Add Java DSL for Camel module and docs (#3937)

* Add Java DSL for Camel module and docs

* Introduce a `LambdaRouteBuilder` option into the `CamelMessageHandler`
to easily provide the Camel route just in-place

* * Fix language in docs

Co-authored-by: Gary Russell <grussell@vmware.com>

Co-authored-by: Gary Russell <grussell@vmware.com>

build.gradle

@@ -496,9 +496,12 @@ project('spring-integration-camel') {
 
     dependencies {
         api project(':spring-integration-core')
-        api 'org.apache.camel:camel-api'
+        api 'org.apache.camel:camel-core-model'
 
         testImplementation 'org.apache.camel:camel-test-junit5'
+        testImplementation ('org.apache.camel:camel-spring') {
+            exclude group: 'org.springframework'
+        }
     }
 }
 

spring-integration-camel/src/main/java/org/springframework/integration/camel/dsl/Camel.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.camel.dsl;
+
+import org.apache.camel.ExchangePattern;
+import org.apache.camel.ProducerTemplate;
+import org.apache.camel.builder.LambdaRouteBuilder;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * Factory class for Apache Camel components DSL.
+ *
+ * @author Artem Bilan
+ *
+ * @since 6.0
+ */
+public final class Camel {
+
+	/**
+	 * Create an instance of {@link CamelMessageHandlerSpec} in a {@link ExchangePattern#InOnly} mode.
+	 * @return the spec.
+	 */
+	public static CamelMessageHandlerSpec handler() {
+		return camelHandler(null, ExchangePattern.InOnly);
+	}
+
+	/**
+	 * Create an instance of {@link CamelMessageHandlerSpec} for the provided {@link ProducerTemplate}
+	 * in a {@link ExchangePattern#InOnly} mode.
+	 * @param producerTemplate the {@link ProducerTemplate} to use.
+	 * @return the spec.
+	 */
+	public static CamelMessageHandlerSpec handler(ProducerTemplate producerTemplate) {
+		return camelHandler(producerTemplate, ExchangePattern.InOnly);
+	}
+
+	/**
+	 * Create an instance of {@link CamelMessageHandlerSpec} in a {@link ExchangePattern#InOut} mode.
+	 * @return the spec.
+	 */
+	public static CamelMessageHandlerSpec gateway() {
+		return camelHandler(null, ExchangePattern.InOut);
+	}
+
+	/**
+	 * Create an instance of {@link CamelMessageHandlerSpec} for the provided {@link ProducerTemplate}
+	 * in a {@link ExchangePattern#InOut} mode.
+	 * @param producerTemplate the {@link ProducerTemplate} to use.
+	 * @return the spec.
+	 */
+	public static CamelMessageHandlerSpec gateway(ProducerTemplate producerTemplate) {
+		return camelHandler(producerTemplate, ExchangePattern.InOut);
+	}
+
+	/**
+	 * Create an instance of {@link CamelMessageHandlerSpec} for the provided {@link LambdaRouteBuilder}
+	 * in a {@link ExchangePattern#InOut} mode.
+	 * The {@code CamelContext} is fetched as a bean from the application context.
+	 * @param route the {@link LambdaRouteBuilder} to use.
+	 * @return the spec.
+	 */
+	public static CamelMessageHandlerSpec route(LambdaRouteBuilder route) {
+		return camelHandler(null, ExchangePattern.InOut)
+				.route(route);
+	}
+
+	private static CamelMessageHandlerSpec camelHandler(@Nullable ProducerTemplate producerTemplate,
+			ExchangePattern exchangePattern) {
+
+		return new CamelMessageHandlerSpec(producerTemplate)
+				.exchangePattern(exchangePattern);
+	}
+
+
+	private Camel() {
+	}
+
+}

