Using WSMX to Bind Requester Provider at Runtime

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Using WSMX to Bind Requester & Provider at Runtime when Executing Semantic Web Services

Using WSMX to Bind Requester & Provider at Runtime when Executing Semantic Web Services Matthew Moran, Michal Zaremba, Adrian Mocan, Christoph Bussler Digital Enterprise Research Institute {matthew. moran, michal. zaremba, adrian. mocan, chris. bussler}@deri. org WSMO Implementation Workshop Frankfurt, Germany, 28 -29 September 2004 07 -07 -2004 <footer>matthew. [email protected] org

Agenda • The problem – Why runtime binding is good – Problem with current

Agenda • The problem – Why runtime binding is good – Problem with current web service technology • Requirements for a solution – Conceptual – Environment • Proposed solution – WSMX and runtime binding – WSMX architecture and operation – Mediation • Wrap-up – Related work – Summary matthew. [email protected] org 2

The Problem • Ideal world – Businesses able to discover and bind to services

The Problem • Ideal world – Businesses able to discover and bind to services at runtime – Issues of security, reliability, trust and interoperability of data, process and protocol automatically resolved • Less ideal world – Businesses have trading partner agreements with multiple companies offering a wide variety of services – Business specify a requirement to be achieved and have that requirement satisfied by a service from one of these companies – Businesses don’t want to have to reprogram their systems each time a new service provider becomes known to them – Runtime binding of requester to provider matthew. [email protected] org 3

The Problem • Current Web Service technology is syntactic – WSDL for service interface

The Problem • Current Web Service technology is syntactic – WSDL for service interface and binding description – UDDI registries for service descriptions written in free text • Assumptions: – Shared understanding of terms used in WSDL – Shared understanding of terms used in UDDI • Automatic stub generation is possible from WSDL but … – Code has to be written to invoke the stub for each service – Shared understanding assumption is made again for the meaning of the service input and output • Positive aspect of current Web Services – Programming language independent e. g. Service in Java, requester in Lisp matthew. [email protected] org 4

Requirements • Semantic descriptions of various aspects of Web Services needed – – Service

Requirements • Semantic descriptions of various aspects of Web Services needed – – Service capabilities: what a service can do Requester goals: what a requester seeks Mediators to bridge between goals and capabilities Non-functional properties: aspects like security, reliability, pricing … • Descriptions written in terms of ontologies • No assumption that provider & requester use same ontologies – Mediators required to provide the bridge – Data mediation is the first step, process and protocol mediation to follow • Computer systems must be able to precisely interpret and reason about the semantic descriptions matthew. [email protected] org 5

Requirements: Environment • Be able to interpret the semantic descriptions • Carry out the

Requirements: Environment • Be able to interpret the semantic descriptions • Carry out the activities of: – – Service discovery Service selection Mediation Service invocation • Should have a modular construction – Clear well defined interfaces shielding implementation details – As technology improves components can be upgraded or replaced without affecting the stability of the system • Should provide access to a registry of service descriptions • Overall enable a complete round trip from requester to provider matthew. [email protected] org 6

Solution: WSMX & Runtime Binding • WSMX is a software framework that allows runtime

Solution: WSMX & Runtime Binding • WSMX is a software framework that allows runtime binding of service requester and provider • Requester provides semantic description of goal • WSMX interprets the goal to: – – Discover matching services Select the service that best fits Provide data mediation if required Make the service invocation • Based on the conceptual model provided by WSMO – Add-ons required for WSMXGoal, Business. Partner, Preferences • WSMX has a formal execution semantics – Describes how WSMX gets from requester goal to service invocation matthew. [email protected] org 7

Solution: WSMX Architecture matthew. moran@deri. org 8

Solution: WSMX Architecture matthew. [email protected] org 8

Solution: WSMX Architecture matthew. moran@deri. org 9

Solution: WSMX Architecture matthew. [email protected] org 9

Solution: WSMX Architecture matthew. moran@deri. org 10

Solution: WSMX Architecture matthew. [email protected] org 10

Solution: WSMX Architecture matthew. moran@deri. org 11

Solution: WSMX Architecture matthew. [email protected] org 11

Solution: WSMX Architecture matthew. moran@deri. org 12

Solution: WSMX Architecture matthew. [email protected] org 12

Solution: WSMX Architecture matthew. moran@deri. org 13

Solution: WSMX Architecture matthew. [email protected] org 13

Solution: WSMX Architecture matthew. moran@deri. org 14

Solution: WSMX Architecture matthew. [email protected] org 14

Solution: WSMX Architecture matthew. moran@deri. org 15

Solution: WSMX Architecture matthew. [email protected] org 15

Solution: WSMX Architecture matthew. moran@deri. org 16

Solution: WSMX Architecture matthew. [email protected] org 16

Solution: WSMX Architecture matthew. moran@deri. org 17

Solution: WSMX Architecture matthew. [email protected] org 17

Solution: WSMX Architecture matthew. moran@deri. org 18

Solution: WSMX Architecture matthew. [email protected] org 18

Solution: WSMX Architecture matthew. moran@deri. org 19

Solution: WSMX Architecture matthew. [email protected] org 19

Solution: WSMX Architecture matthew. moran@deri. org 20

Solution: WSMX Architecture matthew. [email protected] org 20

Solution: WSMX Mediation matthew. moran@deri. org 21

Solution: WSMX Mediation matthew. [email protected] org 21

Solution: WSMX Discovery • • Based on matching of logical Goals with WS Capabilities

Solution: WSMX Discovery • • Based on matching of logical Goals with WS Capabilities Goals and capabilities have postconditions and effects. Capabilities additionally have preconditions and assumptions WSMX adds concept of conditional Web Service to capability Step 1 Goal Step 2 Possible Matches Match requester Collection of WS Step 4 WSMO Registry WSMX Matchmaker Step 3 Network Conditional WS 1 Conditional WS 2 matthew. [email protected] org 22

Solution: WSMX Implementation • Event based component architecture • Current status – – Version

Solution: WSMX Implementation • Event based component architecture • Current status – – Version 1 codebase implemented Opensource at http: //sourceforge. net/projects/wsmx Data mediation component implemented Other component interfaces defined and partially implemented • Main technologies used – Apache Tomcat and Apache Axis – Database – My. SQL – Eclipse IDE and Ant as build tool matthew. [email protected] org 23

Wrap-up: Related Work • IRS 3 – Interoperable, slightly different focus • BPEL 4

Wrap-up: Related Work • IRS 3 – Interoperable, slightly different focus • BPEL 4 WS + DAML-S + SDS – Bottom-up approach – Not clear how the discovery works • Meteor-S – Research into adding semantics to Web Services and publishing these in UDDI directories • Biztalk – Services used in processes must be bound at design time matthew. [email protected] org 24

Wrap-up: WSMX Summary • • Runtime binding of requester and provider Conceptual model is

Wrap-up: WSMX Summary • • Runtime binding of requester and provider Conceptual model is WSMO with some add-ons End-to-end functionality for executing SWS Formal execution semantics Real implementation – demo later Open source code base at Source. Forge Event driven component architecture Developers welcome – http: //www. wsmx. org – http: //sourceforge. net/projects/wsmx matthew. [email protected] org 25

Wrap-up Questions? matthew. moran@deri. org 26

Wrap-up Questions? matthew. [email protected] org 26