Web Services Experience Language Web Services eXperience Language Technical Overview Ravi Konuru e-Business Tools and Frameworks, IBM Research IBM WSXL Team OASIS WSCM Technical Committee January 2002

Web Services Experience Language The Innovation Context Application Back End Services User Experience Services Leverage Web services and XML technologies B2B Integration  Experience Integration Enable simple solutions for syndication, adaptation, delegation and composition of web experience Ensure migration path for existing applications ProvidersIntegratorClient

Web Services Experience Language Experience Integration: Requirements & Related Work –Provider Migrating Interactive Web Applications –Converting existing web applications to interoperable services –Describing their inputs and outputs. Syndication –Separation of Style from Presentation (XML/XSL) –Adaptation description –Explicit MVC decomposition (XFORMS) –Explicit Flow Modeling (WSFL) –Integrator Style Composition –XSL, CSS Data binding, sharing and synchronization across components –XFORMS, XML Events, XLINK, XPATH, XML plug-in? Event interoperability and synchronization –XML Events, XLINK, XPATH, XML plug-in? Flow composition –WSFL

Web Services Experience Language Relationship to WSCM Charter define a set of "base" web services interfaces that can be used to expose interactive web application function and adaptation. define a set of web services interfaces that can be used to partition web applications into model, view and control (MVC). define a "wiring mechanism" to declaratively specify web application semantics.

Web Services Experience Language WSXL Elements WSXL Components are built on four kinds of web services: Base, Data, Presentation and Control. The Extensible Control Language (XLink and XML Events) wires WSXL Components. A WSXL Container service hosts WSXL components and can provide optional functionalities. WSXL Adaptation Description Language enables application providers to specify the adaptability of their service. WSXL Applications can be created from one or more WSXL components (Base, Data, Presentation, and Control) and wired using the Extensible Control language.

Web Services Experience Language WSXL Base Component The WSXL Base Component specifies the interfaces required by all WSXL Components. W3C DOM Events interface is used for describing event listeners, event handlers and WSXL Event types. Lifecycle interfaces is the means to identify and manage instances getMarkup interface provides its output All WSXL Entities can additionally export application specific operations WSXL Base Component W3C DOM Events getMarkup Interface Lifecycle Interfaces

Web Services Experience Language WSXL Data Component The WSXL Data Component - Interfaces to describe and maintain instances of data - Adopts concepts and ideas from XFORMS - Desired functionality in the data interface - Access (DOM subset), - Validation, - Update Control, - Re-computation, - Data Availability. WSXL Data Component WSXL Base Interface Data Interfaces Application Interfaces

Web Services Experience Language WSXL Presentation Component The WSXL Presentation Component - Describes and maintains instances of presentation - Elements from arbitrary namespaces (XHTML, WML, XFORMS, …) - DOM 2 based access interface - Defined events such as focus, select, execute and DOM mutation. WSXL Presentation Component WSXL Base Interface Presentation Interfaces Application Interfaces

Web Services Experience Language WSXL Control Component The WSXL Control Component implements interfaces used to - Manage the arcs connecting WSXL components - Control the propagation of bi-directional event notification - Parse and interpret the Extensible Control Language. WSXL Control Component WSXL Base Interface Control Interfaces (Arc management, Update Model) Application Interfaces Common case: Connecting presentation and data components.

Web Services Experience Language WSXL Event Wiring WSXL Presentation Component WSXL Data Component W3C XML Events WSXL Control Component W3C XML Events W3C XML Events The Extensible Control Language (XLINK and XML Events) wires any WSXL Components together for event synchronization.

Web Services Experience Language WSXL Containers A WSXL Container is responsible for providing an execution and management environment for WSXL Components. Discovery Specialized Lifecycle

Web Services Experience Language Adaptation Description Language Driven by Integrator Requirements –Robust adaptation Reliably observe and/or modify the output of a service Reliably change behavior by replacing invocations of one service to invocations of another service. –Exploit provider capabilities Use provider’s services/operations to perform adaptations. Application Provider specifies –Category of adaptation (XML, CSS, ….) –Points of adaptability –Kinds of adaptability –Assistance for adaptation

Web Services Experience Language Creating Applications A WSXL application can consist of: –A single WSXL component –An adaptation description –Event wiring and synchronization –Flow composition across multiple WSXL components

Web Services Experience Language Distributed Stock Plotting Application

Web Services Experience Language Mapping WSXL to WSCM-specific elements WSXL Base Service WSXL Container WSFL - Flow modeling WSFL - Global modeling WSDL - Operations Event wiring WSXL Event Controller WSXL Data ServiceWSXL Presentation Service Existing WS infrastructure WSXL Adaptation Description Language Extensible Control Language

Web Services Experience Language Questions/Comments?