6 Replies Latest reply on Mar 15, 2012 10:35 AM by smithleej

    Unable to reference a service in a bundle when the Interface it implements is contained in another bundle

    smithleej
    smithleej Nov 29, 2011 6:49 AM

      As part of my investigation into OSGI on JBoss AS 7 I have created four OSGi bundles that are configured using blueprint. 

       

      Here is a brief description of each of the bundles

      • an API bundle that contains an interface named Job that has a single method named getName() which retruns a String.
      • an example job bundle that contains a class named ExampleJob that implements the Job interface.
      • a core services bundle that exports an OSGi service which is used by the ExampleJob class
      • and finally a job repository bundle that contains a blueprint reference-list element that should be populated with every service that implements the Job interface.  The reference-list also contains a reference-listener that intercepts jobs being added to the list and calls the getName() method of the Job and logs out the result.

       

      The idea is that i would be able to deploy the API, Core, and Repository bundles, and then deploy many Job bundles which would have their Jobs (exported as services) automatically added to the list of Jobs in the Repository bundle.

       

      Unfortunately this does not work, the logging from the reference-listener does not get output, instead I see this log line:

       

      WARN  [org.jboss.osgi.framework.internal.ServiceState] (pool-7-thread-3) The service's classloader has no visibility of the requested class: com.efstech.demo.osgi.api.model.Job

       

      Incidentally when I deploy the bundles in this order:

      API -> Core -> Example Job -> Repository

       

      The Job correctly gets added to the list, the reference-listener logs the name of the Job and I do not see the warning from the ServiceState class.

       

      I have also written the bundles as plain OSGi bundles without any blueprint configuration, just relying only on the bundle activators to glue the bundles together and it works as desired i.e. being able to deploy the bundles in the following order:

      API -> Core -> Repository-> Example Job

       

      I have been using the Sun JDK on Ubuntu:

      java version "1.6.0_26"

      Java(TM) SE Runtime Environment (build 1.6.0_26-b03)

      Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02, mixed mode)

       

      I have been testing the OSGi/blueprint bundles on JBoss AS 7.0.2 with both the jbosgi-framework-core-1.0.8.CR8.jar that comes with JBoss AS 7.0.2 and jbosgi-framework-core-1.0.1.jar that I downloaded from from the jboss repository.  I also tested the bundles with JBoss 7.1.0.Beta1 (which comes with jbosgi-framework-core-1.1.0.jar) but all with the same result.

       

      I will attach the compiled bundles and the source code.  Any help would be much appreciated!

       

      Thanks,

      Lee

        • 1. Re: Unable to reference a service in a bundle when the Interface it implements is contained in another bundle
          jye.tucker
          jye.tucker Jan 3, 2012 8:21 AM (in response to smithleej)

          I've also hit this problem on jboss-as-7.1.0.CR1b in our app, and also with the source attached above.

           

          Although I've been using OSGi with declarative services for a few years, we've just migrated to blueprint and JBoss AS 7 and still getting my head around it. I've checked package visibility on the bundles and it looks correct.

           

          This could be the same issue - https://issues.jboss.org/browse/JBOSGI-485

           

          Did you have any luck resolving or working around?

           

          I'll link this forum post to the issue above as this has better detail, and will keep investigating.

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          • 2. Re: Unable to reference a service in a bundle when the Interface it implements is contained in another bundle
            smithleej
            smithleej Feb 29, 2012 10:42 AM (in response to jye.tucker)

            I haven't had any luck resolving the issue unfortunately.  I have managed to get the same bundles working with Eclipse Virgo though so it seems to be the way in which OSGi is implemented within JBoss that is causing the issue.

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            • 3. Re: Unable to reference a service in a bundle when the Interface it implements is contained in another bundle
              thomas.diesler
              thomas.diesler Mar 6, 2012 3:56 AM (in response to smithleej)

              I took a quick look at this in 7.1.0.Final

               

              To enable blueprint, you can use the following configuration

               

              <capabilities>
<capability name="javax.servlet.api:v25"/>
<capability name="javax.transaction.api"/>
<capability name="org.apache.felix.log" startlevel="1"/>
<capability name="org.jboss.osgi.logging" startlevel="1"/>
<capability name="org.apache.felix.configadmin" startlevel="1"/>
<capability name="org.jboss.as.osgi.configadmin" startlevel="1"/>
<capability name="org.apache.aries:org.apache.aries.util:0.4" startlevel="2"/>
<capability name="org.apache.aries.proxy:org.apache.aries.proxy:0.4" startlevel="2"/>
<capability name="org.apache.aries.blueprint:org.apache.aries.blueprint:0.4" startlevel="2"/>
</capabilities>

               

              Your bundles have a dependency on log4j. So you need to setup visibility to that module as well or alternatively deploy a bundle that provides that API

               

              <property name="org.jboss.osgi.system.modules.extra">
org.apache.log4j
</property>
<property name="org.osgi.framework.system.packages.extra">
org.apache.log4j;version=1.2
</property>

               

               

              Whith this in place, I get an output like this.

