code: protected void addFilterQueryParts(CmsSolrQuery query) {
  
          if (!m_state.getCheckedEntries().isEmpty()) {
              StringBuffer value = new StringBuffer();
              value.append("{!tag=").append(m_config.getName()).append('}');
              value.append(m_config.getRange());
              value.append(":(");
              final Iterator<String> fieldIterator = m_state.getCheckedEntries().iterator();
              value.append(generateRange(fieldIterator.next()));
              final String concater = m_config.getIsAndFacet() ? " AND " : " OR ";
              while (fieldIterator.hasNext()) {
                  value.append(concater);
                  value.append(generateRange(fieldIterator.next()));
              }
              if (m_config.getHardEnd()) {
                  value.append(concater);
                  value.append("[" + m_config.getStart() + " TO " + m_config.getEnd() + "}");
              }
              value.append(')');
              query.add("fq", value.toString());
          }
      }
docs: Adds filter parts to the query.
  @param query The query.