GH-1013 - Pick up reference types for event listeners declared in annotations.

We now detect event types a listener is interested in declared in annotations for inclusion the reference documentation. This allows for the rare case that the event listener method not actually declaring the event type as parameter as it might not be needed in the payload but only the fact that an event was published at all.

spring-modulith-core/src/test/java/org/springframework/modulith/core/ArchitecturallyEvidentTypeUnitTest.java

@@ -37,6 +37,7 @@ import org.springframework.data.repository.reactive.ReactiveCrudRepository;
 import org.springframework.modulith.core.ArchitecturallyEvidentType.SpringAwareArchitecturallyEvidentType;
 import org.springframework.modulith.core.ArchitecturallyEvidentType.SpringDataAwareArchitecturallyEvidentType;
 import org.springframework.stereotype.Repository;
+import org.springframework.transaction.event.TransactionalEventListener;
 
 import com.tngtech.archunit.core.domain.JavaClass;
 
@@ -196,6 +197,23 @@ class ArchitecturallyEvidentTypeUnitTest {
 		assertThat(ArchitecturallyEvidentType.of(type, classes).isRepository()).isTrue();
 	}
 
+	@Test
+	void detectsAnnotatedReferenceType() {
+
+		var type = classes.getRequiredClass(SomeEventListener.class);
+
+		var methods = ArchitecturallyEvidentType.of(type, classes).getReferenceMethods();
+
+		var annotatedMethod = methods.filter(it -> it.getMethod().getName().startsWith("annotated"));
+
+		assertThat(annotatedMethod).allSatisfy(it -> {
+
+			assertThat(it.getReferenceTypes())
+					.extracting(Class::getName)
+					.contains(String.class.getName());
+		});
+	}
+
 	private Iterator<ArchitecturallyEvidentType> getTypesFor(Class<?>... types) {
 
 		return Stream.of(types) //
@@ -266,6 +284,12 @@ class ArchitecturallyEvidentTypeUnitTest {
 
 		@EventListener
 		void onOther(Object event) {}
+
+		@EventListener(classes = String.class)
+		void annotatedOn() {}
+
+		@TransactionalEventListener(classes = String.class)
+		void annotatedTxOn() {}
 	}
 
 	class ImplementingEventListener implements ApplicationListener<ApplicationReadyEvent> {