Eric Crahen wrote: > The OSGi doesn't have Context ClassLoaders? Sure it does, but the classloader that is aware of the imported and exported packages would be the same one that loaded the class. > > On 2/20/07, *John E. Conlon* <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> wrote: > > Ceki Gülcü wrote: > > John, > > > > Do you have a suggestion how we could avoid duplication of > slf4j-api > > classes in the various bindings? Can this be done using > maven-bundle-plugin ? > > > At the moment I can think four approaches to removing the > duplication of > classes in the bindings that sit on 'Sally's application's classpath. > > 1. Keep the packages split across the api and binding projects, > continue > to rely on single classloader joining at runtime, and move back to a > Require-Bundle approach for osgi support. We won't need the > maven-bundle-plugin in the binding projects for this. > > 2. Remove the split packages by consolidating the packages into > the api > and binding jars, and use a 'service implementation' discovery similar > that suggested by Eric in the "aufgeregt" thread :-) : > > http://www.qos.ch/pipermail/logback-user/2007-February/000129.html > > We should not depend on a sun impl for this so we would have to > provide > our own implementation, Boris has provided an example at: > > http://marc.theaimsgroup.com/?l=slf4j-dev&m=117157566417290&w=2 > <http://marc.theaimsgroup.com/?l=slf4j-dev&m=117157566417290&w=2> > > While I have not experimented with his code, I do see one area that > would require a change for it to work in an OSGi environment. > > public Object obtainFactory(ClassLoader cl) { > ILoggerFactory ret = null; > InputStream is = cl.getResourceAsStream(SERVICE_ID); > > Note: couldn't use a context classloader as it would not find the > classes in an OSGi runtime. Sun's service api offers similar > signatures. > > 3. Keep split packages and retain current way of combining api and > bindings. Remove OSGi decorations and maven-bundle-plugin from > the five > bindings projects. Create five additional OSGi 'pom' projects that > just wrap the api and bindings to create OSGi binding bundles. These > projects would only have a pom.xml (no code) and the artifacts they > create would be the same bundles as we are now producing in the > binding > projects. All other projects producing native jar/osgi bundles (like > the adapters) would remain unchanged. > (In this case Sally would not use the osgi-xxx-binding bundles.) > > 4. Convince Sally to run OSGi ;-) > > From an OSGi perspective I would rate them in order of functionality > from higher to lower - 4, 3, 2, 1. > > kind regards, > John > > > > > At 07:52 PM 2/19/2007, Ceki Gülcü wrote: > > > > > >> At 08:25 PM 2/18/2007, John E. Conlon wrote: > >> > >> > >>>> Assuming Maven 2 is used by all participants, without particular > >>>> action by Sally, slf4j-api would be packaged in the final > >>>> application along with a user-chosen binding, say > slf4j-log4j12. In > >>>> that case, we would have the contents of slf4j-api project > duplicated, > >>>> once in slf4j-api.jar and once in slf4j-log4j12.jar. It would > most > >>>> probably work as expected, but I don't think it's good > practice to > >>>> have class files duplicated. > >>>> > >>>> > >>> I don't like this class duplication either, but AFAIK given > the same > >>> classloader this should not matter. The same classloader will > load > >>> which ever it encounters first. (Maybe I will eat these words > latter?) ;-) > >>> > >> Hi John, > >> > >> The driving premise behind SLF4J is to reduce surprises. I think we > >> should do things by the book and avoid duplication. Since SLF4J > >> version 1.1, user's have been asked to have two jars, > slfl4-api.jar in > >> addition to a binding. In SLF4J 1.3, the general arrangement > remains > >> the same, except that slf4j-api is now self-sufficient as a > >> compile-time dependency. > >> > >> I quite like this user-story. Alice and Bob expose slf4j-api as a > >> transitive dependency, while Sally, the end-user, chooses to > depend on > >> a binding of her own selection. We respond to Eric Crahen's > initial > >> request [1] without fundamentally changing how SLF4J works. > >> > >> I do not wish to hide behind backward-compatibility excuses. We > >> finally have a nice and clear separation between slf4j-api and > >> slf4j-binding. Let's keep it clean and simple even if it costs an > >> extra jar on the class path. > >> > >> [1] > >> http://www.qos.ch/pipermail/logback-user/2007-February/000129.html > >> > >> > >> > >> > >>> a good weekend for you too, > >>> John > >>> > >> -- > >> Ceki Gülcü > >> Logback: The reliable, generic, fast and flexible logging > framework for Java. > >> http://logback.qos.ch > >> > >> _______________________________________________ > >> dev mailing list > >> dev@slf4j.org <mailto:dev@slf4j.org> > >> http://www.slf4j.org/mailman/listinfo/dev > >> > > > > > > _______________________________________________ > dev mailing list > dev@slf4j.org <mailto:dev@slf4j.org> > http://www.slf4j.org/mailman/listinfo/dev > <http://www.slf4j.org/mailman/listinfo/dev> > > > > > -- > > - Eric > ------------------------------------------------------------------------ > > _______________________________________________ > dev mailing list > dev@slf4j.org > http://www.slf4j.org/mailman/listinfo/dev
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