Richard S. Hall <[EMAIL PROTECTED]> writes: > The spec used to recommend packaging a bundle with its > interfaces...I am not sure if it still does or not, but it is > definitely not anti-OSGi.
Today I've been wondering about this too. In many cases, I wish to define some service interface for clients to use, then write at least one implementation of the service interface. Clients will rely on the interfaces, but should have no knowledge of the implementation(s). What's the right way to package this in OSGi? If I put the interfaces in the same bundle as the implementation, the two have to be in different packages to maintain the intended privacy of the implementation. Alternately, I can place the interfaces in a bundle, and have both the clients and the implementation bundle rely on that interface-only bundle. This is based on the assumption that a given class or interface should only wind up in one bundle. Also, the latter separated approach seems more favorable to there being multiple implementations of a single interface, as it wouldn't make sense to put the interfaces in the first implementation's bundle and have all other implementations rely on the first. Since Felix is written largely as an implementation of a separate set of OSGi interfaces, it's more obvious how it splits the two domains. For an application or system that's more self-contained, though, it's harder to figure out a discipline for separating interfaces and implementations. Advice and examples would be welcome. -- Steven E. Harris
