Thursday, December 22, 2005

Web Services Frameworks Notes

These are notes from chapter on web services framework.
Web service framework comprises of standards, design patterns, other frameworks.
Service itself: This is divided into 2 categories, role and model. Role is basically the temporary role that  the service assumes during the runtime. These are requestor, provider, passive and active intermediaries, ultimate requestor, ultimate provider, and member role in composite scenario. Model is how the service fits into overall enterprise architecture. In this respect a service can fall into these categories, business service, utility service, and controller service.
Service description: This is basically describing to the outside word what the service is or in other words service contract. There are several articats that provides this contract like, wsdl, schema, policy, and legal docuemtns. Providing just the wsdl is most popular. wsdl has two parts abstract and concrete. Abstract describes portTypes, operations, and messages. Concrete describes port, bindings, and service. wsdl however does not provide semantic information about the service. UDDI is based on similar concepts of abstract and concrete. Service entity is abstract and tModels are concrete entities.
Messages: These are autonomous and intelligent messages that can carry with them information like how to process, route, etc. Messages adhere to SOAP protocol and a message is a envelope which has a header and body. Header is extensible and various WS* specifications leverages this feature to provide their own specific entries.

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