In AMQP, transactions cover the semantics of enqueues and dequeues.

When sending messages, a transaction tracks enqueues without actually delivering the messages, a commit places messages on their queues, and a rollback discards the enqueues.

When receiving messages, a transaction tracks dequeues without actually removing acknowledged messages, a commit removes all acknowledged messages, and a rollback discards acknowledgements. A rollback does not release the message, it must be explicitly released to return it to the queue.

Connection connection(broker);
Session session =  connection.createTransactionalSession();
...
if (smellsOk())
   session.commit();
else 
   session.rollback();