You can not simply import different versions of the same package into
the same bundle. Inside one classloader each class name must be unique.
The classloaders are only involved when the object is created though.
So there is no problem to pass an A1.0.0 object into a method as Object.
You can then use reflection to work on the data.
In the same way you can use reflection to create the new A2.0.0 class.
If you need a classloader that can access e.g. A2.0.0 but do not want to
import it directly
you can search the bundle that offers the class and adapt the Bundle to
BundleWiring. From BundleWiring you can then get the classloader of the
bundle and use it
to create the A2.0.0 class.
Additionally there is also the BundleRevision interface that allows you
to browse thorugh the exported packages if you do not know which bundle
to use.
I have recently used this scheme in karaf to allow to create classes on
the karaf shell without using dynamic imports on the command bundle.
See
https://github.com/apache/karaf/commit/8f4ee1ff4370fcf8934364b7b104248ea914d08c
The method getBundleOfferingPackage returns the first bundle that offers
any version of the given package. This is a little simplistic of course
as it currently does not
allow to filter for versions but should show you how to do it.
Christian
Am 12.08.2015 um 08:50 schrieb Frank Langel:
Hello,
Allow a question
Use Case : Data structure evolution
* application evolves, class A evolves from 1.0.0 to 2.0.0
* Need to do an update and retrieve all data by mapping from
A(1.0.0) —> A(2.0.0)
How do I solve this use case
* Does OSGI, perhaps in its latest version, allow for it ?
* I understand that in previous versions, it wasn’t supported
http://stackoverflow.com/questions/18722932/can-an-osgi-bundle-or-package-depend-on-multiple-versions-of-another-bundle-or-p
Current solution
I could use a canonical model A(1.0.0) —> C — > A(2.0.0) , where I
would import A1.0.0 in Bundle b1, and A2.0.0 in Bundle b2, and C into
B1 and b2, and then map A1.0.0 -> C and C —> A2.0.0, but I was
wondering if there is an easier way and allow a point to point mapping
without using the canonical class.
I don’t think there is anything wrong with my current solution, but
perhaps there is some functionality in the latest OSGI version that
simplifies this?
Thanks a lot
Frank
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