SAWSDL: Semantic Annotations for WSDL

SAWSDL Resource Page

Infrastructure : API and Tool support    Use Cases   Background

The members of the METEOR-S project are happy to announce the support for SAWSDL(Semantic Annotations for WSDL)

SAWSDL is a simple extension of WSDL using the extensibility elements. It has two basic types of annotations, the model reference and the schema mapping. The model reference annotation, the same as the WSDL-S model reference, is used to associate interfaces/port types, operations, inputs, outputs, and xml schema elements and attributes with Semantic Concepts. Model reference annotations are used by the METEOR-S framework to support the Discovery of Web Services and for dynamic configuration of Web Processes. The schema mapping annotations, again similar in principle to the WSDL-S version, are used by the METEOR-S framework to deal with data heterogeneity, particularly transforming one data representation into another; such that, it can be used in another Web Service.

In the future, we hope to influence the SAWSDL standard by introducing two more concepts from WSDL-S, preconditions and effects (other significant W3C submissions including OWL-S and WSMO also have made significant early contributions that need to be considered in this area). Currently, preconditions and effects are used by WSDL-S to describe the conditions that must be met before an operation can be invoked and the result that the invocation of the operation will have. As such, the Meteor-S framework will be using SAWSDL in a modified form, with preconditions and effects that is fully compatible with the current W3C working group specification.

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Infrastructure : API and Tool support

SAWSDL4J: API interface is an implementation of the SAWSDL specification. The API would allow developers to create SAWSDL based applications. SAWSDL4J extends the WSDL4J API for WSDL1.1 Get it here

Woden4SAWSDL: This is a WSDL 2.0 parser, based on Apache Woden, with API classes that allow for SAWSDL parsing and creation. Get it here

Radiant: is a eclipse plugin that allows for creating and publishing SAWSDL and WSDL-S service interfaces. Users can add annotations to existing service descriptions in WSDL using the user friendly graphical interface of Radiant. Downloads and documentation for Radiant can be found here.
Please contact Douglas Brewer for additional information.

Lumina: is a eclipse plugin that allows for discovery of Web services based on semantics. Lumina is a graphical user interface built on top of the METEOR-S Web Services Discovery Infrastructure engine/ In MWSDI engine, we create a semantically enhanced services registry based on UDDI. Downloads and documentation for Lumina can be found here. Please contact Douglas Brewer for additional information.

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Use Cases:

Currently as a part of the METEOR-S project, we are creating a SAWSDL/WSDL-S compliant service middleware extension to Apache Axis 2 and Apache Tungsten.
In addition to our work towards creating a SAWSDL based services ecosystem, we also demonstrate the use of SAWSDL in life sciences (SemBowser) and  Semantic Agreement Matching (Semantic WS-Agreement (SWAPS) ) . The Stargate Portal for Services in Life Sciences has a few sample annotated services in the life sciences domain.

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The SAWSDL framework is significantly influenced by WSDL-S, which emerged from our investigations on the role of semantics in the entire life cycle for Web Services and Processes starting 2001. Preliminary ideas related to the WSDL-S approach of adding semantics to Web Service/WSDL were presented in the invited talk at WWW 2003 Workshop on E-Services and the Semantic Web (Semantic Web Process Life cycle: Role of Semantics in Annotation, Discovery, Composition and Orchestration ,Budapest, Hungary, May 20, 2003). (Abstract Slides: pdf  powerpoint-show  htm). The ideas were then documented in our paper,  Adding Semantics to Web Services Standards (ICWS 03, Las Vegas, Nevada (June 2003) pp.395 - 401).

A white paper "WSDL-S: Adding Semantics to WSDL - White Paper," (Innsbruck, Austria,July 15, 2004) submitted to members of WSDL committee though well received, had some shortcomings. After significant collaboration with colleagues at IBM (especially Rama Akkiraju and Joel Farrell) that resulted in improved specifications, members of LSDIS lab and IBM made a member submission to W3C (Web Service Semantics - WSDL-S)

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Also see WSDL-S resource