* Meta-annotate @MessagingGateway with a @MessageEndpoint

* Alias `@MessageEndpoint.value()` with a `@Component.value()`
* Alias `@MessagingGateway.name()` with a `@MessageEndpoint.value()`

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/annotation/MessageEndpoint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -23,13 +23,15 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.annotation.AliasFor;
 import org.springframework.stereotype.Component;
 
 /**
  * Stereotype annotation indicating that a class is capable of serving as a
  * Message Endpoint.
  *
  * @author Mark Fisher
+ * @author Artem Bilan
  */
 @Target(ElementType.TYPE)
 @Retention(RetentionPolicy.RUNTIME)
@@ -41,9 +43,9 @@
 	/**
 	 * The value may indicate a suggestion for a logical component name,
 	 * to be turned into a Spring bean in case of an autodetected component.
-	 *
 	 * @return the suggested component name, if any
 	 */
+	@AliasFor(annotation = Component.class)
 	String value() default "";
 
 }

spring-integration-core/src/main/java/org/springframework/integration/annotation/MessagingGateway.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2021 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.
@@ -21,12 +21,12 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.springframework.stereotype.Indexed;
+import org.springframework.core.annotation.AliasFor;
 
 /**
  * A stereotype annotation to provide an Integration Messaging Gateway Proxy
- * ({@code <gateway/>}) as an abstraction over the messaging API. The target
- * application's business logic may be completely unaware of the Spring Integration
+ * as an abstraction over the messaging API. The target application's
+ * business logic may be completely unaware of the Spring Integration
  * API, with the code interacting only via the interface.
  * <p>
  * Important: The {@link IntegrationComponentScan} annotation is required along with
@@ -41,17 +41,19 @@
  * @since 4.0
  *
  * @see IntegrationComponentScan
+ * @see MessageEndpoint
  */
 @Target(ElementType.TYPE)
 @Retention(RetentionPolicy.RUNTIME)
-@Indexed
+@MessageEndpoint
 public @interface MessagingGateway {
 
 	/**
 	 * The value may indicate a suggestion for a logical component name,
 	 * to be turned into a Spring bean in case of an autodetected component.
 	 * @return the suggested component name, if any
 	 */
+	@AliasFor(annotation = MessageEndpoint.class, attribute = "value")
 	String name() default "";
 
 	/**

spring-integration-core/src/test/java/org/springframework/integration/configuration/EnableIntegrationTests.java

@@ -48,7 +48,10 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.beans.factory.config.AbstractFactoryBean;
+import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.Lifecycle;
 import org.springframework.context.SmartLifecycle;
@@ -64,6 +67,7 @@
 import org.springframework.context.expression.EnvironmentAccessor;
 import org.springframework.context.expression.MapAccessor;
 import org.springframework.core.annotation.AliasFor;
+import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.log.LogAccessor;
 import org.springframework.core.serializer.support.SerializingConverter;
@@ -79,6 +83,7 @@
 import org.springframework.integration.annotation.GatewayHeader;
 import org.springframework.integration.annotation.InboundChannelAdapter;
 import org.springframework.integration.annotation.IntegrationComponentScan;
+import org.springframework.integration.annotation.MessageEndpoint;
 import org.springframework.integration.annotation.MessagingGateway;
 import org.springframework.integration.annotation.Poller;
 import org.springframework.integration.annotation.Publisher;
@@ -143,6 +148,7 @@
 import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.MultiValueMap;
+import org.springframework.util.StringUtils;
 
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -488,6 +494,10 @@ public void testChangePatterns() {
 
 	@Test
 	public void testMessagingGateway() throws InterruptedException {
+		String gatewayBeanName = AnnotatedElementUtils.findMergedAnnotation(TestGateway.class, Component.class).value();
+		assertThat(gatewayBeanName).isEqualTo("namedTestGateway");
+		assertThat(this.testGateway).isSameAs(this.context.getBean(gatewayBeanName));
+
 		String payload = "bar";
 		String result = this.testGateway.echo(payload);
 		assertThat(result.substring(0, payload.length())).isEqualTo(payload.toUpperCase());
@@ -1464,7 +1474,7 @@ public interface ConditionalGateway {
 
 	}
 
-	@TestMessagingGateway
+	@TestMessagingGateway(name = "namedTestGateway")
 	public interface TestGateway {
 
 		@Gateway(headers = @GatewayHeader(name = "calledMethod", expression = "method.name"))
@@ -1494,6 +1504,9 @@ public interface TestGateway2 {
 			defaultHeaders = @GatewayHeader(name = "foo", value = "FOO"))
 	public @interface TestMessagingGateway {
 
+		@AliasFor(annotation = MessagingGateway.class)
+		String name() default "";
+
 		@AliasFor(annotation = MessagingGateway.class, attribute = "defaultRequestChannel")
 		String defaultRequestChannel() default "";
 

src/reference/asciidoc/gateway.adoc

@@ -319,11 +319,9 @@ Along with the `@MessagingGateway` annotation you can mark a service interface w
 
 Starting with version 6.0, an interface with the `@MessagingGateway` can also be marked with a `@Primary` annotation for respective configuration logic as its possible with any Spring `@Component` definition.
 
-The `@MessagingGateway.name()` attribute specifies a name for the target bean registered.
-If it is not provided, the  `@IntegrationComponentScan.nameGenerator()` (since version `6.0`) is consulted.
-And if that is not provided as well, an `AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR` bean, provided for the application context, is used.
-Otherwise, the bean name generation falls back to the `AnnotationBeanNameGenerator` which results with an uncapitalized simple class name.
-In other words, the current naming strategy for gateway proxy beans is aligned with standard Spring Framework `@ComponentScan` approach.
+The `@MessagingGateway` is meta-annotated with a `@MessageEndpoint` since version `6.0` and the `name()` attribute is, essentially, aliased to the `@Compnent.value()`.
+This way the bean names generating strategy for gateway proxies is realigned with the standard Spring annotation configuration for scanned and imported components.
+The default `AnnotationBeanNameGenerator` can be overridden globally via an `AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR` or as a `@IntegrationComponentScan.nameGenerator()` attribute.
 
 NOTE: If you have no XML configuration, the `@EnableIntegration` annotation is required on at least one `@Configuration` class.
 See <<./overview.adoc#configuration-enable-integration,Configuration and `@EnableIntegration`>> for more information.