INT-3932: Redis: add rightPop and leftPush

JIRA: https://jira.spring.io/browse/INT-3932

PR review:

* remove unnecessary spaces

* fix code and doc style

* use property name rightPop/right-pop (default true)

* add reversed feature to the outbound adapter

* add new options to reference manual

* Polishing according PR comments

spring-integration-redis/src/main/java/org/springframework/integration/redis/config/RedisQueueInboundChannelAdapterParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -30,6 +30,7 @@ import org.springframework.util.StringUtils;
  * Parser for the <queue-inbound-channel-adapter> element of the 'redis' namespace.
  *
  * @author Artem Bilan
+ * @author Rainer Frey
  * @since 3.0
  */
 public class RedisQueueInboundChannelAdapterParser extends AbstractChannelAdapterParser {
@@ -51,6 +52,7 @@ public class RedisQueueInboundChannelAdapterParser extends AbstractChannelAdapte
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "expect-message");
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "receive-timeout");
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "recovery-interval");
+		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "right-pop");
 		builder.addPropertyReference("outputChannel", channelName);
 
 		return builder.getBeanDefinition();

spring-integration-redis/src/main/java/org/springframework/integration/redis/config/RedisQueueOutboundChannelAdapterParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -31,6 +31,7 @@ import org.springframework.util.StringUtils;
  * Parser for the <int-redis:queue-outbound-channel-adapter> element.
  *
  * @author Artem Bilan
+ * @author Rainer Frey
  * @since 3.0
  */
 public class RedisQueueOutboundChannelAdapterParser extends AbstractOutboundChannelAdapterParser {
@@ -50,6 +51,7 @@ public class RedisQueueOutboundChannelAdapterParser extends AbstractOutboundChan
 
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "extract-payload");
 		IntegrationNamespaceUtils.setReferenceIfAttributeDefined(builder, element, "serializer");
+		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "left-push");
 
 		return builder.getBeanDefinition();
 	}

spring-integration-redis/src/main/java/org/springframework/integration/redis/inbound/RedisQueueMessageDrivenEndpoint.java

@@ -48,6 +48,7 @@ import org.springframework.util.Assert;
  * @author Gunnar Hillert
  * @author Artem Bilan
  * @author Gary Russell
+ * @author Rainer Frey
  * @since 3.0
  */
 @ManagedResource
@@ -80,6 +81,8 @@ public class RedisQueueMessageDrivenEndpoint extends MessageProducerSupport impl
 
 	private volatile Runnable stopCallback;
 
+	private volatile boolean rightPop = true;
+
 	/**
 	 * @param queueName         Must not be an empty String
 	 * @param connectionFactory Must not be null
@@ -158,6 +161,15 @@ public class RedisQueueMessageDrivenEndpoint extends MessageProducerSupport impl
 		this.recoveryInterval = recoveryInterval;
 	}
 
+	/**
+	 * Specify if {@code POP} operation from Redis List should be {@code BRPOP} or {@code BLPOP}.
+	 * @param rightPop the {@code BRPOP} flag. Defaults to {@code true}.
+	 * @since 4.3
+	 */
+	public void setRightPop(boolean rightPop) {
+		this.rightPop = rightPop;
+	}
+
 	@Override
 	protected void onInit() {
 		super.onInit();
@@ -188,7 +200,12 @@ public class RedisQueueMessageDrivenEndpoint extends MessageProducerSupport impl
 
 		byte[] value = null;
 		try {
-			value = this.boundListOperations.rightPop(this.receiveTimeout, TimeUnit.MILLISECONDS);
+			if (this.rightPop) {
+				value = this.boundListOperations.rightPop(this.receiveTimeout, TimeUnit.MILLISECONDS);
+			}
+			else {
+				value = this.boundListOperations.leftPop(this.receiveTimeout, TimeUnit.MILLISECONDS);
+			}
 		}
 		catch (Exception e) {
 			this.listening = false;
@@ -227,7 +244,12 @@ public class RedisQueueMessageDrivenEndpoint extends MessageProducerSupport impl
 				this.sendMessage(message);
 			}
 			else {
-				this.boundListOperations.rightPush(value);
+				if (this.rightPop) {
+					this.boundListOperations.rightPush(value);
+				}
+				else {
+					this.boundListOperations.leftPush(value);
+				}
 			}
 		}
 	}

