CLF : THE COORDINATION LANGUAGE FACILITY
THE CLF (COORDINATION LANGUAGE FACILITY) IS A DISTRIBUTED OBJECT-ORIENTED APPLICATION DEVELOPMENT TOOL.
It relies on a rich object model, which views objects as resource managers and defines a set of 8 performatives to manipulate these resources. Coordination between objects of this type is expressed by rule-based scripts, which have a high-level declarative meaning in terms of overall cross-object resource manipulations, and a procedural meaning in terms of complex combinations of invocations of the CLF performatives on the different objects. The main features of the CLF are:
- Dynamic extension of services: a CLF service invocation returns an asynchronous stream of offers, so the server may notify new offers at any time.
- Multi-party negotiation: the execution of a CLF coordination script integrates at a deep level a negotiation phase and an enactment phase.
- Reflexivity of the model: CLF coordination scripts are resources which can be manipulated by other scripts.
The CLF has been used in several prototype applications developed at the XRCE: Workflow , XFolders (see the XFolders prototype) and and Electronic Commerce (see the Xpect prototype).
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