Re: [Jython-users] Setting the Jython classloader

[Oti <oh...@gm...>]

On 7/27/07, Charlie Groves <cha...@gm...> wrote:
> On 7/26/07, Oti <oh...@gm...> wrote:
> > On 7/23/07, Charlie Groves <cha...@gm...> wrote:
>
> > > It does seem like it would be possible to eliminate the need for
> > > add_package if we auto-created nonexistent packages if a user imports
> > > a fully qualified Java class.  Since we can ask the classloader if a
> > > class really exists, we could use its existence to confirm the
> > > existence of the packages that contain it.  Those packages would still
> > > be odd since they wouldn't be fully populated with things that haven't
> > > been imported, but I think that would be better than requiring
> > > add_package.  Yet another thing for the list of things it would be
> > > nice to have in Jython....
> >
> > That's exactly what I'm doing when an explicit import of a class in a
> > not package-scanned package happens:
> >  1) find out if it is an existent java package
> >  2) if yes, do the add_package and the import
> > This means that sys.add_package() should not be necessary if explicit
> > imports are used.
>
> What do you mean by an explicit import?  Does 'from
> org.eclipse.jface.viewers import
> IStructuredContentProvider' as in David's example qualify?

Yes, because both java package and java class are mentioned.

> > For step 1), I am using
> >   Thread.currentThread().getContextClassLoader().getResource()
> > Of course this is not the same as Class.forName(), but IMHO both
> > should succeed if the classloader is the same.
> >
> > There might be cases when the context class loader is the wrong one
> > (e.g. if PythonInterpreter is running inside of an Eclipse PLUGIN -
> > they do their own classloader magic).
>
> I think using Py.findClass might be a better way to do this.  It tries
> the ClassLoader in the current PySystemState first, which is what a
> user will have set in an Eclipse plugin or anywhere they're forced to
> use a custom class loader.  It's probably worth writing some bugtests
> to try out various permutations of classloader setups.

Thanks for the tip! I'll check that.

Oti.