Spring Autowiring of Parameterized Collection

Question

Hello everyone and thanks for the help in advance.

I am having a problem where Spring cannot autowire a parametirized member variable of type ArrayBlockingQueue.

Here is the java code:

@Controller
public class SomeController
{
    @Autowired
    private ArrayBlockingQueue<SomeCustomType> myQueue;
}

and in the spring configuration xml:

<bean id="myQueue" class="java.util.concurrent.ArrayBlockingQueue">
    <constructor-arg value="10"/>
</bean>

Specifying the type (SomeCustomType) for the ArrayBlockingQueue seems to confuse spring which fails to find a match and does not perform the autowiring.

Any ideas on how to get this to work? I know I can create my own wrapper class(around ArrayBlockingQueue) that is not parametirized but I would rather not if there is a better way to go about solving this.

Answer 1

If you're trying to auto wire a collection with annotations, then use @Resource instead of @Autowired.

In order to satisfy an @Autowired collection dependency, the IoC container looks for elements of the right type to build such a collection from. In other words, it does not look for the collection itself, but rather builds a collection out of other beans.

For more information, see the Spring docs, ex. here.