code: public void cancelEventWaitInstances(Long activityInstanceId)
          throws DataAccessException {
          TransactionWrapper transaction=null;
          try {
              transaction = startTransaction();
              engineImpl.cancelEventWaitInstances(activityInstanceId);
          } catch (DataAccessException e) {
              if (canRetryTransaction(e)) {
                  transaction = (TransactionWrapper)initTransactionRetry(transaction);
                  ((ProcessExecutor)getTransactionRetrier()).cancelEventWaitInstances(activityInstanceId);
              }
              else
                  throw e;
          } finally {
              stopTransaction(transaction);
          }
      }
docs: /////////////////////////////////////