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Service Contract

A service contract is comprised of one or more published documents (called service description documents) that express meta information about a service. The fundamental part of a service contract consists of the service description documents that express its technical interface. These form the technical service contract which essentially establishes an API into the functionality offered by the service.

When services are implemented as Web services, the most common service description documents are the WSDL definition, XML schema definition, and WS-Policy definition. A Web service generally has one WSDL definition, which can link to multiple XML schema and policy definitions. When services are implemented as components, the technical service contract is comprised of a technology-specific API.

A service contract can be further comprised of human-readable documents, such as a Service Level Agreement (SLA) that describes additional quality-of-service features, behaviors, and limitations.

Within service-orientation, the design of the service contract is of paramount importance. So much so that a separate service-oriented design process exists dedicated solely to the standardized creation of service contracts.


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