code: public CmsResourceFilter addRequireLastModifiedBefore(long time) {
  
          CmsResourceFilter extendedFilter = (CmsResourceFilter)clone();
  
          extendedFilter.m_filterLastModified = true;
          extendedFilter.m_modifiedBefore = time;
          extendedFilter.updateCacheId();
  
          return extendedFilter;
      }
docs: Returns an extended filter to restrict the results to resources modified in the given timerange.<p>
  
  @param time the required time
  @return a filter to restrict the results to resources modified in the given timerange