Workflow utilization in composition of complex applications based on Web Services

1. Workflow utilization in composition of complex applications based on Web Services Maciej Zaremba 2005/02/16

2. Contents • Range of my master thesis, • Implementation part of my master thesis, • Major WSMX Contribution - Dynamic Execution Semantics for WSMX, • Current activities & further plans,

3. Range of my thesis • Overview of distributed processing history(RPC, RMI, CORBA, DCOM), • Web Services concepts in a nutshell, • XML - ubiquitous underlaying standard, • XML Schema and Namespaces, • XSL Transformation, • XPath and XQuery query languages,

4. Range of my thesis • Core Web Services standards - communication protocol (SOAP messaging is used), interfaces (described by WSDL) and Services repositories (UDDI). • Web Services extensions -core technologies do not provide complete solution for many business problems. They do not address explicitly security issues, reliable messaging, choreography and other business concerns.

5. Range of my thesis • Comparison to RPC, RMI, CORBA and DCOM. Advantages of Web Services. • Enriched Web Services – Semantic Web Services. Enabled run-time binding and invocation of Web Service based on requested functionality (Goal approach). • WSMX – enviroment for dynamic discovery, mediation and invocation of SWS.

6. Range of my thesis • Introducting Workflow systems – main areas of exploitation, • Workflow most signified paradigms - Petri net and Pi Calculus, • Workflow expressivness – Workflow patterns, • Composition of Web Services based on workflow systems (BPEL, YAWL), • Workflow Engines – ActiveBPEL, YAWL,

7. Range of my thesis • Convergence of Semantic Web Services and Workflow – Introducing Service Oriented Architecture, • SOA advantages over contemprary solutions (e.g. extremly shorten time of switch between bussiness partners),

8. Implementation part of my thesis Main goal: • Show viability of SOA approach and evaluate results, Implementation: • Example application composed of loosely-coupled Web Services specified in workflow model and executed by workflow engine. Special emphasis will be given on run-time Web Service discovery and invocation – WSMX will be utilized for this purpose,

9. Dynamic Execution Semantics for WSMX Assumptions: • Conformence to loosely-coupled architecture paradigm. Event driven system - components wrappers consume and create events. • Each WSMX component has to fulfill its functionality without direct invocation of other components, • Communication between WSMX backbone (WSMX Manager Core) and particular component implementation has to be carried by components wrappers. Each wrapper is aware only of component interface, not particular component implementation.

10. Dynamic Execution Semantics for WSMX • Wrappers are binding during run-time to concrete component implementations from Components Repository (similarly to deployment of WebApp under Tomcat), • Components implementations might expose diffrent interfaces (Web Services or EJB),

11. Dynamic Execution Semantics for WSMX Twofold approach to generation of Dynamic Execution Semantic: • Wrappers are generated and subscribed to receiving particular Events types out of IN\OUT Components Events specification • Wrappers are invoked by XML messages from worklflow model. XML is being processed by Wrapper and concrete tasks are delegated furher to Components implementation. This approach enables combining Components execution with any XML speaking unit (Web Service in principal),

12. Dynamic Execution Semantics for WSMX

13. Current activities & further plans • Master thesis research carried out in DERI resulted in finished thesis about June, • Contribution to Semantic Web Services Cluster works (e.g. Dynamic Execution Semantics for WSMX, preparation Java classes, presentations, etc.), • Master thesis defence back in Poland in June – July 2005, • Apply for PhD studies in DERI,

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