We think highly of the "ligh weight service" usage of osgi; This is the real reason why we need resolve classes of osgi from host-application;
So we are hoping: if we can build a "light weight service" system based on OSGI, then we can not only achieve benefit of service-orient system, but also we can still using the valuable artifact provided by app-server(etc: web-container, ResourceAdaptor/JCA, TransactionManager, management..) ----- Original Message ----- From: "xuhb" <[email protected]> To: <[email protected]> Sent: Tuesday, October 18, 2011 12:35 PM Subject: Re: How to find a class of bundle from Host application? > > ----- Original Message ----- > From: "Neil Bartlett" <[email protected]> > To: <[email protected]> > Sent: Monday, October 17, 2011 3:46 PM > Subject: Re: How to find a class of bundle from Host application? > > >> Could you please explain a little more why you want to do this. >> >> What you're asking for may be possible, but these kinds of problems can >> nearly always be solved better using OSGi Services. For example, do you >> *really* need a class, or do you just need an instance of an object of a >> particular type? > > Previously, our application are based on a app-server, business module is > implements as Spring/EJB; > But we have encounter such difficult: > > 1) When a new version application is update, the user always don't ask for > the the new version to replace the old version, but ask for the new and old > version system both run for a while simultaneously; Because the different > organize of the customer cannot migrate the new version simultaneously; > > 2) In our application there are always some business logical which should be > extract as shared service, but these services also must be versioned; > > To resolve our practical problem , we need a plugin system, which can > contribute services of different version; and the application could choose > which one it can use; That's why we need first resolve a classes from osgi > before using the osgi service; > > If we doesn't just limited in our practical problem, then we want to treat > the osgi to act as a "light weight service" system. > Here "ligh weight service" composed of two part : 1) contract: the java > interface; 2) implementation: the osgi service object; > That's to say, we wants: > > 1) A new "ligh weight service" could be installed at run time and is > discovered by client (exist in host-application); > etc: A jsp could resolve to the java interface of a "light weight > service", and invoke the osgi service; > 2) The implementation of "light weight service" can be un-aware to client > (exit in host-application). and could be updated dynamically; > > This is osgi's natual; > > 3) The update of "light weight service"' could be awared by the client, and > re-resolve to it. > This is only used for failure test, becuase updating of contract( the java > interface) can cause un-reasonable problem; > Actually, we just need to know: "contract is update, the client may corrupt" > ,and give a report. that's enough; > >> Rgds >> Neil >> >> >> >> On Monday, 17 October 2011 at 07:44, xuhb wrote: >> >>> Sorry, I expressed my requirement un-correctly; >>> >>> Actually, the host application just know the name of class and want to >>> choose such class from embedded osgi environment ? >>> Could I? >>> Must I create a bundle (which import such class) dynamically and retrive >>> class from the dynamic created bundle? Is there other facilitate method? >>> >>> Thanks any suggestion >>> ----- Original Message ----- >>> From: "xuhb" <[email protected] (mailto:[email protected])> >>> To: <[email protected] (mailto:[email protected])> >>> Sent: Monday, October 17, 2011 2:32 PM >>> Subject: How to find a class of bundle from Host application? >>> >>> >>> > Hi: >>> > I am using osgi environment (felix) embedded in a Host Application; >>> > Now the host application want to use a class from a specified osgi >>> > bundle, >>> > Could standard osgi support such usage? >>> > or felix support such extension usage? >>> > Thanks any suggestion >> >>
