code: public synchronized void updateTargetCellule( SIBUuid8 targetMEUuid ) throws SIResourceException
    {
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
        SibTr.entry(tc, "updateTargetCellule", targetMEUuid);
  
      if( pointTopoint)
      {
        this.targetMEUuid = targetMEUuid;
  
        StreamSet streamSet = getStreamSet();
  
         // We may not have had any messages yet in which case there
         // is no streamSet to update
        if( streamSet != null)
        {
          //Update the cellule in the StreamSet
          //and persist this
          streamSet.updateCellule(targetMEUuid);
          Transaction tran = txManager.createAutoCommitTransaction();
          try
          {
            streamSet.requestUpdate(tran);
          }
          catch (MessageStoreException e)
          {
            // MessageStoreException shouldn't occur so FFDC.
            FFDCFilter.processException(
              e,
              "com.ibm.ws.sib.processor.gd.SourceStreamManager.updateTargetCellule",
              "1:1384:1.102",
              this);
  
            SibTr.exception(tc, e);
  
            if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(tc, "updateTargetCellule", e);
  
            throw new SIResourceException(e);
          }
  
          //iterate over the non-null streams
          Iterator itr = streamSet.iterator();
          while(itr.hasNext())
          {
            SourceStream stream = (SourceStream) itr.next();
            stream.noGuessesInStream();
          }
        }
      }
  
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
        SibTr.exit(tc, "updateTargetCellule");
    }
docs: This method should only be called when the PtoPOutputHandler was created
  with an unknown targetCellule and WLM has now told us correct targetCellule.
  This can only happen when the SourceStreamManager is owned by a
  PtoPOutputHandler within a LinkHandler