Remove the unconditional exposure of the transaction manager as a bean

This commit removes the unconditional exposure of the transaction
manager as a bean in the application context. The transaction manager
is still taken from the BatchConfigurer and set where needed (ie on
JobRepository and StepBuilderFactory) as previously done,
but is not exposed anymore as a bean to prevent any clash with a user
defined transaction manager.

If no transaction manager is provided, a DataSourceTransactionManager
will be configured by default as required by batch (without being exposed
as a bean).

Issue spring-projects#816

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/annotation/AbstractBatchConfiguration.java

@@ -86,7 +86,6 @@ public JobRegistry jobRegistry() throws Exception {
 		return this.jobRegistry;
 	}
 
-	@Bean
 	public abstract PlatformTransactionManager transactionManager() throws Exception;
 
 	@Override

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/annotation/EnableBatchProcessing.java

@@ -102,7 +102,6 @@
  * <li>a {@link JobLauncher} (bean name "jobLauncher")</li>
  * <li>a {@link JobRegistry} (bean name "jobRegistry")</li>
  * <li>a {@link org.springframework.batch.core.explore.JobExplorer} (bean name "jobExplorer")</li>
- * <li>a {@link PlatformTransactionManager} (bean name "transactionManager")</li>
  * <li>a {@link JobBuilderFactory} (bean name "jobBuilders") as a convenience to prevent you from having to inject the
  * job repository into every job, as in the examples above</li>
  * <li>a {@link StepBuilderFactory} (bean name "stepBuilders") as a convenience to prevent you from having to inject the

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/annotation/ModularBatchConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -34,6 +34,7 @@
  * available by implementing the {@link BatchConfigurer} interface.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.2
  * @see EnableBatchProcessing
  */
@@ -61,7 +62,6 @@ public JobLauncher jobLauncher() throws Exception {
 	}
 
 	@Override
-	@Bean
 	public PlatformTransactionManager transactionManager() throws Exception {
 		return getConfigurer(configurers).getTransactionManager();
 	}

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/annotation/SimpleBatchConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -41,6 +41,7 @@
  * {@link BatchConfigurer}.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.2
  * @see EnableBatchProcessing
  */
@@ -87,7 +88,6 @@ public JobExplorer jobExplorer() {
 	}
 
 	@Override
-	@Bean
 	public PlatformTransactionManager transactionManager() throws Exception {
 		return createLazyProxy(transactionManager, PlatformTransactionManager.class);
 	}

spring-batch-core/src/test/java/org/springframework/batch/core/configuration/annotation/DataSourceConfiguration.java

@@ -20,6 +20,7 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.jdbc.datasource.DataSourceTransactionManager;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
 import org.springframework.jdbc.datasource.init.DatabasePopulatorUtils;
 import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;
@@ -49,4 +50,9 @@ public DataSource dataSource() {
 				.build();
 	}
 
+	@Bean
+	public DataSourceTransactionManager transactionManager(DataSource dataSource) {
+		return new DataSourceTransactionManager(dataSource);
+	}
+
 }

spring-batch-core/src/test/java/org/springframework/batch/core/configuration/annotation/TransactionManagerConfigurationWithoutBatchConfigurerTests.java

@@ -50,13 +50,10 @@ public void testConfigurationWithNoDataSourceAndTransactionManager() {
 	@Test
 	public void testConfigurationWithDataSourceAndNoTransactionManager() throws Exception {
 		ApplicationContext applicationContext = new AnnotationConfigApplicationContext(BatchConfigurationWithDataSourceAndNoTransactionManager.class);
-		Assert.assertTrue(applicationContext.containsBean("transactionManager"));
-		PlatformTransactionManager platformTransactionManager = applicationContext.getBean(PlatformTransactionManager.class);
-		Object targetObject = AopTestUtils.getTargetObject(platformTransactionManager);
-		Assert.assertTrue(targetObject instanceof DataSourceTransactionManager);
-		DataSourceTransactionManager dataSourceTransactionManager = (DataSourceTransactionManager) targetObject;
+		PlatformTransactionManager platformTransactionManager = getTransactionManagerSetOnJobRepository(applicationContext.getBean(JobRepository.class));
+		Assert.assertTrue(platformTransactionManager instanceof DataSourceTransactionManager);
+		DataSourceTransactionManager dataSourceTransactionManager = (DataSourceTransactionManager) platformTransactionManager;
 		Assert.assertEquals(applicationContext.getBean(DataSource.class), dataSourceTransactionManager.getDataSource());
-		Assert.assertSame(getTransactionManagerSetOnJobRepository(applicationContext.getBean(JobRepository.class)), dataSourceTransactionManager);
 	}
 
 	@Test

spring-batch-integration/src/test/java/org/springframework/batch/integration/chunk/RemoteChunkingManagerStepBuilderTest.java

@@ -52,6 +52,7 @@
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.channel.QueueChannel;
 import org.springframework.integration.core.MessagingTemplate;
+import org.springframework.jdbc.datasource.DataSourceTransactionManager;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
 import org.springframework.lang.Nullable;
 import org.springframework.messaging.PollableChannel;
@@ -350,5 +351,10 @@ public DataSource dataSource() {
 					.build();
 		}
 
+		@Bean
+		public DataSourceTransactionManager transactionManager(DataSource dataSource) {
+			return new DataSourceTransactionManager(dataSource);
+		}
+
 	}
 }

spring-batch-samples/src/main/java/org/springframework/batch/sample/remotechunking/DataSourceConfiguration.java

@@ -24,6 +24,7 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.PropertySource;
+import org.springframework.jdbc.datasource.DataSourceTransactionManager;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
 
 /**
@@ -41,4 +42,9 @@ public DataSource dataSource() {
 				.build();
 	}
 
+	@Bean
+	public DataSourceTransactionManager transactionManager(DataSource dataSource) {
+		return new DataSourceTransactionManager(dataSource);
+	}
+
 }

spring-batch-samples/src/main/java/org/springframework/batch/sample/remotepartitioning/DataSourceConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018 the original author or authors.
+ * Copyright 2018-2021 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.
@@ -24,6 +24,7 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.PropertySource;
+import org.springframework.jdbc.datasource.DataSourceTransactionManager;
 
 /**
  * @author Mahmoud Ben Hassine
@@ -50,4 +51,9 @@ public DataSource dataSource() {
 		return dataSource;
 	}
 
+	@Bean
+	public DataSourceTransactionManager transactionManager(DataSource dataSource) {
+		return new DataSourceTransactionManager(dataSource);
+	}
+
 }