Sumedha and I had a chat on the right way of doing XPath tracing for BAM. If we look at router mediator in ESB where XPath is used, it looks like all messages that pass through are evaluated for XPath in the header (is that correct?)
In case of BAM, we mostly need to evaluate the Body and sometimes even the Header in SOAP message. Now if we are to evaluate this using a handler, we need to evaluate each and every message for the given XPath. When there are multiple XPaths to be evaluated, then the evaluation cost can be high. In oder to make it more efficient, we can make the XPath relate to a service's operation, so that we can evaluate the XPath if and only if, that is the operation that we are interested in. However, then, it needs to be after dispatching that the XPath is evaluated, as we have no idea of the operation prior to that. Hence, it becomes an affair that cannot be handled by a handler, but the dispatcher needs to kick in and evaluate and fire BAM events. Thoughts please... On Wed, Aug 4, 2010 at 9:45 AM, Samisa Abeysinghe <[email protected]> wrote: > OK then we will first look at the AXIOM option. > > > On Wed, Aug 4, 2010 at 9:43 AM, Ruwan Linton <[email protected]> wrote: > >> Sumedha Rubasinghe wrote: >> > On Wed, Aug 4, 2010 at 6:20 AM, Samisa Abeysinghe <[email protected] >> > <mailto:[email protected]>> wrote: >> > >> > We are planning to provide XPath based BAM data collection to users. >> > >> > For e.g., if the payload is supposed to have a PO, the user can >> > specify the path to PO ID in payload and collect a count of POs >> > that pass through. >> > >> > The question is... >> > Do we have an XPath component, or a handler or something like that >> > we can reuse to facilitate this? >> > Also, how to do this for WSAS vs ESB. I think WSAS case is tivial, >> > in that we can evaluate the XPath in a handler. What about the ESB? >> > Note that, in case of ESB, we do not collect our own data, rather >> > we bank on the stat data provided by the ESB itself. >> > >> > I know that we have XPath used in ESB etc, but the idea is to use >> > minimal dependencies here for BAM >> > >> > Generally speaking, reusing things from ESB comes with considerable >> > number of dependencies & size in MBs. >> Synapse/ESB has a set of Xpath extension functions which shouldn't be >> required outside of Synapse runtime, so the ideal should be to use the >> Jaxen Xpath implementation which is there in AXIOM. >> >> Ruwan >> > /sumedha >> > >> > Thanks, >> > Samisa... >> > >> > Samisa Abeysinghe >> > VP Engineering >> > WSO2 Inc. >> > http://wso2.com >> > http://wso2.org >> > >> > >> > >> > >> > _______________________________________________ >> > Carbon-dev mailing list >> > [email protected] <mailto:[email protected]> >> > https://mail.wso2.org/cgi-bin/mailman/listinfo/carbon-dev >> > >> > >> > ------------------------------------------------------------------------ >> > >> > _______________________________________________ >> > Carbon-dev mailing list >> > [email protected] >> > https://mail.wso2.org/cgi-bin/mailman/listinfo/carbon-dev >> > >> >> >> -- >> Ruwan Linton >> Software Architect & Product Manager, WSO2 ESB; http://wso2.org/esb >> WSO2 Inc.; http://wso2.com >> >> Lean . Enterprise . Middleware >> >> phone: +1 408 754 7388 ext 51789 >> email: [email protected]; cell: +94 77 341 3097 >> blog: http://blog.ruwan.org >> linkedin: http://www.linkedin.com/in/ruwanlinton >> tweet: http://twitter.com/ruwanlinton >> >> >> _______________________________________________ >> Carbon-dev mailing list >> [email protected] >> https://mail.wso2.org/cgi-bin/mailman/listinfo/carbon-dev >> > Thanks, > Samisa... > > Samisa Abeysinghe > VP Engineering > WSO2 Inc. > http://wso2.com > http://wso2.org > > > > Thanks, Samisa... Samisa Abeysinghe VP Engineering WSO2 Inc. http://wso2.com http://wso2.org
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