code: public void setDateRanges(Map<String, CmsPair<Date, Date>> dateRanges) {
  
          if ((dateRanges != null) && !dateRanges.isEmpty()) {
              // remove the date ranges
              for (Map.Entry<String, CmsPair<Date, Date>> entry : dateRanges.entrySet()) {
                  removeFacetField(entry.getKey());
              }
              // add the date ranges
              for (Map.Entry<String, CmsPair<Date, Date>> entry : dateRanges.entrySet()) {
                  addDateRangeFacet(
                      entry.getKey(),
                      entry.getValue().getFirst(),
                      entry.getValue().getSecond(),
                      m_facetDateGap);
              }
          }
      }
docs: Sets date ranges.<p>
  
  This call will overwrite all existing date ranges for the given keys (name of the date facet field).<p>
  
  The parameter Map uses as:<p>
  <ul>
  <li><code>keys: </code>Solr field name {@link org.opencms.search.fields.CmsSearchField} and
  <li><code>values: </code> pairs with min date as first and max date as second {@link org.opencms.util.CmsPair}
  </ul>
  Alternatively you can use Solr standard query syntax like:<p>
  <ul>
  <li><code>+created:[* TO NOW]</code>
  <li><code>+lastmodified:[' + date + ' TO NOW]</code>
  </ul>
  whereby date is Solr formatted:
  {@link org.opencms.search.CmsSearchUtil#getDateAsIso8601(Date)}
  <p>
  
  @param dateRanges the ranges map with field name as key and a CmsPair with min date as first and max date as second