1. A DAPT IST-2001-37126 Initial Work on Transactional Composite Web Services and Visual Composition tool Ricardo Jiménez-Peris, Marta Patiño-Martínez Alberto Erice, Francisco Pérez Distributed Systems Laboratory Universidad Politécnica de Madrid (UPM) Lsd

2. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)2 Our Vision of Transactional CSs: Advanced Transaction Models Single advanced transaction models do not provide support for all the scenarios in CSs. Therefore, flexible support should be provided to allow the definition of different transaction models that can be adapted to the needs of each particular application. We will adopt a transaction definition language similar to ACTA that will enable the definition of advanced transaction models by establishing relations among the different transaction lifecycle events (begin, commit, abort).

3. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)3 Our Vision of Transactional CSs: Integration of Composition and Transactions Standards for transactional behavior and coordination (BTP, WSCoordination/WSTransaction) are orthogonal to composition standards (BPEL4WS, WSCI/BPML). It is our opinion that the programmer of the CS should be able to describe the composition in an integrated fashion. Transactional semantics of CSs should be as declarative as possible (as it happens with container managed transactions in J2EE) to ease the programmer task.

4. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)4 Visual Composition Tool A visual programming environment for composite web services is currently being developed in Java. The graphical language is currently based on BPEL4WS. The tool currently loads and stores compositions in XML following the BPEL4WS standard.

5. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)5 Visual Composition Tool: Declarative Transactions Scopes within compositions could be tagged declaratively as transactional. The tool cares about the mapping of the integrated transactional CS definition into separated CS and transactional (e.g. based on WS Transactions) definitions. Exception handling and propagation is integrated with transactions: –Transaction abortions are notified as exceptions to the enclosing scopes. –Exception propagated across transactional scopes cause the abort of the associated transactions.

6. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)6 Visual Composition Tool: Advanced Transaction Models The programming allows the definition of advanced transaction models: –Definition of transaction types. –Definition of dependencies between transaction cycle life events. It also allows the application of these models to assign a particular transactional semantics to compositions. The tool takes charge of generating configuration files for the CS transaction manager to define the advanced transaction model.

7. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)7 Visual Composition Tool: Other Foreseen Facilities UDDI browser for selecting services participating in a composition. Compiler from BPEL4WS to Opera workflow language. Adaptive user interface by means of logical fisheye views. –It will allow to adapt the level of detail of the composition depending on the foci of interest of the user. Support for WS choreography in addition to the WS orchestration support (i.e., support both abstract and concrete processes).

8. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)8 CS Transaction Manager In order to support transactional CSs it is necessary to provide a transaction manager (TM) able to: –Coordinate transactions for locally run transactional CSs. –Participate in the coordination of remotely run transactional CSs. –Propagate the transactional context to locally invoked BSs. The coordination by the TM will be compliant with at least one of the currently proposed standards: –Business Transaction Protocol (BTP). –WSCoordination/WSTransaction.

9. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)9 CS Transaction Manager Work already performed: –Study of the proposed advanced transaction models. –Familiarization with Axis. –Study the implementation of BTP above JOTM (the Jonas JTS/JTA compliant TM). –Run an example of a transactional CS using the above implementation and Axis. –Study the JTS/JTA to invoke local transactional services.

10. A DAPT 2nd Adapt Workshop, 13-14th Feb. 2003, Bologna (Italy)10 CS Transaction Manager Undergoing work: –Design of a TM for CSs. We are aiming to a flexible design that can be adapted to different coordination standards based on our past experience with TransLib. –Design of the language for defining transaction models. Possible extensions: –Support for highly available transactional coordination (by replicating the TM). –Suggestions welcomed.