Support ResolvableTypeProvider on simple event pojo

Previously, the generic type of a simple pojo event implementing
ResolvableTypeProvider wasn't detected properly. This commit fixes the
logic when the generic type is not provided to reuse what
PayloadApplicationEvent is already doing anyway.

Issue: SPR-14029

spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java

@@ -369,7 +369,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		else {
 			applicationEvent = new PayloadApplicationEvent<Object>(this, event);
 			if (eventType == null) {
-				eventType = ResolvableType.forClassWithGenerics(PayloadApplicationEvent.class, event.getClass());
+				eventType = ((PayloadApplicationEvent)applicationEvent).getResolvableType();
 			}
 		}
 

spring-context/src/test/java/org/springframework/context/event/AnnotationDrivenEventListenerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -50,6 +50,7 @@ import org.springframework.context.annotation.ScopedProxyMode;
 import org.springframework.context.event.test.AbstractIdentifiable;
 import org.springframework.context.event.test.AnotherTestEvent;
 import org.springframework.context.event.test.EventCollector;
+import org.springframework.context.event.test.GenericEventPojo;
 import org.springframework.context.event.test.Identifiable;
 import org.springframework.context.event.test.TestEvent;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
@@ -454,6 +455,30 @@ public class AnnotationDrivenEventListenerTests {
 		this.eventCollector.assertTotalEventsCount(1);
 	}
 
+	@Test
+	public void listenerWithResolvableTypeEvent() {
+		load(ResolvableTypeEventListener.class);
+		ResolvableTypeEventListener listener = this.context.getBean(ResolvableTypeEventListener.class);
+
+		this.eventCollector.assertNoEventReceived(listener);
+		GenericEventPojo<String> event = new GenericEventPojo<>("TEST");
+		this.context.publishEvent(event);
+		this.eventCollector.assertEvent(listener, event);
+		this.eventCollector.assertTotalEventsCount(1);
+	}
+
+	@Test
+	public void listenerWithResolvableTypeEventWrongGeneric() {
+		load(ResolvableTypeEventListener.class);
+		ResolvableTypeEventListener listener = this.context.getBean(ResolvableTypeEventListener.class);
+
+		this.eventCollector.assertNoEventReceived(listener);
+		GenericEventPojo<Long> event = new GenericEventPojo<>(123L);
+		this.context.publishEvent(event);
+		this.eventCollector.assertNoEventReceived(listener);
+		this.eventCollector.assertTotalEventsCount(0);
+	}
+
 	@Test
 	public void conditionMatch() {
 		long timestamp = System.currentTimeMillis();
@@ -833,6 +858,16 @@ public class AnnotationDrivenEventListenerTests {
 	}
 
 
+	@Component
+	static class ResolvableTypeEventListener extends AbstractTestEventListener {
+
+		@EventListener
+		public void handleString(GenericEventPojo<String> value) {
+			collectEvent(value);
+		}
+	}
+
+
 	@Component
 	static class ConditionalEventListener extends TestEventListener {
 

spring-context/src/test/java/org/springframework/context/event/test/GenericEventPojo.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2002-2016 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
+ *
+ *      http://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.context.event.test;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.ResolvableTypeProvider;
+
+/**
+ * A simple POJO that implements {@link ResolvableTypeProvider}.
+ *
+ * @author Stephane Nicoll
+ */
+public class GenericEventPojo<T> implements ResolvableTypeProvider {
+	private final T value;
+
+	public GenericEventPojo(T value) {
+		this.value = value;
+	}
+
+	@Override
+	public ResolvableType getResolvableType() {
+		return ResolvableType.forClassWithGenerics(getClass(), ResolvableType.forInstance(this.value));
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) return true;
+		if (o == null || getClass() != o.getClass()) return false;
+
+		GenericEventPojo<?> that = (GenericEventPojo<?>) o;
+
+		return this.value.equals(that.value);
+	}
+
+	@Override
+	public int hashCode() {
+		return this.value.hashCode();
+	}
+}