Re: [rules-dev] Issue with ResourceChangeScanner
Michael,
In this exact case I am not expecting the scanner to ever find an updated
resource; however, the changeset is configured to read one resource from a
URL and another from the classpath. The resource from the URL is expected
to change, but the one from the classpath is not. We have a use case
where we may need classpath resources to be scanned, but I'm not sure it
will ever come up.
Unfortunately I don't think that we can reference that resource any way
other than the classpath at this moment, but we do have another
workaround. Previous to Drools 5 we had a custom way of refreshing our
resources which I think we will go back to for now.
Should I log a feature request for this change?
Steve Ronderos
rules-dev-bounces(a)lists.jboss.org wrote on 10/07/2009 05:29:56 PM:
[image removed]
Re: [rules-dev] Issue with ResourceChangeScanner
Michael Neale
to:
Rules Dev List
10/07/2009 05:31 PM
Sent by:
rules-dev-bounces(a)lists.jboss.org
Please respond to Rules Dev List
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(a)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(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-dev
>
>
--
Michael D Neale
home: www.michaelneale.net
blog: michaelneale.blogspot.com
_______________________________________________
rules-dev mailing list
rules-dev(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-dev
Attachments:
- attachment.html (text/html — 5.2 KB)