GH-349 - Register parameters of methods annotated with @Transactional…

…EventListener for reflection.

spring-modulith-events/spring-modulith-events-core/pom.xml

@@ -52,6 +52,12 @@
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-core-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-aspects</artifactId>

spring-modulith-events/spring-modulith-events-core/src/main/java/org/springframework/modulith/events/aot/TransactionalEventListenerAotProcessor.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.modulith.events.aot;
+
+import java.util.Arrays;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.beans.factory.aot.BeanRegistrationAotContribution;
+import org.springframework.beans.factory.aot.BeanRegistrationAotProcessor;
+import org.springframework.beans.factory.support.RegisteredBean;
+import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.transaction.event.TransactionalEventListener;
+
+/**
+ * A {@link BeanRegistrationAotProcessor} processing beans for methods annotated with {@link TransactionalEventListener}
+ * to register those methods' parameter types for reflection as they will need to be serialized for the event
+ * publication registry.
+ *
+ * @author Oliver Drotbohm
+ * @since 1.1
+ */
+public class TransactionalEventListenerAotProcessor implements BeanRegistrationAotProcessor {
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(TransactionalEventListenerAotProcessor.class);
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.aot.BeanRegistrationAotProcessor#processAheadOfTime(org.springframework.beans.factory.support.RegisteredBean)
+	 */
+	@Override
+	public BeanRegistrationAotContribution processAheadOfTime(RegisteredBean registeredBean) {
+
+		Class<?> type = registeredBean.getBeanType().resolve(Object.class);
+
+		var methods = Arrays.stream(type.getDeclaredMethods())
+				.filter(it -> AnnotatedElementUtils.hasAnnotation(it, TransactionalEventListener.class))
+				.toList();
+
+		return methods.isEmpty() ? null : (context, __) -> {
+
+			var reflection = context.getRuntimeHints().reflection();
+
+			methods.forEach(method -> {
+
+				for (var it : method.getParameterTypes()) {
+
+					LOGGER.info("Registering {} (parameter of transactional event listener method {}) for reflection.",
+							it.getSimpleName(), "%s.%s(…)".formatted(method.getDeclaringClass().getName(), method.getName()));
+
+					reflection.registerType(it,
+							MemberCategory.INVOKE_DECLARED_METHODS, MemberCategory.INVOKE_DECLARED_CONSTRUCTORS);
+				}
+			});
+		};
+	}
+}

spring-modulith-events/spring-modulith-events-core/src/main/resources/META-INF/spring/aot.factories

@@ -0,0 +1,2 @@
+org.springframework.beans.factory.aot.BeanRegistrationAotProcessor=\
+    org.springframework.modulith.events.aot.TransactionalEventListenerAotProcessor

spring-modulith-events/spring-modulith-events-core/src/test/java/org/springframework/modulith/events/aot/TransactionalEventListenerAotProcessorIntegrationTests.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.modulith.events.aot;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
+import org.springframework.aot.test.generate.TestGenerationContext;
+import org.springframework.beans.factory.aot.AotServices;
+import org.springframework.beans.factory.aot.BeanRegistrationAotProcessor;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.beans.factory.support.RegisteredBean;
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.transaction.event.TransactionalEventListener;
+
+/**
+ * Integration tests for {@link TransactionalEventListenerAotProcessor}.
+ *
+ * @author Oliver Drotbohm
+ */
+class TransactionalEventListenerAotProcessorIntegrationTests {
+
+	@Test // GH-349
+	void aotCustomizationsDiscoverable() {
+
+		assertThat(AotServices.factories().load(BeanRegistrationAotProcessor.class))
+				.anyMatch(TransactionalEventListenerAotProcessor.class::isInstance);
+	}
+
+	@Test // GH-349
+	void registersEventListenerMethodParametersForReflection() {
+
+		var factory = new DefaultListableBeanFactory();
+		factory.registerBeanDefinition("sample", new RootBeanDefinition(Sample.class));
+
+		var contribution = new TransactionalEventListenerAotProcessor()
+				.processAheadOfTime(RegisteredBean.of(factory, "sample"));
+
+		assertThat(contribution).isNotNull();
+
+		var context = new TestGenerationContext();
+
+		contribution.applyTo(context, null);
+
+		assertThat(RuntimeHintsPredicates.reflection()
+				.onType(MyEvent.class)
+				.withMemberCategories(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+						MemberCategory.INVOKE_DECLARED_METHODS)).accepts(context.getRuntimeHints());
+	}
+
+	static class Sample {
+
+		@TransactionalEventListener
+		void on(MyEvent event) {}
+	}
+
+	record MyEvent(String payload) {}
+}