Carsten Ziegeler wrote:
I hope that we can remove some of the old class loader/class path
handling in 2.2 and make everything simpler.
In 2.1.x we had a boolean parameter (in web.xml) which could be used to
set the Cocoon class loader (the one used to instantiate Cocoon) as the
thread context class loader.
In addition, we could define extra class paths in web.xml (containing
directories/jars I think) which were added to the class path as well and
finally we have parameters to force load classes (e.g. for jdbc drivers).
With real blocks I think we should always add our class loader as the
thread context CL (this is the current implementation) and we should
forget about defining additional class paths.
yes, with the rise of blocks there shouldn't be a need for this anymore.
I'm not sure about the force loading stuff.
I'd skip it.
In addition I think we should always use the paranoid class loader to
avoid class loading problems. A common problem are either Xalan and
Xerces where you forgot to put the latest version (used by Cocoon) into
the endorsed lib. Or if the application server uses his own version of
let's say commons-logging/log4j and you want to use a different one in
Cocoon.
+1
So, the most important question is: does using an own class loader
inside a web app work in all engines, is it allowed, and is it allowed
to set the thread context CL?
Unfortunatly the spec doesn't say anything whether using your own classloader is
allowed or not:
[...]
J2EE.6.2.4.8 Context Class Loader
---------------------------------
This specification requires that J2EE containers provide a per thread context
class loader for the use of system or library classes in dynamicly loading
classes provided by the application. The EJB specification requires that all EJB
client containers provide a per thread context class loader for dynamicly
loading system value JDBC™ 2.0 Extension Requirements 87
classes. The per thread context class loader is accessed using the Thread method
getContextClassLoader.
The classes used by an application will typically be loaded by a hierarchy of
class loaders. There may be a top level application class loader, an extension
class loader, and so on, down to a system class loader. The top level
application class loader delegates to the lower class loaders as needed. Classes
loaded by lower class loaders, such as portable EJB system value classes, need
to be able to discover the top level application class loader used to dynamicly
load application classes.
We require that containers provide a per thread context class loader that can
be used to load top level application classes as described above.
[...]
--
Reinhard Pötz Independent Consultant, Trainer & (IT)-Coach
{Software Engineering, Open Source, Web Applications, Apache Cocoon}
web(log): http://www.poetz.cc
--------------------------------------------------------------------
___________________________________________________________
Gesendet von Yahoo! Mail - Jetzt mit 1GB Speicher kostenlos - Hier anmelden: http://mail.yahoo.de
