Well, htis might be it. CompB imports a class from CompA.
So, what you are saying there is no way for compB to always use the class from CompA, when the flow is: CompA --> CompB --> CompC. Correct? This issue may be because I use concrete files to test my case. In real life the dependency will be to an interface in CompA. the difference between the version used by CompB and CompC will be only the implementation injected using Spring. I hope to fine that B works with it's own "known" implementation version even when invoked from C. I'll check it out next week. Please advise if my above logic has a flaw. On Thu, Apr 15, 2010 at 7:49 PM, Richard S. Hall <[email protected]>wrote: > On 4/15/10 12:39, Richard S. Hall wrote: > >> On 4/15/10 10:08, Yair Ogen wrote: >> >>> I am not following. I always want CompB to use a fixed version of CompA >>> regardless of the calling API code. >>> >>> Is this possible? The direct dependency between CompC and CompA (newer >>> version) is a real situation. >>> >> >> Apparently, I am not explaining this in an understandable way, so maybe >> someone else can jump in and give it a try. >> >> The main issue has nothing to do with the dependencies of CompC->CompA or >> CompB->CompA...in isolation, CompC and CompB can have dependencies on any >> version of CompA they wish independently. >> >> The only issue is the dependency of CompC->CompB. This requires that the >> class spaces of the two bundles intersect via some common types. If those >> common types come from CompA, then you have a problem since CompC and CompB >> do not use a common version of CompA. If they do not include types from >> CompA, then it will work. >> >> In your case, since you are getting a "uses" constraint violation, it >> likely means your CompB component exposes CompA types to its importers, >> which means CompC can't use it. See the example I created before, does the >> exported package from CompB accept any CompA types as parameters or return >> any of those types from methods? If so, then CompC can't use it, since they >> don't agree on a common set of CompA types. >> > > To try to illustrate a working scenario, since that might be more helpful, > assume CompB exports a package containing only a class like: > > public class CompB { > public String getName(); > public CompB getChildComponent(); > } > > Since none of these types come from CompA 1.0, then CompC could import this > package, because the two versions of CompA would not conflict. Where as > something like this would not work: > > public class CompB { > public String getName(); > public CompA getChildComponent(); > } > > So, if any of the classes in the package exported by CompB (and imported by > CompC) publicly expose a type from CompA, then you have an issue since all > importers must use the same version of the type. > > -> richard > > > >> -> richard >> >> >> >> Please advise. >>> >>> On Thu, Apr 15, 2010 at 4:46 PM, Richard S. Hall<[email protected] >>> >wrote: >>> >>> On 4/15/10 9:17, Yair Ogen wrote: >>>> >>>> Thank you very much and yes this is exactly what I wanted to achieve, I >>>>> know >>>>> regular Java does not allow this, however I thought that OSGi special >>>>> ClassLoader model resolves this issue. >>>>> >>>>> I think this is a real life scenario. for example, assume based on >>>>> my previously described Component Graph that the logic behind the >>>>> scenes >>>>> is >>>>> that CompB was tested with CompA a long time ago. Comp C uses Comp B >>>>> but >>>>> also uses new version of CompA since it is a newer component. >>>>> >>>>> It is a real requirement for me (I think this is common to all?) that >>>>> the >>>>> system engineers do not allow me to have B use the new CompA since this >>>>> combination was never tested. They do not want to have full regressions >>>>> tests either. >>>>> >>>>> So, the route CompC --> CompA should use newer version, but the route >>>>> CompC >>>>> --> CompB --> CompA should use the older version. >>>>> >>>>> So, I need to tell them this is not possible? >>>>> >>>>> >>>>> To be clear, if CompC somehow gets objects from CompB that are >>>> instances >>>> from classes from CompA, then it will not work. This is because CompC is >>>> expecting the CompA instances to be 1.0.1, but the instances that CompB >>>> returns are 1.0.0. A given class can only see one version of a type at a >>>> time. >>>> >>>> However, if CompB only uses class from CompA internally and never >>>> exposes >>>> them to CompC, then it is possible for both CompB and CompC to use >>>> different >>>> versions of that type. >>>> >>>> There is a slight variation where CompB might expose CompA types, but >>>> CompC >>>> doesn't actually ever use those types from CompB. In this case, you >>>> could >>>> technically cheat and modify your CompB bundle metadata so it doesn't >>>> report >>>> the "uses" constraints. But I wouldn't recommend this since it would be >>>> really fragile and would likely blow up in other situations where you >>>> reuse >>>> CompB. >>>> >>>> -> richard >>>> >>>> >>>> Regards, >>>> >>>>> Yair >>>>> >>>>> On Thu, Apr 15, 2010 at 4:03 PM, Richard S. Hall<[email protected] >>>>> >>>>>> wrote: >>>>>> >>>>> >>>>> >>>>> On 4/15/10 2:17, Yair Ogen wrote: >>>>>> >>>>>> >>>>>> >>>>>> Right. this was another problem. >>>>>>> >>>>>>> now A both verrsion and B work ok. >>>>>>> >>>>>>> Problem in C: >>>>>>> >>>>>>> org.osgi.framework.BundleException: The bundle could not be resolved. >>>>>>> Reason: Package uses conflict: Import-Package: com.something.b.main; >>>>>>> version="0.0.0" >>>>>>> >>>>>>> Is this due to conflict between the imported dependency from to Be >>>>>>> and >>>>>>> the >>>>>>> one imported directly from C? >>>>>>> >>>>>>> Is this situation supposed to be supported? I mean C using one >>>>>>> version >>>>>>> of >>>>>>> and using B that uses another version of A? How can I accomplish this >>>>>>> goal? >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> As I mentioned in my original response, it is supported assuming B >>>>>> doesn't >>>>>> expose A to C...it sounds like com.something.b.main exposes A v1 to C >>>>>> who >>>>>> is >>>>>> only allowed to see A v1.0.1. >>>>>> >>>>>> For example, assume B has a class like: >>>>>> >>>>>> public interface com.something.b.main.Foo { >>>>>> com.something.classes.Bar getBar(); >>>>>> } >>>>>> >>>>>> Assuming com.something.classes.Bar comes from bundle A, then bundle C >>>>>> will >>>>>> not be allowed to use com.something.b.main, because it would cause it >>>>>> to >>>>>> see >>>>>> a different version of the package than what it is allowed to see. If >>>>>> this >>>>>> is specifically what you are trying to achieve, then you can't do this >>>>>> with >>>>>> Java at all. A given class can only see one version of another class >>>>>> at a >>>>>> time...otherwise you get class cast exceptions. >>>>>> >>>>>> -> richard >>>>>> >>>>>> >>>>>> Any help appreciated. >>>>>> >>>>>> >>>>>> Thanks, >>>>>>> >>>>>>> Yair >>>>>>> >>>>>>> On Wed, Apr 14, 2010 at 10:38 PM, Richard S. Hall< >>>>>>> [email protected] >>>>>>> >>>>>>> >>>>>>> wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>>> On 4/14/10 14:59, Yair Ogen wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Added the suggested Export-Package as well as Private-Package for >>>>>>>>> the >>>>>>>>> activator. >>>>>>>>> >>>>>>>>> install fails now on: >>>>>>>>> >>>>>>>>> org.codehaus.classworlds.NoSuchRealmException: plexus.core >>>>>>>>> at >>>>>>>>> org.codehaus.classworlds.ClassWorld.getRealm(ClassWorld.java:128) >>>>>>>>> at >>>>>>>>> org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:434) >>>>>>>>> >>>>>>>>> at >>>>>>>>> org.codehaus.classworlds.Launcher.main(Launcher.java:375) >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> This sounds specific to the scenario you are trying to