Hey, I've ran into another split package problem in OpenEJB and I'm trying to understand the "partial=true; mandatory:=partial" trick. So I wanted to double check my understanding of this with OSGi experts here.
First of all, if an exported package is marked with "partial=true; mandatory:=partial", the importers wanting to wire to a bundle that exports that package must provide that mandatory attribute on its Import-Package import. For example, if we have a bundle A with Export-Package: org.apache.geronimo.foo;partial=true; mandatory:=partial" the importer would have to have Import-Package: org.apache.geronimo.foo;partial=true to wire to bundle A. And that means that "partial" attribute really has no special meaning in OSGi. We could have easily archived the same exact result if we marked a package with "a=b; mandatory:=a". Is my understanding right so far? In Geronimo we marked the javax.transaction.xa package with that partial attribute because the JVM only provides a subset of the classes in that package. And now all imports on the xa package will be automatically wired to the Geronimo JTA spec bundle. And since the Geronimo bundle has all the necessary classes all works well. But what happens if you really have a true split package problem where subset of the classes are provided by two different bundles? E.g. bundle 1 provides org.apache.geronimo/classA and bundle 2 provides org.apache.geronimo/classB. That's the problem in OpenEJB in org.apache.openejb.client package. Some client classes are exported in openejb-core bundle and some in openejb-client bundle. The best solution is of course the remove the split package problem in the first place. But if that's not possible, another solution is to combine the mandatory attribute trick with Require-Bundle. That is, bundle 1 exports package X with some mandatory attribute and bundle 2 has Require-Bundle on bundle 1 (and also exports package X). So all imports on package X would always be wired to bundle 2 and bundle 2 would have access to all classes in package X. Do I have that right? OpenEJB seems to be following the Require-Bundle/partial attribute solution but it's definitely not set up right (assuming I understand that solution correctly). Are there better solutions for the split package problem? Jarek
