[rules-dev] Issue with ResourceChangeScanner

[Michael Neale]

Hi Steve - I have seen that issue before reported by others. But you
just explained the cause ! - I don't often use the classpath scanner
myself, so never thought of that.

Yes the lastModified being zero is a problem...

OK, well I think perhaps the solution would be if lastModified is not
a valid value, to NOT use that to decide availablility.

I think using a scanner on  a classpath resource is a bit unusual to
start with, but it is possible in various containers to dynamically
change the classpath, so it kind of technically makes sense.

If I had things in the classpath, I would assume they are constant -
but I assume you are actually expecting the scan to pick up changes in
a future ?

(in the meantime, if you can avoid the classpath one that problem
should go away).

On Thu, Oct 8, 2009 at 5:53 AM, Steve Ronderos <steve.ronderos at ni.com> wrote:
>
> Hello Dev List,
>
> I encountered an issue today with my KnowledgeAgent removing resources from
> its RuleBase shortly after creating it.  I have the ResourceChangeScanner
> running in my application.
>
> I tracked the issue back to the scan() method in ResourceChangeScannerImpl.
>  It appears that the method is trying to identify resources that are no
> longer available and remove them from both the RuleBase and future scans.
>  To do this it is checking lastModified on the resource and on a result of 0
> removing the resource.  The resources that I configured in my change-set
> definitely still exist, but due to URL handler implementation provided by my
> classloader, getLastModified always returns 0.  (The resource I'm retrieving
> is coming from a jar that is in my application's classpath and the URL
> handler implementation is oracle.classloader.SharedCodeSourceURL)
>
> Do you think it would be possible for the scan to identify unavailable
> resources some other way than with the lastModified? and then if
> lastModified is 0 maybe always or never update the resource? I'm not sure
> what the best approach to that would be, but removing resources when their
> lastModified is 0 seems incorrect to me.
>
> Thanks,
>
> Steve Ronderos
> _______________________________________________
> rules-dev mailing list
> rules-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-dev
>
>



-- 
Michael D Neale
home: www.michaelneale.net
blog: michaelneale.blogspot.com