Wires are used to connect clients directly to a service. Many applications, however, require support for broadcast-style interactions where clients send messages to a destination that one or more consumers listen on. These loosely coupled interactions are often referred to as pub-sub messaging. Fabric3 supports assembling pub-sub applications through SCA eventing. This chapter provides an overview of how to use Fabric3's eventing facilities.
Note that as an evolving part of the SCA specifications, eventing is not complete. Therefore, while the Fabric3 implementation is robust, the specifications are subject to change. Depending on how the specifications evolve, it is possible for API and configuration changes to be introduced. While the Fabric3 implementation attempts to avoid implementing parts of eventing that may be subject to significant change, users should be aware that eventing is still a work in progress.
Enabling Eventing
Eventing is a core runtime capability. Consequently, optional extensions do not need to be installed.