You are viewing a plain text version of this content. The canonical link for it is here.
Posted to users@felix.apache.org by Mike Smoot <mi...@gmail.com> on 2008/02/22 03:40:08 UTC
ClassLoader question
Hi,
I'm working on migrating an existing swing application (http://cytoscape.org)
to OSGi using Felix. With the help of bnd, I've gotten everything running
about how it should, with the exception of our legacy plugin mechanism. The
way the old plugin mechanism works is that a plugin jar file (but not a
bundle) is read and we then call ClassLoader.loadClass() on a class found in
the jar file. The problem is that with Felix I get a NoClassDefFoundError
when I try to load the class. I'm assuming this is because none of the
packages defined in the plugin jar are found by Felix since the plugin jars
aren't bundles or loaded as such.
Now, I've managed to work around this problem in two cases. First is using
Equinox, which I'm not terribly keen on using. Second is by running bnd on
each plugin jar, loading them as bundles, jumping through a few hoops to get
the correct ClassLoader, and then loading the class. The problem with the
second approach is that I have to wrap all plugins before anything will
work. I'd very much like to avoid this requirement (for now) because this
will only work with plugins that I have and not those developed by users.
Can anyone provide any guidance on loading classes that aren't part of
bundles? Is this possible with Felix? I apologize if this is a bit vague,
but I'm still very new to OSGi.
thanks,
Mike
--
____________________________________________________________
Michael Smoot, Ph.D. Bioengineering Department
tel: 858-822-4756 University of California San Diego
Re: ClassLoader question
Posted by Mike Smoot <ms...@ucsd.edu>.
Thanks for the pointers! Our long term goal is definitely to migrate to
bundles, but I'll certainly check out the link below as a transition
strategy.
cheers,
Mike
On Thu, Feb 21, 2008 at 9:09 PM, Stuart McCulloch <
stuart.mcculloch@jayway.net> wrote:
> On 22/02/2008, Richard S. Hall <he...@ungoverned.org> wrote:
> >
> > I understand that you resolved the issue, but I am not sure that this
> > is the best approach in the long run. I have some suggestions for
> > different approaches too, but these are not good for the long run
> > either.
> >
> > 1. Since the default class path for a bundle is ".", you should be
> > able to load your plugin class directly from Bundle.loadClass(), I
> > would imagine.
> >
> > 2. You could create a special installer that you used to install your
> > plugin JAR file instead of doing it directly with
> > BundleContext.installBundle(). This special installer could
> > automatically run them plugin JARs through BND.
>
>
> FYI, for a good example of 2 check out the wrap scheme from Pax-URL:
>
> http://wiki.ops4j.org/confluence/display/ops4j/Pax+URL+-+wrap
>
> it provides a URL handler that lets you wrap jars as bundles at runtime
>
> Long run, you probably want to migrate the plugins to bundles in some
> > fashion.
> >
> > -> richard
> >
> >
> > On Feb 21, 2008, at 9:40 PM, Mike Smoot wrote:
> >
> > > Hi,
> > >
> > > I'm working on migrating an existing swing application (
> > http://cytoscape.org
> > > )
> > > to OSGi using Felix. With the help of bnd, I've gotten everything
> > > running
> > > about how it should, with the exception of our legacy plugin
> > > mechanism. The
> > > way the old plugin mechanism works is that a plugin jar file (but
> > > not a
> > > bundle) is read and we then call ClassLoader.loadClass() on a class
> > > found in
> > > the jar file. The problem is that with Felix I get a
> > > NoClassDefFoundError
> > > when I try to load the class. I'm assuming this is because none of
> > > the
> > > packages defined in the plugin jar are found by Felix since the
> > > plugin jars
> > > aren't bundles or loaded as such.
