Hi all,
I'm currently working on a publication application with complex database
queries where we want to prefetch some of the pages linked to by the
page currently being produced, in order to speed up response time on
pages that are likely to be asked for by users.
To achieve this, we have a "PrefetchTransformer" that grabs elements
having a prefetch="true" attribute and starts a background job to load
the corresponding "src" or "href" URL using a "cocoon:".
At first I used JobScheduler.fireJob() to schedule for immediate
execution, but went into *weird* bugs with strange NPEs all around in
pipeline components. After analysis, it appeared that while the
scheduler thread was processing the pipeline, the http thread was
recycling the *background environment*, thus nulling the object model
and other class attributes used by pipeline components.
I spent the *whole day* trying to find the cause for this, without
success (how frustrating).
Then I decided to try another approach and use
JobScheduler.fireJobAt(new Date()), meaning "schedule the job for later
execution... now!". And it worked!
Weird, weird, weird! Anybody having a hint about why fireJob() is doing
this environment mixture?
Sylvain
--
Sylvain Wallez Anyware Technologies
http://apache.org/~sylvain http://anyware-tech.com
Apache Software Foundation Member Research & Technology Director
