JSON Faceting" page in the Solr ref guide. Unfortunately, since this is a recent addition it hasn't been released yet. These classes will be in the next 7x release (if there is one), or in 8.0 when that arrives. This probably isn't super helpful for you.
Without this code, you have a few options: 1. If the facet requests you'd like to make are relatively structured/similar, you can subclass QueryRequest and override getContentWriter(). "ContentWriters" are the abstraction SolrJ is using to write out the request body. So you can trivially implement getContentWriter to wrap a hardcoded string with some templated variables. If interested, also checkout "RequestWriter.StringPayloadContentWriter". This'll be sufficient for very cookie cutter facet requests, where maybe only a few parameters change but nothing else. 2. If hardcoding a string JSON body is too inflexible, the JSON faceting API is "just query params" like everything else. You can build your facet request and attach it to the request as a SolrParams entry. Doing this wouldn't be the most fun code to write, but it's always possible. 3. You can copy-paste the unreleased JSON faceting helper classes I mentioned above into your codebase. They're not released in SolrJ but you can still use them by copying them locally and using those copies until you're able to use a SolrJ that contains these classes. If you go this route, please let me or someone else in the community know your thoughts. Their being unreleased makes them a bit more of a pain to use, but it also gives us an opportunity to iterate and improve them before a release comes and ties us to the existing (maybe awful) interfaces. > It would be wonderful if a document of this caliber was provided solely for > SolrJ in the form of a tutorial. We definitely need more "SolrJ Examples" coverage, though I'm not sure the best way to expose/structure that. Solr has a *ton* of API surface area, and SolrJ is responsible for covering all of it. Even if I imagine a SolrJ version of the standard "Getting Started" tutorial which shows users how to create a collection, index docs, do a query, and do a faceting request...that'd only cover a fraction of what's out there. It might be easier to scale our SolrJ examples by integrating them into the pages we already have for individual APIs instead. I'm all for a SolrJ tutorial, or SolrJ Cookbook sort of thing if you like those ideas better though, and would also volunteer to help edit or review things in that area. Sorry, this got a little long. But hope that helps. Best, Jason On Fri, Nov 30, 2018 at 11:31 AM Cassandra Targett <casstarg...@gmail.com> wrote: > > Support for the JSON Facet API in SolrJ was very recently committed via > https://issues.apache.org/jira/browse/SOLR-12965 > <https://issues.apache.org/jira/browse/SOLR-12965>. This missed the cut-off > for 7.6 but will be included in 7.7 (if there is one) and/or 8.0. You may be > able to use the patch there to see if there are gaps or bugs that could be > fixed before 7.7 / 8.0. > > Jason, who did the work on that issue, also presented on SolrJ at the > Activate conference, you may find it interesting: > https://www.youtube.com/watch?v=ACPUR_GL5zM > <https://www.youtube.com/watch?v=ACPUR_GL5zM> > > If you do find the time to write some docs, I’d be happy to give you some > editing help. Just open a Jira issue when/if you’ve got something and we can > go from there. > > > On Nov 30, 2018, at 9:53 AM, Thomas L. Redman <tomred...@mchsi.com> wrote: > > > > 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? >
