DATAREST-983 - AnnotatedEventHandlerInvoker now resolves generic handler method argument.

We now resolve the handler method argument type of an annotated repository event handler against the concrete handler type to make sure generics are resolved properly.

Author: odrotbohm

spring-data-rest-core/src/main/java/org/springframework/data/rest/core/event/AnnotatedEventHandlerInvoker.java

@@ -31,6 +31,7 @@
 import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
+import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.data.rest.core.annotation.HandleAfterCreate;
@@ -165,13 +166,12 @@ private <T extends Annotation> void inspect(Object handler, Method method, Class
 			return;
 		}
 
-		Class<?>[] parameterTypes = method.getParameterTypes();
-
-		if (parameterTypes.length == 0) {
+		if (method.getParameterCount() == 0) {
 			throw new IllegalStateException(String.format(PARAMETER_MISSING, method));
 		}
 
-		EventHandlerMethod handlerMethod = EventHandlerMethod.of(parameterTypes[0], handler, method);
+		ResolvableType parameter = ResolvableType.forMethodParameter(method, 0, handler.getClass());
+		EventHandlerMethod handlerMethod = EventHandlerMethod.of(parameter.resolve(), handler, method);
 
 		if (LOG.isDebugEnabled()) {
 			LOG.debug("Annotated handler method found: {}", handlerMethod);

spring-data-rest-core/src/test/java/org/springframework/data/rest/core/event/AnnotatedEventHandlerInvokerUnitTests.java

@@ -85,6 +85,23 @@ public void invokesEventHandlerInOrderMethods() {
 		assertThat(orderHandler1.timestamp, is(greaterThan(orderHandler2.timestamp)));
 	}
 
+	@Test // DATAREST-983
+	public void invokesEventHandlerOnParentClass() {
+
+		FirstEventHandler firstHandler = new FirstEventHandler();
+		SecondEventHandler secondHandler = new SecondEventHandler();
+
+		AnnotatedEventHandlerInvoker invoker = new AnnotatedEventHandlerInvoker();
+		invoker.postProcessAfterInitialization(firstHandler, "firstHandler");
+		invoker.postProcessAfterInitialization(secondHandler, "secondHandler");
+
+		invoker.onApplicationEvent(new BeforeCreateEvent(new FirstEntity()));
+		invoker.onApplicationEvent(new BeforeCreateEvent(new SecondEntity()));
+
+		assertThat(firstHandler.callCount, is(1));
+		assertThat(secondHandler.callCount, is(1));
+	}
+
 	@RepositoryEventHandler
 	static class Sample {
 
@@ -130,4 +147,27 @@ private void method(Person sample) {
 			timestamp = System.nanoTime();
 		}
 	}
+
+	// DATAREST-983
+
+	static class AbstractBaseEntityEventHandler<T extends BaseEntity> {
+		int callCount = 0;
+
+		@HandleBeforeCreate
+		private void method(T entity) {
+			callCount += 1;
+		}
+	}
+
+	@RepositoryEventHandler
+	static class FirstEventHandler extends AbstractBaseEntityEventHandler<FirstEntity> {}
+
+	@RepositoryEventHandler
+	static class SecondEventHandler extends AbstractBaseEntityEventHandler<SecondEntity> {}
+
+	static abstract class BaseEntity {}
+
+	static class FirstEntity extends BaseEntity {}
+
+	static class SecondEntity extends BaseEntity {}
 }