Optimized ImportAware processing to avoid re-reading class files

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

@@ -424,8 +424,7 @@ class ConfigurationClassParser {
 					}
 					else {
 						// candidate class not an ImportSelector or ImportBeanDefinitionRegistrar -> process it as a @Configuration class
-						this.importStack.registerImport(importingClassMetadata.getClassName(),
-								candidate.getMetadata().getClassName());
+						this.importStack.registerImport(importingClassMetadata, candidate.getMetadata().getClassName());
 						processConfigurationClass(candidate.asConfigClass(configClass));
 					}
 				}
@@ -558,7 +557,7 @@ class ConfigurationClassParser {
 
 	interface ImportRegistry {
 
-		String getImportingClassFor(String importedClass);
+		AnnotationMetadata getImportingClassFor(String importedClass);
 
 	}
 
@@ -566,14 +565,14 @@ class ConfigurationClassParser {
 	@SuppressWarnings("serial")
 	private static class ImportStack extends Stack<ConfigurationClass> implements ImportRegistry {
 
-		private final Map<String, String> imports = new HashMap<String, String>();
+		private final Map<String, AnnotationMetadata> imports = new HashMap<String, AnnotationMetadata>();
 
-		public void registerImport(String importingClass, String importedClass) {
+		public void registerImport(AnnotationMetadata importingClass, String importedClass) {
 			this.imports.put(importedClass, importingClass);
 		}
 
 		@Override
-		public String getImportingClassFor(String importedClass) {
+		public AnnotationMetadata getImportingClassFor(String importedClass) {
 			return this.imports.get(importedClass);
 		}
 

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

@@ -17,7 +17,6 @@
 package org.springframework.context.annotation;
 
 import java.beans.PropertyDescriptor;
-import java.io.IOException;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
@@ -65,7 +64,6 @@ import org.springframework.core.io.ResourceLoader;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
-import org.springframework.core.type.classreading.SimpleMetadataReaderFactory;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
@@ -379,38 +377,27 @@ public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPo
 	}
 
 
-	private static class ImportAwareBeanPostProcessor implements BeanPostProcessor, PriorityOrdered, BeanFactoryAware {
+	private static class ImportAwareBeanPostProcessor implements BeanPostProcessor, BeanFactoryAware, PriorityOrdered {
 
 		private BeanFactory beanFactory;
 
 		@Override
-		public int getOrder() {
-			return Ordered.HIGHEST_PRECEDENCE;
+		public void setBeanFactory(BeanFactory beanFactory) {
+			this.beanFactory = beanFactory;
 		}
 
 		@Override
-		public void setBeanFactory(BeanFactory beanFactory) {
-			this.beanFactory = beanFactory;
+		public int getOrder() {
+			return Ordered.HIGHEST_PRECEDENCE;
 		}
 
 		@Override
 		public Object postProcessBeforeInitialization(Object bean, String beanName)  {
 			if (bean instanceof ImportAware) {
 				ImportRegistry importRegistry = this.beanFactory.getBean(IMPORT_REGISTRY_BEAN_NAME, ImportRegistry.class);
-				String importingClass = importRegistry.getImportingClassFor(bean.getClass().getSuperclass().getName());
+				AnnotationMetadata importingClass = importRegistry.getImportingClassFor(bean.getClass().getSuperclass().getName());
 				if (importingClass != null) {
-					try {
-						AnnotationMetadata metadata =
-								new SimpleMetadataReaderFactory().getMetadataReader(importingClass).getAnnotationMetadata();
-						((ImportAware) bean).setImportMetadata(metadata);
-					}
-					catch (IOException ex) {
-						// should never occur -> at this point we know the class is present anyway
-						throw new IllegalStateException(ex);
-					}
-				}
-				else {
-					// no importing class was found
+					((ImportAware) bean).setImportMetadata(importingClass);
 				}
 			}
 			return bean;