UDDI | SOA for the Business Developer: Concepts, BPEL, and SCA (Business Developers series)

UDDI is a set of rules for registering and retrieving details about a business and its services. As you design a program, you might search a UDDI registry for Web services to invoke in your code. You also might create a program that queries a UDDI registry at run time to access a set of similar services because (for example) each provides price information for a specific product. The latter use of UDDI is less common, however.

A UDDI registry might include details on business services (not just on software), but the major purpose of such a registry is to publicize what Web services are available in a particular domain such as a business or industry. The publicity exposes redundant Web services and promotes reuse.

Other purposes are possible, especially in products that build on the UDDI standard. Those UDDI-compliant products provide sophisticated user interfaces so that users are better able to register, review, and compare information. The products may track the planning and fulfillment of project tasks when a company is updating Web services so that the software complies with Service Level Agreements (SLAs) or industry standards. UDDI-compliant products also may hold additional details. Use of the word repository in some products suggests that SLAs, WSDL definitions, and supporting documentation of all kinds are immediately available and are not merely on a remote site that is referenced by the UDDI registry.

Among the categories of information in a UDDI registry entry:

business entity, which usually includes
- basic information such as business name and address
- a set of classifications, such as by industry or by a category of products offered
- a reference to the services provided by the business
publisher assertion, which indicates a business relationship, as when one business is a subsidiary of another
business service, which usually includes the service name and description
binding template, which includes a service's access point such as a phone number (as might be appropriate for a non-software service) or a URL (for a Web service)

When interacting with a UDDI registry, you may be exposed to the following terms:

tModel (technical model) is a data structure that references a specification such as a WSDL definition.
Category bag is a list of entries. Each entry identifies an instance of a category, as in the following examples:
- One category bag indicates that a business is in a particular geographical area (such as Connecticut) and handles a particular product (such as insurance).
- A second category bag indicates that a service is described with a particular kind of specification (such as a WSDL definition) and fulfills a particular kind of purpose (such as providing a stock quote).
Identifier bag is a list of similar entries - for example, a list of corporate tax IDs for use in different jurisdictions.

SOAP is the basis for the transfer of data to and from a registry. In the message shown in Listing 5.14, the UDDI directive get_businessDetail retrieves business-specific information that was stored at some previous time.

Listing 5.14: Sample message containing a UDDI directive

 <Envelope xmlns=    "http://schemas.xmlsoap.org/soap/envelope/">    <Body>       <get_businessDetail generic="2.0" xmlns="urn:uddi-org:api_v2">          <businessKey=             "uddi:">          </businessKey>       </get_businessDetail>    </Body> </Envelope>

For further details about UDDI, see the following Web site, which is operated by OASIS: http://www.uddi.org.