Closing the Link
Imports, exports, references, and so on are new terms in this whole new paradigm called the Service Component Architecture (SCA), which was introduced in this chapter. From the developer's perspective, services are packaged in a service module, which is the basic unit of deployment and administration in an SCA runtime.
Service imports are used in a service module to use external services that are not part of the module itself (for example, services exported by other modules, stateless session EJBs, Web services, EIS services, and so on). External services that are referenced by import declarations are valid targets of service wires. The import binding definition does not need to be finalized at development time. Aspects such as the actual endpoint of services to invoke can be late-bound at deployment, administration, or even runtime. Service exports, on the other hand, are used to offer services from the service module to the outside world, such as services for other service modules or as Web services.
The following chapters build on these concepts and use the tooling and runtime examples to fully explain SCA. It is imperative that you understand the SCA model, because it forms the basis of business integration discussed in this book. It is beneficial to reiterate that patterns are not inventions or edicts; they are harvested from repeated experiences from and use by practitioners. Business integration does not always involve business processes, but in a lot of cases, business processes form the centerpiece of integration.