BATCH-2686: Remove usage of BeanDefinitionRegistry in RemoteChunkingM…

…asterStepBuilder

There is no need to register the RemoteChunkHandlerFactoryBean as a bean
in the bean definition registry. The fix uses this factory bean to create
a ChunkProcessorChunkHandler which is already a message endpoint configured
as a service activator

spring-batch-integration/src/main/java/org/springframework/batch/integration/chunk/RemoteChunkingMasterStepBuilder.java

@@ -36,9 +36,7 @@
 import org.springframework.batch.repeat.CompletionPolicy;
 import org.springframework.batch.repeat.RepeatOperations;
 import org.springframework.batch.repeat.exception.ExceptionHandler;
-import org.springframework.beans.factory.config.BeanDefinition;
-import org.springframework.beans.factory.support.BeanDefinitionBuilder;
-import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.core.MessagingTemplate;
 import org.springframework.messaging.PollableChannel;
@@ -54,7 +52,7 @@
  *
  * <ul>
  *     <li>creates and sets a {@link ChunkMessageChannelItemWriter} on the master step</li>
- *     <li>registers a {@link RemoteChunkHandlerFactoryBean} in the given bean definition registry</li>
+ *     <li>creates and configures a {@link ChunkProcessorChunkHandler} as a service activator</li>
  * </ul>
  *
  * @param <I> type of input items
@@ -66,7 +64,6 @@
 public class RemoteChunkingMasterStepBuilder<I, O> extends FaultTolerantStepBuilder<I, O> {
 
 	private MessagingTemplate messagingTemplate;
-	private BeanDefinitionRegistry beanDefinitionRegistry;
 	private PollableChannel inputChannel;
 	private DirectChannel outputChannel;
 
@@ -84,18 +81,6 @@ public RemoteChunkingMasterStepBuilder(String stepName) {
 		super(new StepBuilder(stepName));
 	}
 
-	/**
-	 * Set the bean definition registry in which required beans will be registered.
-	 *
-	 * @param beanDefinitionRegistry the bean definition registry to use.
-	 * @return this builder instance for fluent chaining
-	 */
-	public RemoteChunkingMasterStepBuilder<I, O> beanDefinitionRegistry(BeanDefinitionRegistry beanDefinitionRegistry) {
-		Assert.notNull(beanDefinitionRegistry, "beanDefinitionRegistry must not be null");
-		this.beanDefinitionRegistry = beanDefinitionRegistry;
-		return this;
-	}
-
 	/**
 	 * Set the input channel on which replies from workers will be received.
 	 * The provided input channel will be set as a reply channel on the
@@ -175,11 +160,14 @@ public RemoteChunkingMasterStepBuilder<I, O> throttleLimit(long throttleLimit) {
 	/**
 	 * Build a master {@link TaskletStep}.
 	 *
+	 * <p>Any item writer set using {@link RemoteChunkingMasterStepBuilder#writer(ItemWriter)}
+	 * will be replaced with a {@link ChunkMessageChannelItemWriter}.</p>
+	 *
 	 * @return the configured master step
+	 * @see RemoteChunkHandlerFactoryBean
 	 */
 	public TaskletStep build() {
 
-		Assert.notNull(this.beanDefinitionRegistry, "A BeanDefinitionRegistry must be provided");
 		Assert.notNull(this.inputChannel, "An InputChannel must be provided");
 		Assert.notNull(this.outputChannel, "An OutputChannel must be provided");
 
@@ -195,15 +183,22 @@ public TaskletStep build() {
 		chunkMessageChannelItemWriter.setMaxWaitTimeouts(this.maxWaitTimeouts);
 		chunkMessageChannelItemWriter.setThrottleLimit(this.throttleLimit);
 		chunkMessageChannelItemWriter.setReplyChannel(this.inputChannel);
-		super.writer(chunkMessageChannelItemWriter);
 
-		// register remote chunk handler factory bean
+		// the item writer will be replaced anyway with a
+		// chunkMessageChannelItemWriter by the RemoteChunkHandlerFactoryBean
+		super.writer(items -> { });
 		TaskletStep step = super.build();
-		BeanDefinition remoteChunkHandlerFactoryBeanDefinition = BeanDefinitionBuilder.genericBeanDefinition(RemoteChunkHandlerFactoryBean.class)
-				.addPropertyValue("chunkWriter", chunkMessageChannelItemWriter)
-				.addPropertyValue("step", step)
-				.getBeanDefinition();
-		this.beanDefinitionRegistry.registerBeanDefinition(step.getName() + "_remoteChunkHandler", remoteChunkHandlerFactoryBeanDefinition);
+
+		RemoteChunkHandlerFactoryBean<O> remoteChunkHandlerFactoryBean = new RemoteChunkHandlerFactoryBean<>();
+		remoteChunkHandlerFactoryBean.setChunkWriter(chunkMessageChannelItemWriter);
+		remoteChunkHandlerFactoryBean.setStep(step);
+		try {
+			// the ChunkProcessorChunkHandler created here is already a message
+			// endpoint that is automatically configured as a service activator
+			remoteChunkHandlerFactoryBean.getObject();
+		} catch (Exception e) {
+			throw new BeanCreationException("Unable to create a ChunkProcessorChunkHandler bean.", e);
+		}
 
 		return step;
 	}
@@ -359,6 +354,14 @@ public RemoteChunkingMasterStepBuilder<I, O> chunk(CompletionPolicy completionPo
 		return this;
 	}
 
