DATAJPA-367 - Issue error for missing spring-aspects.jar if auditing is enabled in xml config.

As the auditing feature requires spring-aspects.jar on the classpath we issue now check whether the jar is present - if not we issue an appropriate error message. Added appropriate note to the JPA reference doc. Added test case to AuditingBeanDefinitionParserTests to verify that a XMLParserError message is emitted if the required class from spring-aspects is not on the class path.

Original pull request: #34.

src/docbkx/jpa.xml

@@ -1010,6 +1010,8 @@ public interface UserRepository extends JpaRepository<User, Long> {
       <filename>orm.xml</filename> to be used for all entities in your
       persistence contexts:</para>
 
+      <para>Note that the auditing feature requires <code>spring-aspects.jar</code> to be on the classpath.</para>
+
       <example>
         <title>Auditing configuration orm.xml</title>
 

src/main/java/org/springframework/data/jpa/repository/config/AuditingBeanDefinitionParser.java

@@ -25,6 +25,7 @@ import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.data.config.AuditingHandlerBeanDefinitionParser;
+import org.springframework.util.ClassUtils;
 import org.w3c.dom.Element;
 
 /**
@@ -88,6 +89,14 @@ public class AuditingBeanDefinitionParser implements BeanDefinitionParser {
 		public BeanDefinition parse(Element element, ParserContext parserContext) {
 
 			if (!parserContext.getRegistry().containsBeanDefinition(BEAN_CONFIGURER_ASPECT_BEAN_NAME)) {
+
+				if (!ClassUtils.isPresent(BEAN_CONFIGURER_ASPECT_CLASS_NAME, getClass().getClassLoader())) {
+					parserContext.getReaderContext().error(
+							"Could not configure Spring Data JPA auditing-feature because"
+									+ " spring-aspects.jar is not on the classpath!\n"
+									+ "If you want to use auditing please add spring-aspects.jar to the classpath.", element);
+				}
+
 				RootBeanDefinition def = new RootBeanDefinition();
 				def.setBeanClassName(BEAN_CONFIGURER_ASPECT_CLASS_NAME);
 				def.setFactoryMethodName("aspectOf");

src/test/java/org/springframework/data/jpa/repository/config/AuditingBeanDefinitionParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2012 the original author or authors.
+ * Copyright 2008-2013 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.
@@ -23,14 +23,17 @@ import org.springframework.beans.PropertyValue;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
+import org.springframework.beans.factory.parsing.BeanDefinitionParsingException;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.core.io.ClassPathResource;
+import org.springframework.instrument.classloading.ShadowingClassLoader;
 
 /**
  * Integration tests for {@link AuditingBeanDefinitionParser}.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class AuditingBeanDefinitionParserTests {
 
@@ -65,6 +68,17 @@ public class AuditingBeanDefinitionParserTests {
 		assertThat(bean, is(notNullValue()));
 	}
 
+	/**
+	 * @see DATAJPA-367
+	 */
+	@Test(expected = BeanDefinitionParsingException.class)
+	public void shouldThrowBeanDefinitionParsingExceptionIfClassFromSpringAspectsJarCannotBeFound() {
+
+		ShadowingClassLoader scl = new ShadowingClassLoader(getClass().getClassLoader());
+		scl.excludeClass(AuditingBeanDefinitionParser.AUDITING_ENTITY_LISTENER_CLASS_NAME);
+		DefaultListableBeanFactory factory = loadFactoryFrom("auditing/auditing-namespace-context.xml", scl);
+	}
+
 	private void assertSetDatesIsSetTo(String configFile, String value) {
 
 		BeanDefinition definition = getBeanDefinition(configFile);
@@ -82,6 +96,12 @@ public class AuditingBeanDefinitionParserTests {
 	}
 
 	private DefaultListableBeanFactory loadFactoryFrom(String configFile) {
+		return loadFactoryFrom(configFile, getClass().getClassLoader());
+	}
+
+	private DefaultListableBeanFactory loadFactoryFrom(String configFile, ClassLoader classLoader) {
+
+		Thread.currentThread().setContextClassLoader(classLoader);
 		DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
 		XmlBeanDefinitionReader xmlBeanDefinitionReader = new XmlBeanDefinitionReader(factory);
 		xmlBeanDefinitionReader.loadBeanDefinitions(new ClassPathResource(configFile));