Carsten Ziegeler wrote:
Sylvain Wallez wrote:
<snip/>
This feature is intended for application development-time, as it doesn't take into consideration instances of the previous versions of the reloaded classes that may be stored here and there such as in session attributes. That means that you may get some ClassCastException whenever such a cases arises. This is the current price to pay for fast roundtrips.
Great!!
What about using this for blocks - a simple version - as well? So we
could just drop a block of functionality (or a web app) into Cocoon. The
sitemap has the includes for the components and this extra classpath.
Yes, sure. That's how I started using it today with my mount-table mounted project! Here's a snippet of my sitemap:
<map:components>
<map:classpath>
<class-dir src="BLOCK-INF/classes"/>
<lib-dir src="BLOCK-INF/lib"/>
</map:classpath>
...
</map:components>
Real-block ready!!
For reloading: when the sitemap is reloaded, the classloader could only
reload those classes/jars that have changed since the last load/reload.
Yes, but the classloader is created as part of the TreeProcessor build process and therefore it's an all or nothing operation. Smarter reloading would mean transmitting the classloader from the current processor to the newly created one, checking that the classpath definition hasn't changed and crawling the classpath in search for changes.
Not impossible, but a bit complicated and it won't fully solve the ClassCastException problem for session attributes instance of reloaded classes, although it will reduce the associated annoyances by reducing the number of reloaded classes.
Problem also is that keeping unchanged classes means keeping their classloader and that therefore we need the classloader for reloaded class to be a child of the previous one, thus creating a classloader chain that will grow over time. Maybe that will impact memory and performance.
Hmm... need more thinking ;-)
Sylvain
-- Sylvain Wallez Anyware Technologies http://www.apache.org/~sylvain http://www.anyware-tech.com { XML, Java, Cocoon, OpenSource }*{ Training, Consulting, Projects }