> > >
> > > Now, I've managed to work around this problem in two cases. First
> > > is using
> > > Equinox, which I'm not terribly keen on using. Second is by running
> > > bnd on
> > > each plugin jar, loading them as bundles, jumping through a few
> > > hoops to get
> > > the correct ClassLoader, and then loading the class. The problem
> > > with the
> > > second approach is that I have to wrap all plugins before anything
> > > will
> > > work. I'd very much like to avoid this requirement (for now)
> > > because this
> > > will only work with plugins that I have and not those developed by
> > > users.
> > >
> > > Can anyone provide any guidance on loading classes that aren't part of
> > > bundles? Is this possible with Felix? I apologize if this is a bit
> > > vague,
> > > but I'm still very new to OSGi.
> > >
> > > thanks,
> > > Mike
> > >
> > > --
> > > ____________________________________________________________
> > > Michael Smoot, Ph.D. Bioengineering Department
> > > tel: 858-822-4756 University of California San Diego
> >
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: users-unsubscribe@felix.apache.org
> > For additional commands, e-mail: users-help@felix.apache.org
> >
> >
>
>
> --
> Cheers, Stuart
>
--
____________________________________________________________
Michael Smoot, Ph.D. Bioengineering Department
tel: 858-822-4756 University of California San Diego
Re: ClassLoader question
Posted by Stuart McCulloch <st...@jayway.net>.
On 22/02/2008, Richard S. Hall <he...@ungoverned.org> wrote:
>
> I understand that you resolved the issue, but I am not sure that this
> is the best approach in the long run. I have some suggestions for
> different approaches too, but these are not good for the long run
> either.
>
> 1. Since the default class path for a bundle is ".", you should be
> able to load your plugin class directly from Bundle.loadClass(), I
> would imagine.
>
> 2. You could create a special installer that you used to install your
> plugin JAR file instead of doing it directly with
> BundleContext.installBundle(). This special installer could
> automatically run them plugin JARs through BND.
FYI, for a good example of 2 check out the wrap scheme from Pax-URL:
http://wiki.ops4j.org/confluence/display/ops4j/Pax+URL+-+wrap
it provides a URL handler that lets you wrap jars as bundles at runtime
Long run, you probably want to migrate the plugins to bundles in some
> fashion.
>
> -> richard
>
>
> On Feb 21, 2008, at 9:40 PM, Mike Smoot wrote:
>
> > Hi,
> >
> > I'm working on migrating an existing swing application (
> http://cytoscape.org
> > )
> > to OSGi using Felix. With the help of bnd, I've gotten everything
> > running
> > about how it should, with the exception of our legacy plugin
> > mechanism. The
> > way the old plugin mechanism works is that a plugin jar file (but
> > not a
> > bundle) is read and we then call ClassLoader.loadClass() on a class
> > found in
> > the jar file. The problem is that with Felix I get a
> > NoClassDefFoundError
> > when I try to load the class. I'm assuming this is because none of
> > the
> > packages defined in the plugin jar are found by Felix since the
> > plugin jars
> > aren't bundles or loaded as such.
> >
> > Now, I've managed to work around this problem in two cases. First
> > is using
> > Equinox, which I'm not terribly keen on using. Second is by running
> > bnd on
> > each plugin jar, loading them as bundles, jumping through a few
> > hoops to get
> > the correct ClassLoader, and then loading the class. The problem
> > with the
> > second approach is that I have to wrap all plugins before anything
> > will
> > work. I'd very much like to avoid this requirement (for now)
> > because this
> > will only work with plugins that I have and not those developed by
> > users.
> >
> > Can anyone provide any guidance on loading classes that aren't part of
> > bundles? Is this possible with Felix? I apologize if this is a bit
> > vague,
> > but I'm still very new to OSGi.
> >
> > thanks,
> > Mike
> >
> > --
> > ____________________________________________________________
> > Michael Smoot, Ph.D. Bioengineering Department
> > tel: 858-822-4756 University of California San Diego
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@felix.apache.org
> For additional commands, e-mail: users-help@felix.apache.org
>
>
--
Cheers, Stuart
Re: ClassLoader question
Posted by "Richard S. Hall" <he...@ungoverned.org>.
