Summary

This chapter illustrates the motivation for service orientation, and some of the basics of a service-oriented system. Service orientation requires a focus on the messages that an application sends, receives, or processes. Service-oriented systems can take functionality previously reserved for a transport, and place it in the structure of a message (addresses, security information, relational information, etc.). Focusing on the message provides a way to remove dependencies on platforms, hardware, and runtimes. In my view, the version resiliency of a service-oriented application is the biggest win for most IT organizations, because choreo-graphing system-wide upgrades is one of the more expensive parts of maintenance. In the next chapter, we see some of the different ways we introduce the concepts necessary to build advanced messaging applications.