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).

Resolves #816

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

@@ -84,7 +84,6 @@ public abstract class AbstractBatchConfiguration implements ImportAware, Initial
 		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 @@ import org.springframework.transaction.PlatformTransactionManager;
  * <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 @@ import org.springframework.transaction.PlatformTransactionManager;
  * available by implementing the {@link BatchConfigurer} interface.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.2
  * @see EnableBatchProcessing
  */
@@ -61,7 +62,6 @@ public class ModularBatchConfiguration extends AbstractBatchConfiguration {
 	}
 
 	@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 @@ import org.springframework.transaction.PlatformTransactionManager;
  * {@link BatchConfigurer}.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.2
  * @see EnableBatchProcessing
  */
@@ -87,7 +88,6 @@ public class SimpleBatchConfiguration extends AbstractBatchConfiguration {
 	}
 
 	@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.beans.factory.annotation.Autowired;
 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 class DataSourceConfiguration {
 				.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

@@ -49,13 +49,10 @@ public class TransactionManagerConfigurationWithoutBatchConfigurerTests extends
 	@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/RemoteChunkingManagerStepBuilderTests.java

@@ -52,6 +52,7 @@ import org.springframework.context.annotation.Configuration;
 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 class RemoteChunkingManagerStepBuilderTests {
 					.build();
 		}
 
+		@Bean
+		public DataSourceTransactionManager transactionManager(DataSource dataSource) {
+			return new DataSourceTransactionManager(dataSource);
+		}
+
 	}
 }

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

@@ -20,6 +20,7 @@ import javax.sql.DataSource;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.jdbc.datasource.DataSourceTransactionManager;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
 
 /**
@@ -37,4 +38,9 @@ public class DataSourceConfiguration {
 				.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.beans.factory.annotation.Value;
 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 class DataSourceConfiguration {
 		return dataSource;
 	}
 
+	@Bean
+	public DataSourceTransactionManager transactionManager(DataSource dataSource) {
+		return new DataSourceTransactionManager(dataSource);
+	}
+
 }