code: protected String createQueryStringFromCriteria(Criteria criteria, @Nullable Class<?> domainType) {
  		return createQueryStringFromNode(criteria, domainType);
  	}
docs: Iterates criteria list and concats query string fragments to form a valid query string to be used with
  {@link org.apache.solr.client.solrj.SolrQuery#setQuery(String)}
  
  @param criteria
  @param domainType
  @return
  @since 4.0