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# 6. Diagnosing a silent aspect

Endpoint: [`AopDiagnosticsEndpoint`](../src/main/java/com/ankurm/aop/web/AopDiagnosticsEndpoint.java).

Almost every non-firing aspect is one of three things, and all three are visible in one place.

## The three questions, in order

**1. Is the bean proxied at all?**

```java
AopUtils.isAopProxy(bean)
```

`false` means no pointcut matched this bean, or it is not a bean. Stop here and check the
pointcut and the registration.

**2. Which kind of proxy?**

```java
AopUtils.isJdkDynamicProxy(bean)   // interfaces only
AopUtils.isCglibProxy(bean)        // subclass
```

If it is a JDK proxy and your method is not on an interface, that is your answer.

**3. Is your advice in the advisor list?**

```java
if (bean instanceof Advised advised) {
    Arrays.stream(advised.getAdvisors())
          .map(a -> a.getAdvice().getClass().getSimpleName())
          .forEach(System.out::println);
}
```

Proxied, right kind, and your advice missing means the pointcut matched the *bean* but not the
*method*.

## Output

```
  defaultOrderService    CGLIB subclass     target=DefaultOrderService
      class      : DefaultOrderService$$SpringCGLIB$$0
      interfaces : (none)
      advisors   : 11
```

## Testing a pointcut without an application

The fastest check of all, and it belongs in a test rather than in a diagnostic endpoint:

```java
AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut();
pointcut.setExpression("execution(* com.example.service.*.*(..))");
assertThat(pointcut.matches(Foo.class.getMethod("bar"), Foo.class)).isTrue();
```

Remember that `setExpression` does not parse; the parse happens on first `matches`. So this is
also how you find out that a designator is unsupported before production does.

## Logging

```
logging.level.org.springframework.aop=DEBUG
```

reports proxy creation per bean. Verbose, but it answers question 1 for every bean at once.

## Delete the endpoint before shipping

It reports internal wiring. If you want it permanently, put it behind the management port and
authentication.