code: private static CmsXmlGroupContainer getCache(CmsObject cms, CmsResource resource, boolean keepEncoding) {
  
          if (resource instanceof I_CmsHistoryResource) {
              return null;
          }
          return getCache().getCacheGroupContainer(
              getCache().getCacheKey(resource.getStructureId(), keepEncoding),
              cms.getRequestContext().getCurrentProject().isOnlineProject());
      }
docs: Returns the cached group container.<p>
  
  @param cms the cms context
  @param resource the group container resource
  @param keepEncoding if to keep the encoding while unmarshalling
  
  @return the cached group container, or <code>null</code> if not found