During a discussion today, we (Sanjiva, Asanka, Srinath & I) thought that it will be a good idea to use XPath-like syntax for selecting how to subscribe to Registry resource paths. We could support only some simple scenarios, and not the entire XPath syntax. Let me explain with an example.
The RegistrySynchronizer needs to be notified when deployable artifacts are changed in the Registry. Let's say these artifacts are stored in the _system/config/deployment/*server/* path. Shown below is how the HelloService.aar is stored. /_system/config/deployment/*server/service-groups/foo/bar/HelloService.aar* These are the different way in which we can subscribe to different parts of this hierarchy. 1. /_system/config/deployment/server Selects *server* resource only [1] 2. /_system/config/deployment/server/descendant::* Selects descendants of *server* only, does not select *server. *Selected elements wil be server, service-groups, foo, bar, and HelloService.aar [1] 3. /_system/config/deployment/server/descendant-or-self::* Selects *server* and descendants. Selected elements wil be server, service-groups, foo, bar, and HelloService.aar [1] So, this standard syntax allows us to simply select a node and its descendants in different ways. Thoughts welcome. [1] XPath reference: http://zvon.org/comp/r/tut-XPath_1.html -- *Afkham Azeez* Senior Software Architect & Senior Manager; WSO2, Inc.; http://wso2.com, * * *Member; Apache Software Foundation; **http://www.apache.org/*<http://www.apache.org/> * email: **[email protected]* <[email protected]>* cell: +94 77 3320919 blog: **http://blog.afkham.org* <http://blog.afkham.org>* twitter: **http://twitter.com/afkham_azeez*<http://twitter.com/afkham_azeez> * linked-in: **http://lk.linkedin.com/in/afkhamazeez* * * *Lean . Enterprise . Middleware*
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