I just completed a project to extend Solr as follows:
subclassed the QueryComponent class to add a mandatory filter query (fq) for all user searches
subclassed the UpdateRequestProcessor class to add fields to a document prior to indexing
I then wired up these custom classes in solrconfig.xml and placed my jar file in a lib directory under solr home. Everything ran great. So easy.
Question: Can I do the equivalent in ElasticSearch 4.3.1? I ask because I came across this comparison, which claims that ElasticSearch 2.0 does not provide Pluggable search/update workflow as I described above with Solr. I haven't found any comparisons for more recent versions, nor have I found anything in the ElasticSearch documentation that answers my question.
Thanks in advance for your help!