+	/**
+	 * The item writer set using this setter will be replaced with a {@link ChunkMessageChannelItemWriter}.
+	 *
+	 * @param writer an item writer
+	 * @return this builder instance for fluent chaining
+	 * @see ChunkMessageChannelItemWriter
+	 * @see RemoteChunkHandlerFactoryBean#setChunkWriter(ItemWriter)
+	 */
 	@Override
 	public RemoteChunkingMasterStepBuilder<I, O> writer(ItemWriter<? super O> writer) {
 		super.writer(writer);

spring-batch-integration/src/main/java/org/springframework/batch/integration/chunk/RemoteChunkingMasterStepBuilderFactory.java

@@ -16,13 +16,11 @@
 package org.springframework.batch.integration.chunk;
 
 import org.springframework.batch.core.repository.JobRepository;
-import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.transaction.PlatformTransactionManager;
 
 /**
  * Convenient factory for a {@link RemoteChunkingMasterStepBuilder} which sets
- * the {@link JobRepository}, {@link PlatformTransactionManager} and
- * {@link BeanDefinitionRegistry} automatically.
+ * the {@link JobRepository} and {@link PlatformTransactionManager} automatically.
  *
  * @since 4.1
  * @author Mahmoud Ben Hassine
@@ -33,36 +31,30 @@ public class RemoteChunkingMasterStepBuilderFactory {
 
 	private PlatformTransactionManager transactionManager;
 
-	private BeanDefinitionRegistry beanDefinitionRegistry;
-
 	/**
 	 * Create a new {@link RemoteChunkingMasterStepBuilderFactory}.
 	 *
 	 * @param jobRepository the job repository to use
 	 * @param transactionManager the transaction manager to use
-	 * @param beanDefinitionRegistry the bean definition registry to use
 	 */
 	public RemoteChunkingMasterStepBuilderFactory(
 			JobRepository jobRepository,
-			PlatformTransactionManager transactionManager,
-			BeanDefinitionRegistry beanDefinitionRegistry) {
+			PlatformTransactionManager transactionManager) {
 		this.jobRepository = jobRepository;
 		this.transactionManager = transactionManager;
-		this.beanDefinitionRegistry = beanDefinitionRegistry;
 	}
 
 	/**
 	 * Creates a {@link RemoteChunkingMasterStepBuilder} and initializes its job
-	 * repository, transaction manager and bean definition registry.
+	 * repository and transaction manager.
 	 * 
 	 * @param name the name of the step
 	 * @return a {@link RemoteChunkingMasterStepBuilder}
 	 */
 	public <I, O> RemoteChunkingMasterStepBuilder<I, O> get(String name) {
 		return new RemoteChunkingMasterStepBuilder<I, O>(name)
 				.repository(this.jobRepository)
-				.transactionManager(this.transactionManager)
-				.beanDefinitionRegistry(this.beanDefinitionRegistry);
+				.transactionManager(this.transactionManager);
 	}
 
 }

spring-batch-integration/src/main/java/org/springframework/batch/integration/config/annotation/BatchIntegrationConfiguration.java

@@ -18,11 +18,7 @@
 import org.springframework.batch.core.repository.JobRepository;
 import org.springframework.batch.integration.chunk.RemoteChunkingMasterStepBuilderFactory;
 import org.springframework.batch.integration.chunk.RemoteChunkingWorkerBuilder;
-import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.support.BeanDefinitionRegistry;
-import org.springframework.context.ApplicationContext;
-import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.transaction.PlatformTransactionManager;
@@ -34,14 +30,12 @@
  * @author Mahmoud Ben Hassine
  */
 @Configuration
-public class BatchIntegrationConfiguration implements ApplicationContextAware {
+public class BatchIntegrationConfiguration {
 
 	private JobRepository jobRepository;
 
 	private PlatformTransactionManager transactionManager;
 
-	private BeanDefinitionRegistry beanDefinitionRegistry;
-
 	@Autowired
 	public BatchIntegrationConfiguration(
 			JobRepository jobRepository,
@@ -53,17 +47,12 @@ public BatchIntegrationConfiguration(
 	@Bean
 	public RemoteChunkingMasterStepBuilderFactory remoteChunkingMasterStepBuilderFactory() {
 		return new RemoteChunkingMasterStepBuilderFactory(this.jobRepository,
-				this.transactionManager, this.beanDefinitionRegistry);
+				this.transactionManager);
 	}
 
