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/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 {}
 }