spring-integration-camel/src/main/java/org/springframework/integration/camel/dsl/CamelMessageHandlerSpec.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.camel.dsl;
+
+import java.util.Arrays;
+import java.util.Map;
+import java.util.function.Function;
+
+import org.apache.camel.ExchangePattern;
+import org.apache.camel.ProducerTemplate;
+import org.apache.camel.builder.LambdaRouteBuilder;
+
+import org.springframework.expression.Expression;
+import org.springframework.integration.camel.outbound.CamelMessageHandler;
+import org.springframework.integration.camel.support.CamelHeaderMapper;
+import org.springframework.integration.dsl.MessageHandlerSpec;
+import org.springframework.integration.expression.FunctionExpression;
+import org.springframework.integration.mapping.HeaderMapper;
+import org.springframework.lang.Nullable;
+import org.springframework.messaging.Message;
+import org.springframework.util.Assert;
+
+/**
+ * The {@link MessageHandlerSpec} for {@link CamelMessageHandler}.
+ *
+ * @author Artem Bilan
+ *
+ * @since 6.0
+ */
+public class CamelMessageHandlerSpec extends
+		MessageHandlerSpec<CamelMessageHandlerSpec, CamelMessageHandler> {
+
+	private String[] inboundHeaderNames = { "*" };
+
+	private String[] outboundHeaderNames = { "*" };
+
+	protected CamelMessageHandlerSpec(@Nullable ProducerTemplate producerTemplate) {
+		this.target = producerTemplate == null ? new CamelMessageHandler() : new CamelMessageHandler(producerTemplate);
+	}
+
+	public CamelMessageHandlerSpec endpointUri(String endpointUri) {
+		this.target.setEndpointUri(endpointUri);
+		return this;
+	}
+
+	public CamelMessageHandlerSpec endpointUri(Function<Message<?>, String> endpointUriFunction) {
+		return endpointUriExpression(new FunctionExpression<>(endpointUriFunction));
+	}
+
+	public CamelMessageHandlerSpec endpointUriExpression(String endpointUriExpression) {
+		return endpointUriExpression(PARSER.parseExpression(endpointUriExpression));
+	}
+
+	public CamelMessageHandlerSpec endpointUriExpression(Expression endpointUriExpression) {
+		this.target.setEndpointUriExpression(endpointUriExpression);
+		return this;
+	}
+
+	protected CamelMessageHandlerSpec route(LambdaRouteBuilder route) {
+		this.target.setRoute(route);
+		return this;
+	}
+
+	public CamelMessageHandlerSpec exchangePattern(ExchangePattern exchangePattern) {
+		this.target.setExchangePattern(exchangePattern);
+		return this;
+	}
+
+	public CamelMessageHandlerSpec exchangePattern(Function<Message<?>, ExchangePattern> exchangePatternFunction) {
+		return exchangePatternExpression(new FunctionExpression<>(exchangePatternFunction));
+	}
+
+	public CamelMessageHandlerSpec exchangePatternExpression(String exchangePatternExpression) {
+		return exchangePatternExpression(PARSER.parseExpression(exchangePatternExpression));
+	}
+
+	public CamelMessageHandlerSpec exchangePatternExpression(Expression exchangePatternExpression) {
+		this.target.setExchangePatternExpression(exchangePatternExpression);
+		return this;
+	}
+
+	public CamelMessageHandlerSpec inboundHeaderNames(String... inboundHeaderNames) {
+		Assert.notEmpty(inboundHeaderNames, "'inboundHeaderNames' must not be empty");
+		this.inboundHeaderNames = Arrays.copyOf(inboundHeaderNames, inboundHeaderNames.length);
+		return addCamelHeaderMapper();
+	}
+
+	public CamelMessageHandlerSpec outboundHeaderNames(String... outboundHeaderNames) {
+		Assert.notEmpty(outboundHeaderNames, "'outboundHeaderNames' must not be empty");
+		this.outboundHeaderNames = Arrays.copyOf(outboundHeaderNames, outboundHeaderNames.length);
+		return addCamelHeaderMapper();
+	}
+
+	private CamelMessageHandlerSpec addCamelHeaderMapper() {
+		CamelHeaderMapper headerMapper = new CamelHeaderMapper();
+		headerMapper.setInboundHeaderNames(this.inboundHeaderNames);
+		headerMapper.setOutboundHeaderNames(this.outboundHeaderNames);
+		return headerMapper(headerMapper);
+	}
+
+	public CamelMessageHandlerSpec headerMapper(HeaderMapper<org.apache.camel.Message> headerMapper) {
+		this.target.setHeaderMapper(headerMapper);
+		return this;
+	}
+
+	public CamelMessageHandlerSpec exchangeProperties(Map<String, Object> exchangeProperties) {
+		this.target.setExchangeProperties(exchangeProperties);
+		return this;
+	}
+
+	public CamelMessageHandlerSpec exchangePropertiesExpression(String exchangePropertiesExpression) {
+		return exchangePropertiesExpression(PARSER.parseExpression(exchangePropertiesExpression));
+	}
+
+	public CamelMessageHandlerSpec exchangePropertiesExpression(Expression exchangePropertiesExpression) {
+		this.target.setExchangePropertiesExpression(exchangePropertiesExpression);
+		return this;
+	}
+
+}

