Invocation pattern for the UDDI Registry

 

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To prepare an application to take advantage of a remote Web service that is registered within the UDDI registry by other businesses or entities, prepare that application to use the information found in the registry for the specific service being invoked.

The bindingTemplate data obtained from the UDDI registry represents the specific details about an instance of a given interface type, including the location at which a program starts interacting with the service. The calling application or program should cache this information and use it to contact the service at the registered address whenever the calling application needs to communicate with the service instance. In previously popular remote procedure technologies tools have automated the tasks associated with caching (or hard coding) location information. Problems arise however when a remote service is moved without any knowledge on the part of the callers. Moves occur for a variety of reasons, including server upgrades, disaster recovery, and service acquisition and business name changes.

When a call fails using cached information previously obtained from a UDDI Registry, the proper behavior is to query the UDDI Registry for fresh bindingTemplate information. If the data returned is different from the cached information, the service invocation should automatically retry the invocation using the fresh information. If the result of this retry is successful, the new information should replace the cached information.

By using this pattern with Web services, a business using a UDDI Registry can automate the recovery of a large number of partners without undue communication and coordination costs. For example, if a business has activated a disaster recovery site, most of the calls from partners fail when they try to invoke services at the failed site. By updating the UDDI information with the new address for the service, partners who use the invocation pattern automatically locate the new service information and recover without further administrative action.