Support @Counted on classes

micrometer-core/src/main/java/io/micrometer/core/annotation/Counted.java

@@ -35,7 +35,7 @@
  * @see io.micrometer.core.aop.CountedAspect
  */
 @Inherited
-@Target(ElementType.METHOD)
+@Target({ ElementType.ANNOTATION_TYPE, ElementType.TYPE, ElementType.METHOD })
 @Retention(RetentionPolicy.RUNTIME)
 public @interface Counted {
 

micrometer-core/src/main/java/io/micrometer/core/aop/CountedAspect.java

@@ -16,6 +16,7 @@
 package io.micrometer.core.aop;
 
 import io.micrometer.common.lang.NonNullApi;
+import io.micrometer.common.lang.Nullable;
 import io.micrometer.core.annotation.Counted;
 import io.micrometer.core.instrument.*;
 import org.aspectj.lang.ProceedingJoinPoint;
@@ -67,6 +68,7 @@
  *
  * @author Ali Dehghani
  * @author Jonatan Ivanov
+ * @author Johnny Lim
  * @since 1.2.0
  * @see Counted
  */
@@ -164,6 +166,23 @@ public CountedAspect(MeterRegistry registry, Function<ProceedingJoinPoint, Itera
         this.shouldSkip = shouldSkip;
     }
 
+    @Around("@within(io.micrometer.core.annotation.Counted)")
+    @Nullable
+    public Object countedClass(ProceedingJoinPoint pjp) throws Throwable {
+        if (shouldSkip.test(pjp)) {
+            return pjp.proceed();
+        }
+
+        Method method = ((MethodSignature) pjp.getSignature()).getMethod();
+        Class<?> declaringClass = method.getDeclaringClass();
+        if (!declaringClass.isAnnotationPresent(Counted.class)) {
+            declaringClass = pjp.getTarget().getClass();
+        }
+        Counted counted = declaringClass.getAnnotation(Counted.class);
+
+        return perform(pjp, counted);
+    }
+
     /**
      * Intercept methods annotated with the {@link Counted} annotation and expose a few
      * counters about their execution status. By default, this aspect records both failed
@@ -188,6 +207,10 @@ public Object interceptAndRecord(ProceedingJoinPoint pjp, Counted counted) throw
             return pjp.proceed();
         }
 
+        return perform(pjp, counted);
+    }
+
+    private Object perform(ProceedingJoinPoint pjp, Counted counted) throws Throwable {
         final Method method = ((MethodSignature) pjp.getSignature()).getMethod();
         final boolean stopWhenCompleted = CompletionStage.class.isAssignableFrom(method.getReturnType());
 

micrometer-core/src/test/java/io/micrometer/core/aop/CountedAspectTest.java

@@ -35,6 +35,8 @@
  * Unit tests for the {@link CountedAspect} aspect.
  *
  * @author Ali Dehghani
+ * @author Tommy Ludwig
+ * @author Johnny Lim
  */
 class CountedAspectTest {
 
@@ -291,4 +293,51 @@ synchronized void complete(RuntimeException withException) {
 
     }
 
+    @Test
+    void countClassWithSuccess() {
+        CountedClassService service = getAdvisedService(new CountedClassService());
+
+        service.hello();
+
+        assertThat(meterRegistry.get("class.counted")
+            .tag("class", "io.micrometer.core.aop.CountedAspectTest$CountedClassService")
+            .tag("method", "hello")
+            .tag("result", "success")
+            .tag("exception", "none")
+            .counter()
+            .count()).isEqualTo(1);
+    }
+
+    @Test
+    void countClassWithFailure() {
+        CountedClassService service = getAdvisedService(new CountedClassService());
+
+        assertThatThrownBy(() -> service.fail()).isInstanceOf(RuntimeException.class);
+
+        meterRegistry.forEachMeter((m) -> {
+            System.out.println(m.getId().getTags());
+        });
+
+        assertThat(meterRegistry.get("class.counted")
+            .tag("class", "io.micrometer.core.aop.CountedAspectTest$CountedClassService")
+            .tag("method", "fail")
+            .tag("result", "failure")
+            .tag("exception", "RuntimeException")
+            .counter()
+            .count()).isEqualTo(1);
+    }
+
+    @Counted("class.counted")
+    static class CountedClassService {
+
+        String hello() {
+            return "hello";
+        }
+
+        void fail() {
+            throw new RuntimeException("Oops");
+        }
+
+    }
+
 }