Configuration class parsing reuses metadata from AnnotatedBeanDefinition as far as possible

Issue: SPR-12394

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClass.java

@@ -68,11 +68,10 @@ final class ConfigurationClass {
 	 * Create a new {@link ConfigurationClass} with the given name.
 	 * @param metadataReader reader used to parse the underlying {@link Class}
 	 * @param beanName must not be {@code null}
-	 * @throws IllegalArgumentException if beanName is null (as of Spring 3.1.1)
 	 * @see ConfigurationClass#ConfigurationClass(Class, ConfigurationClass)
 	 */
 	public ConfigurationClass(MetadataReader metadataReader, String beanName) {
-		Assert.hasText(beanName, "bean name must not be null");
+		Assert.hasText(beanName, "Bean name must not be null");
 		this.metadata = metadataReader.getAnnotationMetadata();
 		this.resource = metadataReader.getResource();
 		this.beanName = beanName;
@@ -96,7 +95,6 @@ final class ConfigurationClass {
 	 * Create a new {@link ConfigurationClass} with the given name.
 	 * @param clazz the underlying {@link Class} to represent
 	 * @param beanName name of the {@code @Configuration} class bean
-	 * @throws IllegalArgumentException if beanName is null (as of Spring 3.1.1)
 	 * @see ConfigurationClass#ConfigurationClass(Class, ConfigurationClass)
 	 */
 	public ConfigurationClass(Class<?> clazz, String beanName) {
@@ -120,6 +118,19 @@ final class ConfigurationClass {
 		this.importedBy.add(importedBy);
 	}
 
+	/**
+	 * Create a new {@link ConfigurationClass} with the given name.
+	 * @param metadata the metadata for the underlying class to represent
+	 * @param beanName name of the {@code @Configuration} class bean
+	 * @see ConfigurationClass#ConfigurationClass(Class, ConfigurationClass)
+	 */
+	public ConfigurationClass(AnnotationMetadata metadata, String beanName) {
+		Assert.hasText(beanName, "Bean name must not be null");
+		this.metadata = metadata;
+		this.resource = new DescriptiveResource(metadata.getClassName());
+		this.beanName = beanName;
+	}
+
 
 	public AnnotationMetadata getMetadata() {
 		return this.metadata;

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -41,6 +41,7 @@ import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.beans.factory.BeanDefinitionStoreException;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinitionHolder;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
@@ -158,7 +159,10 @@ class ConfigurationClassParser {
 		for (BeanDefinitionHolder holder : configCandidates) {
 			BeanDefinition bd = holder.getBeanDefinition();
 			try {
-				if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) {
+				if (bd instanceof AnnotatedBeanDefinition) {
+					parse(((AnnotatedBeanDefinition) bd).getMetadata(), holder.getBeanName());
+				}
+				else if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) {
 					parse(((AbstractBeanDefinition) bd).getBeanClass(), holder.getBeanName());
 				}
 				else {
@@ -169,32 +173,26 @@ class ConfigurationClassParser {
 				throw ex;
 			}
 			catch (Exception ex) {
-				throw new BeanDefinitionStoreException("Failed to parse configuration class [" + bd.getBeanClassName() + "]", ex);
+				throw new BeanDefinitionStoreException(
+						"Failed to parse configuration class [" + bd.getBeanClassName() + "]", ex);
 			}
 		}
 		processDeferredImportSelectors();
 	}
 
-	/**
-	 * Parse the specified {@link Configuration @Configuration} class.
-	 * @param className the name of the class to parse
-	 * @param beanName may be null, but if populated represents the bean id
-	 * (assumes that this configuration class was configured via XML)
-	 */
 	protected final void parse(String className, String beanName) throws IOException {
 		MetadataReader reader = this.metadataReaderFactory.getMetadataReader(className);
 		processConfigurationClass(new ConfigurationClass(reader, beanName));
 	}
 
-	/**
-	 * Parse the specified {@link Configuration @Configuration} class.
-	 * @param clazz the Class to parse
-	 * @param beanName must not be null (as of Spring 3.1.1)
-	 */
 	protected final void parse(Class<?> clazz, String beanName) throws IOException {
 		processConfigurationClass(new ConfigurationClass(clazz, beanName));
 	}
 
+	protected final void parse(AnnotationMetadata metadata, String beanName) throws IOException {
+		processConfigurationClass(new ConfigurationClass(metadata, beanName));
+	}
+
 
 	protected void processConfigurationClass(ConfigurationClass configClass) throws IOException {
 		if (this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) {

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassUtils.java

@@ -23,6 +23,7 @@ import java.util.Set;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
 import org.springframework.core.Conventions;
@@ -70,41 +71,47 @@ abstract class ConfigurationClassUtils {
 	 * @return whether the candidate qualifies as (any kind of) configuration class
 	 */
 	public static boolean checkConfigurationClassCandidate(BeanDefinition beanDef, MetadataReaderFactory metadataReaderFactory) {
-		AnnotationMetadata metadata = null;
+		String className = beanDef.getBeanClassName();
+		if (className == null) {
+			return false;
+		}
 
-		// Check already loaded Class if present...
-		// since we possibly can't even load the class file for this Class.
-		if (beanDef instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) beanDef).hasBeanClass()) {
+		AnnotationMetadata metadata;
+		if (beanDef instanceof AnnotatedBeanDefinition &&
+				className.equals(((AnnotatedBeanDefinition) beanDef).getMetadata().getClassName())) {
+			// Can reuse the pre-parsed metadata from the given BeanDefinition...
+			metadata = ((AnnotatedBeanDefinition) beanDef).getMetadata();
+		}
+		else if (beanDef instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) beanDef).hasBeanClass()) {
+			// Check already loaded Class if present...
+			// since we possibly can't even load the class file for this Class.
 			Class<?> beanClass = ((AbstractBeanDefinition) beanDef).getBeanClass();
 			metadata = new StandardAnnotationMetadata(beanClass, true);
 		}
 		else {
-			String className = beanDef.getBeanClassName();
-			if (className != null) {
-				try {
-					MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(className);
-					metadata = metadataReader.getAnnotationMetadata();
-				}
-				catch (IOException ex) {
-					if (logger.isDebugEnabled()) {
-						logger.debug("Could not find class file for introspecting factory methods: " + className, ex);
-					}
-					return false;
+			try {
+				MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(className);
+				metadata = metadataReader.getAnnotationMetadata();
+			}
+			catch (IOException ex) {
+				if (logger.isDebugEnabled()) {
+					logger.debug("Could not find class file for introspecting configuration annotations: " + className, ex);
 				}
+				return false;
 			}
 		}
 
-		if (metadata != null) {
-			if (isFullConfigurationCandidate(metadata)) {
-				beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_FULL);
-				return true;
-			}
-			else if (isLiteConfigurationCandidate(metadata)) {
-				beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_LITE);
-				return true;
-			}
+		if (isFullConfigurationCandidate(metadata)) {
+			beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_FULL);
+			return true;
+		}
+		else if (isLiteConfigurationCandidate(metadata)) {
+			beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_LITE);
+			return true;
+		}
+		else {
+			return false;
 		}
-		return false;
 	}
 
 	/**