spring-integration-redis/src/main/java/org/springframework/integration/redis/outbound/RedisQueueOutboundChannelAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors
+ * Copyright 2013-2016 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.
@@ -33,6 +33,7 @@ import org.springframework.util.Assert;
  * @author Mark Fisher
  * @author Gunnar Hillert
  * @author Artem Bilan
+ * @author Rainer Frey
  * @since 3.0
  */
 public class RedisQueueOutboundChannelAdapter extends AbstractMessageHandler {
@@ -51,6 +52,8 @@ public class RedisQueueOutboundChannelAdapter extends AbstractMessageHandler {
 
 	private volatile boolean serializerExplicitlySet;
 
+	private volatile boolean leftPush = true;
+
 	public RedisQueueOutboundChannelAdapter(String queueName, RedisConnectionFactory connectionFactory) {
 		this(new LiteralExpression(queueName), connectionFactory);
 	}
@@ -77,6 +80,15 @@ public class RedisQueueOutboundChannelAdapter extends AbstractMessageHandler {
 		this.serializerExplicitlySet = true;
 	}
 
+	/**
+	 * Specify if {@code PUSH} operation to Redis List should be {@code LPUSH} or {@code RPUSH}.
+	 * @param leftPush the {@code LPUSH} flag. Defaults to {@code true}.
+	 * @since 4.3
+	 */
+	public void setLeftPush(boolean leftPush) {
+		this.leftPush = leftPush;
+	}
+
 	public void setIntegrationEvaluationContext(EvaluationContext evaluationContext) {
 		this.evaluationContext = evaluationContext;
 	}
@@ -113,7 +125,12 @@ public class RedisQueueOutboundChannelAdapter extends AbstractMessageHandler {
 		}
 
 		String queueName = this.queueNameExpression.getValue(this.evaluationContext, message, String.class);
-		this.template.boundListOps(queueName).leftPush(value);
+		if (this.leftPush) {
+			this.template.boundListOps(queueName).leftPush(value);
+		}
+		else {
+			this.template.boundListOps(queueName).rightPush(value);
+		}
 	}
 
 }

spring-integration-redis/src/main/resources/org/springframework/integration/redis/config/spring-integration-redis-4.3.xsd

@@ -390,6 +390,14 @@
 							</xsd:documentation>
 						</xsd:annotation>
 					</xsd:attribute>
+					<xsd:attribute name="right-pop" type="xsd:string" default="true">
+						<xsd:annotation>
+							<xsd:documentation>
+								When 'false', specifies that data is read using a 'left pop' operation instead of a 'right pop'.
+								Default is 'true'.
+							</xsd:documentation>
+						</xsd:annotation>
+					</xsd:attribute>
 					<xsd:attribute name="task-executor" type="xsd:string">
 						<xsd:annotation>
 							<xsd:documentation><![CDATA[
@@ -605,7 +613,17 @@
 					<xsd:attribute name="extract-payload" type="xsd:string" default="true">
 						<xsd:annotation>
 							<xsd:documentation>
-								Specifies if the Message payload or the entire (serialized) Message will be send to the Redis queue.
+								Specifies if the Message payload or the entire (serialized) Message will be send
+								to the Redis queue.
+								Default is 'true'.
+							</xsd:documentation>
+						</xsd:annotation>
+					</xsd:attribute>
+					<xsd:attribute name="left-push" type="xsd:string" default="true">
+						<xsd:annotation>
+							<xsd:documentation>
+								When 'false', specifies that data is written using a 'right push' operation instead
+								of a 'left push'.
 								Default is 'true'.
 							</xsd:documentation>
 						</xsd:annotation>

spring-integration-redis/src/test/java/org/springframework/integration/redis/config/RedisQueueInboundChannelAdapterParserTests-context.xml

