From 869c5c7088910e097d4425496f38991adc35e811 Mon Sep 17 00:00:00 2001
From: abilan <abilan@vmware.com>
Date: Sat, 15 Apr 2023 20:00:38 -0400
Subject: [PATCH] Fix new Sonar smells

---
 .../dsl/BaseIntegrationFlowDefinition.java    | 10 ++---
 .../integration/dsl/EndpointSpec.java         |  6 ++-
 .../integration/dsl/HeaderEnricherSpec.java   | 38 ++++++++--------
 .../dsl/RecipientListRouterSpec.java          | 45 +++++++++++--------
 .../dsl/StandardIntegrationFlow.java          | 18 +++-----
 .../dsl/KotlinRecipientListRouterSpec.kt      | 18 +++-----
 .../GroovyIntegrationFlowDefinition.groovy    |  4 +-
 7 files changed, 69 insertions(+), 70 deletions(-)

diff --git a/spring-integration-core/src/main/java/org/springframework/integration/dsl/BaseIntegrationFlowDefinition.java b/spring-integration-core/src/main/java/org/springframework/integration/dsl/BaseIntegrationFlowDefinition.java
index 21be9fac73..f623d4c423 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/dsl/BaseIntegrationFlowDefinition.java
+++ b/spring-integration-core/src/main/java/org/springframework/integration/dsl/BaseIntegrationFlowDefinition.java
@@ -450,7 +450,7 @@ public abstract class BaseIntegrationFlowDefinition<B extends BaseIntegrationFlo
 	 * @param wireTapConfigurer the {@link Consumer} to accept options for the {@link WireTap}.
 	 * @return the current {@link BaseIntegrationFlowDefinition}.
 	 */
-	public B wireTap(String wireTapChannel, Consumer<WireTapSpec> wireTapConfigurer) {
+	public B wireTap(String wireTapChannel, @Nullable Consumer<WireTapSpec> wireTapConfigurer) {
 		DirectChannel internalWireTapChannel = new DirectChannel();
 		addComponent(IntegrationFlow.from(internalWireTapChannel).channel(wireTapChannel).get());
 		return wireTap(internalWireTapChannel, wireTapConfigurer);
@@ -639,7 +639,7 @@ public abstract class BaseIntegrationFlowDefinition<B extends BaseIntegrationFlo
 	 * @see MethodInvokingTransformer
 	 */
 	public B transform(MessageProcessorSpec<?> messageProcessorSpec,
-			Consumer<GenericEndpointSpec<MessageTransformingHandler>> endpointConfigurer) {
+			@Nullable Consumer<GenericEndpointSpec<MessageTransformingHandler>> endpointConfigurer) {
 
 		Assert.notNull(messageProcessorSpec, MESSAGE_PROCESSOR_SPEC_MUST_NOT_BE_NULL);
 		MessageProcessor<?> processor = messageProcessorSpec.getObject();
@@ -1087,7 +1087,7 @@ public abstract class BaseIntegrationFlowDefinition<B extends BaseIntegrationFlo
 	 * @return the current {@link BaseIntegrationFlowDefinition}.
 	 */
 	public B handle(MessageProcessorSpec<?> messageProcessorSpec,
-			Consumer<GenericEndpointSpec<ServiceActivatingHandler>> endpointConfigurer) {
+			@Nullable Consumer<GenericEndpointSpec<ServiceActivatingHandler>> endpointConfigurer) {
 
