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Colin Atkinson, Philipp Bostan, Oliver Hummel and Dietmar Stoll 2007 IEEE International Conference on Web Services (ICWS 2007) Speaker: Chun-Hung Wang Date: 2009.08.19 Outline Introduction Standard Web Service Brokerage Model Web Service Indices Lucene/java’s jar Index Creation Index Maintenance Suggested Improvements to Web Service Standards Conclusion Introduction One of the fundamental pillars of the web service vision is a brokerage system that enables services to be published to a searchable repository and later retrieved by potential users. This paper point out the argument is that concepts from component- based development have been too naively transferred to web services, with the result that many of the related problems have been inherited as well. Standard Web Service Brokerage Model Web Service Indices Lucene Application & Lucene Diagram Lucene EX: Body1：Tom lives in Guangzhou,I live in Guangzhou too. Body2：He once lived in Shanghai. Body1 Keyword：[tom] [live] [guangzhou] [i] [live] [guangzhou] Body2 Keyword：[he] [live] [shanghai] Lucene No. Keyword Times 1 guangzhou，i，live，tom 1，1，1，1 2 he，live，shanghai 1，1，1 Tab1： General index structure Keyword No.[Times] Position guangzhou 1[2] 3，6 he 2[1] 1 i 1[1] 4 live 1[2]，2[1] 2，5，2 shanghai 2[1] 3 tom 1[1] 1 Tab2： Lucene index structure Index Creation One way is through the explicit publication efforts of web service developers . The other is by means of some kind of “crawling” activity which is focused on finding and analyzing web services. Crawling the visible web for WSDL descriptions of web services presents two basic challenges recognition of valid WSDL files and dependencies detection of properly working web services Index Maintenance Conventional search engines like Google and Yahoo keep their content up to date by recrawling the web on a periodic basis. For search engines that index web services this is not possible because the availability of a WSDL description does not necessary imply that the web service is on-line and working. Periodically test the availability of the web services in its index, or to test their availability before delivering a search result. Suggested Improvements to Web Service Standards The first convention propose is that every web service should implement a standard “liveness” operation which can be used to check that it is still on line and has not been retired. They propose to mark them by adding additional attributes (such as "sessionID")to the XML schema data types definition in a WSDL document. Since there will always be a large number of web services which are not annotated in this way, at least for some time to come, heuristics of the kind proposed in the previous section have to be used for identifying these management parameters and indexing them accordingly. Conclusion Using a combination of these techniques, our merobase[1] search engine has been able to assemble a repository of about 3000 existing web services. [1] http://www.merobase.com/