@@ -31,7 +31,8 @@
 											  recovery-interval="3000"
 											  task-executor="executor"
 											  auto-startup="false"
-											  phase="100"/>
+											  phase="100"
+											  right-pop="false"/>
 
 	<bean id="executor" class="org.springframework.integration.util.ErrorHandlingTaskExecutor">
 		<constructor-arg ref="threadPoolTaskExecutor"/>

spring-integration-redis/src/test/java/org/springframework/integration/redis/config/RedisQueueInboundChannelAdapterParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -44,6 +44,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 /**
  * @author Artem Bilan
  * @author Gary Russell
+ * @author Rainer Frey
  * @since 3.0
  */
 @ContextConfiguration
@@ -103,6 +104,7 @@ public class RedisQueueInboundChannelAdapterParserTests {
 		assertTrue(TestUtils.getPropertyValue(this.defaultAdapter, "autoStartup", Boolean.class));
 		assertEquals(Integer.MAX_VALUE / 2, TestUtils.getPropertyValue(this.defaultAdapter, "phase"));
 		assertSame(this.defaultAdapterChannel, TestUtils.getPropertyValue(this.defaultAdapter, "outputChannel"));
+		assertTrue(TestUtils.getPropertyValue(this.defaultAdapter, "rightPop", Boolean.class));
 	}
 
 	@Test
@@ -119,6 +121,7 @@ public class RedisQueueInboundChannelAdapterParserTests {
 		assertFalse(TestUtils.getPropertyValue(this.customAdapter, "autoStartup", Boolean.class));
 		assertEquals(100, TestUtils.getPropertyValue(this.customAdapter, "phase"));
 		assertSame(this.sendChannel, TestUtils.getPropertyValue(this.customAdapter, "outputChannel"));
+		assertFalse(TestUtils.getPropertyValue(this.customAdapter, "rightPop", Boolean.class));
 	}
 
 }

spring-integration-redis/src/test/java/org/springframework/integration/redis/config/RedisQueueOutboundChannelAdapterParserTests-context.xml

@@ -26,7 +26,8 @@
 											  queue-expression="headers['redis_queue']"
 											  extract-payload="false"
 											  serializer="serializer"
-											  connection-factory="customRedisConnectionFactory"/>
+											  connection-factory="customRedisConnectionFactory"
+											  left-push="false"/>
 
 	<bean id="serializer" class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
 

spring-integration-redis/src/test/java/org/springframework/integration/redis/config/RedisQueueOutboundChannelAdapterParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -44,6 +44,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 /**
  * @author Artem Bilan
  * @author Gary Russell
+ * @author Rainer Frey
  * @since 3.0
  */
 @ContextConfiguration
@@ -89,6 +90,7 @@ public class RedisQueueOutboundChannelAdapterParserTests {
 
 		assertThat(TestUtils.getPropertyValue(handler, "h.advised.advisors.first.item.advice"),
 				Matchers.instanceOf(RequestHandlerRetryAdvice.class));
+		assertTrue(TestUtils.getPropertyValue(this.defaultAdapter, "leftPush", Boolean.class));
 	}
 
 	@Test
@@ -98,6 +100,7 @@ public class RedisQueueOutboundChannelAdapterParserTests {
 		assertFalse(TestUtils.getPropertyValue(this.customAdapter, "extractPayload", Boolean.class));
 		assertTrue(TestUtils.getPropertyValue(this.customAdapter, "serializerExplicitlySet", Boolean.class));
 		assertSame(this.serializer, TestUtils.getPropertyValue(this.customAdapter, "serializer"));
+		assertFalse(TestUtils.getPropertyValue(this.customAdapter, "leftPush", Boolean.class));
 	}
 
 }

spring-integration-redis/src/test/java/org/springframework/integration/redis/inbound/RedisQueueMessageDrivenEndpointTests.java

@@ -73,6 +73,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
  * @author Gunnar Hillert
  * @author Artem Bilan
  * @author Gary Russell
+ * @author Rainer Frey
  * @since 3.0
  */
 @ContextConfiguration
@@ -157,7 +158,8 @@ public class RedisQueueMessageDrivenEndpointTests extends RedisAvailableTests {
 