I understand that you resolved the issue, but I am not sure that this
is the best approach in the long run. I have some suggestions for
different approaches too, but these are not good for the long run
either.
1. Since the default class path for a bundle is ".", you should be
able to load your plugin class directly from Bundle.loadClass(), I
would imagine.
2. You could create a special installer that you used to install your
plugin JAR file instead of doing it directly with
BundleContext.installBundle(). This special installer could
automatically run them plugin JARs through BND.
Long run, you probably want to migrate the plugins to bundles in some
fashion.
-> richard
On Feb 21, 2008, at 9:40 PM, Mike Smoot wrote:
> Hi,
>
> I'm working on migrating an existing swing application (http://cytoscape.org
> )
> to OSGi using Felix. With the help of bnd, I've gotten everything
> running
> about how it should, with the exception of our legacy plugin
> mechanism. The
> way the old plugin mechanism works is that a plugin jar file (but
> not a
> bundle) is read and we then call ClassLoader.loadClass() on a class
> found in
> the jar file. The problem is that with Felix I get a
> NoClassDefFoundError
> when I try to load the class. I'm assuming this is because none of
> the
> packages defined in the plugin jar are found by Felix since the
> plugin jars
> aren't bundles or loaded as such.
>
> Now, I've managed to work around this problem in two cases. First
> is using
> Equinox, which I'm not terribly keen on using. Second is by running
> bnd on
> each plugin jar, loading them as bundles, jumping through a few
> hoops to get
> the correct ClassLoader, and then loading the class. The problem
> with the
> second approach is that I have to wrap all plugins before anything
> will
> work. I'd very much like to avoid this requirement (for now)
> because this
> will only work with plugins that I have and not those developed by
> users.
>
> Can anyone provide any guidance on loading classes that aren't part of
> bundles? Is this possible with Felix? I apologize if this is a bit
> vague,
> but I'm still very new to OSGi.
>
> thanks,
> Mike
>
> --
> ____________________________________________________________
> Michael Smoot, Ph.D. Bioengineering Department
> tel: 858-822-4756 University of California San Diego
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@felix.apache.org
For additional commands, e-mail: users-help@felix.apache.org
Re: ClassLoader question
Posted by Rodrigo Madera <ro...@gmail.com>.
Uh, ok...
I just deleted a chunk off this email then...
Anyways, take a look at the Spring OSGi project (I know I know... it was
renamed... but you get it...)
It has excellent features for OSGi.
Regards,
Rodrigo
On Fri, Feb 22, 2008 at 3:17 AM, Mike Smoot <ms...@ucsd.edu> wrote:
> Argh! I just got it working. The list of urls going into the
> URLClassLoader was incorrect...
>
> Thanks for your patience!
>
> Mike
>
> On Thu, Feb 21, 2008 at 7:11 PM, Mike Smoot <ms...@ucsd.edu> wrote:
>
> >
> >
> > On Thu, Feb 21, 2008 at 7:01 PM, Rodrigo Madera <
> rodrigo.madera@gmail.com>
> > wrote:
> >
> > > Classpaths and OSGi spell tricky when on the same sentence.
> > >
> >
> > Indeed! :)
> >
> >
> > >
> > > How do you *search *for classes in your class loading mechanism?
> >
> >
> > Using a list of urls pointing to the plugin jars, we create a
> > URLClassLoader. As I understand things, this adds all classes in the
> jars to
> > the search path for that ClassLoader. Once we've got the
> URLClassLoader, we
> > open each jar, read the manifest which tells us which class we should be
> > looking for, and call loadClass on that class name.
