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Demonstrating WSMX: Least Cost Supply Management

Demonstrating WSMX: Least Cost Supply Management. Table of Contents. Introduction Use case: Ordering Broadband Internet WSMX Overview WS-BPEL Overview Extending WSMX Conclusion and Future Work. Introduction. Web services. Semantic web. Semantic Web services. Introduction

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Demonstrating WSMX: Least Cost Supply Management

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  1. Demonstrating WSMX:Least Cost Supply Management

  2. Table of Contents • Introduction • Use case: Ordering Broadband Internet • WSMX Overview • WS-BPELOverview • Extending WSMX • Conclusion and Future Work

  3. Introduction • Web services. • Semantic web. • Semantic Web services.

  4. Introduction • Use case: Ordering Broadband Internet • WSMX Overview • WS-BPELOverview • Extending WSMX • Conclusion and Future Work

  5. Motivation • For demonstrating the potential of WSMX we selected a use case from the telecommunications sector. • Internet Service providers are extending their business with wholesaling of mobile and fixed line telephone services and unbundled data lines. • Easy and flexible dynamic integration of suppliers that offer these services is needed.

  6. Description • An ADSL line is a broadband Internet connection on top of a regular telephone line. • Several suppliers of unbundled ADSL lines are available depending on region where the customer is located. • Wholesalers need a flexible and dynamic integration of these suppliers in their back-end systems.

  7. Objectives • ADSL line suppliers have different end point interfaces. Message mediation between wholesalers and ADSL supplier is needed. • Line suppliers differ in capability to provide an ADSL line for given phone number (it depends on region). • Least cost supplier which can provide ADSL line for given phone number must be dynamic found and bounded into a ordering process flow.

  8. Process Flow Steps • Static wholesaler ordering ADSL line process is realized as a WS-BPEL complex process controlled by an BPEL execution engine. • Web services for check of a bank card, availability of internet domain, billing etc. are invoked directly by the BPEL execution engine. • ADSL suppliers have to register their services within the WSMX service repository where the capabilities and mapping rules should be stored. • To find proper ADSL provider, BPEL process of wholesalerinvokes WSMX engine sending him goal description and other needed information in form of a SOAP message.

  9. Use Case Process Flow Diagram

  10. Introduction • Use case: Ordering Broadband Internet • WSMX Overview • WS-BPELOverview • Extending WSMX • Conclusion and Future Work

  11. Introduction • Execution environment for Semantic Web Services. • A reference implementation for WSMO. • Service oriented and event-based architecture. • Decouples service providers and requesters. • Dynamic discovery based on Goal-Capability matching. • Mediation. • Data. • Process. • Protocol.

  12. WSMX Architecture

  13. WSMX Discovery Mechanism • Based on matching of logical goals with WS capabilities. • Goals and capabilities have postconditions and effects. • Capabilities additionally have preconditions and assumptions.

  14. Current WSMX Architecture

  15. Implementation • Event based service oriented architecture. • Current status: • Code base established – available at SourceForge. • Data mediation component implemented. • Other component interfaces defined and partially implemented. • Main technologies used: • Apache Tomcat and Apache Axis. • Database – mySQL. • Eclipse IDE and Ant as build tool.

  16. Introduction • Use case: Ordering Broadband Internet • WSMX Overview • WS-BPELOverview • Extending WSMX • Conclusion and Future Work

  17. WS-BPEL Standard • Process modelling language based on Web services. • Widely used for automation of business processes. • BPEL was originally developed by BEA, IBM, and Microsoft. Version 1.1 also includes input from SAP and Siebel.5. • The OASIS TC “web services business execution language” now continues the standardization of BPEL.

  18. WS-BPEL Overview • WS-BPEL defines business processes consisting of stateful long-running interactions in which each interaction has a beginning, a defined behavior and an end, modeled by a flow. • Flow is composed by a sequence of activities. • The behavior context for each activity is provided by a scope. • A scope can provide fault handlers, event handlers, compensation handlers and a set of data variables and correlation sets.

  19. WS-BPEL Process Flow Scope 1

  20. WS-BPEL Process Flow Scope 2 • Events, for event driven flow execution. • Variables, in WSDL schema defined messages for internal or external purposes. • Correlations, definitions of message parts which identify particularly process instance (session ID). • Fault handling, defines what happen if an exception has been thrown. • Event handling, defines what happen if an event occurs.

  21. WS-BPEL Activities 1 • Receive - do a blocking wait for a matching message to arrive. • Reply - send a message in reply to a message which was sent by a <receive>. • Invoke - invoke a one-way or request-response operation on a port type offered by a partner. • Assign - update values in variables. • Throw - generates a fault inside the business process. • Wait - wait till a certain time has passed. • Empty - insert a “no-op” instruction into a business process.

