Re: think I found a bug

[Andreas Delmelle]

On May 5, 2008, at 10:55, Andreas Schröder wrote:

Hi

I already posted in the user group, but they only wonder about my  
error and can't help. So I think that it is a bug.

I use Apache FOP 0.95beta but the same error also occured in 0.94  
stable version: When trying to make a new instance of the fop  
factory with "FopFactory fopFactory = FopFactory.newInstance();" I  
get an exception with the following stack trace:


java.lang.ClassCastException:  
org.apache.fop.render.afp.extensions.AFPExtensionHandlerFactory
cannot be cast to org.apache.fop.util.ContentHandlerFactory

I dug up the earlier thread on fop-users@, and I suspect that Jörg's  
reply is the one that holds the key.
<quote>
In a web application, this may also be happen if the
AFPExtensionHandlerFactory has been loaded in a different
security context , which means it is an implementation of
the ContentHandlerFactory of the other context.
</quote>

From the stack trace, we can deduce that you create a new fopFactory  
instance for each run ('newInstance()' always means 'new FopFactory 
();').
The original ContentHandlerFactory class has probably already been  
loaded when the servlet container first initialized, by the default  
ClassLoader (or by the ClassLoader used in the first run).

No idea how this can be verified, though. To ascertain whether this  
is the case, my personal first shot would be to try to set up a  
central fopFactory instance, which would also be loaded only once,  
when the webapp is first initialized. The big difference would be  
that you'd use that very same FopFactory for all the requests, which  
should eliminate the issue...


HTH!

Andreas