Updating a document in Solr with Java

Question

As everybody knows, the documentation of Solrj in the wiki is pretty poor. I managed to query the index using the CommonsHttpSolrServer, but never with the Embedded version. Anyway, now I'm using the EdgeNGrams to display auto-suggestions, and I have a field "count" in my index, so that I can sort the results by the number of times people queried the element.

What I want to do now, is to be able to update this "count" field in my Java program, which should be quite easy I guess? I looked at the test files from the source code, but it's very complicated, and trying to do something similar always failed for me. Maybe by using Solrj?

Thanks for your help.

Edit: In my java code, I have:

CoreContainer.Initializer initializer = new CoreContainer.Initializer();
CoreContainer coreContainer = initializer.initialize();

What I expect to get at this point, is the cores defines in solr.xml present in the coreContainer, but there is no core there (but defaultCoreName says collection1). My solr.xml file is the same as in the example dir:

<solr persistent="false">
  <cores adminPath="/admin/cores" defaultCoreName="collection1">
    <core name="collection1" instanceDir="." />
  </cores>
</solr>

Solution 1

I finally just store this count in Solr, then retrieve it and update it, then run an update, since it is not possible to update a single field in Solr and also the count field, which could be very handy!

Solution 2

Modified from this test example. To add a value to Solr and then subsequently modify it you can do the following:

//add value to Solr
doc = new SolrInputDocument();
doc.addField("id", "A");
doc.addField("value", 10);
client.add(doc);
client.commit();

//query Solr
SolrQuery q = new SolrQuery("id:A");
QueryResponse r = client.query(q);

//update value
SolrDocument oldDoc = r.getResults().get(0);
SolrInputDocument newDoc = new SolrInputDocument();
newDoc.addField("id", oldDoc.getFieldValue("id");
HashMap<String, Object> map = new HashMap<String, Object>();
map.put("inc", 15);
newDoc.addField("value", map);
client.add(newDoc);
client.commit();

This increments the original 10 value to 25. You can also "add" to an existing field or simply "set" an existing value by changing what command you put what you put the in the HashMap.