Vadim Gritsenko wrote: >>From: Chris Newland [mailto:[EMAIL PROTECTED]] >> >>Hi All, >> >>I'm encountering a null pointer exception in the >>org.apache.cocoon.components.source.URLSource file when I run a stress >> >test > >>of my Cocoon 2 system: >> >>java.lang.NullPointerException >> at >> >org.apache.cocoon.components.source.URLSource.getInfos(URLSource.java:95 >) > >> at >> >org.apache.cocoon.components.source.URLSource.getLastModified(URLSource. >java > >>:110) >> at org.apache.cocoon.Cocoon.modifiedSince(Cocoon.java:376) >> at >> > ><snip> > > >>Looking at the code makes me think this might be a >> >threading/synchronization > >>bug as IMHO 'this.connection' is null and should have thrown the NPE >> >on the > >>previous line. >> > >It *is* threading bug. URLSource is not intended to be used by multiple >threads simultaneously. However, Cocoon.java uses it exactly this way. > > >>I'll do my best to trace the problem's origin but I'm out of the >> >country for > >>3 weeks as of tomorrow. >> > >The quick (==bad performance) fix will be to surround call with >synchronized: > > public boolean modifiedSince(long date) { > synchronized(this.configurationFile) { > this.configurationFile.refresh(); > return date < this.configurationFile.getLastModified(); > } > } > >The better solution is to use ActiveMonitor. There was a discussion >about it but I do not remember the results of it. > >Regards, >Vadim > I made a quick update using DelayedSourceWrapper : getLastModified() is called only once per second (we should make it configurable) and is in a synchronized block.
This solves the concurrency issue at the price of one synchronized statement each second, which should be acceptable ;) Sylvain -- Sylvain Wallez Anyware Technologies - http://www.anyware-tech.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
