Introduce getAnnotation() in AnnotatedElementUtils

This commit introduces a "synthesized annotation" alternative to
getAnnotationAttributes() in AnnotatedElementUtils, analogous to the
recently introduced findAnnotation() methods.

Issue: SPR-13082

spring-core/src/main/java/org/springframework/core/annotation/AnnotatedElementUtils.java

@@ -218,6 +218,32 @@ public class AnnotatedElementUtils {
 		}));
 	}
 
+	/**
+	 * Get the first annotation of the specified {@code annotationType} within
+	 * the annotation hierarchy <em>above</em> the supplied {@code element},
+	 * merge that annotation's attributes with <em>matching</em> attributes from
+	 * annotations in lower levels of the annotation hierarchy, and synthesize
+	 * the result back into an annotation of the specified {@code annotationType}.
+	 *
+	 * <p>{@link AliasFor @AliasFor} semantics are fully supported, both
+	 * within a single annotation and within the annotation hierarchy.
+	 *
+	 * <p>This method delegates to {@link #getAnnotationAttributes(AnnotatedElement, Class)}
+	 * and {@link AnnotationUtils#synthesizeAnnotation(Map, Class, AnnotatedElement)}.
+	 *
+	 * @param element the annotated element; never {@code null}
+	 * @param annotationType the annotation type to find; never {@code null}
+	 * @return the merged {@code AnnotationAttributes}, or {@code null} if not found
+	 * @since 4.2
+	 * @see #getAnnotationAttributes(AnnotatedElement, Class)
+	 * @see #findAnnotation(AnnotatedElement, Class)
+	 * @see AnnotationUtils#synthesizeAnnotation(Map, Class, AnnotatedElement)
+	 */
+	public static <A extends Annotation> A getAnnotation(AnnotatedElement element, Class<A> annotationType) {
+		AnnotationAttributes attributes = getAnnotationAttributes(element, annotationType);
+		return ((attributes != null) ? AnnotationUtils.synthesizeAnnotation(attributes, annotationType, element) : null);
+	}
+
 	/**
 	 * Get the first annotation of the specified {@code annotationType} within
 	 * the annotation hierarchy <em>above</em> the supplied {@code element} and
@@ -232,9 +258,10 @@ public class AnnotatedElementUtils {
 	 * @param element the annotated element; never {@code null}
 	 * @param annotationType the annotation type to find; never {@code null}
 	 * @return the merged {@code AnnotationAttributes}, or {@code null} if not found
+	 * @since 4.2
 	 * @see #getAnnotationAttributes(AnnotatedElement, String, boolean, boolean)
-	 * @see #getAllAnnotationAttributes(AnnotatedElement, String)
 	 * @see #findAnnotationAttributes(AnnotatedElement, String, boolean, boolean)
+	 * @see #getAnnotation(AnnotatedElement, Class)
 	 * @see #findAnnotation(AnnotatedElement, Class)
 	 */
 	public static AnnotationAttributes getAnnotationAttributes(AnnotatedElement element,
@@ -945,8 +972,9 @@ public class AnnotatedElementUtils {
 	 * target annotation during the {@link #process} phase and then merges
 	 * annotation attributes from lower levels in the annotation hierarchy
 	 * during the {@link #postProcess} phase.
-	 * @see AnnotationUtils#getAnnotationAttributes(Annotation)
 	 * @since 4.2
+	 * @see AnnotationUtils#getAnnotationAttributes(AnnotatedElement, Annotation, boolean, boolean, boolean)
+	 * @see AnnotationUtils#postProcessAnnotationAttributes
 	 */
 	private static class MergedAnnotationAttributesProcessor implements Processor<AnnotationAttributes> {
 

spring-core/src/main/java/org/springframework/core/annotation/AnnotationUtils.java

@@ -766,8 +766,8 @@ public abstract class AnnotationUtils {
 	 * @param annotation the annotation to retrieve the attributes for
 	 * @return the annotation attributes (a specialized Map) with attribute names as keys
 	 * and corresponding attribute values as values; never {@code null}
-	 * @see #getAnnotationAttributes(AnnotatedElement, Annotation, boolean, boolean)
 	 * @since 4.2
+	 * @see #getAnnotationAttributes(AnnotatedElement, Annotation, boolean, boolean)
 	 */
 	public static AnnotationAttributes getAnnotationAttributes(AnnotatedElement annotatedElement, Annotation annotation) {
 		return getAnnotationAttributes(annotatedElement, annotation, false, false);
@@ -1233,8 +1233,8 @@ public abstract class AnnotationUtils {
 	 * not from an annotation, or if the supplied target type is {@link Annotation}
 	 * @throws AnnotationConfigurationException if invalid configuration of
 	 * {@code @AliasFor} is detected
-	 * @see #getAliasedAttributeName(Method, Class)
 	 * @since 4.2
+	 * @see #getAliasedAttributeName(Method, Class)
 	 */
 	static String getAliasedAttributeName(Method attribute) {
 		return getAliasedAttributeName(attribute, null);

spring-core/src/test/java/org/springframework/core/annotation/AnnotatedElementUtilsTests.java

@@ -322,6 +322,19 @@ public class AnnotatedElementUtilsTests {
 		assertTrue(isAnnotated(element, name));
 	}
 
+	@Test
+	public void getAnnotationWithAliasedValueComposedAnnotation() {
+		Class<?> element = AliasedValueComposedContextConfigClass.class;
+		ContextConfig contextConfig = getAnnotation(element, ContextConfig.class);
+
+		assertNotNull("Should find @ContextConfig on " + element.getSimpleName(), contextConfig);
+		assertArrayEquals("locations", new String[] { "test.xml" }, contextConfig.locations());
+		assertArrayEquals("value", new String[] { "test.xml" }, contextConfig.value());
+
+		// Verify contracts between utility methods:
+		assertTrue(isAnnotated(element, ContextConfig.class.getName()));
+	}
+
 	@Test
 	public void getAnnotationAttributesWithInvalidConventionBasedComposedAnnotation() {
 		Class<?> element = InvalidConventionBasedComposedContextConfigClass.class;