/** @param e Error. */
  void onError(Throwable e) {
    tx.commitError(e);

    if (err.compareAndSet(null, e)) {
      boolean marked = tx.setRollbackOnly();

      if (e instanceof GridCacheTxRollbackException) {
        if (marked) {
          try {
            tx.rollback();
          } catch (GridException ex) {
            U.error(log, "Failed to automatically rollback transaction: " + tx, ex);
          }
        }
      } else if (tx.implicit()
          && tx.isSystemInvalidate()) { // Finish implicit transaction on heuristic error.
        try {
          tx.close();
        } catch (GridException ex) {
          U.error(log, "Failed to invalidate transaction: " + tx, ex);
        }
      }

      onComplete();
    }
  }
  /** @param e Error. */
  void onError(Throwable e) {
    tx.commitError(e);

    if (err.compareAndSet(null, e)) {
      boolean marked = tx.setRollbackOnly();

      if (e instanceof GridCacheTxRollbackException)
        if (marked) {
          try {
            tx.rollback();
          } catch (GridException ex) {
            U.error(log, "Failed to automatically rollback transaction: " + tx, ex);
          }
        }

      onComplete();
    }
  }