> >
> >
> > thanks,
> > Mike
> >
> >
> >
> >
> > >
> > >
> > > Rodrigo
> > >
> > > On Fri, Feb 22, 2008 at 2:58 AM, Mike Smoot <ms...@ucsd.edu> wrote:
> > >
> > > > I'm not sure I understand the question, but once we get a Class
> object
> > > > from
> > > > the ClassLoader given a name, we call newInstance() on it. Then
> it's
> > > up
> > > > to
> > > > the plugin to do it's thing.
> > > >
> > > > Or are you asking how we get the ClassLoader in the first place? We
> > > do
> > > > that
> > > > by creating a URLClassLoader with a list of urls that point to the
> > > plugin
> > > > jar files.
> > > >
> > > > Or are you asking something else?
> > > >
> > > > thanks,
> > > > Mike
> > > >
> > > > On Thu, Feb 21, 2008 at 6:45 PM, Rodrigo Madera <
> > > rodrigo.madera@gmail.com>
> > > > wrote:
> > > >
> > > > > What algorithm does your class loading use?
> > > > >
> > > > > Regards,
> > > > > Rodrigo
> > > > >
> > > > > On Fri, Feb 22, 2008 at 2:40 AM, Mike Smoot <mi...@gmail.com>
> > > > wrote:
> > > > >
> > > > > > Hi,
> > > > > >
> > > > > > I'm working on migrating an existing swing application (
> > > > > > http://cytoscape.org)
> > > > > > to OSGi using Felix. With the help of bnd, I've gotten
> everything
> > > > > running
> > > > > > about how it should, with the exception of our legacy plugin
> > > > mechanism.
> > > > > > The
> > > > > > way the old plugin mechanism works is that a plugin jar file
> (but
> > > not
> > > > a
> > > > > > bundle) is read and we then call ClassLoader.loadClass() on a
> > > class
> > > > > found
> > > > > > in
> > > > > > the jar file. The problem is that with Felix I get a
> > > > > NoClassDefFoundError
> > > > > > when I try to load the class. I'm assuming this is because
> none
> > > of
> > > > the
> > > > > > packages defined in the plugin jar are found by Felix since the
> > > plugin
> > > > > > jars
> > > > > > aren't bundles or loaded as such.
> > > > > >
> > > > > > Now, I've managed to work around this problem in two cases.
> First
> > > is
> > > > > > using
> > > > > > Equinox, which I'm not terribly keen on using. Second is by
> > > running
> > > > bnd
> > > > > > on
> > > > > > each plugin jar, loading them as bundles, jumping through a few
> > > hoops
> > > > to
> > > > > > get
> > > > > > the correct ClassLoader, and then loading the class. The
> problem
> > > with
> > > > > the
> > > > > > second approach is that I have to wrap all plugins before
> anything
> > > > will
> > > > > > work. I'd very much like to avoid this requirement (for now)
> > > because
> > > > > this
> > > > > > will only work with plugins that I have and not those developed
> by
> > > > > users.
> > > > > >
> > > > > > Can anyone provide any guidance on loading classes that aren't
> > > part of
> > > > > > bundles? Is this possible with Felix? I apologize if this is a
> > > bit
> > > > > > vague,
> > > > > > but I'm still very new to OSGi.
> > > > > >
> > > > > > thanks,
> > > > > > Mike
> > > > > >
> > > > > > --
> > > > > > ____________________________________________________________
> > > > > > Michael Smoot, Ph.D. Bioengineering Department
> > > > > > tel: 858-822-4756 University of California San Diego
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > ____________________________________________________________
> > > > Michael Smoot, Ph.D. Bioengineering Department
> > > > tel: 858-822-4756 University of California San Diego
> > > >
> > >
> >
> >
> >
> > --
> > ____________________________________________________________
> > Michael Smoot, Ph.D. Bioengineering Department
> > tel: 858-822-4756 University of California San Diego
> >
>
>
>
> --
> ____________________________________________________________
> Michael Smoot, Ph.D. Bioengineering Department
> tel: 858-822-4756 University of California San Diego
>
Re: ClassLoader question
Posted by Mike Smoot <ms...@ucsd.edu>.
