1. A DAPT IST-2001-37126 Deliverable D4 Transactional Engine Francisco Pérez, Marta Patiño, Ricardo Jiménez Distributed Systems Laboratory Universidad Politécnica de Madrid (UPM) Lsd

2. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)2 Goal This deliverable aims to provide support for advanced transaction models. We have adopted the Java Activity Service specification to provide this support.

3. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)3 Overall Architecture The Java Activity Service is structured in two components: –The activity service itself. –One or more high level services. The activity service is a kind of low level general- purpose engine for registering events. A high level service implements a particular advanced transaction model.

4. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)4 Overall Architecture Users only access high level services (HLSs). The Java activity service only specifies the interface between HLSs and the activity service. HLS functionality is not constrained in any other way.

5. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)5 Activity Service AS UserActivityActivityMng HLS ServiceMng JTA UserTxnTxnMng Client App. Application ActionsUserHLS Begin/End Activity AddAction BroadcastSignal Begin/End Txn Suspend/Resume GetSignalSet Action invocations

6. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)6 Open Nested Transactions AS UserActivityActivityMng Open Nested HLS ServiceMng JTA UserTxnTxnMng Client App. Compensating ActionsUserHLS Begin/End Activity AddAction BroadcastSignal Begin/End Txn Suspend/Resume GetSignalSet Comp. Action Invocations The application brackets its activities through UserHLS

7. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)7 Integration with CSs The HLS will be used by CSs to bracket advanced transactions. Since our HLSs will be accessible through JNDI and running on the application server, the integration with CSs should be straightforward. It should be noticed that the activity service, as it happens with JTA/JTS, it is only aware of what is done within the application server by EJBs. This means that only CSs whose logic is implemented as EJBs can really exploit the Java activity service.

8. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)8 What will be delivered A basic implementation of the Java Activity Service: –No context propagation. –No context groups. –Implemented as an mbean in JBoss. As suggested by Maartens, an implementation of a concrete advanced transaction model: –A high level service implementing the open nested transactions. –Implemented as an mbean in JBoss. –Based on a JTA and the Java activity service.

9. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)9 Extensions for later deliverables Implementation of web service interoperability. –Implementation of servlets for intercepting invocations within a transactional context (ws-coordination/ws- transaction). –Implementation of the ws-coordination/ws-transaction services (as web services). –Use of the activity service to coordinate business activities and distributed atomic transactions.

10. A DAPT 4th Adapt Workshop, 11-12th Dec. 2003, Bologna (Italy)10 Extensions for later deliverables Completion of the full activity service specification: –Context propagation. –Context groups. Implementation of a generic high level service: –The vision is that it will be customizable in a declarative way.