spring-integration-camel/src/main/java/org/springframework/integration/camel/dsl/package-info.java

@@ -0,0 +1,7 @@
+/**
+ * Provides supporting classes for JavaDSL with Apache Camel components.
+ */
+
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
+package org.springframework.integration.camel.dsl;

spring-integration-camel/src/main/java/org/springframework/integration/camel/outbound/CamelMessageHandler.java

@@ -19,12 +19,18 @@ package org.springframework.integration.camel.outbound;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 
+import org.apache.camel.CamelContext;
 import org.apache.camel.CamelExecutionException;
 import org.apache.camel.Endpoint;
 import org.apache.camel.Exchange;
 import org.apache.camel.ExchangePattern;
 import org.apache.camel.ProducerTemplate;
+import org.apache.camel.builder.LambdaRouteBuilder;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.model.RouteDefinition;
 
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanInitializationException;
 import org.springframework.expression.Expression;
 import org.springframework.expression.common.LiteralExpression;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
@@ -62,13 +68,16 @@ import org.springframework.util.StringUtils;
  */
 public class CamelMessageHandler extends AbstractReplyProducingMessageHandler {
 
-	private final ProducerTemplate producerTemplate;
+	private ProducerTemplate producerTemplate;
 
 	private Expression exchangePatternExpression = new ValueExpression<>(ExchangePattern.InOnly);
 
 	@Nullable
 	private Expression endpointUriExpression;
 
+	@Nullable
+	private LambdaRouteBuilder route;
+
 	private HeaderMapper<org.apache.camel.Message> headerMapper = new CamelHeaderMapper();
 
 	@Nullable
@@ -76,21 +85,47 @@ public class CamelMessageHandler extends AbstractReplyProducingMessageHandler {
 
 	private StandardEvaluationContext evaluationContext;
 
+	public CamelMessageHandler() {
+	}
+
 	public CamelMessageHandler(ProducerTemplate producerTemplate) {
 		Assert.notNull(producerTemplate, "'producerTemplate' must not be null");
 		this.producerTemplate = producerTemplate;
 	}
 
+	/**
+	 * Set Camel route endpoint uri to send a message.
+	 * Mutually exclusive with {@link #setEndpointUriExpression(Expression)} and {@link #setRoute(LambdaRouteBuilder)}.
+	 * @param endpointUri the Camel route endpoint to send a message.
+	 */
 	public void setEndpointUri(String endpointUri) {
 		Assert.hasText(endpointUri, "'endpointUri' must not be empty");
 		setEndpointUriExpression(new LiteralExpression(endpointUri));
 	}
 
+	/**
+	 * Set Camel route endpoint uri to send a message.
+	 * Mutually exclusive with {@link #setEndpointUri(String)} and {@link #setRoute(LambdaRouteBuilder)}.
+	 * @param endpointUriExpression the SpEL expression to determine a Camel route endpoint to send a message.
+	 */
 	public void setEndpointUriExpression(Expression endpointUriExpression) {
 		Assert.notNull(endpointUriExpression, "'endpointUriExpression' must not be null");
 		this.endpointUriExpression = endpointUriExpression;
 	}
 
