Grouping by query in solrj

Enviornment- solr-8.9.0

curl -G http://localhost:8983/solr/testColl/select?indent=true --data-urlencode "q=*:*" --data-urlencode "group=true" --data-urlencode "group.query=UnivesityName:'University~' AND UnivesityName:'Toronto~' --data-urlencode "group.query=UnivesityName:'University~' AND UnivesityName:'british~' AND UnivesityName:'columbia~'" --data-urlencode "group.limit=30"

The following code is solrj implementation of the above curl query

import org.apache.solr.client.solrj.SolrQuery;
import org.apache.solr.client.solrj.response.Group;
import org.apache.solr.client.solrj.response.GroupCommand;
import org.apache.solr.client.solrj.response.QueryResponse;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrDocumentList;
import org.apache.solr.common.params.CommonParams;

    //Preparing the Solr query   
      SolrQuery query = new SolrQuery();

      query.add(CommonParams.Q, "*:*");
      query.set("group", "true");
      query.set("group.limit", "30");
      
      query.set("group.query", "UnivesityName:'University~' AND UnivesityName:'Toronto~'");

How can I set multiple group.query (1."UnivesityName:'University~' AND UnivesityName:'Toronto~'" 2.UnivesityName:'University~' AND UnivesityName:'british~' AND UnivesityName:'columbia~'") in solrj API in order to create multiple groups, as described in curl query?

Solution

According to the docs, query.set overrides the prior value. Try using query.add with the same arguments, ie

query.add("group.query", "UnivesityName:'University~' AND UnivesityName:'Toronto~'");
query.add("group.query", "UnivesityName:'University~' AND UnivesityName:'british~' AND UnivesityName:'columbia~'");

The docs also say set takes an array, so you might be able to do this. This would be preferable, since it's a little less error prone since you can't forget that you added something.

query.set("group.query", [
  "UnivesityName:'University~' AND UnivesityName:'Toronto~'",
  "UnivesityName:'University~' AND UnivesityName:'british~' AND UnivesityName:'columbia~'"
]);

Note I haven't tested these.

Docs: https://solr.apache.org/docs/8_11_0/solr-solrj/org/apache/solr/common/params/ModifiableSolrParams.html (Note SolrQuery inherits from ModifiableSolrParams, which is what has the add/set methods)