Polishing.

Update exception messages, align method names, extract methods
Original Pull Request: #2488

Author: christophstrobl

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

@@ -108,27 +108,23 @@ public Optional<AbstractBeanDefinition> detectCustomImplementation(Implementatio
 				.filter(lookup::matches) //
 				.collect(StreamUtils.toUnmodifiableSet());
 
-		return selectImplementationCandidate(lookup, definitions, () -> {
-
-			if (definitions.isEmpty()) {
-				return Optional.empty();
-			}
-
-			return Optional.of(definitions.iterator().next());
-		});
+		return selectImplementationCandidate(lookup, definitions);
 	}
 
 	private static Optional<AbstractBeanDefinition> selectImplementationCandidate(
-			ImplementationLookupConfiguration lookup, Set<BeanDefinition> definitions,
-			Supplier<Optional<BeanDefinition>> fallback) {
+			ImplementationLookupConfiguration lookup, Set<BeanDefinition> definitions) {
 
 		return SelectionSet //
-				.of(definitions, c -> c.isEmpty() ? fallback.get() : throwAmbiguousCustomImplementationException(c)) //
+				.of(definitions, c -> c.isEmpty() ? firstOrEmptyBeanDefinition(definitions) : throwAmbiguousCustomImplementationException(c)) //
 				.filterIfNecessary(lookup::hasMatchingBeanName) //
 				.uniqueResult() //
 				.map(AbstractBeanDefinition.class::cast);
 	}
 
+	static Optional<BeanDefinition> firstOrEmptyBeanDefinition(Set<BeanDefinition> definitions) {
+		return definitions.isEmpty() ? Optional.empty() : Optional.of(definitions.iterator().next());
+	}
+
 	private Set<BeanDefinition> findCandidateBeanDefinitions(ImplementationDetectionConfiguration config) {
 
 		String postfix = config.getImplementationPostfix();

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

@@ -46,7 +46,7 @@ class DefaultImplementationLookupConfiguration implements ImplementationLookupCo
 
 		Assert.notNull(config, "ImplementationDetectionConfiguration must not be null");
 		Assert.hasText(interfaceName, "Interface name must not be null or empty");
-		Assert.hasText(beanName, "Bean name must not be null or empty!");
+		Assert.hasText(beanName, "Bean name must not be null or empty");
 
 		this.config = config;
 		this.interfaceName = interfaceName;

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

@@ -27,7 +27,6 @@
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
@@ -195,31 +194,8 @@ private Optional<String> registerCustomImplementation(RepositoryConfiguration<?>
 			return Optional.of(configurationBeanName);
 		}
 
-		Optional<AbstractBeanDefinition> beanDefinition = implementationDetector.detectCustomImplementation(lookup);
-
-		return beanDefinition.map(it -> {
-
-			String scannedBeanName = configuration.getConfigurationSource().generateBeanName(it);
-			it.setSource(configuration.getSource());
-
-			if (registry.containsBeanDefinition(scannedBeanName)) {
-
-				if (logger.isDebugEnabled()) {
-					logger.debug(String.format("Custom repository implementation already registered: %s %s", scannedBeanName,
-							it.getBeanClassName()));
-				}
-			} else {
-
-				if (logger.isDebugEnabled()) {
-					logger.debug(String.format("Registering custom repository implementation: %s %s", scannedBeanName,
-							it.getBeanClassName()));
-				}
-
-				registry.registerBeanDefinition(scannedBeanName, it);
-			}
-
-			return scannedBeanName;
-		});
+		return implementationDetector.detectCustomImplementation(lookup)
+				.map(it -> potentiallyRegisterRepositoryImplementation(configuration, it));
 	}
 
 	private String registerRepositoryFragments(RepositoryConfiguration<?> configuration) {
@@ -264,6 +240,31 @@ private Optional<RepositoryFragmentConfiguration> detectRepositoryFragmentConfig
 				configuration.getConfigurationSource().generateBeanName(bd)));
 	}
 
+	private String potentiallyRegisterRepositoryImplementation(RepositoryConfiguration<?> configuration,
+			AbstractBeanDefinition beanDefinition) {
+
+		String targetBeanName = configuration.getConfigurationSource().generateBeanName(beanDefinition);
+		beanDefinition.setSource(configuration.getSource());
+
+		if (registry.containsBeanDefinition(targetBeanName)) {
+
+			if (logger.isDebugEnabled()) {
+				logger.debug(String.format("Custom repository implementation already registered: %s %s", targetBeanName,
+						beanDefinition.getBeanClassName()));
+			}
+		} else {
+
+			if (logger.isDebugEnabled()) {
+				logger.debug(String.format("Registering custom repository implementation: %s %s", targetBeanName,
+						beanDefinition.getBeanClassName()));
+			}
+
+			registry.registerBeanDefinition(targetBeanName, beanDefinition);
+		}
+
+		return targetBeanName;
+	}
+
 	private void potentiallyRegisterFragmentImplementation(RepositoryConfiguration<?> repositoryConfiguration,
 			RepositoryFragmentConfiguration fragmentConfiguration) {
 

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

@@ -75,9 +75,9 @@ public RepositoryFragmentConfiguration(String interfaceName, AbstractBeanDefinit
 	private RepositoryFragmentConfiguration(String interfaceName, String className,
 			Optional<AbstractBeanDefinition> beanDefinition, String beanName) {
 
-		Assert.hasText(interfaceName, "Interface name must not be null or empty!");
-		Assert.notNull(beanDefinition, "Bean definition must not be null!");
-		Assert.notNull(beanName, "Bean name must not be null!");
+		Assert.hasText(interfaceName, "Interface name must not be null or empty");
+		Assert.notNull(beanDefinition, "Bean definition must not be null");
+		Assert.notNull(beanName, "Bean name must not be null");
 
 		this.interfaceName = interfaceName;
 		this.className = className;

src/main/java/org/springframework/data/repository/core/RepositoryInformationSupport.java

@@ -46,8 +46,8 @@ public abstract class RepositoryInformationSupport implements RepositoryInformat
 
 	public RepositoryInformationSupport(Supplier<RepositoryMetadata> metadata, Supplier<Class<?>> repositoryBaseClass) {
 
-		Assert.notNull(metadata, "Repository metadata must not be null!");
-		Assert.notNull(repositoryBaseClass, "Repository base class must not be null!");
+		Assert.notNull(metadata, "Repository metadata must not be null");
+		Assert.notNull(repositoryBaseClass, "Repository base class must not be null");
 
 		this.metadata = Lazy.of(metadata);
 		this.repositoryBaseClass = Lazy.of(repositoryBaseClass);