Thanks a lo for the insights. Type erasure spoils all the fun. On 3/18/15, 5:00 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. Register generic service - > bundleContext.registerService(Map<Integer, Object>.class, .., ..) > (Frank Langel) > 2. Re: Register generic service - > bundleContext.registerService(Map<Integer, Object>.class, .., ..) > (BJ Hargrave) > 3. Re: Register generic service - > bundleContext.registerService(Map<Integer, Object>.class, .., ..) > (Raymond Auge) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Wed, 18 Mar 2015 14:04:08 +0100 >From: Frank Langel <fr...@frankjlangel.com> >To: "osgi-dev@mail.osgi.org" <osgi-dev@mail.osgi.org> >Subject: [osgi-dev] Register generic service - > bundleContext.registerService(Map<Integer, Object>.class, .., ..) >Message-ID: <d12f30ed.1ec14%fr...@frankjlangel.com> >Content-Type: text/plain; charset="ISO-8859-1" > >Hi, > >I did some research, but didn?t find a way to register a generic service. >I would like to do sth like this > > context.registerService(Map<K,V>.class, service, properties), I.e. > context.registerService(Map<Integer,String>.class, new >HashMap<Integer,String>(), null) > >The injection should then only work if the registered and the injected K >and V are the same. Assuming I only have one service of type Map >registered, > > @Reference > public void setMapService(Map<Integer,String> mymap) { > This.map = my map; > } > > Would succeed. > > The following would fail as V (registered) != V(referenced service) > > @Reference > public void setMapService(Map<Integer,Integer> mymap) { > this.map = mymap; > } > >As a workaround, I could define K and V as service properties and filter >for them, but that?s not very elegant and very error prone > >Any feedback would be appreciated >Frank > > > > >------------------------------ > >Message: 2 >Date: Wed, 18 Mar 2015 09:11:31 -0400 >From: BJ Hargrave <hargr...@us.ibm.com> >To: OSGi Developer Mail List <osgi-dev@mail.osgi.org> >Subject: Re: [osgi-dev] Register generic service - > bundleContext.registerService(Map<Integer, Object>.class, .., ..) >Message-ID: > <of00c34a5d.d8c66ce9-on85257e0c.004829a4-85257e0c.00487...@us.ibm.com> >Content-Type: text/plain; charset="iso-8859-1" > >osgi-dev-boun...@mail.osgi.org wrote on 2015/03/18 09:04:08: > >> From: Frank Langel <fr...@frankjlangel.com> >> Hi, >> >> I did some research, but didn?t find a way to register a generic >service. >> I would like to do sth like this >> >> context.registerService(Map<K,V>.class, service, properties), I.e. >> context.registerService(Map<Integer,String>.class, new >> HashMap<Integer,String>(), null) > >'Map<Integer,String>.class' does not exist at runtime. Only 'Map.class' >exists at runtime due to generics erasure. So there is no way to look up >a >class using generics since they are erased at runtime. > >> >> The injection should then only work if the registered and the injected K >> and V are the same. Assuming I only have one service of type Map >> registered, >> >> @Reference >> public void setMapService(Map<Integer,String> mymap) { >> This.map = my map; >> } >> >> Would succeed. >> >> The following would fail as V (registered) != V(referenced service) >> >> @Reference >> public void setMapService(Map<Integer,Integer> mymap) { >> this.map = mymap; >> } >> >> As a workaround, I could define K and V as service properties and filter >> for them, but that?s not very elegant and very error prone >> >> Any feedback would be appreciated >> Frank > > >-- > >BJ Hargrave >Senior Technical Staff Member, IBM >OSGi Fellow and CTO of the OSGi Alliance >hargr...@us.ibm.com > >office: +1 386 848 1781 >mobile: +1 386 848 3788 >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: ><http://mail.osgi.org/pipermail/osgi-dev/attachments/20150318/4d43f1f0/att >achment-0001.html> > >------------------------------ > >Message: 3 >Date: Wed, 18 Mar 2015 10:00:33 -0400 >From: Raymond Auge <raymond.a...