code: public CmsContainerElementBean getCachedElement(String clientId, String pageRootPath) throws CmsException {
  
          String id = clientId;
          CmsContainerElementBean element = null;
          element = getSessionCache().getCacheContainerElement(id);
          if (element != null) {
              return element;
          }
          if (id.contains(CmsADEManager.CLIENT_ID_SEPERATOR)) {
              throw new CmsException(Messages.get().container(Messages.ERR_MISSING_CACHED_ELEMENT_0));
          }
          // this is necessary if the element has not been cached yet
          CmsResource resource = getCmsObject().readResource(convertToServerId(id), CmsResourceFilter.IGNORE_EXPIRATION);
          CmsADEConfigData configData = getConfigData(pageRootPath);
          CmsResourceTypeConfig typeConfig = configData.getResourceType(
              OpenCms.getResourceManager().getResourceType(resource).getTypeName());
          element = new CmsContainerElementBean(
              convertToServerId(id),
              null,
              null,
              (typeConfig != null) && typeConfig.isCopyInModels());
          getSessionCache().setCacheContainerElement(element.editorHash(), element);
          return element;
      }
docs: Reads the cached element-bean for the given client-side-id from cache.<p>
  
  @param clientId the client-side-id
  @param pageRootPath the container page root path
  
  @return the cached container element bean
  
  @throws CmsException in case reading the element resource fails