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Acknowledgement and Legal notice / Disclaimer |
The
CONTRACT project is co-funded by the European Commission under the 6th
Framework Programme for RTD with project number FP6-034418.
Notwithstanding
this fact, this web site and its content reflects only the project
consortium's / authors' views.The European Commission is not
responsible for its contents, or liable for the possible effects of any
usage of the information contained therein.
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Contract based e-business Web Services Application Environment |
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While existing Web Services technologies are seeing significant take up, work on contracts has not reached the main stream. Specifically there are no currently available plug-in components which provide contracting facilities for existing Web Services tools which developers can use to add contracting layers to their applications.
One of the aims of the CONTRACT project was to design and develop a contract-based application environment which provides a new layer of system specification and design between current workflow/process based methods to help bridge the gap between business contractual needs and system specification: creating sound models and practical tools which help developers exploit this new layer.
In order to achieve this aim, the individual elements of CONTRACT's theoretical framework were mapped to concrete specifications for components and systems in Web Services environments - specifically instantiating abstract / logical definitions in a concrete Web Services environment. This Web services framework includes details of components, their behaviours, interfaces and other details that would be necessary for interoperability.
The figure above illustrates the main components of a Web services contracting system:
- Business contract parties can find each other through a directory service accessing a registry (not shown in the figure) where parties are described, along with details how to be contacted.
- Observer, manager, contract storer and notary are administrative contract parties and they respectively deal with monitoring contract execution, reacting to contract states taking some actions and providing certification for contract creation and maintenance.
- A contract storer, is involved in the communication with other agents, keeps knowledge about contract templates, contract proposals and contract instances and provide interfaces to retrieve and store them from/to the contract repository.
To perform contract-related business interactions, contract party agents exchange messages and supporting systems provide the functionality exposed through their public interfaces. In such an environment the contract repository can be accessed by contract storer. Contract storer is, on one hand, involved in the communication with other agents and, on the other hand, responsible for storing and retrieving contracts in a contract repository.
From this Web services framework, the project created a reusable application development environment which builds contracting functions and features directly into existing Web Services application environments, thereby allowing application developers to model and use inter-component concepts directly as part of their build and execution process: functioning as an additional specification and control above the usual method-call based specification. The results are available both in open source and industrial platform based forms.
Further reading
- CONTRACT deliverable D4.1 Web Services framework for contract based computing
- R. Confalonieri, S. Álvarez-Napagao, S. Panagiotidi, J. Vázquez Salceda and S. Willmott. A Middleware for building Contract-Aware Agent-Based Services. In Ryszard Kowalczyk, Michael Huhns, Matthias Klusch, Zakaria Maamar, Quoc Bao Vo (eds). Service-Oriented Computing: Agents, Semantics, and Engineering. Proceedings of the International Workshop on Service-Oriented Computing: Agents, Semantics, and Engineering -SOCASE'08-, at AAMAS'08, Estoril, Portugal, May 2008. Lecture Notes in Computer Science vol. 5006, pp. 1-14. Springer, 2008. ISBN 978-3-540-79967-2
- Biba, J., Hodik, J., Jakob, M. Contract observation in web services environments. In: Proceedings of Internatonal Workshop on Service-Oriented Computing: Agents, Semantics, and Engineering (SOCASE 2009), London, UK. Springer, Heidelberg, 2009
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Copyright 2006 - 2009, IST Contract Project. All rights reserved.
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Start Date / Duration |
The project started on the 1st of September, 2006 and finished on July 31st 2009.
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European Commission Framework 6 IST Project
