Consider annotated methods in AnnotationRevisionMetadata.

We now detect annotated methods.

Closes #2569

Author: mp911de

src/main/java/org/springframework/data/history/AnnotationRevisionMetadata.java

@@ -23,6 +23,7 @@
 import java.util.Optional;
 
 import org.springframework.data.util.AnnotationDetectionFieldCallback;
+import org.springframework.data.util.AnnotationDetectionMethodCallback;
 import org.springframework.data.util.Lazy;
 import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
@@ -34,6 +35,7 @@
  *
  * @author Oliver Gierke
  * @author Jens Schauder
+ * @author Mark Paluch
  */
 public class AnnotationRevisionMetadata<N extends Number & Comparable<N>> implements RevisionMetadata<N> {
 
@@ -98,11 +100,19 @@ public <T> T getDelegate() {
 		return (T) entity;
 	}
 
+	@SuppressWarnings("unchecked")
 	private static <T> Lazy<Optional<T>> detectAnnotation(Object entity, Class<? extends Annotation> annotationType) {
 
 		return Lazy.of(() -> {
 
-			var callback = new AnnotationDetectionFieldCallback(annotationType);
+			AnnotationDetectionMethodCallback<? extends Annotation> methodCallback = new AnnotationDetectionMethodCallback<>(
+					annotationType);
+			ReflectionUtils.doWithMethods(entity.getClass(), methodCallback);
+			if (methodCallback.getMethod() != null) {
+				return Optional.ofNullable((T) ReflectionUtils.invokeMethod(methodCallback.getRequiredMethod(), entity));
+			}
+
+			AnnotationDetectionFieldCallback callback = new AnnotationDetectionFieldCallback(annotationType);
 			ReflectionUtils.doWithFields(entity.getClass(), callback);
 			return Optional.ofNullable(callback.getValue(entity));
 		});

src/main/java/org/springframework/data/util/AnnotationDetectionMethodCallback.java

@@ -21,13 +21,15 @@
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ReflectionUtils;
 import org.springframework.util.ReflectionUtils.MethodCallback;
 
 /**
  * {@link MethodCallback} to find annotations of a given type.
  *
  * @author Oliver Gierke
  * @author Christoph Strobl
+ * @author Mark Paluch
  */
 public class AnnotationDetectionMethodCallback<A extends Annotation> implements MethodCallback {
 
@@ -121,6 +123,8 @@ public void doWith(Method method) throws IllegalArgumentException, IllegalAccess
 			}
 
 			this.annotation = foundAnnotation;
+
+			ReflectionUtils.makeAccessible(method);
 			this.foundMethod = method;
 		}
 	}

src/test/java/org/springframework/data/history/AnnotationRevisionMetadataUnitTests.java

@@ -33,6 +33,7 @@
  *
  * @author Oliver Gierke
  * @author Jens Schauder
+ * @author Mark Paluch
  */
 class AnnotationRevisionMetadataUnitTests {
 
@@ -83,6 +84,21 @@ void exposesRevisionDateAndInstantForLocalDateTime() {
 		softly.assertAll();
 	}
 
+	@Test // GH-2569
+	void exposesRevisionMetadataUsingMethodAccessors() {
+
+		SampleWithMethodAnnotations sample = new SampleWithMethodAnnotations();
+		sample.revisionNumber = 1L;
+		sample.revisionDate = Instant.now();
+
+		RevisionMetadata<Long> metadata = getMetadata(sample);
+
+		softly.assertThat(metadata.getRevisionNumber()).hasValue(1L);
+		softly.assertThat(metadata.getRevisionInstant()).hasValue(sample.revisionDate);
+
+		softly.assertAll();
+	}
+
 	@Test // DATACMNS-1251
 	void exposesRevisionDateAndInstantForInstant() {
 
@@ -149,6 +165,22 @@ static class Sample {
 		@Reference LocalDateTime revisionDate;
 	}
 
+	static class SampleWithMethodAnnotations {
+
+		Long revisionNumber;
+		Instant revisionDate;
+
+		@Autowired
+		public Long getRevisionNumber() {
+			return revisionNumber;
+		}
+
+		@Reference
+		public Instant getRevisionDate() {
+			return revisionDate;
+		}
+	}
+
 	static class SampleWithInstant {
 
 		@Autowired Long revisionNumber;