On Wed, Nov 24, 2010 at 12:39 AM, Richard S. Hall <he...@ungoverned.org> wrote: > On 11/23/10 5:58 PM, Marcel Offermans wrote: >> >> On 23 Nov 2010, at 23:45 , Bram de Kruijff wrote: >> >>> On Tue, Nov 23, 2010 at 9:54 PM, Richard S. Hall<he...@ungoverned.org> >>> wrote: >>>> >>>> On 11/23/10 15:51, Bram de Kruijff wrote: >>>>> >>>>> Hi List, >>>>> >>>>> we are embedding a 3rd party library (in this case Apache Cassandra) >>>>> in a bundle . At startup it uses ClassLoader.getSystemClassLoader to >>>>> load a resource which fails. >>>>> >>>>> 1) Is there a way to intercept this call so that the resource is >>>>> loaded from the bundle classpath? >>>> >>>> No. >>> >>> Was afraid you where gonna say that >>> >>>>> 2) What would the desired patch on Cassandra be. Eg. >>>>> ContextClassLoader? >>>> >>>> Shouldn't it be using its own bundle class loader? >>> >>> My guess is the Cassandra developers are not "OSGi aware" and we are >>> just wrapping that library. So in general what best practice pattern >>> should non OSGi projects follow to be "embedable". a) use their own >>> this.getClass().getClassLoader(), b) use the ContextClassLoader so we >>> can switch it c) ... >> >> I general they should allow you to plugin a classloader instead of make >> assumptions that are not overridable. >> >> So whenever they load a class, they should allow you to provide a >> classloader for it. That way, if all classes are on the bundle classpath, >> you can provide the library with your option a). Even if not all classes are >> on the bundle classpath, but somehow provided by some other bundle, this >> gives you enough hooks to attempt to load them on another bundle's >> classloader (for example when trying to deserialize an object graph that had >> instances that were private to several bundles that created those instances >> but did not share the implementation packages). > > Agreed, this is the only way. They must provide a hook for the lookup rather > than burying it inside and performing it based on assumptions. > > Even better if they don't expect to directly use a class at all and instead > provide a hook for injecting some instance implementing an interface, then > we could just give them the service we want to use rather than them > expecting to create their own instance.
Thanks for the insight guys! Regards, Bram --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@felix.apache.org For additional commands, e-mail: users-h...@felix.apache.org
