Notifications and Resources in the WS-Resource Framework - Notification of WS-Resource Termination
(Page 5 of 6 )
WS-ResourceLifetime also standardizes the way WS-Notification can be used to inform interested parties about the termination of a WS-Resource. There is a standardized topic (recall the topics concept we discussed in the section "Topics") in the WS-ResourceLifetime namespace ResourceTermination. Requestors can use this topic to subscribe for a notification message when a WS-Resource of interest is terminated.
In order for this facility to work, the following pieces must be in place:
The Web service component of the WS-Resource must support the notification producer operations (for example, the subscribe operation).
The Web service component of the WS-Resource must include the wsrl:ResourceTermination topic in its list of topics (recall the Topics resource property described in the section "Resource Properties of a Notification Producer").
SkatesTown's POPortType Web service supports generating the notification messages on the ResourceTermination topic as described earlier. The Skateboard Warehouse can issue a subscribe operation as follows to register interest in when a PurchaseOrder WS-Resource is destroyed:
<soap:Envelope
...
<soap:Header>
...
<!-- the reference property to id the PO -->
<poRP:POResourceID>43871</poRP:POResourceID>
</soap:Header>
<soap:Body>
<wsnt:Subscribe>
<wsnt:ConsumerReference>
<wsa:Address>
http://www.skateboardwarehouse.com
/services/inventoryManagement
</wsa:Address>
</wsnt:ConsumerReference>
<wsnt:TopicExpression dialect=
"http://www.ibm.com/xmlns/stdwip/web-
services/WS-Topics/TopicExpression/
simple">
wsrl:ResourceTermination
</wsnt:TopicPathExpression>
...
</wsnt: Subscribe>
</soap:Body>
</soap:Envelope>
When the PurchaseOrder WS-Resource is terminated, a notification message will be delivered to the notification consumer indicating (among other information) the time the WS-Resource was terminated and the reason for its termination. WS-ResourceLifetime specifies that the notification message must contain an element of the following form:
<wsrl:TerminationNotification>
<wsrl:TerminationTime>xsd:dateTime</wsrl:
TerminationTime>
<wsrl:TerminationReason>xsd:any</wsrl:
TerminationReason>?
</wsrl:TerminationNotification>
Next: Other WS-Resource Framework Specifications >>
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 This article is excerpted from chapter 8 of the book Building Web Services with Java: Making sense of XML, SOAP, WSDL, and UDDI, written by Steve Graham et al. (Sams; ISBN: 0672326418). Check it out today at your favorite bookstore. Buy this book now.
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