implement. >>>>>>>> Not >>>>>>>> sure, >>>>>>>> I have no idea what Class Worlds is... >>>>>>>> >>>>>>>> -> richard >>>>>>>> >>>>>>>> >>>>>>>> Yair >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Wed, Apr 14, 2010 at 8:42 PM, Richard S. Hall< >>>>>>>>> [email protected] >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> To include packages without exporting them, you should use >>>>>>>>>> Private-Package. >>>>>>>>>> For example, you shouldn't export your activator package. >>>>>>>>>> >>>>>>>>>> Is sounds like you want something like this: >>>>>>>>>> >>>>>>>>>> CompA v1 >>>>>>>>>> Export-Package: com.something.classes; version=1.0.0 >>>>>>>>>> >>>>>>>>>> CompA v1.0.1 >>>>>>>>>> Export-Package: com.something.classes; version=1.0.1 >>>>>>>>>> >>>>>>>>>> CompB >>>>>>>>>> Import-Package: com.something.classes; version="[1.0.0, 1.0.0]" >>>>>>>>>> >>>>>>>>>> Export-Package: com.something.b.main >>>>>>>>>> Private-Package: com.something.activator.b >>>>>>>>>> >>>>>>>>>> CompC >>>>>>>>>> Import-Package: com.something.classes; version="[1.0.1, 1.0.1]", >>>>>>>>>> com.something.b.main >>>>>>>>>> Private-Package: com.something.activator.c >>>>>>>>>> >>>>>>>>>> -> richard >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Regards, >>>>>>>>>>> >>>>>>>>>>> Yair >>>>>>>>>>> >>>>>>>>>>> On Wed, Apr 14, 2010 at 4:40 PM, Richard S. Hall< >>>>>>>>>>> [email protected] >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On 4/14/10 9:19, Christopher Brind wrote: >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> Hi Richard, >>>>>>>>>>>>> >>>>>>>>>>>>> Would you agree that a good rule of thumb (subject to specific >>>>>>>>>>>>> circumstance >>>>>>>>>>>>> of course) is that bundles should only import packages OR >>>>>>>>>>>>> export >>>>>>>>>>>>> packages, >>>>>>>>>>>>> but not both? >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> Well, as long as you extend that with, ..."and package API >>>>>>>>>>>> separately >>>>>>>>>>>> from >>>>>>>>>>>> the implementation." >>>>>>>>>>>> >>>>>>>>>>>> Then, yes, that'd be a good rule of thumb for the average case, >>>>>>>>>>>> since >>>>>>>>>>>> it >>>>>>>>>>>> would result in the fewest issues overall at the expense of >>>>>>>>>>>> creating >>>>>>>>>>>> more >>>>>>>>>>>> bundles to manage. >>>>>>>>>>>> >>>>>>>>>>>> -> richard >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> Cheers, >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> Chris >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> On 14 April 2010 14:13, Richard S. Hall<[email protected]> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> Technically, what you want to do is possible assuming that >>>>>>>>>>>>>> CompB >>>>>>>>>>>>>> doesn't >>>>>>>>>>>>>> expose CompA v1 to CompC. From the sounds of it, you've >>>>>>>>>>>>>> packaged >>>>>>>>>>>>>> your >>>>>>>>>>>>>> bundles incorrectly. Don't embed the Person package into your >>>>>>>>>>>>>> bundles, >>>>>>>>>>>>>> package them as separate bundles and them use Import-Package >>>>>>>>>>>>>> in >>>>>>>>>>>>>> the >>>>>>>>>>>>>> client >>>>>>>>>>>>>> bundles to access them. You might want to start with some >>>>>>>>>>>>>> introductory >>>>>>>>>>>>>> OSGi >>>>>>>>>>>>>> tutorials to understand the basics. >>>>>>>>>>>>>> >>>>>>>>>>>>>> -> richard >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> On 4/14/10 6:53, Yair Ogen wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Hi, >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> I am a newbie. I've created dummy projects to test this out. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> What I am trying to achieve is as follows: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> CompA version 1.0.0 defines class Person that has 2 >>>>>>>>>>>>>>> properties: >>>>>>>>>>>>>>> name, >>>>>>>>>>>>>>> lastName >>>>>>>>>>>>>>> CompA version 1.0.1 defines class Person that has 2 >>>>>>>>>>>>>>> properties: >>>>>>>>>>>>>>> name, >>>>>>>>>>>>>>> myLastName >>>>>>>>>>>>>>> CompB version 1.0.0 calls API on person compiled with CompA >>>>>>>>>>>>>>> version >>>>>>>>>>>>>>> 1.0.0. >>>>>>>>>>>>>>> CompC version 1.0.0 calls API on person compiled with CompA >>>>>>>>>>>>>>> version >>>>>>>>>>>>>>> 1.0.1. >>>>>>>>>>>>>>> Additionally calls API on CompB. