Thanks a lot for the quick verification/clarificaton! Much appreciated On 8/12/15, 2:28 PM, "osgi-dev-requ...@mail.osgi.org" <osgi-dev-requ...@mail.osgi.org> wrote:
>Send osgi-dev mailing list submissions to > osgi-dev@mail.osgi.org > >To subscribe or unsubscribe via the World Wide Web, visit > https://mail.osgi.org/mailman/listinfo/osgi-dev >or, via email, send a message with subject or body 'help' to > osgi-dev-requ...@mail.osgi.org > >You can reach the person managing the list at > osgi-dev-ow...@mail.osgi.org > >When replying, please edit your Subject line so it is more specific >than "Re: Contents of osgi-dev digest..." > > >Today's Topics: > > 1. Accessing the different versions of the same class from same > bundle (Frank Langel) > 2. Re: Accessing the different versions of the same class from > same bundle (Christian Schneider) > 3. Re: Accessing the different versions of the same class from > same bundle (Neil Bartlett) > 4. Re: Accessing the different versions of the same class from > same bundle (Thomas Watson) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Wed, 12 Aug 2015 08:50:46 +0200 >From: Frank Langel <fr...@frankjlangel.com> >To: <osgi-dev@mail.osgi.org> >Subject: [osgi-dev] Accessing the different versions of the same class > from same bundle >Message-ID: <d1f0b966.2d63b%fr...@frankjlangel.com> >Content-Type: text/plain; charset="iso-8859-1" > >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- >de >pend-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 > > > > > > >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: ><http://mail.osgi.org/pipermail/osgi-dev/attachments/20150812/2ef7a32f/att >achment-0001.html> > >------------------------------ > >Message: 2 >Date: Wed, 12 Aug 2015 09:23:08 +0200 >From: Christian Schneider <ch...@die-schneider.net> >To: OSGi Developer Mail List <osgi-dev@mail.osgi.org> >Subject: Re: [osgi-dev] Accessing the different versions of the same > class from same bundle >Message-ID: <55caf45c.5070...@die-schneider.net> >Content-Type: text/plain; charset="windows-1252"; Format="flowed" > >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/8f4ee1ff4370fcf8934364b7b104248ea91 >4d08c > >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 >> >> >> >> >> >> >> _______________________________________________ >> OSGi Developer Mail List >> osgi-dev@mail.osgi.org >> https://mail.osgi.org/mailman/listinfo/osgi-dev > >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: ><http://mail.osgi.org/pipermail/osgi-dev/attachments/20150812/b1f54e9a/att >achment-0001.html> > >------------------------------ > >Message: 3 >Date: Wed, 12 Aug 2015 17:00:54 +0900 >From: Neil Bartlett <njbartl...@gmail.com> >To: OSGi Developer Mail List <osgi-dev@mail.osgi.org> >Subject: Re: [osgi-dev] Accessing the different versions of the same > class from same bundle >Message-ID: <b89c8410-ef09-4b4b-99e9-de4b2ca26...@gmail.com> >Content-Type: text/plain; charset="windows-1252" > >I agree with Christian?s solution, and would add that the limitation of >being exposed to at-most-one version of each type per bundle is a >restriction of the underlying Java class loaders, not really OSGi at all. > >Unless Java itself changes the way classes are loaded ? highly unlikely >since it would break lots of applications ? then future versions of OSGi >will all have the same restriction. > >Regards, >Neil > > >> On 12 Aug 2015, at 16:23, Christian Schneider <ch...@die-schneider.net> >>wrote: >> >> 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/8f4ee1ff4370fcf8934364b7b104248ea9 >>14d08c >><https://github.com/apache/karaf/commit/8f4ee1ff4370fcf8934364b7b104248ea >>914d08c> >> >> 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-packa >>>ge-depend-on-multiple-versions-of-another-bundle-or-p>http://stackoverfl >>>ow.com/questions/18722932/can-an-osgi-bundle-or-package-depend-on-multip >>>le-versions-of-another-bundle-or-p >>><http://stackoverflow.com/questions/18722932/can-an-osgi-bundle-or-packa >>>ge-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 >>> >>> >>> >>> >>> >>> >>> _______________________________________________ >>> OSGi Developer Mail List >>> osgi-dev@mail.osgi.org <mailto:osgi-dev@mail.osgi.org> >>> https://mail.osgi.org/mailman/listinfo/osgi-dev >>><https://mail.osgi.org/mailman/listinfo/osgi-dev> >> _______________________________________________ >> OSGi Developer Mail List >> osgi-dev@mail.osgi.org >> https://mail.osgi.org/mailman/listinfo/osgi-dev > >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: ><http://mail.osgi.org/pipermail/osgi-dev/attachments/20150812/33f30267/att >achment-0001.html> > >------------------------------ > >Message: 4 >Date: Wed, 12 Aug 2015 12:27:48 +0000 >From: "Thomas Watson" <tjwat...@us.ibm.com> >To: ch...@die-schneider.net, osgi-dev@mail.osgi.org >Subject: Re: [osgi-dev] Accessing the different versions of the same > class from same bundle >Message-ID: <201508121228.t7ccslyj002...@d01av01.pok.ibm.com> >Content-Type: text/plain; charset="us-ascii" > >An HTML attachment was scrubbed... >URL: ><http://mail.osgi.org/pipermail/osgi-dev/attachments/20150812/bc14ca29/att >achment.html> > >------------------------------ > >_______________________________________________ >OSGi Developer Mail List >osgi-dev@mail.osgi.org >https://mail.osgi.org/mailman/listinfo/osgi-dev > >End of osgi-dev Digest, Vol 106, Issue 11 >***************************************** _______________________________________________ OSGi Developer Mail List osgi-dev@mail.osgi.org https://mail.osgi.org/mailman/listinfo/osgi-dev