 		PollableChannel errorChannel = new QueueChannel();
 
-		RedisQueueMessageDrivenEndpoint endpoint = new RedisQueueMessageDrivenEndpoint(queueName, this.connectionFactory);
+		RedisQueueMessageDrivenEndpoint endpoint =
+				new RedisQueueMessageDrivenEndpoint(queueName, this.connectionFactory);
 		endpoint.setBeanFactory(Mockito.mock(BeanFactory.class));
 		endpoint.setExpectMessage(true);
 		endpoint.setOutputChannel(channel);
@@ -175,7 +177,8 @@ public class RedisQueueMessageDrivenEndpointTests extends RedisAvailableTests {
 		assertNotNull(receive);
 		assertThat(receive, Matchers.instanceOf(ErrorMessage.class));
 		assertThat(receive.getPayload(), Matchers.instanceOf(MessagingException.class));
-		assertThat(((Exception) receive.getPayload()).getMessage(), Matchers.containsString("Deserialization of Message failed."));
+		assertThat(((Exception) receive.getPayload()).getMessage(),
+				Matchers.containsString("Deserialization of Message failed."));
 		assertThat(((Exception) receive.getPayload()).getCause(), Matchers.instanceOf(ClassCastException.class));
 		assertThat(((Exception) receive.getPayload()).getCause().getMessage(),
 				Matchers.containsString("java.lang.String cannot be cast to org.springframework.messaging.Message"));
@@ -193,7 +196,8 @@ public class RedisQueueMessageDrivenEndpointTests extends RedisAvailableTests {
 		redisTemplate.setConnectionFactory(this.connectionFactory);
 		redisTemplate.afterPropertiesSet();
 
-		redisTemplate.boundListOps("si.test.Int3017IntegrationInbound").leftPush("{\"payload\":\"" + payload + "\",\"headers\":{}}");
+		redisTemplate.boundListOps("si.test.Int3017IntegrationInbound")
+				.leftPush("{\"payload\":\"" + payload + "\",\"headers\":{}}");
 
 		Message<?> receive = this.fromChannel.receive(2000);
 		assertNotNull(receive);
@@ -340,6 +344,50 @@ public class RedisQueueMessageDrivenEndpointTests extends RedisAvailableTests {
 		endpoint.stop();
 	}
 
+	@Test
+	@RedisAvailable
+	@SuppressWarnings("unchecked")
+	public void testInt3932ReadFromLeft() throws Exception {
+
+		String queueName = "si.test.redisQueueInboundChannelAdapterTests3932";
+
+		RedisTemplate<String, Object> redisTemplate = new RedisTemplate<String, Object>();
+		redisTemplate.setConnectionFactory(this.connectionFactory);
+		redisTemplate.setEnableDefaultSerializer(false);
+		redisTemplate.setKeySerializer(new StringRedisSerializer());
+		redisTemplate.setValueSerializer(new JdkSerializationRedisSerializer());
+		redisTemplate.afterPropertiesSet();
+
+		String payload = "testing";
+
+		redisTemplate.boundListOps(queueName).rightPush(payload);
+
+		Date payload2 = new Date();
+
+		redisTemplate.boundListOps(queueName).rightPush(payload2);
+
+		PollableChannel channel = new QueueChannel();
+
+		RedisQueueMessageDrivenEndpoint endpoint =
+				new RedisQueueMessageDrivenEndpoint(queueName, this.connectionFactory);
+		endpoint.setBeanFactory(Mockito.mock(BeanFactory.class));
+		endpoint.setOutputChannel(channel);
+		endpoint.setReceiveTimeout(1000);
+		endpoint.setRightPop(false);
+		endpoint.afterPropertiesSet();
+		endpoint.start();
+
+		Message<Object> receive = (Message<Object>) channel.receive(2000);
+		assertNotNull(receive);
+		assertEquals(payload, receive.getPayload());
+
+		receive = (Message<Object>) channel.receive(2000);
+		assertNotNull(receive);
+		assertEquals(payload2, receive.getPayload());
+
+		endpoint.stop();
+	}
+
 	private void waitListening(RedisQueueMessageDrivenEndpoint endpoint) throws InterruptedException {
 		int n = 0;
 		do {

