Can Blueprint beans have @Reference services auto injected?

Question

Can instances created by the Blueprint <bean> tag be auto injected with service references specified using the OSGi Declarative Services mechanism?

import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;

@Component(service={})
public class DatabaseThing{
    @Reference
    public void setDataSource(DataSource ds){
    ...
    }

If I instantiate via immediate=true in the @Component then my DataSource OSGi service is injected. If I create the instance via blueprint <bean class="DatabaseThing"> then no auto-injection occurs.

I've had a look at the Aries source, and it seems that the service injection is specific to org.apache.aries.blueprint.container.ServiceRecipe and isn't part of ...BeanRecipe which is used for <bean> style instantiation.

Christian Schneider Christian Schneider · Accepted Answer · 2015-12-10T21:09:23

That does not work. The DS annotations are processed by bnd and result in a DS xml file that will then be evaluated by felix scr at runtime. In this case the full lifecycle of the object is controller by scr.

If you additionally declare a blueprint bean for the same class then it will be a separate instance. Blueprint can the inject services and beans into this instance but it is completely disconnected from DS.

If your main concern is to use annoations for blueprint injections then I recommend the blueprint-maven-plugin. It allows to use CDI and Java EE annotations in your code. These are translated to a blueprint.xml at build time. So the result is similar to DS but powered by blueprint.

Can Blueprint beans have @Reference services auto injected?

1 Answers