The UDDI Business Registry (UBR) is a global implementation of the UDDI specification. The UBR is a single registry for Web services. A group of companies operate and host UBR nodes, each of which is an identical copy of all other nodes. New entries or updates are entered into a single node, but are propagated to all other nodes.
The UBR is a key element of the deployment of Web services and provides the following capabilities:
A small group of companies operate and manage a set of UBR nodes. In July 2002, the UBR was updated to support version 2 of the UDDI specification. Initially, IBM, Microsoft, and SAP comprised the UBR V2, operating 3 UBR nodes. NTT Communications later launched an UBR node to become the fourth UBR V2 node. More than 10,000 businesses are registered with the initial three UBR nodes, publishing over 7,000 Web services. NTT expects to add another 1,000 businesses within the first operational year of the fourth UBR node.
Each UBR node provides a Web home page for human-friendly navigation of the registry as well as information about the use of the registry. Today, most searches for available Web services are done through human-friendly means: phone conversations between existing business partners, the home pages of the UBR, Web service aggregator portals such as www.xmethods.com, or standard Web search engines such as Google. UBR node home pages also provide other information pertaining to UDDI or to that particular UBR node. This information includes policies on data replication, publishing restrictions, and other administrative or usage issues.
UBR nodes also implement a simple API for direct electronic (computer-to-computer) access to the contents of the registry. The two most important and relevant features of the APIs are inquiry and publication.
The inquiry API allows searching through the registry for information about businesses, the Web services the business makes available, as well as implementation and interface information for each service.
The publication API allows adding, changing, and deleting business and service information within the registry.
Figure 4-3 depicts some typical means of accessing and interacting with an UDDI registry.
Figure 4-3. The various means of accessing an UDDI registry.
The URL access endpoint information of the home page, inquiry API, and publication API of each UBR node is different, and the information for each of the UBR V2 nodes is listed in Table 4-1. The publication API endpoint requires authentication and uses the HTTPS protocol, while the inquiry API and home page use standard HTTP.
The UBR operators also provide fully functional test environments where companies can develop and test their offerings without affecting other users. Some of these test nodes do not support version 2 of the UDDI specification as yet. Table 4-2 lists the endpoint access information for the test nodes of the UBR.
Later in the chapter we look at how to programmatically access the information at these UBR nodes to locate the latest information about a particular Web service.