 		Assert.notNull(messageProcessorSpec, MESSAGE_PROCESSOR_SPEC_MUST_NOT_BE_NULL);
 		MessageProcessor<?> processor = messageProcessorSpec.getObject();
@@ -2362,7 +2362,7 @@ public abstract class BaseIntegrationFlowDefinition<B extends BaseIntegrationFlo
 	 * @return the current {@link BaseIntegrationFlowDefinition}.
 	 * @see #wireTap(WireTapSpec)
 	 */
-	public <P> B log(LoggingHandler.Level level, String category, Function<Message<P>, Object> function) {
+	public <P> B log(LoggingHandler.Level level, @Nullable String category, Function<Message<P>, Object> function) {
 		Assert.notNull(function, FUNCTION_MUST_NOT_BE_NULL);
 		return log(level, category, new FunctionExpression<>(function));
 	}
@@ -2650,7 +2650,7 @@ public abstract class BaseIntegrationFlowDefinition<B extends BaseIntegrationFlo
 	 * @see #bridge()
 	 */
 	@Deprecated
-	public <P> IntegrationFlow logAndReply(LoggingHandler.Level level, String category,
+	public <P> IntegrationFlow logAndReply(LoggingHandler.Level level, @Nullable String category,
 			Function<Message<P>, Object> function) {
 
 		Assert.notNull(function, FUNCTION_MUST_NOT_BE_NULL);
diff --git a/spring-integration-core/src/main/java/org/springframework/integration/dsl/EndpointSpec.java b/spring-integration-core/src/main/java/org/springframework/integration/dsl/EndpointSpec.java
index 742c78a5f9..ab52cc100b 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/dsl/EndpointSpec.java
+++ b/spring-integration-core/src/main/java/org/springframework/integration/dsl/EndpointSpec.java
@@ -61,8 +61,10 @@ public abstract class EndpointSpec<S extends EndpointSpec<S, F, H>, F extends Be
 	}
 
 	@Override
-	public S id(String id) {
-		this.endpointFactoryBean.setBeanName(id);
+	public S id(@Nullable String id) {
+		if (id != null) {
+			this.endpointFactoryBean.setBeanName(id);
+		}
 		return super.id(id);
 	}
 
diff --git a/spring-integration-core/src/main/java/org/springframework/integration/dsl/HeaderEnricherSpec.java b/spring-integration-core/src/main/java/org/springframework/integration/dsl/HeaderEnricherSpec.java
index 240286afc8..55a7846546 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/dsl/HeaderEnricherSpec.java
+++ b/spring-integration-core/src/main/java/org/springframework/integration/dsl/HeaderEnricherSpec.java
@@ -216,7 +216,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @param overwrite true to overwrite existing headers.
 	 * @return the header enricher spec.
 	 */
-	public HeaderEnricherSpec headerExpressions(MapBuilder<?, String, String> headers, Boolean overwrite) {
+	public HeaderEnricherSpec headerExpressions(MapBuilder<?, String, String> headers, @Nullable Boolean overwrite) {
 		Assert.notNull(headers, HEADERS_MUST_NOT_BE_NULL);
 		return headerExpressions(headers.get(), overwrite);
 	}
@@ -285,7 +285,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @param overwrite true to overwrite existing headers.
 	 * @return the header enricher spec.
 	 */
-	public HeaderEnricherSpec headerExpressions(Map<String, String> headers, Boolean overwrite) {
+	public HeaderEnricherSpec headerExpressions(Map<String, String> headers, @Nullable Boolean overwrite) {
 		Assert.notNull(headers, HEADERS_MUST_NOT_BE_NULL);
 		for (Entry<String, String> entry : headers.entrySet()) {
 			AbstractHeaderValueMessageProcessor<Object> processor =
@@ -314,7 +314,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec correlationId(Object correlationId, Boolean overwrite) {
+	public HeaderEnricherSpec correlationId(Object correlationId, @Nullable Boolean overwrite) {
 		return header(IntegrationMessageHeaderAccessor.CORRELATION_ID, correlationId, overwrite);
 	}
 
@@ -341,7 +341,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec correlationIdExpression(String correlationIdExpression, Boolean overwrite) {
+	public HeaderEnricherSpec correlationIdExpression(String correlationIdExpression, @Nullable Boolean overwrite) {
 		return headerExpression(IntegrationMessageHeaderAccessor.CORRELATION_ID, correlationIdExpression, overwrite);
 	}
 
