1. A method of using a message-oriented protocol in a gaming machine, said method comprising: generating, by a processing circuit of the gaming machine, a topic subscription request by a bonus-determining application on the gaming machine, the topic subscription request associated with a bonus-related topic; sending, by the gaming machine, the topic subscription request to a message broker; receiving, by the message broker, the topic subscription request and subscribing the bonus-determining application to the bonus-related topic; receiving, by the message broker, a message published to the bonus-related topic by a primary-game application on the gaming machine, the primary-game application different from the bonus-determining application; determining, by the message broker, which of a plurality of different applications subscribe to the bonus-related topic; sending, by the message broker, the message published to the bonus-related topic to each application subscribed to the designated topic, including the bonus-determining application; receiving, at the processing circuit, the message published to the bonus-related topic; and altering execution of the bonus-determining application on the gaming machine based in part on the received message.