Cache target type per bean definition and allow for specifying it in advance

Issue: SPR-10335

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractAutowireCapableBeanFactory.java

@@ -572,25 +572,30 @@ else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) {
 	}
 
 	@Override
-	protected Class predictBeanType(String beanName, RootBeanDefinition mbd, Class... typesToMatch) {
-		Class beanClass = (mbd.getFactoryMethodName() != null ?
-				getTypeForFactoryMethod(beanName, mbd, typesToMatch) :
-				resolveBeanClass(mbd, beanName, typesToMatch));
+	protected Class<?> predictBeanType(String beanName, RootBeanDefinition mbd, Class... typesToMatch) {
+		Class<?> targetType = mbd.getTargetType();
+		if (targetType == null) {
+			targetType = (mbd.getFactoryMethodName() != null ? getTypeForFactoryMethod(beanName, mbd, typesToMatch) :
+					resolveBeanClass(mbd, beanName, typesToMatch));
+			if (ObjectUtils.isEmpty(typesToMatch) || getTempClassLoader() == null) {
+				mbd.setTargetType(targetType);
+			}
+		}
 		// Apply SmartInstantiationAwareBeanPostProcessors to predict the
 		// eventual type after a before-instantiation shortcut.
-		if (beanClass != null && !mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
+		if (targetType != null && !mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
 			for (BeanPostProcessor bp : getBeanPostProcessors()) {
 				if (bp instanceof SmartInstantiationAwareBeanPostProcessor) {
 					SmartInstantiationAwareBeanPostProcessor ibp = (SmartInstantiationAwareBeanPostProcessor) bp;
-					Class predicted = ibp.predictBeanType(beanClass, beanName);
+					Class predicted = ibp.predictBeanType(targetType, beanName);
 					if (predicted != null && (typesToMatch.length != 1 || !FactoryBean.class.equals(typesToMatch[0]) ||
 							FactoryBean.class.isAssignableFrom(predicted))) {
 						return predicted;
 					}
 				}
 			}
 		}
-		return beanClass;
+		return targetType;
 	}
 
 	/**
@@ -607,8 +612,8 @@ protected Class predictBeanType(String beanName, RootBeanDefinition mbd, Class..
 	 * @return the type for the bean if determinable, or {@code null} else
 	 * @see #createBean
 	 */
-	protected Class getTypeForFactoryMethod(String beanName, RootBeanDefinition mbd, Class[] typesToMatch) {
-		Class factoryClass;
+	protected Class<?> getTypeForFactoryMethod(String beanName, RootBeanDefinition mbd, Class[] typesToMatch) {
+		Class<?> factoryClass;
 		boolean isStatic = true;
 
 		String factoryBeanName = mbd.getFactoryBeanName();

spring-beans/src/main/java/org/springframework/beans/factory/support/RootBeanDefinition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -61,8 +61,12 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 
 	boolean allowCaching = true;
 
+	private volatile Class<?> targetType;
+
 	boolean isFactoryMethodUnique = false;
 
+	final Object constructorArgumentLock = new Object();
+
 	/** Package-visible field for caching the resolved constructor or factory method */
 	Object resolvedConstructorOrFactoryMethod;
 
@@ -75,15 +79,13 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 	/** Package-visible field for caching partly prepared constructor arguments */
 	Object[] preparedConstructorArguments;
 
-	final Object constructorArgumentLock = new Object();
-
-	/** Package-visible field that indicates a before-instantiation post-processor having kicked in */
-	volatile Boolean beforeInstantiationResolved;
+	final Object postProcessingLock = new Object();
 
 	/** Package-visible field that indicates MergedBeanDefinitionPostProcessor having been applied */
 	boolean postProcessed = false;
 
-	final Object postProcessingLock = new Object();
+	/** Package-visible field that indicates a before-instantiation post-processor having kicked in */
+	volatile Boolean beforeInstantiationResolved;
 
 
 	/**
@@ -236,6 +238,8 @@ public RootBeanDefinition(RootBeanDefinition original) {
 		if (original instanceof RootBeanDefinition) {
 			RootBeanDefinition originalRbd = (RootBeanDefinition) original;
 			this.decoratedDefinition = originalRbd.decoratedDefinition;
+			this.allowCaching = originalRbd.allowCaching;
+			this.targetType = originalRbd.targetType;
 			this.isFactoryMethodUnique = originalRbd.isFactoryMethodUnique;
 		}
 	}
@@ -251,6 +255,21 @@ public void setParentName(String parentName) {
 		}
 	}
 
+	/**
+	 * Specify the target type of this bean definition, if known in advance.
+	 */
+	public void setTargetType(Class<?> targetType) {
+		this.targetType = targetType;
+	}
+
+	/**
+	 * Return the target type of this bean definition, if known
+	 * (either specified in advance or resolved on first instantiation).
+	 */
+	public Class<?> getTargetType() {
+		return this.targetType;
+	}
+
 	/**
 	 * Specify a factory method name that refers to a non-overloaded method.
 	 */