docs: protected IPortletDefinition getChannelDefinition(String subId) throws PortalException {
          IPortletDefinition chanDef = mChanMap.get(subId);
  
          if (null == chanDef) {
              String fname = getFname(subId);
              if (log.isDebugEnabled())
                  log.debug(
                          "TransientUserLayoutManagerWrapper>>getChannelDefinition, "
                                  + "attempting to get a channel definition using functional name: "
                                  + fname);
              try {
                  chanDef =
                          PortletDefinitionRegistryLocator.getPortletDefinitionRegistry()
                                  .getPortletDefinitionByFname(fname);
              } catch (Exception e) {
                  throw new PortalException(
                          "Failed to get channel information " + "for subscribeId: " + subId);
              }
              mChanMap.put(subId, chanDef);
          }
  
          return chanDef;
      }