GH-2007: Subclass for IntComponentScanRegistrar

Fixes GH-2007 (https://github.com/spring-projects/spring-integration/issues/2007)

To allow more straightforward extension and avoid some extra mocking provide some `protected` methods for the `IntegrationComponentScanRegistrar` which can be implement in some specific cases, like Spring Boot auto-configuration

The `EnableComponentScanTests` demonstrates how it can be done now in case of `basePackage` overriding

spring-integration-core/src/main/java/org/springframework/integration/config/IntegrationComponentScanRegistrar.java

@@ -18,6 +18,8 @@ package org.springframework.integration.config;
 
 import java.lang.annotation.Annotation;
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -48,6 +50,7 @@ import org.springframework.core.type.filter.AspectJTypeFilter;
 import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.core.type.filter.RegexPatternTypeFilter;
 import org.springframework.core.type.filter.TypeFilter;
+import org.springframework.integration.annotation.IntegrationComponentScan;
 import org.springframework.integration.annotation.MessagingGateway;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -86,26 +89,13 @@ public class IntegrationComponentScanRegistrar implements ImportBeanDefinitionRe
 
 	@Override
 	public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
-		Map<String, Object> componentScan = importingClassMetadata
-				.getAnnotationAttributes("org.springframework.integration.annotation.IntegrationComponentScan");
+		Map<String, Object> componentScan =
+				importingClassMetadata.getAnnotationAttributes(IntegrationComponentScan.class.getName());
 
-		Set<String> basePackages = new HashSet<String>();
-		for (String pkg : (String[]) componentScan.get("value")) {
-			if (StringUtils.hasText(pkg)) {
-				basePackages.add(pkg);
-			}
-		}
-		for (String pkg : (String[]) componentScan.get("basePackages")) {
-			if (StringUtils.hasText(pkg)) {
-				basePackages.add(pkg);
-			}
-		}
-		for (Class<?> clazz : (Class[]) componentScan.get("basePackageClasses")) {
-			basePackages.add(ClassUtils.getPackageName(clazz));
-		}
+		Collection<String> basePackages = getBasePackages(importingClassMetadata, registry);
 
 		if (basePackages.isEmpty()) {
-			basePackages.add(ClassUtils.getPackageName(importingClassMetadata.getClassName()));
+			basePackages = Collections.singleton(ClassUtils.getPackageName(importingClassMetadata.getClassName()));
 		}
 
 		ClassPathScanningCandidateComponentProvider scanner = new ClassPathScanningCandidateComponentProvider(false) {
@@ -150,6 +140,26 @@ public class IntegrationComponentScanRegistrar implements ImportBeanDefinitionRe
 		}
 	}
 
+	protected Collection<String> getBasePackages(AnnotationMetadata importingClassMetadata,
+			BeanDefinitionRegistry registry) {
+		Map<String, Object> componentScan =
+				importingClassMetadata.getAnnotationAttributes(IntegrationComponentScan.class.getName());
+
+		Set<String> basePackages = new HashSet<>();
+
+		for (String pkg : (String[]) componentScan.get("value")) {
+			if (StringUtils.hasText(pkg)) {
+				basePackages.add(pkg);
+			}
+		}
+
+		for (Class<?> clazz : (Class[]) componentScan.get("basePackageClasses")) {
+			basePackages.add(ClassUtils.getPackageName(clazz));
+		}
+
+		return basePackages;
+	}
+
 	private List<TypeFilter> typeFiltersFor(AnnotationAttributes filter, BeanDefinitionRegistry registry) {
 		List<TypeFilter> typeFilters = new ArrayList<>();
 		FilterType filterType = filter.getEnum("type");

spring-integration-core/src/test/java/org/springframework/integration/dsl/flows/IntegrationFlowTests.java

@@ -419,7 +419,7 @@ public class IntegrationFlowTests {
 
 
 	@MessagingGateway(defaultRequestChannel = "controlBus")
-	private interface ControlBusGateway {
+	public interface ControlBusGateway {
 
 		void send(String command);
 	}

spring-integration-core/src/test/java/org/springframework/integration/enablecomponentscan/EnableComponentScanTests.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://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.enablecomponentscan;
+
+import static org.hamcrest.Matchers.emptyArray;
+import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertThat;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.core.type.StandardAnnotationMetadata;
+import org.springframework.integration.annotation.IntegrationComponentScan;
+import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.config.IntegrationComponentScanRegistrar;
+import org.springframework.integration.dsl.flows.IntegrationFlowTests;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.util.ClassUtils;
+
+/**
+ * @author Artem Bilan
+ * @author Gary Russell
+ * @since 4.0
+ */
+@RunWith(SpringRunner.class)
+@DirtiesContext
+public class EnableComponentScanTests {
+
+	@Autowired
+	private ApplicationContext applicationContext;
+
+	@Test
+	public void testCustomIntegrationComponentScan() {
+		assertThat(applicationContext.getBeanNamesForType(IntegrationFlowTests.ControlBusGateway.class),
+				not(emptyArray()));
+	}
+
+	@Configuration
+	@EnableIntegration
+	@Import(CustomIntegrationComponentScanRegistrar.class)
+	public static class IntegrationComponentScanAutoConfiguration {
+
+	}
+
+	private static class CustomIntegrationComponentScanRegistrar extends IntegrationComponentScanRegistrar {
+
+		@Override
+		public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata,
+				BeanDefinitionRegistry registry) {
+			super.registerBeanDefinitions(new StandardAnnotationMetadata(
+					IntegrationComponentScanConfiguration.class, true), registry);
+		}
+
+		@Override
+		protected Collection<String> getBasePackages(AnnotationMetadata importingClassMetadata,
+				BeanDefinitionRegistry registry) {
+			return Collections.singleton(ClassUtils.getPackageName(IntegrationFlowTests.ControlBusGateway.class));
+		}
+
+		@IntegrationComponentScan
+		private static class IntegrationComponentScanConfiguration {
+
+		}
+
+	}
+
+}