@liferay.com> >To: OSGi Developer Mail List <osgi-dev@mail.osgi.org> >Subject: Re: [osgi-dev] Register generic service - > bundleContext.registerService(Map<Integer, Object>.class, .., ..) >Message-ID: > <CAMm6HcDszC_ze8hryL6pBseM=apugcpyvx_qycoug-4vhz+...@mail.gmail.com> >Content-Type: text/plain; charset="utf-8" > >The only way to retrain generic information at runtime is with a class >that >extends from a generic one without declaring a generic signature itself. > >For instance: > > class MyMap extends HashMap<Integer, String> {} > >The compiler retains the generic information directly in the class. At >that >point you can, at runtime, check if the type has generic arguments and >obtain what those argument types were. > > Type[] genericInterfaces = clazz.getGenericInterfaces(); > > for (Type genericInterface : genericInterfaces) { > if (!(genericInterface instanceof ParameterizedType)) { > continue; > } > > ParameterizedType parameterizedType = > (ParameterizedType)genericInterface; > > Type rawType = parameterizedType.getRawType(); > > ... > } > > >However, you still can't register the service using generics: > > context.registerService(Map.class, new MyMap(), null) > >But if you need you could technically impose the restriction from the >other >side and ignore any services which don't have retrained generic >information. > >That might make things a little harder for developers to reason about but >if this is for "personal" use only, then it may do what you want. > >- Ray > > >On Wed, Mar 18, 2015 at 9:11 AM, BJ Hargrave <hargr...@us.ibm.com> wrote: > >> osgi-dev-boun...@mail.osgi.org wrote on 2015/03/18 09:04:08: >> >> > From: Frank Langel <fr...@frankjlangel.com> >> > Hi, >> > >> > I did some research, but didn?t find a way to register a generic >>service. >> > I would like to do sth like this >> > >> > context.registerService(Map<K,V>.class, service, properties), I.e. >> > context.registerService(Map<Integer,String>.class, new >> > HashMap<Integer,String>(), null) >> >> 'Map<Integer,String>.class' does not exist at runtime. Only 'Map.class' >> exists at runtime due to generics erasure. So there is no way to look >>up a >> class using generics since they are erased at runtime. >> >> > >> > The injection should then only work if the registered and the >>injected K >> > and V are the same. Assuming I only have one service of type Map >> > registered, >> > >> > @Reference >> > public void setMapService(Map<Integer,String> mymap) { >> > This.map = my map; >> > } >> > >> > Would succeed. >> > >> > The following would fail as V (registered) != V(referenced service) >> > >> > @Reference >> > public void setMapService(Map<Integer,Integer> mymap) { >> > this.map = mymap; >> > } >> > >> > As a workaround, I could define K and V as service properties and >>filter >> > for them, but that?s not very elegant and very error prone >> > >> > Any feedback would be appreciated >> > Frank >> >> >> -- >> >> *BJ Hargrave* >> Senior Technical Staff Member, IBM >> OSGi Fellow and CTO of the *OSGi Alliance* <http://www.osgi.org/> >> *hargr...@us.ibm.com* <hargr...@us.ibm.com> >> >> office: +1 386 848 1781 >> mobile: +1 386 848 3788 >> >> >> _______________________________________________ >> OSGi Developer Mail List >> osgi-dev@mail.osgi.org >> https://mail.osgi.org/mailman/listinfo/osgi-dev >> > > > >-- >*Raymond Aug?* <http://www.liferay.com/web/raymond.auge/profile> > (@rotty3000) >Senior Software Architect *Liferay, Inc.* <http://www.liferay.com> > (@Liferay) >Board Member & EEG Co-Chair, OSGi Alliance <http://osgi.org> >(@OSGiAlliance) >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: ><http://mail.osgi.org/pipermail/osgi-dev/attachments/20150318/0512cacf/att >achment-0001.html> > >------------------------------ > >_______________________________________________ >OSGi Developer Mail List >osgi-dev@mail.osgi.org >https://mail.osgi.org/mailman/listinfo/osgi-dev > >End of osgi-dev Digest, Vol 101, Issue 25 >***************************************** _______________________________________________ OSGi Developer Mail List osgi-dev@mail.osgi.org https://mail.osgi.org/mailman/listinfo/osgi-dev
