Contemporary SOA emphasizes extensibility

Contemporary SOA emphasizes extensibility

When expressing encapsulated functionality through a service description, SOA encourages you to think beyond immediate, point-to-point communication requirements. When service logic is properly partitioned via an appropriate level of interface granularity, the scope of functionality offered by a service can sometimes be extended without breaking the established interface (Figure 3.12).
Figure 3.12. Extensible services can expand functionality with minimal impact.






Extensibility is also a characteristic that is promoted throughout SOA as a whole. Extending entire solutions can be accomplished by adding services or by merging with other service-oriented applications (which also, effectively, "adds services"). Because the loosely coupled relationship fostered among all services minimizes inter-service dependencies, extending logic can be achieved with significantly less impact.

Time to revisit our original definition to add a few adjectives that represent the characteristics we've covered.


Contemporary SOA represents an open, extensible, federated, composablearchitecture that promotes service-orientation and is comprised of autonomous, QoS-capable, vendor diverse, interoperable, discoverable , andpotentially reusable services, implemented as Web services .