@@ -371,7 +371,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @see FunctionExpression
 	 */
 	public <P> HeaderEnricherSpec correlationIdFunction(Function<Message<P>, ?> correlationIdFunction,
-			Boolean overwrite) {
+			@Nullable Boolean overwrite) {
 
 		return headerFunction(IntegrationMessageHeaderAccessor.CORRELATION_ID, correlationIdFunction, overwrite);
 	}
@@ -394,7 +394,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec replyChannel(Object replyChannel, Boolean overwrite) {
+	public HeaderEnricherSpec replyChannel(Object replyChannel, @Nullable Boolean overwrite) {
 		return header(MessageHeaders.REPLY_CHANNEL, replyChannel, overwrite);
 	}
 
@@ -419,7 +419,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec replyChannelExpression(String replyChannelExpression, Boolean overwrite) {
+	public HeaderEnricherSpec replyChannelExpression(String replyChannelExpression, @Nullable Boolean overwrite) {
 		return headerExpression(MessageHeaders.REPLY_CHANNEL, replyChannelExpression, overwrite);
 	}
 
@@ -449,7 +449,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @see FunctionExpression
 	 */
 	public <P> HeaderEnricherSpec replyChannelFunction(Function<Message<P>, ?> replyChannelFunction,
-			Boolean overwrite) {
+			@Nullable Boolean overwrite) {
 
 		return headerFunction(MessageHeaders.REPLY_CHANNEL, replyChannelFunction, overwrite);
 	}
@@ -472,7 +472,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec errorChannel(Object errorChannel, Boolean overwrite) {
+	public HeaderEnricherSpec errorChannel(Object errorChannel, @Nullable Boolean overwrite) {
 		return header(MessageHeaders.ERROR_CHANNEL, errorChannel, overwrite);
 	}
 
@@ -497,7 +497,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec errorChannelExpression(String errorChannelExpression, Boolean overwrite) {
+	public HeaderEnricherSpec errorChannelExpression(String errorChannelExpression, @Nullable Boolean overwrite) {
 		return headerExpression(MessageHeaders.ERROR_CHANNEL, errorChannelExpression, overwrite);
 	}
 
@@ -527,7 +527,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @see FunctionExpression
 	 */
 	public <P> HeaderEnricherSpec errorChannelFunction(Function<Message<P>, ?> errorChannelFunction,
-			Boolean overwrite) {
+			@Nullable Boolean overwrite) {
 
 		return headerFunction(MessageHeaders.ERROR_CHANNEL, errorChannelFunction, overwrite);
 	}
@@ -550,7 +550,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec priority(Number priority, Boolean overwrite) {
+	public HeaderEnricherSpec priority(Number priority, @Nullable Boolean overwrite) {
 		return header(IntegrationMessageHeaderAccessor.PRIORITY, priority, overwrite);
 	}
 
@@ -575,7 +575,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec priorityExpression(String priorityExpression, Boolean overwrite) {
+	public HeaderEnricherSpec priorityExpression(String priorityExpression, @Nullable Boolean overwrite) {
 		return headerExpression(IntegrationMessageHeaderAccessor.PRIORITY, priorityExpression, overwrite);
 	}
 
@@ -604,7 +604,9 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @since 5.2
 	 * @see FunctionExpression
 	 */
-	public <P> HeaderEnricherSpec priorityFunction(Function<Message<P>, ?> priorityFunction, Boolean overwrite) {
+	public <P> HeaderEnricherSpec priorityFunction(Function<Message<P>, ?> priorityFunction,
+			@Nullable Boolean overwrite) {
+
 		return headerFunction(IntegrationMessageHeaderAccessor.PRIORITY, priorityFunction, overwrite);
 	}
 
@@ -626,7 +628,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec expirationDate(Object expirationDate, Boolean overwrite) {
+	public HeaderEnricherSpec expirationDate(Object expirationDate, @Nullable Boolean overwrite) {
 		return header(IntegrationMessageHeaderAccessor.EXPIRATION_DATE, expirationDate, overwrite);
 	}
 
