Spring autowiring using @Configurable

Question

I'm playing with the idea of using Spring @Configurable and @Autowire to inject DAOs into domain objects so that they do not need direct knowledge of the persistence layer.

I'm trying to follow http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/aop.html#aop-atconfigurable, but my code seems to have no effect.

Basically, I have:

@Configurable
public class Artist {

    @Autowired
    private ArtistDAO artistDao;

    public void setArtistDao(ArtistDAO artistDao) {
        this.artistDao = artistDao;
    }

    public void save() {
        artistDao.save(this);
    }

}

And:

public interface ArtistDAO {

    public void save(Artist artist);

}

and

@Component
public class ArtistDAOImpl implements ArtistDAO {

    @Override
    public void save(Artist artist) {
        System.out.println("saving");
    }

}

In application-context.xml, I have:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springsource.org/dtd/spring-beans-2.0.dtd">
<beans>

    <bean class="org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator" />
    <bean class="org.springframework.beans.factory.aspectj.AnnotationBeanConfigurerAspect" factory-method="aspectOf"/>

</beans>

Class path scanning and initialisation is performed by the spring module for Play! framework, although other autowired beans work, so I'm pretty sure this is not the root cause. I'm using Spring 3.0.5.

In other code (inside a method in bean that's injected into my controller using Spring, in fact), I'm doing this:

Artist artist = new Artist();
artist.save();

This gives me a NullPointerException trying to access the artistDao in Artist.save().

Any idea what I'm doing wrong?

Martin

Answer 1

You need to enable load-time weaving (or other kinds of weaving) in order to use @Configurable. Make sure you enabled it correctly, as described in 7.8.4 Load-time weaving with AspectJ in the Spring Framework.