This module develops techniques for Web-service publishing and discovery, specifically using the Universal Description, Discovery and Integration (UDDI) 2.0 APIs and the Java API for XML Registries (JAXR) 1.0. The relatively specific problem of Web-service publishing and discovery is first put in the broader context of Web registries, which manage a wide range of information types and instances. Students learn UDDI concepts, architecture and API in depth, and then move on to JAXR, both as an API for UDDI and an information-management model in its own right, with mappings also to ebXML repositories.

The UDDI information model is considered in some depth, especially the “tModel” as a means of defining taxonomies for classification by different criteria, such as business type or geographical location. Then students learn the UDDI inquiry and publishing APIs, at a summary level and also by sending specific SOAP messages to UDDI registries and viewing the SOAP responses. Both local and remote/public repositories are queried in hands-on exercises, and students learn to publish service descriptors and locations using a local UDDI registry.

Then the JAXR is brought into play. JAXR has its own information model, which is meant to adapt to both UDDI and ebXML, so there is some mapping to be understood; it is a thick, rather than thin, wrapper over the UDDI API. JAXR tools of various types are built, including console applications that perform scripted replication tasks, a simple “yellow pages” business browser, and a graphical administration console that allows the user to associate technical specifications with a registered Web service. Students wrap up with exercises focusing on the original problem: publishing and discovering a deployed SOAP-based Web service.

Web Services Training LEARNING OBJECTIVES

• Understand the basic UDDI information model.
• Understand the use of a tModel as a "technical fingerprint" for service classification.
• Understand the use of a tModel in defining a taxonomy for classification or identification of businesses, services, or other tModels.
• Understand the UDDI inquiry and publishing APIs.
• Query a UDDI registry using raw SOAP messages.
• Publish a limited set of service information to UDDI using SOAP.
• Understand the JAXR information model and how it maps to UDDI's model.
• Understand the refinements JAXR brings to the problem of object classification.
• Query a UDDI registry using Java and JAXR.
• Publish a Web service via the JAXR to a UDDI registry.
• Write a client that can discover a needed Web service by running UDDI queries based on desired tModels for WSDL-described functionality.
• Build scriptable and interactive tools for UDDI administrative tasks, such as interactive update of service details, replication, and client-side browsing.