@@ -653,7 +655,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec expirationDateExpression(String expirationDateExpression, Boolean overwrite) {
+	public HeaderEnricherSpec expirationDateExpression(String expirationDateExpression, @Nullable Boolean overwrite) {
 		return headerExpression(IntegrationMessageHeaderAccessor.EXPIRATION_DATE, expirationDateExpression, overwrite);
 	}
 
@@ -683,7 +685,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @see FunctionExpression
 	 */
 	public <P> HeaderEnricherSpec expirationDateFunction(Function<Message<P>, ?> expirationDateFunction,
-			Boolean overwrite) {
+			@Nullable Boolean overwrite) {
 
 		return headerFunction(IntegrationMessageHeaderAccessor.EXPIRATION_DATE, expirationDateFunction, overwrite);
 	}
@@ -726,7 +728,7 @@ public class HeaderEnricherSpec extends ConsumerEndpointSpec<HeaderEnricherSpec,
 	 * @return the header enricher spec.
 	 * @since 5.2
 	 */
-	public HeaderEnricherSpec routingSlip(Boolean overwrite, Object... routingSlipPath) {
+	public HeaderEnricherSpec routingSlip(@Nullable Boolean overwrite, Object... routingSlipPath) {
 		RoutingSlipHeaderValueMessageProcessor routingSlipHeaderValueMessageProcessor =
 				new RoutingSlipHeaderValueMessageProcessor(routingSlipPath);
 		routingSlipHeaderValueMessageProcessor.setOverwrite(overwrite);
diff --git a/spring-integration-core/src/main/java/org/springframework/integration/dsl/RecipientListRouterSpec.java b/spring-integration-core/src/main/java/org/springframework/integration/dsl/RecipientListRouterSpec.java
index 2f6246c6ae..b154e24138 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/dsl/RecipientListRouterSpec.java
+++ b/spring-integration-core/src/main/java/org/springframework/integration/dsl/RecipientListRouterSpec.java
@@ -42,7 +42,7 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	}
 
 	/**
-	 * Adds a recipient channel that always will be selected.
+	 * Adds a recipient channel that is always selected.
 	 * @param channelName the channel name.
 	 * @return the router spec.
 	 */
@@ -51,12 +51,12 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	}
 
 	/**
-	 * Adds a recipient channel that will be selected if the the expression evaluates to 'true'.
+	 * Adds a recipient channel that will be selected if the expression evaluates to 'true'.
 	 * @param channelName the channel name.
 	 * @param expression the expression.
 	 * @return the router spec.
 	 */
-	public RecipientListRouterSpec recipient(String channelName, String expression) {
+	public RecipientListRouterSpec recipient(String channelName, @Nullable String expression) {
 		if (StringUtils.hasText(expression)) {
 			return recipient(channelName, PARSER.parseExpression(expression));
 		}
@@ -67,7 +67,7 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	}
 
 	/**
-	 * Adds a recipient channel that will be selected if the the expression evaluates to 'true'.
+	 * Adds a recipient channel that will be selected if the expression evaluates to 'true'.
 	 * @param channelName the channel name.
 	 * @param expression the expression.
 	 * @return the router spec.
@@ -80,7 +80,7 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	}
 
 	/**
-	 * Adds a recipient channel that will be selected if the the selector's accept method returns 'true'.
+	 * Adds a recipient channel that will be selected if the selector's accept method returns 'true'.
 	 * @param channelName the channel name.
 	 * @param selector the selector.
 	 * @return the router spec.
@@ -129,7 +129,13 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	 * @return the router spec.
 	 */
 	public RecipientListRouterSpec recipient(MessageChannel channel, @Nullable String expression) {
-		return recipient(channel, StringUtils.hasText(expression) ? PARSER.parseExpression(expression) : null);
+		if (StringUtils.hasText(expression)) {
+			return recipient(channel, PARSER.parseExpression(expression));
+		}
+		else {
+			this.handler.addRecipient(channel);
+			return this;
+		}
 	}
 
