Remove BatchConfigurer#getTransactionManager

Before this commit, the transaction manager was configurable
by implementing `BatchConfigurer#getTransactionManager`.

The transaction manager being an implementation detail of the
`JobRepository`, it should not be configurable at the same level
as the `JobRepository` (ie in the same interface).

This commit removes the method `getTransactionManager` from
the `BatchConfigurer` interface. If needed, a custom transaction
manager could be supplied by implementing `getJobRepository`,
or via the constructor of `DefaultBatchConfigurer`.

Resolves spring-projects#4191

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

@@ -92,13 +92,6 @@ public JobRegistry jobRegistry() throws Exception {
 		return this.jobRegistry;
 	}
 
-	/**
-	 * Establish the {@link PlatformTransactionManager} for the batch execution.
-	 * @return The instance of the {@link PlatformTransactionManager}.
-	 * @throws Exception The {@link Exception} thrown if an error occurs.
-	 */
-	public abstract PlatformTransactionManager transactionManager() throws Exception;
-
 	/**
 	 * If a {@link BatchConfigurer} exists, return it. Otherwise, create a
 	 * {@link DefaultBatchConfigurer}. If more than one configurer is present, an

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

@@ -25,6 +25,7 @@
  * a Batch system.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  *
  */
 public interface BatchConfigurer {
@@ -35,12 +36,6 @@ public interface BatchConfigurer {
 	 */
 	JobRepository getJobRepository() throws Exception;
 
-	/**
-	 * @return The {@link PlatformTransactionManager}.
-	 * @throws Exception The {@link Exception} thrown if an error occurs.
-	 */
-	PlatformTransactionManager getTransactionManager() throws Exception;
-
 	/**
 	 * @return The {@link JobLauncher}.
 	 * @throws Exception The {@link Exception} thrown if an error occurs.

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

@@ -101,11 +101,19 @@ public JobExplorer getJobExplorer() {
 		return this.jobExplorer;
 	}
 
-	@Override
 	public PlatformTransactionManager getTransactionManager() {
 		return this.transactionManager;
 	}
 
+	/**
+	 * Set the transaction manager.
+	 * @param transactionManager the transaction manager to use. Must not be {@code null}.
+	 */
+	public void setTransactionManager(PlatformTransactionManager transactionManager) {
+		Assert.notNull(transactionManager, "TransactionManager must not be null");
+		this.transactionManager = transactionManager;
+	}
+
 	@Override
 	public void afterPropertiesSet() throws Exception {
 		initialize();

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

@@ -53,9 +53,4 @@ public JobExplorer jobExplorer() throws Exception {
 		return getOrCreateConfigurer().getJobExplorer();
 	}
 
-	@Override
-	public PlatformTransactionManager transactionManager() throws Exception {
-		return getOrCreateConfigurer().getTransactionManager();
-	}
-
 }

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

@@ -42,7 +42,7 @@ class TransactionManagerConfigurationWithBatchConfigurerTests extends Transactio
 	void testConfigurationWithDataSourceAndNoTransactionManager() throws Exception {
 		ApplicationContext applicationContext = new AnnotationConfigApplicationContext(
 				BatchConfigurationWithDataSourceAndNoTransactionManager.class);
-		BatchConfigurer batchConfigurer = applicationContext.getBean(BatchConfigurer.class);
+		DefaultBatchConfigurer batchConfigurer = applicationContext.getBean(DefaultBatchConfigurer.class);
 
 		PlatformTransactionManager platformTransactionManager = batchConfigurer.getTransactionManager();
 		assertTrue(platformTransactionManager instanceof JdbcTransactionManager);
@@ -56,7 +56,7 @@ void testConfigurationWithDataSourceAndNoTransactionManager() throws Exception {
 	void testConfigurationWithDataSourceAndTransactionManager() throws Exception {
 		ApplicationContext applicationContext = new AnnotationConfigApplicationContext(
 				BatchConfigurationWithDataSourceAndTransactionManager.class);
-		BatchConfigurer batchConfigurer = applicationContext.getBean(BatchConfigurer.class);
+		DefaultBatchConfigurer batchConfigurer = applicationContext.getBean(DefaultBatchConfigurer.class);
 
 		PlatformTransactionManager platformTransactionManager = batchConfigurer.getTransactionManager();
 		assertSame(transactionManager, platformTransactionManager);