spring-integration-redis/src/test/java/org/springframework/integration/redis/outbound/RedisQueueOutboundChannelAdapterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2014 the original author or authors
+ * Copyright 2013-2016 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.
@@ -49,6 +49,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 /**
  * @author Gunnar Hillert
  * @author Artem Bilan
+ * @author Rainer Frey
  * @since 3.0
  */
 @ContextConfiguration
@@ -177,4 +178,42 @@ public class RedisQueueOutboundChannelAdapterTests extends RedisAvailableTests {
 		assertEquals(message.getPayload(), resultMessage.getPayload());
 	}
 
+	@Test
+	@RedisAvailable
+	public void testInt3932LeftPushFalse() throws Exception {
+
+		final String queueName = "si.test.Int3932LeftPushFalse";
+
+		final RedisQueueOutboundChannelAdapter handler = new RedisQueueOutboundChannelAdapter(queueName,
+				this.connectionFactory);
+		handler.setLeftPush(false);
+
+		String payload = "testing";
+		handler.handleMessage(MessageBuilder.withPayload(payload).build());
+
+		Date payload2 = new Date();
+		handler.handleMessage(MessageBuilder.withPayload(payload2).build());
+
+		RedisTemplate<String, ?> redisTemplate = new StringRedisTemplate();
+		redisTemplate.setConnectionFactory(this.connectionFactory);
+		redisTemplate.afterPropertiesSet();
+
+		Object result = redisTemplate.boundListOps(queueName).leftPop(5000, TimeUnit.MILLISECONDS);
+		assertNotNull(result);
+
+		assertEquals(payload, result);
+
+		RedisTemplate<String, ?> redisTemplate2 = new RedisTemplate<String, Object>();
+		redisTemplate2.setConnectionFactory(this.connectionFactory);
+		redisTemplate2.setEnableDefaultSerializer(false);
+		redisTemplate2.setKeySerializer(new StringRedisSerializer());
+		redisTemplate2.setValueSerializer(new JdkSerializationRedisSerializer());
+		redisTemplate2.afterPropertiesSet();
+
+		Object result2 = redisTemplate2.boundListOps(queueName).leftPop(5000, TimeUnit.MILLISECONDS);
+		assertNotNull(result2);
+
+		assertEquals(payload2, result2);
+	}
+
 }

src/reference/asciidoc/redis.adoc

@@ -170,7 +170,8 @@ These attributes are mutually exclusive.
 [[redis-queue-inbound-channel-adapter]]
 ==== Redis Queue Inbound Channel Adapter
 
-Since _Spring Integration 3.0_, a Queue Inbound Channel Adapter is available to 'right pop' messages from a Redis List.
+Since _Spring Integration 3.0_, a Queue Inbound Channel Adapter is available to 'pop' messages from a Redis List. By default it uses 'right pop', but
+it can be configured to use 'left pop' instead.
 The adapter is message-driven using an internal listener thread and does not use a poller.
 [source,xml]
 ----
@@ -185,7 +186,8 @@ The adapter is message-driven using an internal listener thread and does not use
                     receive-timeout=""  <9>
                     recovery-interval=""  <10>
                     expect-message=""  <11>
-                    task-executor=""/>  <12>
+                    task-executor=""  <12>
+                    right-pop=""/>  <13>
 
 ----
 
@@ -211,7 +213,7 @@ Default is `0`.
 Defaults to `redisConnectionFactory`.
 
 
-<6> The name of the Redis List on which the queue-based 'right pop' operation is performed to get Redis messages.
+<6> The name of the Redis List on which the queue-based 'pop' operation is performed to get Redis messages.
 
 
 <7> The `MessageChannel` to which to send `ErrorMessage` s with `Exception` s from the listening task of the Endpoint.
@@ -224,11 +226,11 @@ In this case the raw `byte[]` from the inbound Redis message is sent to the `cha
 By default it is a `JdkSerializationRedisSerializer`.
 