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> So, CompA, both versions, are not dependent on anything. >>>>>>>>>>>>>>> CompB is dependant on CompA version *1.0.0*. >>>>>>>>>>>>>>> CompC is dependant on CompB version 1.0.0 and CompA version >>>>>>>>>>>>>>> *1.0.1*. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> When I read about OSGi I thought that I should be able to see >>>>>>>>>>>>>>> that >>>>>>>>>>>>>>> the >>>>>>>>>>>>>>> API >>>>>>>>>>>>>>> used directly between C and A will activate Person from A >>>>>>>>>>>>>>> version >>>>>>>>>>>>>>> 1.0.1, >>>>>>>>>>>>>>> but >>>>>>>>>>>>>>> the API called from C to B to A will activate the person from >>>>>>>>>>>>>>> A >>>>>>>>>>>>>>> version >>>>>>>>>>>>>>> 1.0.0. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> This is not the case. Pure B API activate the "right" person. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Person used from C (regardless of the origin - API in C or >>>>>>>>>>>>>>> API >>>>>>>>>>>>>>> in >>>>>>>>>>>>>>> B) >>>>>>>>>>>>>>> activates the same Person - 1.0.1. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> When investigating I saw that the person class was embedded >>>>>>>>>>>>>>> in B >>>>>>>>>>>>>>> and >>>>>>>>>>>>>>> in >>>>>>>>>>>>>>> C, >>>>>>>>>>>>>>> so of course they can only work with one class at a time. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> My question is - isn't there a non embedded approach, where >>>>>>>>>>>>>>> both >>>>>>>>>>>>>>> A >>>>>>>>>>>>>>> versions >>>>>>>>>>>>>>> jars are in the classpath and the container will pick up the >>>>>>>>>>>>>>> correct >>>>>>>>>>>>>>> dependency on the fly? >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> This must work for me, because this is the heart of what I >>>>>>>>>>>>>>> need >>>>>>>>>>>>>>> from >>>>>>>>>>>>>>> OSGi >>>>>>>>>>>>>>> - >>>>>>>>>>>>>>> Manage multiple version of the same artifacts in a single >>>>>>>>>>>>>>> jvm... >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Regards, >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Yair >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> --------------------------------------------------------------------- >>>>>>>>>>>>>> To unsubscribe, e-mail: [email protected] >>>>>>>>>>>>>> For additional commands, e-mail: [email protected] >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> --------------------------------------------------------------------- >>>>>>>>>>>> To unsubscribe, e-mail: [email protected] >>>>>>>>>>>> For additional commands, e-mail: [email protected] >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> --------------------------------------------------------------------- >>>>>>>>>> To unsubscribe, e-mail: [email protected] >>>>>>>>>> For additional commands, e-mail: [email protected] >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> --------------------------------------------------------------------- >>>>>>>> To unsubscribe, e-mail: [email protected] >>>>>>>> For additional commands, e-mail: [email protected] >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> --------------------------------------------------------------------- >>>>>> To unsubscribe, e-mail: [email protected] >>>>>> For additional commands, e-mail: [email protected] >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: [email protected] >>>> For additional commands, e-mail: [email protected] >>>> >>>> >>>> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [email protected] >> For additional commands, e-mail: [email protected] >> >> > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > >
