code: @Override
      public void register(String store, String key, KeyInformation information, BaseTransaction tx) throws BackendException {
          if (mode==Mode.CLOUD) {
              CloudSolrClient client = (CloudSolrClient) solrClient;
              try {
                  createCollectionIfNotExists(client, configuration, store);
              } catch (IOException e) {
                  throw new PermanentBackendException(e);
              } catch (SolrServerException e) {
                  throw new PermanentBackendException(e);
              } catch (InterruptedException e) {
                  throw new PermanentBackendException(e);
              } catch (KeeperException e) {
                  throw new PermanentBackendException(e);
              }
          }
          //Since all data types must be defined in the schema.xml, pre-registering a type does not work
      }
docs: Unlike the ElasticSearch Index, which is schema free, Solr requires a schema to
  support searching. This means that you will need to modify the solr schema with the
  appropriate field definitions in order to work properly.  If you have a running instance
  of Solr and you modify its schema with new fields, don't forget to re-index!
  @param store Index store
  @param key New key to register
  @param information Datatype to register for the key
  @param tx enclosing transaction
  @throws com.thinkaurelius.titan.diskstorage.BackendException