Support for reactive transactions in TransactionInterceptor

Introduces TransactionManager marker interface for PlatformTransactionManager as well as ReactiveTransactionManager, allowing for a common configuration type in TransactionAspectSupport and TransactionManagementConfigurer.

Closes gh-22590

spring-test/src/main/java/org/springframework/test/context/transaction/TestContextTransactionUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -29,6 +29,7 @@
 import org.springframework.lang.Nullable;
 import org.springframework.test.context.TestContext;
 import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.TransactionManager;
 import org.springframework.transaction.annotation.TransactionManagementConfigurer;
 import org.springframework.transaction.interceptor.DelegatingTransactionAttribute;
 import org.springframework.transaction.interceptor.TransactionAttribute;
@@ -202,7 +203,14 @@ public static PlatformTransactionManager retrieveTransactionManager(TestContext
 				Assert.state(configurers.size() <= 1,
 						"Only one TransactionManagementConfigurer may exist in the ApplicationContext");
 				if (configurers.size() == 1) {
-					return configurers.values().iterator().next().annotationDrivenTransactionManager();
+					TransactionManager tm = configurers.values().iterator().next().annotationDrivenTransactionManager();
+					if (tm instanceof PlatformTransactionManager) {
+						return (PlatformTransactionManager) tm;
+					}
+					else {
+						throw new IllegalStateException(
+								"Specified transaction manager is not a PlatformTransactionManager: " + tm);
+					}
 				}
 			}
 

spring-tx/src/main/java/org/springframework/transaction/PlatformTransactionManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -43,7 +43,7 @@
  * @see org.springframework.transaction.interceptor.TransactionInterceptor
  * @see org.springframework.transaction.interceptor.TransactionProxyFactoryBean
  */
-public interface PlatformTransactionManager {
+public interface PlatformTransactionManager extends TransactionManager {
 
 	/**
 	 * Return a currently active transaction or create a new one, according to

spring-tx/src/main/java/org/springframework/transaction/ReactiveTransactionManager.java

@@ -27,9 +27,8 @@
  * @author Mark Paluch
  * @author Juergen Hoeller
  * @since 5.2
- * @see org.springframework.transaction.interceptor.TransactionProxyFactoryBean
  */
-public interface ReactiveTransactionManager {
+public interface ReactiveTransactionManager extends TransactionManager {
 
 	/**
 	 * Emit a currently active reactive transaction or create a new one, according to

spring-tx/src/main/java/org/springframework/transaction/TransactionManager.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2002-2019 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.transaction;
+
+/**
+ * Marker interface for Spring transaction manager implementations,
+ * either traditional or reactive.
+ *
+ * @author Juergen Hoeller
+ * @since 5.2
+ * @see PlatformTransactionManager
+ * @see ReactiveTransactionManager
+ */
+public interface TransactionManager {
+
+}

spring-tx/src/main/java/org/springframework/transaction/annotation/AbstractTransactionManagementConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -27,7 +27,7 @@
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.lang.Nullable;
-import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.TransactionManager;
 import org.springframework.transaction.config.TransactionManagementConfigUtils;
 import org.springframework.transaction.event.TransactionalEventListenerFactory;
 import org.springframework.util.CollectionUtils;
@@ -51,7 +51,7 @@ public abstract class AbstractTransactionManagementConfiguration implements Impo
 	 * Default transaction manager, as configured through a {@link TransactionManagementConfigurer}.
 	 */
 	@Nullable
-	protected PlatformTransactionManager txManager;
+	protected TransactionManager txManager;
 
 
 	@Override

spring-tx/src/main/java/org/springframework/transaction/annotation/TransactionManagementConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -16,15 +16,16 @@
 
 package org.springframework.transaction.annotation;
 
-import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.TransactionManager;
 
 /**
  * Interface to be implemented by @{@link org.springframework.context.annotation.Configuration
  * Configuration} classes annotated with @{@link EnableTransactionManagement} that wish to
- * or need to explicitly specify the default {@link PlatformTransactionManager} bean to be
- * used for annotation-driven transaction management, as opposed to the default approach
- * of a by-type lookup. One reason this might be necessary is if there are two
- * {@code PlatformTransactionManager} beans present in the container.
+ * (or need to) explicitly specify the default {@code PlatformTransactionManager} bean
+ * (or {@code ReactiveTransactionManager} bean) to be used for annotation-driven
+ * transaction management, as opposed to the default approach of a by-type lookup.
+ * One reason this might be necessary is if there are two {@code PlatformTransactionManager}
+ * beans present in the container.
  *
  * <p>See @{@link EnableTransactionManagement} for general examples and context;
  * see {@link #annotationDrivenTransactionManager()} for detailed instructions.
@@ -40,6 +41,8 @@
  * @since 3.1
  * @see EnableTransactionManagement
  * @see org.springframework.context.annotation.Primary
+ * @see org.springframework.transaction.PlatformTransactionManager
+ * @see org.springframework.transaction.ReactiveTransactionManager
  */
 public interface TransactionManagementConfigurer {
 
@@ -76,7 +79,9 @@ public interface TransactionManagementConfigurer {
 	 * container as all {@code PlatformTransactionManager} implementations take advantage
 	 * of Spring lifecycle callbacks such as {@code InitializingBean} and
 	 * {@code BeanFactoryAware}.
+	 * @return a {@link org.springframework.transaction.PlatformTransactionManager} or
+	 * {@link org.springframework.transaction.ReactiveTransactionManager} implementation
 	 */
-	PlatformTransactionManager annotationDrivenTransactionManager();
+	TransactionManager annotationDrivenTransactionManager();
 
 }