docs: public void updateXIDToRolledback(PersistentTranId xid) 
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(tc, "updateXIDToRolledback", "XID="+xid);
  
          if (_deferredException == null)
          {
              // We are rolling back a transaction. This should only be 
              // applied to prepared transactions as single-phase rollbacks
              // should not get as far as the persistence layer.
              if (_state == STATE_PREPARED)
              {
                  _state = STATE_ROLLINGBACK;
              }
              else
              {
                  _deferredException = new PersistenceException("Cannot ROLLBACK batch as it not in the correct state! State="+_stateToString[_state]);
              }
          }
          else
          {
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) SibTr.debug(tc, "No work attempted as an exception has already been thrown during this batch!");
          }
          
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(tc, "updateXIDToRolledback");
      }