The Web Services Resource Framework defines a system for creating stateful resources between Web services in terms of an implied resource pattern.

The Web Services Resource Framework defines a family of specifications for accessing stateful resources using Web services. It includes the WS-ResourceProperties, WS-ResourceLifetime, WS-BaseFaults, and WS-ServiceGroup specifications. The motivation for these new specifications is that while Web service implementations typically do not maintain state information during their interactions, their interfaces must frequently allow for the manipulation of state, that is, data values that persist across and evolve as a result of Web service interactions. For example, an online airline reservation system must maintain state concerning flight status, reservations made by specific customers, and the system itself: its current location, load, and performance. Web service interfaces that allow requestors to query flight status, make reservations, change reservation status, and manage the reservation system must necessarily provide access to this state. In the Web Services Resource Framework we model state as stateful resources and codify the relationship between Web services in terms of an implied resource pattern.

Get the specification and related material

WS-Resource Properties defines how the data associated with a stateful resource can be queried and changed using Web services technologies. This allows a standard means by which data associated with a WS-Resource can be accessed by clients. The declaration of the WS-Resource’s properties represents a projection of or a view on the WS-Resource’s state. This projection represents an implied resource type which serves to define a basis for access to the resource properties through Web service interfaces.

WS-Resource Lifetime defines two ways of destroying a WS-Resource: immediate and scheduled. This allows designers flexibility to design how their Web services applications can clean up resources no longer needed.

WS-BaseFaults defines an XML Schema type for a base fault, along with rules for how this fault type is used by Web services. A designer of a Web services application often uses interfaces defined by others. Managing faults in such an application is more difficult when each interface uses a different convention for representing common information in fault messages. Support for problem determination and fault management can be enhanced by specifying Web services fault messages in a common way. When the information available in faults from various interfaces is consistent, it is easier for requestors to understand faults. It is also more likely that common tooling can be created to assist in the handling of faults.

WS-ServiceGroup defines a means by which Web services and WS-Resources can be aggregated or grouped together for a domain specific purpose. In order for requestors to form meaningful queries against the contents of the ServiceGroup, membership in the group must be constrained in some fashion. The constraints for membership are expressed by intension using a classification mechanism. Further, the members of each intension must share a common set of information over which queries can be expressed.

You can also get the earlier versions of these specifications and their associated WSDL and XSD files by clicking on the following links:

• WS-ResourceProperties specification. (PDF, March 2004)
• WS-ResourceLifetime specification. (PDF, March 2004)
• WS-BaseFaults specification. (PDF, March 2004)
• WS-ServiceGroup specification. (PDF, March 2004)
• WS-ResourceProperties (WSDL, March 2004)
• WS-ResourceProperties (XSD, March 2004)
• WS-ResourceLifetime (WSDL, March 2004)
• WS-ResourceLifetime (XSD, March 2004)
• WS-BaseFaults (WSDL, March 2004)
• WS-BaseFaults (XSD, March 2004)
• WS-ServiceGroup (WSDL, March 2004)
• WS-ServiceGroup (XSD, March 2004)

Resources

• Get downloads and more information on the specifications included in the Web Services Notification family of specifications: WS-BaseNotification, WS-BrokeredNotification, and WS-Topics.
  
  
• Explore the relationship between OGSI and WSRF and the related WS-Notification specification in this whitepaper, which explains the common requirements that both address.
  
  
• Understand the relationship between stateful resources and Web services in the WS-Resource Framework whitepaper.
  
  
• The whitepaper, Modeling Stateful Resources with Web services, explains the structure and operation of the WS-Resource Framework.
  
  
• The Open Grid Services Architecture shows how Grid computing can take advantage of Web services and build a service-oriented architecture for the Grid model.
  
  
• Stateful resource management is important to the maintenance of the current state of any Grid computing system.
  
  
• The developerWorks Grid computing section keeps regular coverage of new developments in Grid technology.
  
  

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