[WICKET-5808] SpringBean, support generic beans

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Implemented
• Affects Version/s: 6.18.0, 7.0.0-M4
• Fix Version/s: 7.0.0-M5
• Component/s: wicket-spring
• Labels: generics spring
• Environment: Spring Framework 4.1.4.RELEASE (currently the latest version)
• Assignee: Andrea Del Bene
• Reporter: Flying Wolf
• Created: 08/Jan/15 11:45
• Updated: 03/May/15 20:41
• Resolved: 24/Jan/15 18:43

Description

Short Description:
Since Spring Framework 4.0, Spring is able to inject/autowire generic beans like:

@Autowired public GenericDao<Car> genericCarDao;

As is described here: http://spring.io/blog/2013/12/03/spring-framework-4-0-and-java-generics .
However, SpringBean doesn't seem to support this yet, resulting in a IllegalStateException.

Detailed Description
Given the following code:

public interface GenericDao<T> {}

@Repository
public class CarDao implements GenericDao<Car> {}

@Repository
public class PhoneDao implements GenericDao<Phone> {}

@Component
public class DaoClient {
    @Autowired public GenericDao<Car> genericCarDao;
    @Autowired public CarDao nonGenericCarDao;
}

Spring 4 is able to inject both "genericCaoDao" and "nonGenericCarDao" into the DaoClient class.

Performing the same using SpringBean, fails:

public class HomePage extends WebPage {
	@SpringBean private CarDao nonGenericCarDao;
	@SpringBean private GenericDao<Car> genericCarDao;

	//.....
}

In this case, SpringBean is unable to inject "genericCarDao", and throws the following error:

Caused by: java.lang.IllegalStateException: More than one bean of type [com.mycompany.springcomponents.GenericDao] found, you have to specify the name of the bean (@SpringBean(name="foo")) or (@Named("foo") if using @javax.inject classes) in order to resolve this conflict. Matched beans: carDao,phoneDao
	at org.apache.wicket.spring.injection.annot.AnnotProxyFieldValueFactory.getBeanNameOfClass(AnnotProxyFieldValueFactory.java:289)
	at org.apache.wicket.spring.injection.annot.AnnotProxyFieldValueFactory.getBeanName(AnnotProxyFieldValueFactory.java:198)
	at org.apache.wicket.spring.injection.annot.AnnotProxyFieldValueFactory.getFieldValue(AnnotProxyFieldValueFactory.java:130)
	at org.apache.wicket.injection.Injector.inject(Injector.java:111)
	at org.apache.wicket.spring.injection.annot.SpringComponentInjector.inject(SpringComponentInjector.java:124)
	at org.apache.wicket.spring.injection.annot.SpringComponentInjector.onInstantiation(SpringComponentInjector.java:130)
	at org.apache.wicket.application.ComponentInstantiationListenerCollection$1.notify(ComponentInstantiationListenerCollection.java:38)
	at org.apache.wicket.application.ComponentInstantiationListenerCollection$1.notify(ComponentInstantiationListenerCollection.java:34)
	at org.apache.wicket.util.listener.ListenerCollection.notify(ListenerCollection.java:80)
	at org.apache.wicket.application.ComponentInstantiationListenerCollection.onInstantiation(ComponentInstantiationListenerCollection.java:33)
	at org.apache.wicket.Component.<init>(Component.java:687)
	at org.apache.wicket.MarkupContainer.<init>(MarkupContainer.java:121)
	at org.apache.wicket.Page.<init>(Page.java:168)
	at org.apache.wicket.Page.<init>(Page.java:157)
	at org.apache.wicket.markup.html.WebPage.<init>(WebPage.java:106)
	at com.mycompany.HomePage.<init>(HomePage.java:22)

Workaround solution:
Explicitly using bean names (qualifiers) does work. In this case

@SpringBean private CarDao nonGenericCarDao;
@SpringBean private GenericDao<Car> genericCarDao;

has to be changed to:

@SpringBean(name = "carDao") private CarDao nonGenericCarDao;
@SpringBean(name = "carDao") private GenericDao<Car> genericCarDao;

Description of some of the attached files:

• pom.xml: added spring-context, spring-web, wicket-spring dependencies. Changed java version to 1.8.
• WicketApplication: added Spring support
• SpringApp: boots plain Spring and shows that DaoClient is able to autowire generic beans.
• HomePage: a Wicket WebPage that shows that SpringBean throws the error when using generic beans.

Issue Links

• links to: Report at users@