DATACMNS-609 - Improved bean definition registration for repository configuration.

The bean definitions that were registered for a repository configuration setup we registered once for every usage of the repository configuration element (annotation or XML). This caused multiple registrations of the very same bean definition which - as in case of the RepositoryInterfaceAwareBeanPostProcessor - apparently leads to performance problems in the container startup. Feedback for the latter claim is already asked for but we improved the registration setup nonetheless.

Introduced a registerIfNotAlreadyRegistered(…) method on RepositoryConfigurationExtensionSupport to allow easy registration of to-b-registered-once-and-only-once beans. We now hint towards the newly introduced method in registerWithSourceAndGeneratedBeanName(…).

src/main/java/org/springframework/data/repository/config/RepositoryConfigurationExtensionSupport.java

@@ -118,7 +118,7 @@ public abstract class RepositoryConfigurationExtensionSupport implements Reposit
 		AbstractBeanDefinition definition = BeanDefinitionBuilder.rootBeanDefinition(REPOSITORY_INTERFACE_POST_PROCESSOR)
 				.getBeanDefinition();
 
-		registerWithSourceAndGeneratedBeanName(registry, definition, configurationSource.getSource());
+		registerIfNotAlreadyRegistered(definition, registry, REPOSITORY_INTERFACE_POST_PROCESSOR, configurationSource);
 	}
 
 	/**
@@ -169,12 +169,15 @@ public abstract class RepositoryConfigurationExtensionSupport implements Reposit
 
 	/**
 	 * Sets the given source on the given {@link AbstractBeanDefinition} and registers it inside the given
-	 * {@link BeanDefinitionRegistry}.
+	 * {@link BeanDefinitionRegistry}. For {@link BeanDefinition}s to be registerd once-and-only-once for all
+	 * configuration elements (annotation or XML), prefer calling
+	 * {@link #registerIfNotAlreadyRegistered(AbstractBeanDefinition, BeanDefinitionRegistry, String, Object)} with a
+	 * dedicated bean name to avoid the bead definition being registered multiple times. *
 	 * 
-	 * @param registry
-	 * @param bean
-	 * @param source
-	 * @return
+	 * @param registry must not be {@literal null}.
+	 * @param bean must not be {@literal null}.
+	 * @param source must not be {@literal null}.
+	 * @return the bean name generated for the given {@link BeanDefinition}
 	 */
 	public static String registerWithSourceAndGeneratedBeanName(BeanDefinitionRegistry registry,
 			AbstractBeanDefinition bean, Object source) {
@@ -187,6 +190,26 @@ public abstract class RepositoryConfigurationExtensionSupport implements Reposit
 		return beanName;
 	}
 
+	/**
+	 * Registers the given {@link AbstractBeanDefinition} with the given registry with the given bean name unless the
+	 * registry already contains a bean with that name.
+	 * 
+	 * @param bean must not be {@literal null}.
+	 * @param registry must not be {@literal null}.
+	 * @param beanName must not be {@literal null} or empty.
+	 * @param source must not be {@literal null}.
+	 */
+	public static void registerIfNotAlreadyRegistered(AbstractBeanDefinition bean, BeanDefinitionRegistry registry,
+			String beanName, Object source) {
+
+		if (registry.containsBeanDefinition(beanName)) {
+			return;
+		}
+
+		bean.setSource(source);
+		registry.registerBeanDefinition(beanName, bean);
+	}
+
 	/**
 	 * Returns whether the given {@link BeanDefinitionRegistry} already contains a bean of the given type assuming the
 	 * bean name has been autogenerated.

src/test/java/org/springframework/data/repository/config/RepositoryConfigurationExtensionSupportUnitTests.java

@@ -23,7 +23,12 @@ import java.util.Collection;
 import java.util.Collections;
 
 import org.junit.Test;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.context.annotation.Primary;
+import org.springframework.core.env.StandardEnvironment;
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.core.type.StandardAnnotationMetadata;
 import org.springframework.data.repository.Repository;
 import org.springframework.data.repository.core.support.RepositoryFactorySupport;
 
@@ -60,6 +65,26 @@ public class RepositoryConfigurationExtensionSupportUnitTests {
 		assertThat(extension.isStrictRepositoryCandidate(ExtendingInterface.class), is(true));
 	}
 
+	/**
+	 * @see DATACMNS-609
+	 */
+	@Test
+	public void registersRepositoryInterfaceAwareBeanPostProcessorOnlyOnceForMultipleConfigurations() {
+
+		DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
+		AnnotationMetadata annotationMetadata = new StandardAnnotationMetadata(SampleConfiguration.class, true);
+
+		DefaultResourceLoader resourceLoader = new DefaultResourceLoader();
+		StandardEnvironment environment = new StandardEnvironment();
+		AnnotationRepositoryConfigurationSource configurationSource = new AnnotationRepositoryConfigurationSource(
+				annotationMetadata, EnableRepositories.class, resourceLoader, environment);
+
+		extension.registerBeansForRoot(beanFactory, configurationSource);
+		extension.registerBeansForRoot(beanFactory, configurationSource);
+
+		assertThat(beanFactory.getBeanDefinitionCount(), is(1));
+	}
+
 	static class SampleRepositoryConfigurationExtension extends RepositoryConfigurationExtensionSupport {
 
 		@Override
@@ -95,4 +120,7 @@ public class RepositoryConfigurationExtensionSupportUnitTests {
 	interface StoreInterface {}
 
 	interface ExtendingInterface extends StoreInterface, Repository<PlainType, Long> {}
+
+	@EnableRepositories
+	static class SampleConfiguration {}
 }