+	/**
+	 * Set a {@link LambdaRouteBuilder} to add an inline Camel route definition.
+	 * Can be used as a lambda {@code rb -> rb.from("direct:inbound").bean(MyBean.class)}
+	 * or reference to external instance.
+	 * Mutually exclusive with {@link #setEndpointUri(String)} and {@link #setEndpointUriExpression(Expression)}.
+	 * The endpoint to send a message is extracted from the target {@link RouteBuilder}.
+	 * @param route the {@link LambdaRouteBuilder} to use.
+	 */
+	public void setRoute(LambdaRouteBuilder route) {
+		Assert.notNull(route, "'route' must not be null");
+		this.route = route;
+	}
+
 	public void setExchangePattern(ExchangePattern exchangePattern) {
 		Assert.notNull(exchangePattern, "'exchangePattern' must not be null");
 		setExchangePatternExpression(new ValueExpression<>(exchangePattern));
@@ -126,7 +161,38 @@ public class CamelMessageHandler extends AbstractReplyProducingMessageHandler {
 
 	@Override
 	protected final void doInit() {
-		this.evaluationContext = ExpressionUtils.createStandardEvaluationContext(getBeanFactory());
+		Assert.state(this.endpointUriExpression == null || this.route == null,
+				"The 'endpointUri' option is mutually exclusive with 'route'");
+
+		BeanFactory beanFactory = getBeanFactory();
+		if (this.producerTemplate == null) {
+			this.producerTemplate = beanFactory.getBean(CamelContext.class).createProducerTemplate();
+		}
+
+		if (this.route != null) {
+			CamelContext camelContext = this.producerTemplate.getCamelContext();
+			RouteBuilder routeBuilder =
+					new RouteBuilder(camelContext) {
+
+						@Override
+						public void configure() throws Exception {
+							CamelMessageHandler.this.route.accept(this);
+						}
+
+					};
+
+			try {
+				camelContext.addRoutes(routeBuilder);
+			}
+			catch (Exception ex) {
+				throw new BeanInitializationException("Cannot load Camel route", ex);
+			}
+
+			RouteDefinition routeDefinition = routeBuilder.getRouteCollection().getRoutes().get(0);
+			this.endpointUriExpression = new LiteralExpression(routeDefinition.getInput().getEndpointUri());
+		}
+
+		this.evaluationContext = ExpressionUtils.createStandardEvaluationContext(beanFactory);
 	}
 
 	@Override

spring-integration-camel/src/test/java/org/springframework/integration/camel/dsl/CamelDslTests.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.camel.dsl;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.apache.camel.CamelContext;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.spring.SpringCamelContext;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.event.ContextRefreshedEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.core.MessagingTemplate;
+import org.springframework.integration.dsl.IntegrationFlow;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+/**
+ * @author Artem Bilan
+ *
+ * @since 6.0
+ */
+@SpringJUnitConfig
+@DirtiesContext
+public class CamelDslTests {
+
+	@Autowired
+	@Qualifier("camelFlow.input")
+	MessageChannel input;
+
+	@Test
+	void sendAndReceiveCamelRoute() {
+		String result = new MessagingTemplate().convertSendAndReceive(this.input, "apache camel", String.class);
+		assertThat(result).isEqualTo("___APACHE CAMEL___");
+	}
+
+	@Configuration
+	@EnableIntegration
+	public static class Config {
+
+		@Bean
+		CamelContext springCamelContext() {
+			return new SpringCamelContext();
+		}
+
+		@EventListener(ContextRefreshedEvent.class)
+		public void simpleRoute() throws Exception {
+			RouteBuilder.addRoutes(springCamelContext(),
+					rb -> rb.from("direct:simple").bean("camelDslTests.Config", "transformPayload"));
+		}
+
+		@Bean
+		IntegrationFlow camelFlow() {
+			return f -> f
+					.handle(Camel.gateway().endpointUri("direct:simple"))
+					.handle(Camel.route(this::camelRoute));
+		}
+
+		private void camelRoute(RouteBuilder routeBuilder) {
+			routeBuilder.from("direct:inbound").transform(routeBuilder.simple("${body.toUpperCase()}"));
+		}
+
+		public String transformPayload(String payload) {
+			return "___" + payload + "___";
+		}
+
+	}
+
+}

spring-integration-camel/src/test/java/org/springframework/integration/camel/outbound/CamelMessageHandlerTests.java

@@ -183,6 +183,7 @@ public class CamelMessageHandlerTests extends CamelTestSupport {
 			public void configure() {
 				from("direct:simple").to("mock:result");
 			}
+
 		};
 	}
 

src/reference/asciidoc/camel.adoc

@@ -0,0 +1,101 @@
+[[camel]]
+== Apache Camel Support
+
+Spring Integration provides an API and configuration to communicate with https://camel.apache.org[Apache Camel] endpoints declared in the same application context.
+
+You need to include this dependency into your project:
+
+====
+[source, xml, subs="normal", role="primary"]
+.Maven
+----
+<dependency>
+    <groupId>org.springframework.integration</groupId>
+    <artifactId>spring-integration-camel</artifactId>
+    <version>{project-version}</version>
+</dependency>
+----
+[source, groovy, subs="normal", role="secondary"]
+.Gradle
+----
+compile "org.springframework.integration:spring-integration-camel:{project-version}"
+----
+====
+
+Spring Integration and Apache Camel implement Enterprise Integration Patterns and provide a convenient way to compose them, but the projects use a different approach for their API and abstractions implementation.
+Spring Integration fully relies on a dependency injection container from Spring Core.
+It uses many other Spring projects (Spring Data, Spring AMQP, Spring for Apache Kafka etc.) for its channel adapter implementations.
+It also uses the `MessageChannel` abstraction as a first class citizen of which developers need to be aware of, when composing their integration flows.
+Apache Camel, on the other hand, does not provide a first class citizen abstraction of a message channel and proposes to compose its routes via internal exchanges, hidden from the API.
+In addition, it requires some extra https://camel.apache.org/components/3.18.x/spring-summary.html[dependencies and configurations] for it to be used in a Spring application.
+
+Even if it doesn't matter for the final enterprise integration solution how its parts are implemented, a developer experience and high productivity are taken into account.
+Therefore, developers may choose one framework over another for many reasons, or both if there is a gap in some target systems support.
+Spring Integration and Apache Camel applications can interact with each other through many external protocols for which they implement channel adapters.
+For example, a Spring Integration flow may publish a record to an Apache Kafka topic which is consumed by an Apache Camel endpoint on the consumer side.
+Or, an Apache Camel route may write data into an SFTP file the directory, which is polled by a SFTP Inbound Channel Adapter from Spring Integration.
+Or, within the same Spring application context they can communicate via an `ApplicationEvent` https://camel.apache.org/components/3.18.x/spring-event-component.html[abstraction].
+
+To make a development process easier, and to avoid unnecessary network hops, Apache Camel provides a https://camel.apache.org/components/3.18.x/spring-integration-component.html[module] to communicate with Spring Integration via message channels.
+All that is needed is a reference to a `MessageChannel` from the application context, to send or consume messages.
+This works well when Apache Camel routes are initiators of the message flow and Spring Integration plays only a supporting role as a part of the solution.
+
+For a similar developer experience, Spring Integration now provides a channel adapter to call an Apache Camel endpoint and, optionally, wait for a reply.
+There is no inbound channel adapter because subscribing to a `MessageChannel` for consuming Apache Camel messages is enough from the Spring Integration API and abstractions perspective.
+
+[[camel-channel-adapter]]
+=== Outbound Channel Adapter for Apache Camel
+
+The `CamelMessageHandler` is an `AbstractReplyProducingMessageHandler` implementation and can work in both one-way (default) and request-reply modes.
+It uses an `org.apache.camel.ProducerTemplate` to send (or send and receive) into an `org.apache.camel.Endpoint`.
+An interaction mode can be controlled by the `ExchangePattern` option (which can be evaluated at runtime against the request message via a SpEL expression).
+The target Apache Camel endpoint can be configured explicitly or as a SpEL expression to be evaluated at runtime.
+Otherwise, it falls back to the `defaultEndpoint` provided on the `ProducerTemplate`.
+Instead of specifying the endpoint, an in-line, explicit `LambdaRouteBuilder` can be provided, for example to make a call into an Apache Camel component for which there is no channel adapter support in Spring Integration.
+
+In addition, a `HeaderMapper<org.apache.camel.Message>` (the `CamelHeaderMapper` is a default implementation) can be provided, to determine which headers to map between the Spring Integration and Apache Camel messages.
+By default, all headers are mapped.
+
+The `CamelMessageHandler` supports an `async` mode calling `ProducerTemplate.asyncSend()` and producing a `CompletableFuture` for reply processing (if any).
+
+The `exchangeProperties` can be customized via a SpEL expression, which must evaluate to a `Map`.
+
+If a `ProducerTemplate` is not provided, it is created via a `CamelContext` bean resolved from the application context.
+
+====
+[source, java]
+----
+@Bean
+@ServiceActivator(inputChannel = "sendToCamel")
+CamelMessageHandler camelService(ProducerTemplate producerTemplate) {
+    CamelHeaderMapper headerMapper = new CamelHeaderMapper();
+    headerMapper.setOutboundHeaderNames("");
+    headerMapper.setInboundHeaderNames("testHeader");
+
+    CamelMessageHandler camelMessageHandler = new CamelMessageHandler(producerTemplate);
+    camelMessageHandler.setEndpointUri("direct:simple");
+    camelMessageHandler.setExchangePatternExpression(spelExpressionParser.parseExpression("headers.exchangePattern"));
+    camelMessageHandler.setHeaderMapper(headerMapper);
+    return camelMessageHandler;
+}
+----
+====
+
+For Java DSL flow definitions this channel adapter can be configured with a few variants provided by the `Camel` factory:
+
+====
+[source, java]
+----
+@Bean
+IntegrationFlow camelFlow() {
+    return f -> f
+            .handle(Camel.gateway().endpointUri("direct:simple"))
+            .handle(Camel.route(this::camelRoute))
+            .handle(Camel.handler().endpointUri("log:com.mycompany.order?level=WARN"));
+}
+
+private void camelRoute(RouteBuilder routeBuilder) {
+    routeBuilder.from("direct:inbound").transform(routeBuilder.simple("${body.toUpperCase()}"));
+}
+----
+====