  22. WS-BPEL Activities 2 • Sequence - define a collection of activities to be performed sequentially. • Switch - select a branch of activities from a set of choices. • While - repeat an activity till a certain condition of success has been met. • Pick - block and wait for a suitable message to arrive. • Flow - specify one or more activities to be performed concurrently. • Scope - define a nested activity with its own associated variables, fault handlers and compensation handlers. • Compensate - invoke compensation in an inner scope i.e. from a fault handler or a compensation handler.

  23. Disadvantages of WS-BPEL • Static process composition. • Process participants (partner‘s web services) must be defined and bound to the process flow at design time. • BPEL standard is not about Semantic Web services: • Partner discovery and bounding at run time not possible. • Message mediation not possible.

  24. BPEL Engine Implementations • BPWS4J (Test engine from IBM Alphaworks) • http://www.alphaworks.ibm.com/tech/bpws4j • ActiveBPEL (First Open Source BPEL engine) • http://www.activebpel.org/ • Oracle BPEL Process manager • http://www.oracle.com/technology/products/ias/bpel/index.html

  25. Introduction • Use case: Ordering Broadband Internet • WSMX Overview • WS-BPELOverview • Extending WSMX • Conclusion and Future Work

  26. BPEL & WSMX • Integration of WS-BPEL and WSMX. • Static defined process flow provided by BPEL. • Known services are invoked statically as described in the BPEL process flow. • Dynamic services will be discovered and invoked through invocation of WSMX engine by BPEL process flow.

  27. Dynamic Service Invocation • BPEL static process invokes WSMX using its web service interface. • Input message sent from BPEL has a goal and input parameters. • WSMX finds suitable services based on an Input goal and handles with message mediation between BPEL message format and message format of a chosen web service.

  28. Extending WSMX • To implement our use case is needed an extension of current WSMX service discovery mechanism. • In our use case a capabilities of a web services can not be described static, they can differ (ADSL line providers supports some telephone numbers, set of supported ones differs and can not be coded directly as a service capabilities).

  29. Current shortcomings in WSMX • Assumption that providers are able to completely describe their Web Services in WSMX Capabilities Repositories at design time (static description) – providers need a mechanism to defer specification of their capabilities during runtime, • Limited operational behavior – WSMX does not support complex goals consisting of several subgoals. Further step: WSMX understanding some process modeling language.

  30. Conditional WS Implementation • Providers cannot store a range of number they can provide a ASDL line for in WS Capability since it is changing very frequently, • Before ASDL line is purchased, its availability has to be checked for requested landline number, • Assumption: There is list of Conditional WS, which must be executed before selected Web Service can be executed itself – in future this should be specified within logic expressions or in process modeling language.

  31. Conditional WS Implementation • 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. WSMX Matchmaker Step 1 Step 2 Match requester Goal Possible Matches Collection of WS Step 4 Step 3 ConditionalWS1 ConditionalWS2

  32. Conditional WS Implementation • Each of the Conditions creates a new Event in the system, all new Events return typed Values, which can be processed by initializing component, • If all return results from intermediate Web Services indicate successful result, then WS conditions are fulfilled and execution of given WS can be performed, • New component called Correlation Manager maintains the relationships between main event and conditional events; Correlation Manager puts main event into sleep and once all the conditional events are in state consumed, it wakes the main event up.

  33. Conditional WS Implementation • Implementation started – not finished yet

  34. Business Process Engine in WSMX • Process execution engine is able to understand the given specification of the ordering process and manages the runtime execution of this process, • No decision has yet been made on a formalism for specifying complex goals. Solutions that are considered include YAWL or WS-BPEL, • Two approaches to Complex Goal: Conditional WS within logic expressions or Conditional WS specified in modeling language,

  35. Introduction • Use case: Ordering Broadband Internet • WSMX Overview • WS-BPELOverview • Extending WSMX • Conclusion and Future Work

  36. Conclusion • We have shown how to integrate the WS-BPEL with WSMX to provide supporting for dynamic real integration use case. • The general assumption of WSMX that providers should completely describe the functionality of their services at design time is unreasonable.

  37. Known Problems • Security. • Transaction Management. • Performances. • Using of WS-BPEL can be seen as temporary solution, the WSMX should have service composition capabilities.

  38. Future Work • Realization of the presented use case. • Extending of WSMX functionality: • Extend the logical language to include a built-in function that evaluates during run time to a web service call. • Include the process modelling component in WSMX that is able to execute complex goals.

  39. The End

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