Argh! I just got it working. The list of urls going into the
URLClassLoader was incorrect...
Thanks for your patience!
Mike
On Thu, Feb 21, 2008 at 7:11 PM, Mike Smoot <ms...@ucsd.edu> wrote:
>
>
> On Thu, Feb 21, 2008 at 7:01 PM, Rodrigo Madera <ro...@gmail.com>
> wrote:
>
> > Classpaths and OSGi spell tricky when on the same sentence.
> >
>
> Indeed! :)
>
>
> >
> > How do you *search *for classes in your class loading mechanism?
>
>
> Using a list of urls pointing to the plugin jars, we create a
> URLClassLoader. As I understand things, this adds all classes in the jars to
> the search path for that ClassLoader. Once we've got the URLClassLoader, we
> open each jar, read the manifest which tells us which class we should be
> looking for, and call loadClass on that class name.
>
>
> thanks,
> Mike
>
>
>
>
> >
> >
> > Rodrigo
> >
> > On Fri, Feb 22, 2008 at 2:58 AM, Mike Smoot <ms...@ucsd.edu> wrote:
> >
> > > I'm not sure I understand the question, but once we get a Class object
> > > from
> > > the ClassLoader given a name, we call newInstance() on it. Then it's
> > up
> > > to
> > > the plugin to do it's thing.
> > >
> > > Or are you asking how we get the ClassLoader in the first place? We
> > do
> > > that
> > > by creating a URLClassLoader with a list of urls that point to the
> > plugin
> > > jar files.
> > >
> > > Or are you asking something else?
> > >
> > > thanks,
> > > Mike
> > >
> > > On Thu, Feb 21, 2008 at 6:45 PM, Rodrigo Madera <
> > rodrigo.madera@gmail.com>
> > > wrote:
> > >
> > > > What algorithm does your class loading use?
> > > >
> > > > Regards,
> > > > Rodrigo
> > > >
> > > > On Fri, Feb 22, 2008 at 2:40 AM, Mike Smoot <mi...@gmail.com>
> > > wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > I'm working on migrating an existing swing application (
> > > > > http://cytoscape.org)
> > > > > to OSGi using Felix. With the help of bnd, I've gotten everything
> > > > running
> > > > > about how it should, with the exception of our legacy plugin
> > > mechanism.
> > > > > The
> > > > > way the old plugin mechanism works is that a plugin jar file (but
> > not
> > > a
> > > > > bundle) is read and we then call ClassLoader.loadClass() on a
> > class
> > > > found
> > > > > in
> > > > > the jar file. The problem is that with Felix I get a
> > > > NoClassDefFoundError
> > > > > when I try to load the class. I'm assuming this is because none
> > of
> > > the
> > > > > packages defined in the plugin jar are found by Felix since the
> > plugin
> > > > > jars
> > > > > aren't bundles or loaded as such.
> > > > >
> > > > > Now, I've managed to work around this problem in two cases. First
> > is
> > > > > using
> > > > > Equinox, which I'm not terribly keen on using. Second is by
> > running
> > > bnd
> > > > > on
> > > > > each plugin jar, loading them as bundles, jumping through a few
> > hoops
> > > to
> > > > > get
> > > > > the correct ClassLoader, and then loading the class. The problem
> > with
> > > > the
> > > > > second approach is that I have to wrap all plugins before anything
> > > will
> > > > > work. I'd very much like to avoid this requirement (for now)
> > because
> > > > this
> > > > > will only work with plugins that I have and not those developed by
> > > > users.
> > > > >
> > > > > Can anyone provide any guidance on loading classes that aren't
> > part of
> > > > > bundles? Is this possible with Felix? I apologize if this is a
> > bit
> > > > > vague,
> > > > > but I'm still very new to OSGi.