               

              16:50:18,106 INFO  [org.jboss.osgi.framework.internal.FrameworkActive] (MSC service thread 1-1) OSGi Framework started
16:50:18,144 INFO  [org.jboss.as] (Controller Boot Thread) JBAS015874: JBoss AS 7.1.0.Final "Thunder" started in 7625ms - Started 135 of 205 services (69 services are passive or on-demand)
16:50:34,541 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-2) JBAS015876: Starting deployment of "coreapibundle-1.0-SNAPSHOT.jar"
16:50:34,730 INFO  [org.jboss.osgi.framework.internal.BundleManager] (MSC service thread 1-1) Install bundle: coreapibundle:1.0.0.SNAPSHOT
16:50:34,745 INFO  [org.jboss.osgi.framework.internal.HostBundleState] (MSC service thread 1-2) Bundle started: coreapibundle:1.0.0.SNAPSHOT
16:50:34,850 INFO  [org.jboss.as.server] (DeploymentScanner-threads - 2) JBAS018559: Deployed "coreapibundle-1.0-SNAPSHOT.jar"
16:50:39,880 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-2) JBAS015876: Starting deployment of "core-1.0-SNAPSHOT.jar"
16:50:39,905 INFO  [org.jboss.osgi.framework.internal.BundleManager] (MSC service thread 1-1) Install bundle: core:1.0.0.SNAPSHOT
16:50:39,927 INFO  [org.jboss.as.server] (DeploymentScanner-threads - 2) JBAS018559: Deployed "core-1.0-SNAPSHOT.jar"
16:50:39,957 INFO  [org.jboss.osgi.framework.internal.HostBundleState] (MSC service thread 1-3) Bundle started: core:1.0.0.SNAPSHOT
16:50:39,969 INFO  [com.efstech.demo.osgi.core.CoreServicesActivator] (Blueprint Extender: 2) Started Core Services Bundle
16:50:49,943 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-4) JBAS015876: Starting deployment of "repo-1.0-SNAPSHOT.jar"
16:50:49,961 INFO  [org.jboss.osgi.framework.internal.BundleManager] (MSC service thread 1-1) Install bundle: repo:1.0.0.SNAPSHOT
16:50:49,993 INFO  [org.jboss.osgi.framework.internal.HostBundleState] (MSC service thread 1-1) Bundle started: repo:1.0.0.SNAPSHOT
16:50:49,994 INFO  [org.jboss.as.server] (DeploymentScanner-threads - 1) JBAS018559: Deployed "repo-1.0-SNAPSHOT.jar"
16:50:50,031 INFO  [org.apache.aries.blueprint.container.BlueprintContainerImpl] (Blueprint Extender: 1) Bundle repo is waiting for dependencies [(objectClass=com.efstech.demo.osgi.api.model.Job)]
16:51:00,010 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-4) JBAS015876: Starting deployment of "examplejob-1.0-SNAPSHOT.jar"
16:51:00,029 INFO  [org.jboss.osgi.framework.internal.BundleManager] (MSC service thread 1-2) Install bundle: examplejob:1.0.0.SNAPSHOT
16:51:00,045 INFO  [org.jboss.osgi.framework.internal.HostBundleState] (MSC service thread 1-4) Bundle started: examplejob:1.0.0.SNAPSHOT
16:51:00,082 INFO  [org.jboss.as.server] (DeploymentScanner-threads - 1) JBAS018559: Deployed "examplejob-1.0-SNAPSHOT.jar"
16:51:00,095 INFO  [com.efstech.demo.osgi.examplejob.ExampleJobActivator] (Blueprint Extender: 3) Bundle ExampleJob Installed
16:51:00,111 INFO  [com.efstech.demo.osgi.core.services.VeryUsefulServiceImpl] (Blueprint Extender: 2) Wow, this is so useful!!

               

              I guess, this is all good.

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              • 4. Re: Unable to reference a service in a bundle when the Interface it implements is contained in another bundle
                jye.tucker
                jye.tucker Mar 5, 2012 11:30 AM (in response to thomas.diesler)

                I've also confirmed this is working in 7.1.0.Final. I have a similar set of capabilities to what Thomas describes above, and a bunch of bundles with blueprint services and it is all working well.

                 

                Lee - if you're still having issues after upgrading, let me know and I'd be happy to help.

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                • 5. Re: Unable to reference a service in a bundle when the Interface it implements is contained in another bundle
                  thomas.diesler
                  thomas.diesler Mar 6, 2012 4:01 AM (in response to thomas.diesler)

                  In 7.1.0.Final it is sufficient to define an extra system module like this

                   

                  <property name="org.jboss.osgi.system.modules.extra">
    org.apache.log4j
</property>
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                  • 6. Re: Unable to reference a service in a bundle when the Interface it implements is contained in another bundle
                    smithleej
                    smithleej Mar 15, 2012 10:35 AM (in response to smithleej)

                    Thanks very much for your help guys I will give 7.1.0.Final a try when I next get a chance.

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