AspectJ and CDI

Question

I\'m trying to figure out a way to inject a bean into an aspect.

I mean

public class Greeter {
    public String greet(String name) {....}
}

...

pu         


        

Answer 1

I'm not familiar with CDI, but if it's not picking up the aspect as a candidate for dependency injection, you should set it manually, preferably as soon as the aspect's dependencies are ready. You can gain access to an aspect (singleton by default), with AspectName.aspectOf().

Maybe a startup singleton bean similar to this one:

@Singleton
@Startup
public class GreeterAspectSetup {

    @Inject
    private Greeter greeter;

    @PostConstruct
    private void setupGreeterAspect() {
        GreeterAspect.aspectOf().setGreeter(greeter);
    }

}

Of course, you would have to add the setter for the Greeter to the aspect, or change the field's visibility in the aspect and set it directly.

Answer 2

Thanks to the help of the community, I managed to come out with a solution for both the problems. Leaving track here.

PART ONE - aspectjrt.jar in deployment

First, added Shrinkwrap to my dependencies:

<dependency>
    <groupId>org.jboss.shrinkwrap.resolver</groupId>
    <artifactId>shrinkwrap-resolver-api-maven</artifactId>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.jboss.shrinkwrap.resolver</groupId>
    <artifactId>shrinkwrap-resolver-impl-maven</artifactId>
          <scope>test</scope>
</dependency>
<dependency>
       <groupId>org.jboss.shrinkwrap.resolver</groupId>
       <artifactId>shrinkwrap-resolver-impl-maven-archive</artifactId>
      <scope>test</scope>
</dependency>

<version> is not needed: Arquillian's BOM - already included - will take care of that.

Then add aspectj to deployment classpath:

@RunWith(Arquillian.class)
public class ArquillianTest {
    private static final String[] DEPENDENCIES = {
        "org.aspectj:aspectjrt:1.8.7"
    };

    @Deployment
    public static JavaArchive createEnvironement() {
        JavaArchive lib = ShrinkWrap.create(JavaArchive.class, "libs.jar");
        for (String dependency : DEPENDENCIES) {
            lib.merge(Maven.resolver().resolve(dependency).withTransitivity().asSingle(JavaArchive.class));
        }

        JavaArchive jar = ShrinkWrap.create(JavaArchive.class)
            // create you deployment here
            .as(JavaArchive.class);

        JavaArchive toBeDeployed = jar.merge(lib);

        return toBeDeployed;
    }

    // other stuff, like tests

}

PART TWO: Injecting a bean into an aspect

After further inquiries I think simas_ch was correct in saying that CDI does not inject beans into aspects.

Came out with a workaround: adding an @Injected member into a bean via the aspect.

public interface Advised {
    String buildGreeting(String name);
}

public class AdvisedImpl implements Advised {
    String buildGreeting(String name) {
        return "ADVISED";
    }
}

public class Greeter {
    public String greet(String name) {
        return "Hello, " + name + ".";
    }
}

...

public aspect GreeterAspect {
    @Inject
    private Greeter Advised.greeter; // adding the member to the interface / class. No need for getters / setters

    private pointcut pc() : execution(* x.y.z.Advised.buildGreeting(String));

    String around(Advised adv, String name) : pc() && target(adv) && args(name) {
        log.debug("Aspect is about to say something...");
        String result = proceed(adv, name) + " - " + adv.greeter.greet(name);
        log.debug("Aspect said: '" + result + "'");
        return result;
    }
}

Given the test

@Test
public void test() {
    assertThat(advised, not(is(nullValue())));
    assertThat(advised.buildGreeting("Stefano"), equalToIgnoringCase("advised - hello, stefano."));
}

it succeeds.