DATAJDBC-216 - Polishing.

Simplified code by using constructor injection plus Lombok.
Removed superfluous handling of BeforeSave events with null entity.

Original pull request: #71.

src/main/java/org/springframework/data/jdbc/domain/support/JdbcAuditingEventListener.java

@@ -15,15 +15,14 @@
  */
 package org.springframework.data.jdbc.domain.support;
 
-import org.springframework.beans.factory.ObjectFactory;
+import lombok.RequiredArgsConstructor;
+
 import org.springframework.context.ApplicationListener;
 import org.springframework.data.auditing.AuditingHandler;
 import org.springframework.data.jdbc.mapping.event.BeforeSaveEvent;
 import org.springframework.data.jdbc.mapping.model.JdbcMappingContext;
 import org.springframework.data.jdbc.mapping.model.JdbcPersistentEntityInformation;
 import org.springframework.data.jdbc.repository.config.EnableJdbcAuditing;
-import org.springframework.lang.Nullable;
-import org.springframework.util.Assert;
 
 /**
  * Spring JDBC event listener to capture auditing information on persisting and updating entities.
@@ -31,36 +30,15 @@ import org.springframework.util.Assert;
  * An instance of this class gets registered when you apply {@link EnableJdbcAuditing} to your Spring config.
  *
  * @author Kazuki Shimizu
+ * @author Jens Schauder
  * @see EnableJdbcAuditing
  * @since 1.0
  */
+@RequiredArgsConstructor
 public class JdbcAuditingEventListener implements ApplicationListener<BeforeSaveEvent> {
 
-	@Nullable private AuditingHandler handler;
-	private JdbcMappingContext context;
-
-	/**
-	 * Configures the {@link AuditingHandler} to be used to set the current auditor on the domain types touched.
-	 *
-	 * @param auditingHandler must not be {@literal null}.
-	 */
-	public void setAuditingHandler(ObjectFactory<AuditingHandler> auditingHandler) {
-
-		Assert.notNull(auditingHandler, "AuditingHandler must not be null!");
-
-		this.handler = auditingHandler.getObject();
-	}
-
-	/**
-	 * Configures a {@link JdbcMappingContext} that use for judging whether new object or not.
-	 * @param context must not be {@literal null}
-	 */
-	public void setJdbcMappingContext(JdbcMappingContext context) {
-
-		Assert.notNull(context, "JdbcMappingContext must not be null!");
-
-		this.context = context;
-	}
+	private final AuditingHandler handler;
+	private final JdbcMappingContext context;
 
 	/**
 	 * {@inheritDoc}
@@ -70,19 +48,22 @@ public class JdbcAuditingEventListener implements ApplicationListener<BeforeSave
 	@Override
 	public void onApplicationEvent(BeforeSaveEvent event) {
 
-		if (handler != null) {
+		Object entity = event.getEntity();
+
+		@SuppressWarnings("unchecked")
+		Class<Object> entityType = event.getChange().getEntityType();
+		JdbcPersistentEntityInformation<Object, ?> entityInformation = context
+				.getRequiredPersistentEntityInformation(entityType);
+
+		invokeHandler(entity, entityInformation);
+	}
+
+	private <T> void invokeHandler(T entity, JdbcPersistentEntityInformation<T, ?> entityInformation) {
 
-			event.getOptionalEntity().ifPresent(entity -> {
-				@SuppressWarnings("unchecked")
-				Class<Object> entityType = event.getChange().getEntityType();
-				JdbcPersistentEntityInformation<Object, ?> entityInformation =
-						context.getRequiredPersistentEntityInformation(entityType);
-				if (entityInformation.isNew(entity)) {
-					handler.markCreated(entity);
-				} else {
-					handler.markModified(entity);
-				}
-			});
+		if (entityInformation.isNew(entity)) {
+			handler.markCreated(entity);
+		} else {
+			handler.markModified(entity);
 		}
 	}
 }

src/main/java/org/springframework/data/jdbc/repository/config/JdbcAuditingRegistrar.java

@@ -17,14 +17,12 @@ package org.springframework.data.jdbc.repository.config;
 
 import java.lang.annotation.Annotation;
 
-import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport;
 import org.springframework.data.auditing.config.AuditingConfiguration;
-import org.springframework.data.config.ParsingUtils;
 import org.springframework.data.jdbc.domain.support.JdbcAuditingEventListener;
 
 /**
@@ -33,10 +31,14 @@ import org.springframework.data.jdbc.domain.support.JdbcAuditingEventListener;
  *
  * @see EnableJdbcAuditing
  * @author Kazuki Shimizu
+ * @author Jens Schauder
  * @since 1.0
  */
 class JdbcAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 
+	private static final String AUDITING_HANDLER_BEAN_NAME = "jdbcAuditingHandler";
+	private static final String JDBC_MAPPING_CONTEXT_BEAN_NAME = "jdbcMappingContext";
+
 	/**
 	 * {@inheritDoc}
 	 * 
@@ -56,7 +58,7 @@ class JdbcAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 	 */
 	@Override
 	protected String getAuditingHandlerBeanName() {
-		return "jdbcAuditingHandler";
+		return AUDITING_HANDLER_BEAN_NAME;
 	}
 
 	/*
@@ -67,7 +69,7 @@ class JdbcAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 	protected BeanDefinitionBuilder getAuditHandlerBeanDefinitionBuilder(AuditingConfiguration configuration) {
 
 		BeanDefinitionBuilder builder = super.getAuditHandlerBeanDefinitionBuilder(configuration);
-		return builder.addConstructorArgReference("jdbcMappingContext");
+		return builder.addConstructorArgReference(JDBC_MAPPING_CONTEXT_BEAN_NAME);
 	}
 
 	/**
@@ -81,10 +83,10 @@ class JdbcAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
 			BeanDefinitionRegistry registry) {
 
 		Class<?> listenerClass = JdbcAuditingEventListener.class;
-		BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(listenerClass);
-		builder.addPropertyValue("auditingHandler",
-				ParsingUtils.getObjectFactoryBeanDefinition(getAuditingHandlerBeanName(), null));
-		builder.setAutowireMode(AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE);
+		BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(listenerClass) //
+				.addConstructorArgReference(AUDITING_HANDLER_BEAN_NAME) //
+				.addConstructorArgReference(JDBC_MAPPING_CONTEXT_BEAN_NAME);
+
 		registerInfrastructureBeanWithId(builder.getRawBeanDefinition(), listenerClass.getName(), registry);
 	}
 

src/test/java/org/springframework/data/jdbc/repository/config/EnableJdbcAuditingHsqlIntegrationTests.java

@@ -183,7 +183,6 @@ public class EnableJdbcAuditingHsqlIntegrationTests {
 		};
 	}
 
-
 	private void sleepMillis(int timeout) {
 
 		try {