I just spent some time debugging a problem (which turned out to be a classpath issue, as always) and I just wanted to share my experience.
First of all, the way I develop with Cocoon is that I build the cocoon jar, and jars for all the blocks I use, and I copy these jars plus all the jars from lib/core and the blocks/*/lib dirs into my own webapp development area.
I've been using the Sysdeo Tomcat Eclipse plugin with Cocoon for a few days now and it has been working very well. I've been able to hot update the actions and things I've been working on. However, when hitting one particular pipeline that uses the JXTemplateGenerator, I would get a blank page. View source, and nothing at all. No exceptions on the console, nothing in the log files. The code running in Tomcat separately worked fine, so it must have something to do with the Sysdeo Tomcat environment.
After some stepping through code, it seems like there was a problem getting an instance of the JXTemplateGenerator. It was very hard to pinpoint because the invokeNodes methods in the AbstractParentProcessingNode class just seems to silently swallow any exception that is thrown by the node it is invoking:
try {
for (int i = 0; i < nodes.length; i++) {
if (nodes[i].invoke(env, context)) {
// Success
return true;
}
}
}
finally {
// No success
context.popMap();
}
return false;After editing this code and catching the exception, I was able to quickly tell that is was a NoClassDefFoundError, and that it had something to do with Commons Loggings stuff. Turns out I didn't have the commons-logging-1.0.3.jar in my classpath. The reason why I didn't notice this before is because my Tomcat install has this jar in its server/lib dir.
A few observations:
- Should commons-logging-1.0.3.jar be in lib/core rather than lib/optional? In my case, the JXTemplateGenerator wouldn't run without it.
- Should the invokeNodes() method in AbstractParentProcessingNode just ignore the exception? Maybe it should be caught and logged?
cheers, -steve
