My "AllServiceListener" takes place when serviceChanged( ) has just a print to console. In this situation all osgi services fire the serviceChanged() method.
The problem appears when I build a 'special listener' (for example for BundleService1 as i said) in order to fill an handle to the service to be called later. In this situation, to declare a variable of service1 interface to save the service object reference, I have to put the import statement and the special listener does not detects service1 anymore, only service 2,3, 4,etc... May be i am using ServiceListener in a worng way, but it is logic for me to get the pointer to the service when it is up... Thanks Alex On Thu, Feb 14, 2013 at 6:55 PM, Richard S. Hall <[email protected]>wrote: > The OSGi framework attempts to deliver service events that are usable by > your bundle (i.e., class compatible), so by having or not having imports > and depending on the provider of your imports you may or may not see events > if the framework thinks they might cause you class cast problems. > > If you want to test this out, you can implement *AllServiceListener* as a > test to see if you get all events; this listener will get all service event > irrespective of whether they might cause class cast exceptions. > > Generally, you only want to use an "all" listener if you are monitoring an > entire system, but not really interacting with services (or are using > reflection to do so). Normally, you only want the framework sending events > to service you can access without a class cast exception using the normal > ServiceListener. > > -> richard > > p.s. For completeness, here a description of what the Felix framework > tries to do from ServiceRegistrationImpl.java: > > // There are four situations that may occur here: > // 1. Neither the requester, nor provider have wires for the > package. > // 2. The requester does not have a wire for the package. > // 3. The provider does not have a wire for the package. > // 4. Both the requester and provider have a wire for the > package. > // For case 1, if the requester does not have access to the > class at > // all, we assume it is using reflection and do not filter. If > the > // requester does have access to the class, then we make sure > it is > // the same class as the service. For case 2, we do not filter > if the > // requester is the exporter of the package to which the > provider of > // the service is wired. Otherwise, as in case 1, if the > requester > // does not have access to the class at all, we do not filter, > but if > // it does have access we check if it is the same class > accessible to > // the providing revision. For case 3, the provider will not > have a wire > // if it is exporting the package, so we determine if the > requester > // is wired to it or somehow using the same class. For case 4, > we > // simply compare the exporting revisions from the package > wiring to > // determine if we need to filter the service reference. > > > On 2/14/13 11:50 , Imóveis Nacionais wrote: > >> Hi all, me again… >> >> >> Suppose you have the following OSGi bundles and the related exposed >> services: >> >> BundleService1 -> exports service 1 and interface for service 1 >> >> BundleService2 -> exports service 2 and interface for service 2 >> >> >> >> Now I want to write the Bundle3 which will use both Service1 and Service2 >> (for now, just service1). >> >> So, Bundle3 (activator class) implements BundleActivator and >> ServiceListener. >> >> On start() I do: context.addServiceListener(**this); >> >> On the serviceChanged() method I simply have a print to console. >> >> This works with no problem. >> >> ------------------------------**------------------------------** >> ------------------------------**------------------ >> >> Suppose now that you want to call service1 from serviceChanged method >> (just >> an example!): >> >> To call service1 I need to add dependence to pom.xml for BundleService1 in >> order to get reference and cast the reference to the service1 interface. >> >> Then, on the activator class I need to put an import for the service1 >> interface. Then I get the reference, evaluate the property, cast it to >> service1 and call the service1. >> >> >> Now, testing this stuff: >> >> I install Bundle3 and start it. >> >> I install BundleService1 and start it. Nothing happens on bundle3 >> serviceChanged!!! >> >> Then I install BundleService2 and start it. The bundle3 serviceChanged is >> called!!! >> >> >> If I install and start any other bundles serviceChanged is always called, >> except for BundleService1! >> >> If I remove the import directive from Bundle3 (while the POM dependence >> remains) and comment the related code, Bundle3 serviceChanged is called >> for >> BundleService1! >> >> >> >> My conclusion is that, the ServiceListener only works for those bundles >> that have no “connection” (import) with Bundle3. Is this true? >> >> If this is true, how can I get the reference and cast to the service in >> order to call it without using imports? >> >> >> >> Note: In an attempt to solve the problem I did the following: in the >> serviceChanged I called another bundle3 class giving it the event in order >> to remove the import from activator class, and move it to the other class. >> But serviceChanged did not detects the Service1 too. It seems that if the >> (client) bundle project has an import for some service bundles those >> bundles are not “detected” in the serviceChanged method. >> >> >> >> Thank you >> >> Alex >> >> > > ------------------------------**------------------------------**--------- > To unsubscribe, e-mail: > users-unsubscribe@felix.**apache.org<[email protected]> > For additional commands, e-mail: [email protected] > >
