Even though SOA has been around for years, the community at large did not have a clear declaration of intent and "values", although individually, there appeared to be a large degree of consensus. Formalizing this consensus, a group of seasoned SOA practitioners got together recently and agreed to a high level declaration of intent.
Service orientation is a paradigm that frames what you do. Service-oriented architecture (SOA) is a type of architecture that results from applying service orientation.
We have been applying service orientation to help organizations consistently deliver sustainable business value, with increased agility and cost effectiveness, in line with changing business needs.
Through our work we have come to prioritize:
- Business value over technical strategy
- Strategic goals over project-specific benefits
- Intrinsic interoperability over custom integration
- Shared services over specific-purpose implementations
- Flexibility over optimization
- Evolutionary refinement over pursuit of initial perfection
That is, while we value the items on the right, we value the items on the left more.
We follow these principles:
- Respect the social and power structure of the organization.
- Recognize that SOA ultimately demands change on many levels.
- The scope of SOA adoption can vary. Keep efforts manageable and within meaningful boundaries.
- Products and standards alone will neither give you SOA nor apply the service orientation paradigm for you.
- SOA can be realized through a variety of technologies and standards.
- Establish a uniform set of enterprise standards and policies based on industry, de facto, and community standards.
- Pursue uniformity on the outside while allowing diversity on the inside.
- Identify services through collaboration with business and technology stakeholders.
- Maximize service usage by considering the current and future scope of utilization.
- Verify that services satisfy business requirements and goals.
- Evolve services and their organization in response to real use.
- Separate the different aspects of a system that change at different rates.
- Reduce implicit dependencies and publish all external dependencies to increase robustness and reduce the impact of change.
- At every level of abstraction, organize each service around a cohesive and manageable unit of functionality.