code: protected void addFacetOptions(StringBuffer query, final boolean useLimit) {
  
          // mincount
          if (m_config.getMinCount() != null) {
              appendFacetOption(query, "mincount", m_config.getMinCount().toString());
          }
          // limit
          if (useLimit && (m_config.getLimit() != null)) {
              appendFacetOption(query, "limit", m_config.getLimit().toString());
          }
          // sort
          if (m_config.getSortOrder() != null) {
              appendFacetOption(query, "sort", m_config.getSortOrder().toString());
          }
          // prefix
          if (!m_config.getPrefix().isEmpty()) {
              appendFacetOption(query, "prefix", m_config.getPrefix());
          }
      }
docs: Adds the query parts for the facet options, except the filter parts.
  @param query The query part that is extended with the facet options.
  @param useLimit Flag, if the limit option should be set.