 
-<9> The timeout in milliseconds for 'right pop' operation to wait for a Redis message from the queue.
+<9> The timeout in milliseconds for 'pop' operation to wait for a Redis message from the queue.
 Default is 1 second.
 
 
-<10> The time in milliseconds for which the listener task should sleep after exceptions on the 'right pop' operation, before restarting the listener task.
+<10> The time in milliseconds for which the listener task should sleep after exceptions on the 'pop' operation, before restarting the listener task.
 
 
 <11> Specify if this Endpoint expects data from the Redis queue to contain entire `Message` s.
@@ -240,10 +242,18 @@ Default is `false`.
 It is used for the underlying listening task.
 By default a `SimpleAsyncTaskExecutor` is used.
 
+
+<13> Specify whether this Endpoint should use 'right pop' (when `true`) or 'left pop' (when `false`) to read messages from the Redis List.
+If `true`, the Redis List acts as a `FIFO` queue when used with a default _Redis Queue Outbound Channel Adapter_. Set to `false` to use with software
+that writes to the list with 'right push', or to achieve a stack-like message order.
+Default is `true`.
+Since _version 4.3_.
+
 [[redis-queue-outbound-channel-adapter]]
 ==== Redis Queue Outbound Channel Adapter
 
-Since _Spring Integration 3.0_, a Queue Outbound Channel Adapter is available to 'left push' to a Redis List from Spring Integration messages:
+Since _Spring Integration 3.0_, a Queue Outbound Channel Adapter is available to 'push' to a Redis List from Spring Integration messages. By default,
+it uses 'left push', but it can be configured to use 'right push' instead.
 [source,xml]
 ----
 <int-redis:queue-outbound-channel-adapter id=""  <1>
@@ -252,7 +262,8 @@ Since _Spring Integration 3.0_, a Queue Outbound Channel Adapter is available to
                     queue=""  <4>
                     queue-expression=""  <5>
                     serializer=""  <6>
-                    extract-payload="" /> <7>
+                    extract-payload=""  <7>
+                    left-push=""/>  <8>
 
 ----
 
@@ -270,7 +281,7 @@ In this case, the endpoint is registered with the bean name `id + '.adapter'`.
 Defaults to `redisConnectionFactory`.
 
 
-<4> The name of the Redis List on which the queue-based 'left push' operation is performed to send Redis messages.
+<4> The name of the Redis List on which the queue-based 'push' operation is performed to send Redis messages.
 This attribute is mutually exclusive with `queue-expression`.
 
 
@@ -286,6 +297,14 @@ However, for `String` payloads, a `StringRedisSerializer` is used, if a `seriali
 <7> Specify if this Endpoint should send just the _payload_ to the Redis queue, or the entire `Message`.
 Default is `true`.
 
+
+<8> Specify whether this Endpoint should use 'left push' (when `true`) or 'right push' (when `false`) to write messages to the Redis List.
+If `true`, the Redis List acts as a `FIFO` queue when used with a default _Redis Queue Inbound Channel Adapter_. Set to `false` to use with software
+that reads from the list with 'left pop', or to achieve a stack-like message order.
+Default is `true`.
+Since _version 4.3_.
+
+
 [[redis-application-events]]
 ==== Redis Application Events
 

src/reference/asciidoc/whats-new.adoc

@@ -77,3 +77,11 @@ See <<file-flushing>> for more information.
 The outbound endpoints now support a `RabbitTemplate` configured with a `ContentTypeDelegatingMessageConverter` such
 that the converter can be chosen based on the message content type.
 See <<content-type-conversion-outbound>> for more information.
+
+==== Redis Changes
+
+Previously, the queue channel adapters always used the Redis List in a fixed direction,
+pushing to the left end and reading from the right end.
+It is now possible to configure the reading and writing direction using `rightPop` and `leftPush` options for the
+`RedisQueueMessageDrivenEndpoint` and `RedisQueueOutboundChannelAdapter` respectively.
+See <<redis-queue-inbound-channel-adapter>> and <<redis-queue-outbound-channel-adapter>> for more information.