GH-1484: RabbitListener.batch() Override

Resolves https://github.com/spring-projects/spring-amqp/issues/1484

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/annotation/RabbitListener.java

@@ -332,4 +332,18 @@ public @interface RabbitListener {
 	 */
 	String converterWinsContentType() default "true";
 
+	/**
+	 * Override the container factory's {@code batchListener} property. The listener
+	 * method signature should receive a {@code List<?>}; refer to the reference
+	 * documentation. This allows a single container factory to be used for both record
+	 * and batch listeners; previously separate container factories were required.
+	 * @return "true" for the annotated method to be a batch listener or "false" for a
+	 * single message listener. If not set, the container factory setting is used. SpEL and
+	 * property place holders are not supported because the listener type cannot be
+	 * variable.
+	 * @since 3.0
+	 * @see Boolean#parseBoolean(String)
+	 */
+	String batch() default "";
+
 }

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/annotation/RabbitListenerAnnotationBeanPostProcessor.java

@@ -461,6 +461,9 @@ public class RabbitListenerAnnotationBeanPostProcessor
 		resolvePostProcessor(endpoint, rabbitListener, target, beanName);
 		resolveMessageConverter(endpoint, rabbitListener, target, beanName);
 		resolveReplyContentType(endpoint, rabbitListener);
+		if (StringUtils.hasText(rabbitListener.batch())) {
+			endpoint.setBatchListener(Boolean.parseBoolean(rabbitListener.batch()));
+		}
 		RabbitListenerContainerFactory<?> factory = resolveContainerFactory(rabbitListener, target, beanName);
 
 		this.registrar.registerEndpoint(endpoint, factory);

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/config/AbstractRabbitListenerContainerFactory.java

@@ -381,7 +381,9 @@ public abstract class AbstractRabbitListenerContainerFactory<C extends AbstractM
 				.acceptIfNotNull(endpoint.getAckMode(), instance::setAcknowledgeMode)
 				.acceptIfNotNull(endpoint.getBatchingStrategy(), instance::setBatchingStrategy);
 			instance.setListenerId(endpoint.getId());
-			endpoint.setBatchListener(this.batchListener);
+			if (endpoint.getBatchListener() == null) {
+				endpoint.setBatchListener(this.batchListener);
+			}
 		}
 		applyCommonOverrides(endpoint, instance);
 

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/listener/AbstractRabbitListenerEndpoint.java

@@ -84,7 +84,7 @@ public abstract class AbstractRabbitListenerEndpoint implements RabbitListenerEn
 
 	private TaskExecutor taskExecutor;
 
-	private boolean batchListener;
+	private Boolean batchListener;
 
 	private BatchingStrategy batchingStrategy;
 
@@ -293,7 +293,21 @@ public abstract class AbstractRabbitListenerEndpoint implements RabbitListenerEn
 		this.taskExecutor = taskExecutor;
 	}
 
+	/**
+	 * True if this endpoint is for a batch listener.
+	 * @return true if batch.
+	 */
 	public boolean isBatchListener() {
+		return this.batchListener == null ? false : this.batchListener;
+	}
+
+	/**
+	 * True if this endpoint is for a batch listener.
+	 * @return {@link Boolean#TRUE} if batch.
+	 * @since 3.0
+	 */
+	@Nullable
+	public Boolean getBatchListener() {
 		return this.batchListener;
 	}
 

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/listener/MethodRabbitListenerEndpoint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2020 the original author or authors.
+ * Copyright 2014-2022 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.
@@ -130,7 +130,7 @@ public class MethodRabbitListenerEndpoint extends AbstractRabbitListenerEndpoint
 	protected MessagingMessageListenerAdapter createMessageListener(MessageListenerContainer container) {
 		Assert.state(this.messageHandlerMethodFactory != null,
 				"Could not create message listener - MessageHandlerMethodFactory not set");
-		MessagingMessageListenerAdapter messageListener = createMessageListenerInstance();
+		MessagingMessageListenerAdapter messageListener = createMessageListenerInstance(getBatchListener());
 		messageListener.setHandlerAdapter(configureListenerAdapter(messageListener));
 		String replyToAddress = getDefaultReplyToAddress();
 		if (replyToAddress != null) {
@@ -159,11 +159,12 @@ public class MethodRabbitListenerEndpoint extends AbstractRabbitListenerEndpoint
 
 	/**
 	 * Create an empty {@link MessagingMessageListenerAdapter} instance.
+	 * @param batch whether this endpoint is for a batch listener.
 	 * @return the {@link MessagingMessageListenerAdapter} instance.
 	 */
-	protected MessagingMessageListenerAdapter createMessageListenerInstance() {
-		return this.adapterProvider.getAdapter(isBatchListener(), this.bean, this.method, this.returnExceptions,
-					this.errorHandler, getBatchingStrategy());
+	protected MessagingMessageListenerAdapter createMessageListenerInstance(@Nullable Boolean batch) {
+		return this.adapterProvider.getAdapter(batch == null ? isBatchListener() : batch, this.bean, this.method,
+				this.returnExceptions, this.errorHandler, getBatchingStrategy());
 	}
 
 	@Nullable

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/listener/RabbitListenerEndpoint.java

@@ -116,6 +116,14 @@ public interface RabbitListenerEndpoint {
 	default void setBatchListener(boolean batchListener) {
 	}
 
+	/**
+	 * Whether this endpoint is for a batch listener.
+	 * @return {@link Boolean#TRUE} if batch.
+	 * @since 3.0
+	 */
+	@Nullable
+	Boolean getBatchListener();
+
 	/**
 	 * Set a {@link BatchingStrategy} to use when debatching messages.
 	 * @param batchingStrategy the batching strategy.

spring-rabbit/src/test/java/org/springframework/amqp/rabbit/annotation/EnableRabbitBatchIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2020 the original author or authors.
+ * Copyright 2019-2022 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.
@@ -143,7 +143,7 @@ public class EnableRabbitBatchIntegrationTests {
 		public SimpleRabbitListenerContainerFactory consumerBatchContainerFactory() {
 			SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
 			factory.setConnectionFactory(connectionFactory());
-			factory.setBatchListener(true);
+			factory.setBatchListener(false);
 			factory.setConsumerBatchEnabled(true);
 			factory.setBatchSize(2);
 			return factory;
@@ -202,7 +202,7 @@ public class EnableRabbitBatchIntegrationTests {
 			this.fooMessagesLatch.countDown();
 		}
 
-		@RabbitListener(queues = "batch.3", containerFactory = "consumerBatchContainerFactory")
+		@RabbitListener(queues = "batch.3", containerFactory = "consumerBatchContainerFactory", batch = "true")
 		public void listen3(List<Foo> in) {
 			this.foosConsumerBatchToo = in;
 			this.fooConsumerBatchTooLatch.countDown();