Advice on @Autowired

[tooms4444]

Hi all,

I'd like to weave an aspect on the @Autowired annotation in order to detect beans resolution failure, within a port from a Carbon environment.
The idea, is to inject in the Spring converted components some Carbon components using Spring's annotation. So through the porting process I won't have to come back to these injections.


My first idea was to weave a NoSuchBeanException aspect (throwing) on @Autowired ; but I could not manage to weave on an annotation ; furthermore, at the exception's throwing, arm is already done : impossible to stop the exception I guess.

Thus, I did that :

<aop:aspectj-autoproxy />
<bean id="carbonAutowiredAdvice" class="com.egencia.carbon.components.CarbonAutowir edAdvice" />

@Aspect
public class CarbonAutowiredAdvice {
private static final Log LOG = LogFactory.getLog(CarbonAutowiredAdvice.class);

@Around("execution(* org.springframework.beans.factory.support.DefaultL istableBeanFactory.resolveDependency(..)) " +
"&& args(descriptor,beanName)")
public Object carbonAutowired(ProceedingJoinPoint invocation,
DependencyDescriptor descriptor, String beanName)
throws Throwable {
Object result = null;
try {
result = invocation.proceed();
} catch (NoSuchBeanDefinitionException se) {
LOG.info("////////// attempt to inject Carbon component...");
try {
// find the targeted interface
Class c = Class.forName(beanName);
assert c.isInterface();
// look for an inner DEFAULT_COMPONENT_PATH field
Field f = c.getField("DEFAULT_COMPONENT_PATH");
String componentPath = (String) f.get(null); //FIXME ok static fields ?

// retrieve the component in Carbon context
result = Lookup.getInstance().fetchComponent(componentPath) ;
} catch (Exception ce) {
LOG.debug(ce);
throw se; // in case of failure, let's be forgotten
}
}
return result;
}
}

But nothing happens. My impression is that the weaving is only occurring after beans instantiation, right ?
If anyone sees thoughts or code errors, has another idea... please let me know because I'm feeling a bit depressed about this right now ;-)
Thanks in advance.

[Marten Deinum]

there is no weaving.... I suggest you read chapter 7 of the reference guide (or 6 prior to spring 3).

Spring uses proxy based aop and proxies are created AFTER the dependencies are injected so what you want to achieve isn't possible with spring aop, you will have to use either loadtime or compile time weaving.