 	@Bean
 	public <I,O> RemoteChunkingWorkerBuilder<I, O> remoteChunkingWorkerBuilder() {
 		return new RemoteChunkingWorkerBuilder<>();
 	}
 
-	@Override
-	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
-		this.beanDefinitionRegistry = (BeanDefinitionRegistry) applicationContext;
-	}
-
 }

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

@@ -29,20 +29,18 @@
 import org.springframework.batch.item.ItemReader;
 import org.springframework.batch.item.support.ListItemReader;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.channel.QueueChannel;
 import org.springframework.messaging.PollableChannel;
 import org.springframework.test.context.ContextConfiguration;
-import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.junit4.SpringRunner;
 import org.springframework.transaction.PlatformTransactionManager;
 
 /**
  * @author Mahmoud Ben Hassine
  */
-@RunWith(SpringJUnit4ClassRunner.class)
+@RunWith(SpringRunner.class)
 @ContextConfiguration(classes = {RemoteChunkingMasterStepBuilderTest.BatchConfiguration.class})
 public class RemoteChunkingMasterStepBuilderTest {
 
@@ -54,37 +52,6 @@ public class RemoteChunkingMasterStepBuilderTest {
 	@Autowired
 	private PlatformTransactionManager transactionManager;
 
-	private ItemReader<String> itemReader = new ListItemReader<>(Arrays.asList("a", "b", "c"));
-
-	@Test
-	public void testMandatoryBeanDefinitionRegistry() {
-		// given
-		RemoteChunkingMasterStepBuilder<String, String> builder = new RemoteChunkingMasterStepBuilder<>("step");
-		this.expectedException.expect(IllegalArgumentException.class);
-		this.expectedException.expectMessage("A BeanDefinitionRegistry must be provided");
-
-		// when
-		builder.build();
-
-		// then
-		// expected exception
-	}
-
-	@Test
-	public void beanDefinitionRegistryMustNotBeNull() {
-		// given
-		this.expectedException.expect(IllegalArgumentException.class);
-		this.expectedException.expectMessage("beanDefinitionRegistry must not be null");
-
-		// when
-		TaskletStep step = new RemoteChunkingMasterStepBuilder<String, String>("step")
-				.beanDefinitionRegistry(null)
-				.build();
-
-		// then
-		// expected exception
-	}
-
 	@Test
 	public void inputChannelMustNotBeNull() {
 		// given
@@ -163,8 +130,7 @@ public void throttleLimitMustNotBeGreaterThanZero() {
 	@Test
 	public void testMandatoryInputChannel() {
 		// given
-		RemoteChunkingMasterStepBuilder<String, String> builder = new RemoteChunkingMasterStepBuilder<String, String>("step")
-				.beanDefinitionRegistry(new GenericApplicationContext());
+		RemoteChunkingMasterStepBuilder<String, String> builder = new RemoteChunkingMasterStepBuilder<>("step");
 
 		this.expectedException.expect(IllegalArgumentException.class);
 		this.expectedException.expectMessage("An InputChannel must be provided");
@@ -180,7 +146,6 @@ public void testMandatoryInputChannel() {
 	public void testMandatoryOutputChannel() {
 		// given
 		RemoteChunkingMasterStepBuilder<String, String> builder = new RemoteChunkingMasterStepBuilder<String, String>("step")
-				.beanDefinitionRegistry(new GenericApplicationContext())
 				.inputChannel(new QueueChannel());
 
 		this.expectedException.expect(IllegalArgumentException.class);
@@ -194,25 +159,23 @@ public void testMandatoryOutputChannel() {
 	}
 
 	@Test
-	public void testRemoteChunkHandlerRegistration() {
+	public void testMasterStepCreation() {
 		// given
-		BeanDefinitionRegistry beanDefinitionRegistry = new GenericApplicationContext();
+		ItemReader<String> itemReader = new ListItemReader<>(Arrays.asList("a", "b", "c"));
 		PollableChannel inputChannel = new QueueChannel();
 		DirectChannel outputChannel = new DirectChannel();
 
 		// when
 		TaskletStep taskletStep = new RemoteChunkingMasterStepBuilder<String, String>("step")
-				.reader(this.itemReader)
+				.reader(itemReader)
 				.repository(this.jobRepository)
 				.transactionManager(this.transactionManager)
-				.beanDefinitionRegistry(beanDefinitionRegistry)
 				.inputChannel(inputChannel)
 				.outputChannel(outputChannel)
 				.build();
 
 		// then
 		Assert.assertNotNull(taskletStep);
-		Assert.assertTrue(beanDefinitionRegistry.containsBeanDefinition("step_remoteChunkHandler"));
 	}
 
 	@Configuration