> > > > >
> > > > > thanks,
> > > > > Mike
> > > > >
> > > > > --
> > > > > ____________________________________________________________
> > > > > Michael Smoot, Ph.D. Bioengineering Department
> > > > > tel: 858-822-4756 University of California San Diego
> > > > >
> > > >
> > >
> > >
> > >
> > > --
> > > ____________________________________________________________
> > > Michael Smoot, Ph.D. Bioengineering Department
> > > tel: 858-822-4756 University of California San Diego
> > >
> >
>
>
>
> --
> ____________________________________________________________
> Michael Smoot, Ph.D. Bioengineering Department
> tel: 858-822-4756 University of California San Diego
>
--
____________________________________________________________
Michael Smoot, Ph.D. Bioengineering Department
tel: 858-822-4756 University of California San Diego
Re: ClassLoader question
Posted by Mike Smoot <ms...@ucsd.edu>.
On Thu, Feb 21, 2008 at 7:01 PM, Rodrigo Madera <ro...@gmail.com>
wrote:
> Classpaths and OSGi spell tricky when on the same sentence.
>
Indeed! :)
>
> How do you *search *for classes in your class loading mechanism?
Using a list of urls pointing to the plugin jars, we create a
URLClassLoader. As I understand things, this adds all classes in the jars to
the search path for that ClassLoader. Once we've got the URLClassLoader, we
open each jar, read the manifest which tells us which class we should be
looking for, and call loadClass on that class name.
thanks,
Mike
>
>
> Rodrigo
>
> On Fri, Feb 22, 2008 at 2:58 AM, Mike Smoot <ms...@ucsd.edu> wrote:
>
> > I'm not sure I understand the question, but once we get a Class object
> > from
> > the ClassLoader given a name, we call newInstance() on it. Then it's up
> > to
> > the plugin to do it's thing.
> >
> > Or are you asking how we get the ClassLoader in the first place? We do
> > that
> > by creating a URLClassLoader with a list of urls that point to the
> plugin
> > jar files.
> >
> > Or are you asking something else?
> >
> > thanks,
> > Mike
> >
> > On Thu, Feb 21, 2008 at 6:45 PM, Rodrigo Madera <
> rodrigo.madera@gmail.com>
> > wrote:
> >
> > > What algorithm does your class loading use?
> > >
> > > Regards,
> > > Rodrigo
> > >
> > > On Fri, Feb 22, 2008 at 2:40 AM, Mike Smoot <mi...@gmail.com>
> > wrote:
> > >
> > > > Hi,
> > > >
> > > > I'm working on migrating an existing swing application (
> > > > http://cytoscape.org)
> > > > to OSGi using Felix. With the help of bnd, I've gotten everything
> > > running
> > > > about how it should, with the exception of our legacy plugin
> > mechanism.
> > > > The
> > > > way the old plugin mechanism works is that a plugin jar file (but
> not
> > a
> > > > bundle) is read and we then call ClassLoader.loadClass() on a class
> > > found
> > > > in
> > > > the jar file. The problem is that with Felix I get a
> > > NoClassDefFoundError
> > > > when I try to load the class. I'm assuming this is because none of
> > the
> > > > packages defined in the plugin jar are found by Felix since the
> plugin
> > > > jars
> > > > aren't bundles or loaded as such.
> > > >
> > > > Now, I've managed to work around this problem in two cases. First
> is
> > > > using
> > > > Equinox, which I'm not terribly keen on using. Second is by running
> > bnd
> > > > on
> > > > each plugin jar, loading them as bundles, jumping through a few
> hoops
> > to
> > > > get
> > > > the correct ClassLoader, and then loading the class. The problem
> with
> > > the
> > > > second approach is that I have to wrap all plugins before anything
> > will
> > > > work. I'd very much like to avoid this requirement (for now)
> because
> > > this
> > > > will only work with plugins that I have and not those developed by
> > > users.
> > > >
> > > > Can anyone provide any guidance on loading classes that aren't part
> of
> > > > bundles? Is this possible with Felix? I apologize if this is a bit
> > > > vague,
> > > > but I'm still very new to OSGi.
