1. Web Services Part II Yongqun He

2. J2EE-based Web Services

3. Type of clientExamplesHow this client connects Business Partners Distributors, resellers, large customers XML-based web services technologies (SOAP, UDDI, WSDL, ebXML) Thin Clients Web browsers, PDAs, wireless devices Lightweight protocol (HTTP) Thick Clients Applets, applications, existing systems Heavyweight protocol (IIOP) Types in Client Tier ** PDAs: Personal Digital Assistants ** Thick Clients: e.g. within a company’s internal LAN topology. May use more efficient protocol such as Java RMI-IIOP (Java Remote Method Invocation over the Internet Inter-ORB Protocol).

4. Using JAXR,UDDI, and WSDL ** JAXR (Java APIs for XML Registries) For publishing, querying, & editing

5. An EJB Business Layer

6. JAX* APIs to Invoke a Business Web Service The Java API for XML registries (JAXR): look up the business partner’s web service that is published in a UDDI registry. The Java API for XML RPC (JAX/RPC): perform RPC requests to the external web service. The Java API for XML Messaging (JAXM): send SOAP or ebXML messages to the external web service. The Java API for XML parsing (JAXP) and the Java API for XML Binding (JAXB): transform Java data into an XML format suitable for the partner; convert the received XML data back into a Java language construct; perform XSLT transforms to convert schemas.

7. JAX* APIs to Invoke Business Web Service

8. Relationship of Web Services Architecture to MS Windows DNA (n-tier) Architecture

9. Microsoft.NET-based Web Services

10. Analogies between J2EE and.NET FeatureJ2EE.NET Type of technologyStandardProduct Middleware Vendors30+Microsoft InterpreterJRECLR Dynamic Web PagesJSPASP.NET Middle-Tier Components EJB.NET Managed Components Database accessJDBC SQL/JADO.NET SOAP, WSDL, UDDI Yes Implicit middleware (load-balancing, etc) Yes

11. More Components XLANG: used by web services to perform complex undo operations. XAML (Transaction Authority Markup Language): provides a more traditional two- phase commit style transactional semantics over web services. XLANG/XAML provides transactional support for complex web transactions involving multiple web services.

12. More Components (cont’d) XKMS (XML Key Management Specification): ongoing work by Microsoft and Verisign to support authentication and registration. Key idea: delegate the signature processing to a trust server on the web. Rely on XML signature and encryption specification by W3C. Two parts: X-KISS (XML Key information Service Specification) X-KRSS (XML Key Registration Service Specification)

13. ebXML (e-business XML) A suite of XML specifications and related processes and behavior designed to provide an e-infrastructure for B2B collaboration and integration. Enables enterprises of any size and in any geographical location to conduct business over the Internet. Sponsored by UN/CEFACT and OASIS. UN/CEFACT: United Nations Center for Trade Facilitation and Electronic Business OASIS: Organization for the Advancement of Structured Information Standards

14. ebXML (e-business XML) Key components: Collaboration Protocol Profile (CPP): describes a company’s offerings in a standard, portable way. Collaboration Protocol Agreement (CPA): describes the exact requirements and mechanisms for the transactions. Business Process and Information Modeling: in XMLCore Components: a set of XML schemas Messaging: built on top of SOAP-encapsulated message-passing invocations; extend SOAP by adding layered frameworks. Registry/Repository: a service that stores CPPs, CPAs, core components, and other ebXML documents and fragments.

15. Dynamic e-business Definition: the next generation of e-business focusing on the integration and infrastructure complexities of B2B by leveraging the benefits of Internet standards and common infrastructure to produce optimal efficiencies for intra- and inter-enterprise computing. Service-Oriented Architecture (SOA): conceptual architecture for implementing dynamic e- business. SOA includes three participants and three fundamental operations.

16. SOA Architecture ** Service providers publish services to a service broker. Service requesters find required services using a Service Broker and bind to them.

17. Comparison with CORBA/DCOM Competing approaches Using the same principles Discovery of distributed services Interaction through a common protocol CORBA/DCOM success is limited Dependent on vendor’s implementation Weak for client-to-server communications, esp. when the client machines are scattered across the Internet. Web Services: existing Internet standards or widely-accepted specifications: HTTP, XML, SOAP, WSDL, UDDI.

18. References A Web Services Primer: http://www.xml.com/lpt/a/2001/04/04/webservices/index.html http://www.xml.com/lpt/a/2001/04/04/webservices/index.html Developer’s Guide to Building XML-based Web Services: http://www.theserverside.com/resources/article.jsp?l=WebServices -Dev-Guide http://www.theserverside.com/resources/article.jsp?l=WebServices -Dev-Guide Getting Started on Developing Web Services: http://dcb.sun.com/practices/howtos/developing_webserv.jsp http://dcb.sun.com/practices/howtos/developing_webserv.jsp A Platform for Web Services: http://msdn.microsoft.com/library/default.asp?url=/library/en- us/dnwebsrv/html/websvcs_platform.asp http://msdn.microsoft.com/library/default.asp?url=/library/en- us/dnwebsrv/html/websvcs_platform.asp J2EE vs. Microsoft.NET: http://www.theserverside.com/resources/articles/J2EE-vs- DOTNET/article.html http://www.theserverside.com/resources/articles/J2EE-vs- DOTNET/article.html IBM Web Services Zone: http://www-106.ibm.com/developerworks/webservices/