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https://issues.apache.org/jira/browse/FELIX-3090?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13093256#comment-13093256
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Pierre De Rop commented on FELIX-3090:
--------------------------------------
But isn't it difficult to define the reference as optional ?
I mean for instance, if the factory component has many required dependencies
and also provides a service,
then this service might be registered when another component invokes
newInstance...
So the registered service might be used while the required dependencies are not
there.
Another point that is troubling me is that in the spec, chapter 112.5.5
(Factory Component), it is stated the following:
"SCR must register a Component Factory service as soon as the component factory
becomes satisfied. The component factory is satisfied when the following
conditions are all satisfied:
• The component is enabled.
• Using the component properties specified by the component
description, all the component’s references are satisfied. A reference is
satisfied when the reference specifies optional cardinality or there is at
least one target service for the reference"
So, I don't understand why the component factory is currently registered, even
if a reference filter is not satisfied ?
For clarity, I have joined to this issue a maven sample code (sample.tgz),
which illustrates what I'm talking about:
- I have made a factory component "A", which depends on service "B" with target
filter "(foo=B2)".
- I then have "AFactory" which tracks the "A" ComponentFactory.
This component will instantiate "A" when the component factory is injected.
- I then have two component "B1" which implements B(foo=B1), and "B2" which
implements B(foo=B2).
Both B1 and B2 are disabled.
So, when running the framework, go the webconsole/component.
At this point, "A" and "AFactory" are both unsatisfied (because we don't have
any B services).
Now, enable B1 -> this will trigger the A's component factory registration, and
AFactory will then catch it and will invoke
newInstance. However, because A required B2 (not B1), then the newInstance will
throw:
org.osgi.service.component.ComponentException: Failed activating component
at
org.apache.felix.scr.impl.manager.ComponentFactoryImpl.newInstance(ComponentFactoryImpl.java:120)
at test.scr.factory.AFactory.bind(AFactory.java:17)
...
Finally; enable "B2" from webconsole: this will have no effect, and in the end,
the "AFactory" won't ever be able to instantiate "A".
So, am I making sense with this ? or am I missing something else ?
Thanks for your help.
> SCR factory components ignore reference target filters
> ------------------------------------------------------
>
> Key: FELIX-3090
> URL: https://issues.apache.org/jira/browse/FELIX-3090
> Project: Felix
> Issue Type: Bug
> Components: Declarative Services (SCR)
> Affects Versions: scr-1.6.0
> Reporter: Pierre De Rop
> Assignee: Felix Meschberger
>
> This issue is described in the following post:
> http://www.mail-archive.com/users@felix.apache.org/msg10925.html
> Basically, when a component is declaring a factory (in order to register a
> ComponentFactory in the registry),
> then any extra Reference' target filters are not taken into acount.
> This is a problem because the ComponentFactory is registered in the registry
> even if some References are not satisfied.
> Consider the following example (It uses the BND SCR annotations):
> @Component(factory = "AFactory")
> public class A {
> @Reference(name="YDependency", target = "(name=Z)")
> void bind(Y y) {
> System.out.println("A.bind(" + y + ")");
> }
> @Activate
> void start() {
> System.out.println("A.start");
> }
> }
> public interface Y {
> }
> @Component(properties = { "name=ZZZZZ" })
> public class YImpl implements Y {
> }
> @Component
> public class AFactory {
> @Reference(target = "(component.factory=AFactory)")
> void bind(ComponentFactory AFactory) {
> System.out.println("AFactory.bind(" + AFactory + ")");
> try {
> ComponentInstance ci = AFactory.newInstance(null);
> A a = (A) ci.getInstance();
> System.out.println("Created " + a);
> }
> catch (Throwable t) {
> t.printStackTrace();
> }
> }
> }
> Here, the "YDependency" Reference of the "A" component is not satisfied, but
> the ComponentFactory for the
> "A" component is somehow registered, and when the "AFactory" component
> catches it, then it get the following exception,
> when trying to instantiate the "A" component instance:
> org.osgi.service.component.ComponentException: Failed activating component
> at
> org.apache.felix.scr.impl.manager.ComponentFactoryImpl.newInstance(ComponentFactoryImpl.java:120)
> at test.scr.factory.AFactory.bind(AFactory.java:15)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> org.apache.felix.scr.impl.helper.BaseMethod.invokeMethod(BaseMethod.java:227)
> at
> org.apache.felix.scr.impl.helper.BaseMethod.access$1(BaseMethod.java:219)
> at
> org.apache.felix.scr.impl.helper.BaseMethod$Resolved.invoke(BaseMethod.java:591)
> at
> org.apache.felix.scr.impl.helper.BaseMethod$NotResolved.invoke(BaseMethod.java:548)
> at
> org.apache.felix.scr.impl.helper.BaseMethod.invoke(BaseMethod.java:472)
> at
> org.apache.felix.scr.impl.manager.DependencyManager.invokeBindMethod(DependencyManager.java:1028)
> at
> org.apache.felix.scr.impl.manager.DependencyManager.bind(DependencyManager.java:944)
> at
> org.apache.felix.scr.impl.manager.DependencyManager.open(DependencyManager.java:868)
> at
> org.apache.felix.scr.impl.manager.ImmediateComponentManager.createImplementationObject(ImmediateComponentManager.java:200)
> at
> org.apache.felix.scr.impl.manager.ImmediateComponentManager.createComponent(ImmediateComponentManager.java:118)
> at
> org.apache.felix.scr.impl.manager.AbstractComponentManager$Unsatisfied.activate(AbstractComponentManager.java:1013)
> at
> org.apache.felix.scr.impl.manager.AbstractComponentManager.activateInternal(AbstractComponentManager.java:333)
> at
> org.apache.felix.scr.impl.manager.AbstractComponentManager.enable(AbstractComponentManager.java:157)
> at
> org.apache.felix.scr.impl.config.ImmediateComponentHolder.enableComponents(ImmediateComponentHolder.java:313)
> at
> org.apache.felix.scr.impl.BundleComponentActivator.loadDescriptor(BundleComponentActivator.java:253)
> at
> org.apache.felix.scr.impl.BundleComponentActivator.initialize(BundleComponentActivator.java:147)
> at
> org.apache.felix.scr.impl.BundleComponentActivator.<init>(BundleComponentActivator.java:111)
> at
> org.apache.felix.scr.impl.Activator.loadComponents(Activator.java:274)
> at
> org.apache.felix.scr.impl.Activator.bundleChanged(Activator.java:192)
> at
> org.apache.felix.framework.util.EventDispatcher.invokeBundleListenerCallback(EventDispatcher.java:807)
> at
> org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:729)
> at
> org.apache.felix.framework.util.EventDispatcher.fireBundleEvent(EventDispatcher.java:610)
> at org.apache.felix.framework.Felix.fireBundleEvent(Felix.java:3879)
> at org.apache.felix.framework.Felix.startBundle(Felix.java:1850)
> at
> org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1192)
> at
> org.apache.felix.framework.StartLevelImpl.run(StartLevelImpl.java:266)
> at java.lang.Thread.run(Thread.java:662)
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