> > > >
> > > > thanks,
> > > > Mike
> > > >
> > > > --
> > > > ____________________________________________________________
> > > > Michael Smoot, Ph.D. Bioengineering Department
> > > > tel: 858-822-4756 University of California San Diego
> > > >
> > >
> >
> >
> >
> > --
> > ____________________________________________________________
> > Michael Smoot, Ph.D. Bioengineering Department
> > tel: 858-822-4756 University of California San Diego
> >
>
--
____________________________________________________________
Michael Smoot, Ph.D. Bioengineering Department
tel: 858-822-4756 University of California San Diego
Re: ClassLoader question
Posted by Rodrigo Madera <ro...@gmail.com>.
Classpaths and OSGi spell tricky when on the same sentence.
How do you *search *for classes in your class loading mechanism?
Rodrigo
On Fri, Feb 22, 2008 at 2:58 AM, Mike Smoot <ms...@ucsd.edu> wrote:
> I'm not sure I understand the question, but once we get a Class object
> from
> the ClassLoader given a name, we call newInstance() on it. Then it's up
> to
> the plugin to do it's thing.
>
> Or are you asking how we get the ClassLoader in the first place? We do
> that
> by creating a URLClassLoader with a list of urls that point to the plugin
> jar files.
>
> Or are you asking something else?
>
> thanks,
> Mike
>
> On Thu, Feb 21, 2008 at 6:45 PM, Rodrigo Madera <ro...@gmail.com>
> wrote:
>
> > What algorithm does your class loading use?
> >
> > Regards,
> > Rodrigo
> >
> > On Fri, Feb 22, 2008 at 2:40 AM, Mike Smoot <mi...@gmail.com>
> wrote:
> >
> > > Hi,
> > >
> > > I'm working on migrating an existing swing application (
> > > http://cytoscape.org)
> > > to OSGi using Felix. With the help of bnd, I've gotten everything
> > running
> > > about how it should, with the exception of our legacy plugin
> mechanism.
> > > The
> > > way the old plugin mechanism works is that a plugin jar file (but not
> a
> > > bundle) is read and we then call ClassLoader.loadClass() on a class
> > found
> > > in
> > > the jar file. The problem is that with Felix I get a
> > NoClassDefFoundError
> > > when I try to load the class. I'm assuming this is because none of
> the
> > > packages defined in the plugin jar are found by Felix since the plugin
> > > jars
> > > aren't bundles or loaded as such.
> > >
> > > Now, I've managed to work around this problem in two cases. First is
> > > using
> > > Equinox, which I'm not terribly keen on using. Second is by running
> bnd
> > > on
> > > each plugin jar, loading them as bundles, jumping through a few hoops
> to
> > > get
> > > the correct ClassLoader, and then loading the class. The problem with
> > the
> > > second approach is that I have to wrap all plugins before anything
> will
> > > work. I'd very much like to avoid this requirement (for now) because
> > this
> > > will only work with plugins that I have and not those developed by
> > users.
> > >
> > > Can anyone provide any guidance on loading classes that aren't part of
> > > bundles? Is this possible with Felix? I apologize if this is a bit
> > > vague,
> > > but I'm still very new to OSGi.
> > >
> > > thanks,
> > > Mike
> > >
> > > --
> > > ____________________________________________________________
> > > Michael Smoot, Ph.D. Bioengineering Department
> > > tel: 858-822-4756 University of California San Diego
> > >
> >
>
>
>
> --
> ____________________________________________________________
> Michael Smoot, Ph.D. Bioengineering Department
> tel: 858-822-4756 University of California San Diego
>
Re: ClassLoader question
Posted by Mike Smoot <ms...@ucsd.edu>.
I'm not sure I understand the question, but once we get a Class object from
the ClassLoader given a name, we call newInstance() on it. Then it's up to
the plugin to do it's thing.