 	/**
@@ -138,16 +144,11 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	 * @param expression the expression.
 	 * @return the router spec.
 	 */
-	public RecipientListRouterSpec recipient(MessageChannel channel, @Nullable Expression expression) {
-		if (expression != null) {
-			ExpressionEvaluatingSelector selector = new ExpressionEvaluatingSelector(expression);
-			this.handler.addRecipient(channel, selector);
-			this.componentsToRegister.put(selector, null);
-		}
-		else {
-			this.handler.addRecipient(channel);
-		}
-		return _this();
+	public RecipientListRouterSpec recipient(MessageChannel channel, Expression expression) {
+		ExpressionEvaluatingSelector selector = new ExpressionEvaluatingSelector(expression);
+		this.handler.addRecipient(channel, selector);
+		this.componentsToRegister.put(selector, null);
+		return this;
 	}
 
 	/**
@@ -170,7 +171,7 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	public <P> RecipientListRouterSpec recipient(MessageChannel channel, GenericSelector<P> selector) {
 		MessageSelector messageSelector = wrapToMessageSelectorIfNecessary(selector);
 		this.handler.addRecipient(channel, messageSelector);
-		return _this();
+		return this;
 	}
 
 	/**
@@ -212,7 +213,13 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	 * @return the router spec.
 	 */
 	public RecipientListRouterSpec recipientFlow(@Nullable String expression, IntegrationFlow subFlow) {
-		return recipientFlow(StringUtils.hasText(expression) ? PARSER.parseExpression(expression) : null, subFlow);
+		if (StringUtils.hasText(expression)) {
+			return recipientFlow(PARSER.parseExpression(expression), subFlow);
+		}
+		else {
+			MessageChannel channel = obtainInputChannelFromFlow(subFlow);
+			return recipient(channel);
+		}
 	}
 
 	/**
@@ -221,7 +228,7 @@ public class RecipientListRouterSpec extends AbstractRouterSpec<RecipientListRou
 	 * @param subFlow the subflow.
 	 * @return the router spec.
 	 */
-	public RecipientListRouterSpec recipientFlow(@Nullable Expression expression, IntegrationFlow subFlow) {
+	public RecipientListRouterSpec recipientFlow(Expression expression, IntegrationFlow subFlow) {
 		MessageChannel channel = obtainInputChannelFromFlow(subFlow);
 		return recipient(channel, expression);
 	}
diff --git a/spring-integration-core/src/main/java/org/springframework/integration/dsl/StandardIntegrationFlow.java b/spring-integration-core/src/main/java/org/springframework/integration/dsl/StandardIntegrationFlow.java
index c99bd4831d..f9dd9f7296 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/dsl/StandardIntegrationFlow.java
+++ b/spring-integration-core/src/main/java/org/springframework/integration/dsl/StandardIntegrationFlow.java
@@ -136,8 +136,8 @@ public class StandardIntegrationFlow
 			ListIterator<Object> iterator = components.listIterator(this.integrationComponents.size());
 			while (iterator.hasPrevious()) {
 				Object component = iterator.previous();
-				if (component instanceof SmartLifecycle) {
-					((SmartLifecycle) component).start();
+				if (component instanceof SmartLifecycle lifecycle) {
+					lifecycle.start();
 				}
 			}
 			this.running = true;
@@ -148,11 +148,9 @@ public class StandardIntegrationFlow
 	public void stop(Runnable callback) {
 		AggregatingCallback aggregatingCallback = new AggregatingCallback(this.integrationComponents.size(), callback);
 		for (Object component : this.integrationComponents.keySet()) {
-			if (component instanceof SmartLifecycle lifecycle) {
-				if (lifecycle.isRunning()) {
-					lifecycle.stop(aggregatingCallback);
-					continue;
-				}
+			if (component instanceof SmartLifecycle lifecycle && lifecycle.isRunning()) {
+				lifecycle.stop(aggregatingCallback);
+				continue;
 			}
 			aggregatingCallback.run();
 		}
@@ -162,10 +160,8 @@ public class StandardIntegrationFlow
 	@Override
 	public void stop() {
 		for (Object component : this.integrationComponents.keySet()) {
-			if (component instanceof SmartLifecycle lifecycle) {
-				if (lifecycle.isRunning()) {
-					lifecycle.stop();
-				}
+			if (component instanceof SmartLifecycle lifecycle && lifecycle.isRunning()) {
+				lifecycle.stop();
 			}
 		}
 		this.running = false;
diff --git a/spring-integration-core/src/main/kotlin/org/springframework/integration/dsl/KotlinRecipientListRouterSpec.kt b/spring-integration-core/src/main/kotlin/org/springframework/integration/dsl/KotlinRecipientListRouterSpec.kt
index c9312c817f..308a0c0cf8 100644
--- a/spring-integration-core/src/main/kotlin/org/springframework/integration/dsl/KotlinRecipientListRouterSpec.kt
+++ b/spring-integration-core/src/main/kotlin/org/springframework/integration/dsl/KotlinRecipientListRouterSpec.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2020 the original author or authors.
+ * Copyright 2020-2023 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.
@@ -35,11 +35,7 @@ import org.springframework.messaging.MessageChannel
 class KotlinRecipientListRouterSpec(override val delegate: RecipientListRouterSpec)
 	: AbstractKotlinRouterSpec<RecipientListRouterSpec, RecipientListRouter>(delegate) {
 
