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https://issues.apache.org/jira/browse/FELIX-6353?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Carsten Ziegeler reassigned FELIX-6353:
---------------------------------------
Assignee: Tom Watson
> Constructor injection: activation with optional reference fails if service
> not available
> ----------------------------------------------------------------------------------------
>
> Key: FELIX-6353
> URL: https://issues.apache.org/jira/browse/FELIX-6353
> Project: Felix
> Issue Type: Bug
> Components: Declarative Services (SCR)
> Affects Versions: scr-2.1.24
> Reporter: Tobias Gunkel
> Assignee: Tom Watson
> Priority: Major
> Fix For: scr-2.1.26
>
> Attachments: constructorinjection.patch,
> optionalreferenceconstructor-example.zip
>
>
> A service that uses constructor injection for an optional service will crash
> with an "activation failed" exception if the optional service is not
> available.
> According to the OSGi R7 specification a "null" value should be injected
> instead.
>
> Example:
> {code}
> @Activate
> public SomeService(
> @Reference(cardinality = ReferenceCardinality.OPTIONAL)
> OptionalService optionalService)
> {}
> {code}
> The above code works if an OptionalService instance is present but it fails
> and crashes if no OptionalService instance is present during activation time:
> Error message in log:
> {code}
> ERROR : bundle optionalreferenceconstructor:0.1.0..
> (1)[optionalreferenceconstructor.SomeService(0)] : Error during instantiation
> of the implementation object: Unable to get service for reference
> optionalService
> {code}
> Stack trace shown with scr:info:
> {code}
> State: FAILED ACTIVATION
> References: (total 1)
> - optionalService: optionalreferenceconstructor.OptionalService SATISFIED
> 0..1 static
> target=(*) scope=bundle (no active bindings)
> Failure: java.lang.InstantiationException: Unable to get service for
> reference optionalService
> java.lang.InstantiationException: Unable to get service for reference
> additionalSettingsStorage at
> org.apache.felix.scr.impl.inject.internal.ComponentConstructorImpl.newInstance(ComponentConstructorImpl.java:301)
> at
> org.apache.felix.scr.impl.manager.SingleComponentManager.createImplementationObject(SingleComponentManager.java:286)
> at
> org.apache.felix.scr.impl.manager.SingleComponentManager.createComponent(SingleComponentManager.java:115)
> at
> org.apache.felix.scr.impl.manager.SingleComponentManager.getService(SingleComponentManager.java:1000)
> at
> org.apache.felix.scr.impl.manager.SingleComponentManager.getServiceInternal(SingleComponentManager.java:973)
> at
> org.apache.felix.scr.impl.manager.AbstractComponentManager.activateInternal(AbstractComponentManager.java:785)
> at
> org.apache.felix.scr.impl.manager.DependencyManager$SingleStaticCustomizer.addedService(DependencyManager.java:1271)
> at
> org.apache.felix.scr.impl.manager.DependencyManager$SingleStaticCustomizer.addedService(DependencyManager.java:1222)
> at
> org.apache.felix.scr.impl.manager.ServiceTracker$Tracked.customizerAdded(ServiceTracker.java:1200)
> at
> org.apache.felix.scr.impl.manager.ServiceTracker$Tracked.customizerAdded(ServiceTracker.java:1121)
> at
> org.apache.felix.scr.impl.manager.ServiceTracker$AbstractTracked.trackAdding(ServiceTracker.java:928)
> at
> org.apache.felix.scr.impl.manager.ServiceTracker$AbstractTracked.track(ServiceTracker.java:864)
> at
> org.apache.felix.scr.impl.manager.ServiceTracker$Tracked.serviceChanged(ServiceTracker.java:1152)
> at
> org.apache.felix.scr.impl.BundleComponentActivator$ListenerInfo.serviceChanged(BundleComponentActivator.java:114)
> at
> org.apache.felix.framework.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:990)
> at
> org.apache.felix.framework.EventDispatcher.fireEventImmediately(EventDispatcher.java:838)
> at
> org.apache.felix.framework.EventDispatcher.fireServiceEvent(EventDispatcher.java:545)
> at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:4833) at
> org.apache.felix.framework.Felix.registerService(Felix.java:3804) at
> org.apache.felix.framework.BundleContextImpl.registerService(BundleContextImpl.java:328)
> at
> ...
> {code}
> It seems that the ComponentConstructorImpl (line 301) does only check for
> multiple cardinality but not for optional cardinality.
> Propably ComponentConstructorImpl.java (line 299) should be:
> {code}
> if ( !refMetadata.isMultiple())
> {
> if ( !refMetadata.isOptional() && (ref == null) )
> {
> throw new InstantiationException("Unable to get service for
> reference " + refMetadata.getName());
> }
> }
> {code}
> Instead of:
> {code}
> if ( !refMetadata.isMultiple())
> {
> if ( ref == null )
> {
> throw new InstantiationException("Unable to get service for
> reference " + refMetadata.getName());
> }
> }
> {code}
> The change is also attached a patch file. Please note that I did not have the
> opportunity to test the change. It might not fix the problem or cause other
> crashes.
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