Or are you asking how we get the ClassLoader in the first place? We do that
by creating a URLClassLoader with a list of urls that point to the plugin
jar files.
Or are you asking something else?
thanks,
Mike
On Thu, Feb 21, 2008 at 6:45 PM, Rodrigo Madera <ro...@gmail.com>
wrote:
> What algorithm does your class loading use?
>
> Regards,
> Rodrigo
>
> On Fri, Feb 22, 2008 at 2:40 AM, Mike Smoot <mi...@gmail.com> wrote:
>
> > Hi,
> >
> > I'm working on migrating an existing swing application (
> > http://cytoscape.org)
> > to OSGi using Felix. With the help of bnd, I've gotten everything
> running
> > about how it should, with the exception of our legacy plugin mechanism.
> > The
> > way the old plugin mechanism works is that a plugin jar file (but not a
> > bundle) is read and we then call ClassLoader.loadClass() on a class
> found
> > in
> > the jar file. The problem is that with Felix I get a
> NoClassDefFoundError
> > when I try to load the class. I'm assuming this is because none of the
> > packages defined in the plugin jar are found by Felix since the plugin
> > jars
> > aren't bundles or loaded as such.
> >
> > Now, I've managed to work around this problem in two cases. First is
> > using
> > Equinox, which I'm not terribly keen on using. Second is by running bnd
> > on
> > each plugin jar, loading them as bundles, jumping through a few hoops to
> > get
> > the correct ClassLoader, and then loading the class. The problem with
> the
> > second approach is that I have to wrap all plugins before anything will
> > work. I'd very much like to avoid this requirement (for now) because
> this
> > will only work with plugins that I have and not those developed by
> users.
> >
> > Can anyone provide any guidance on loading classes that aren't part of
> > bundles? Is this possible with Felix? I apologize if this is a bit
> > vague,
> > but I'm still very new to OSGi.
> >
> > thanks,
> > Mike
> >
> > --
> > ____________________________________________________________
> > Michael Smoot, Ph.D. Bioengineering Department
> > tel: 858-822-4756 University of California San Diego
> >
>
--
____________________________________________________________
Michael Smoot, Ph.D. Bioengineering Department
tel: 858-822-4756 University of California San Diego
Re: ClassLoader question
Posted by Rodrigo Madera <ro...@gmail.com>.
What algorithm does your class loading use?
Regards,
Rodrigo
On Fri, Feb 22, 2008 at 2:40 AM, Mike Smoot <mi...@gmail.com> wrote:
> Hi,
>
> I'm working on migrating an existing swing application (
> http://cytoscape.org)
> to OSGi using Felix. With the help of bnd, I've gotten everything running
> about how it should, with the exception of our legacy plugin mechanism.
> The
> way the old plugin mechanism works is that a plugin jar file (but not a
> bundle) is read and we then call ClassLoader.loadClass() on a class found
> in
> the jar file. The problem is that with Felix I get a NoClassDefFoundError
> when I try to load the class. I'm assuming this is because none of the
> packages defined in the plugin jar are found by Felix since the plugin
> jars
> aren't bundles or loaded as such.
>
> Now, I've managed to work around this problem in two cases. First is
> using
> Equinox, which I'm not terribly keen on using. Second is by running bnd
> on
> each plugin jar, loading them as bundles, jumping through a few hoops to
> get
> the correct ClassLoader, and then loading the class. The problem with the
> second approach is that I have to wrap all plugins before anything will
> work. I'd very much like to avoid this requirement (for now) because this
> will only work with plugins that I have and not those developed by users.
>
> Can anyone provide any guidance on loading classes that aren't part of
> bundles? Is this possible with Felix? I apologize if this is a bit
> vague,
> but I'm still very new to OSGi.
>
> thanks,
> Mike
>
> --
> ____________________________________________________________
> Michael Smoot, Ph.D. Bioengineering Department
> tel: 858-822-4756 University of California San Diego
>