src/reference/asciidoc/endpoint-summary.adoc

@@ -54,6 +54,12 @@ The following table summarizes the various endpoints with quick links to the app
 | <<./amqp.adoc#amqp-inbound-gateway,Inbound Gateway>>
 | <<./amqp.adoc#amqp-outbound-gateway,Outbound Gateway>>
 
+| *Apache Camel*
+| N
+| <<./camel.adoc#camel-channel-adapter,Outbound Channel Adapter>>
+| N
+| <<./camel.adoc#camel-channel-adapter,Outbound Gateway>>
+
 | *Apache Cassandra*
 | N
 | <<./cassandra.adoc#cassandra-outbound,Outbound Channel Adapter>>

src/reference/asciidoc/index-single.adoc

@@ -45,6 +45,8 @@ include::./endpoint-summary.adoc[]
 
 include::./amqp.adoc[]
 
+include::./camel.adoc[]
+
 include::./cassandra.adoc[]
 
 include::./event.adoc[]

src/reference/asciidoc/index.adoc

@@ -35,6 +35,7 @@ Welcome to the Spring Integration reference documentation!
 [horizontal]
 <<./endpoint-summary.adoc#spring-integration-endpoints,Integration Endpoint Summary>> :: Protocol-specific channel adapters and gateways summary
 <<./amqp.adoc#amqp,AMQP Support>> :: AMQP channels, adapters and gateways
+<<./camel.adoc#camel,Apache Camel Support>> :: Apache Camel channel adapters and gateways
 <<./cassandra.adoc#cassandra,Apache Cassandra Support>> :: Apache Cassandra channel adapters
 <<./event.adoc#applicationevent,Spring `ApplicationEvent` Support>> :: Handling and consuming Spring application events with channel adapters
 <<./feed.adoc#feed,Feed Adapter>> :: RSS and Atom channel adapters

src/reference/asciidoc/whats-new.adoc

@@ -32,6 +32,12 @@ See <<./mqtt.adoc#mqtt-shared-client,Shared MQTT Client Support>> for more infor
 The GraphQL support has been added.
 See <<./graphql.adoc#graphql,GraphQL Support>> for more information.
 
+[[x6.0-camel]]
+==== Apache Camel Support
+
+Support for Apache Camel routes has been introduced.
+See <<./camel.adoc#camel,Apache Camel Support>> for more information.
+
 [[x6.0-smb]]
 ==== SMB Support