-	fun recipient(channelName: String) {
-		this.delegate.recipient(channelName)
-	}
-
-	fun recipient(channelName: String, expression: String) {
+	fun recipient(channelName: String, expression: String? = null) {
 		this.delegate.recipient(channelName, expression)
 	}
 
@@ -54,11 +50,7 @@ class KotlinRecipientListRouterSpec(override val delegate: RecipientListRouterSp
 			this.delegate.recipient<P>(channelName) { selector(it) }
 	}
 
-	fun recipient(channel: MessageChannel) {
-		this.delegate.recipient(channel)
-	}
-
-	fun recipient(channel: MessageChannel, expression: String) {
+	fun recipient(channel: MessageChannel, expression: String? = null) {
 		this.delegate.recipient(channel, expression)
 	}
 
@@ -68,9 +60,9 @@ class KotlinRecipientListRouterSpec(override val delegate: RecipientListRouterSp
 
 	inline fun <reified P> recipient(channel: MessageChannel, crossinline selector: (P) -> Boolean) {
 		if (Message::class.java.isAssignableFrom(P::class.java))
-			this.delegate.recipientMessageSelector(channel, MessageSelector { selector(it as P) })
+			this.delegate.recipientMessageSelector(channel) { selector(it as P) }
 		else
-			this.delegate.recipient<P>(channel, GenericSelector { selector(it) })
+			this.delegate.recipient<P>(channel) { selector(it) }
 	}
 
 	inline fun <reified P> recipientFlow(crossinline selector: (P) -> Boolean,
diff --git a/spring-integration-groovy/src/main/groovy/org/springframework/integration/groovy/dsl/GroovyIntegrationFlowDefinition.groovy b/spring-integration-groovy/src/main/groovy/org/springframework/integration/groovy/dsl/GroovyIntegrationFlowDefinition.groovy
index 262d466d07..b8187380a2 100644
--- a/spring-integration-groovy/src/main/groovy/org/springframework/integration/groovy/dsl/GroovyIntegrationFlowDefinition.groovy
+++ b/spring-integration-groovy/src/main/groovy/org/springframework/integration/groovy/dsl/GroovyIntegrationFlowDefinition.groovy
@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 the original author or authors.
+ * Copyright 2022-2023 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.
@@ -126,7 +126,7 @@ class GroovyIntegrationFlowDefinition {
 	 * at the current {@link IntegrationFlow} chain position using the {@link MessageChannelSpec}
 	 * fluent API.
 	 * @param messageChannelSpec the {@link MessageChannelSpec} to use.
-	 * @see MessageChannels
+	 * @see org.springframework.integration.dsl.MessageChannels
 	 */
 	GroovyIntegrationFlowDefinition channel(MessageChannelSpec messageChannelSpec) {
 		this.delegate.channel messageChannelSpec