RootBeanDefinition accepts ResolvableType for target type hint

Issue: SPR-14580

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

@@ -624,10 +624,11 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	protected Class<?> determineTargetType(String beanName, RootBeanDefinition mbd, Class<?>... typesToMatch) {
 		Class<?> targetType = mbd.getTargetType();
 		if (targetType == null) {
-			targetType = (mbd.getFactoryMethodName() != null ? getTypeForFactoryMethod(beanName, mbd, typesToMatch) :
+			targetType = (mbd.getFactoryMethodName() != null ?
+					getTypeForFactoryMethod(beanName, mbd, typesToMatch) :
 					resolveBeanClass(mbd, beanName, typesToMatch));
 			if (ObjectUtils.isEmpty(typesToMatch) || getTempClassLoader() == null) {
-				mbd.setTargetType(targetType);
+				mbd.resolvedTargetType = targetType;
 			}
 		}
 		return targetType;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -74,21 +74,31 @@ public class GenericTypeAwareAutowireCandidateResolver implements AutowireCandid
 			// No generic type -> we know it's a Class type-match, so no need to check again.
 			return true;
 		}
+
 		ResolvableType targetType = null;
+		boolean cacheType = false;
 		RootBeanDefinition rbd = null;
 		if (bdHolder.getBeanDefinition() instanceof RootBeanDefinition) {
 			rbd = (RootBeanDefinition) bdHolder.getBeanDefinition();
 		}
 		if (rbd != null) {
-			// First, check factory method return type, if applicable
-			targetType = getReturnTypeForFactoryMethod(rbd, descriptor);
+			targetType = rbd.targetType;
 			if (targetType == null) {
-				RootBeanDefinition dbd = getResolvedDecoratedDefinition(rbd);
-				if (dbd != null) {
-					targetType = getReturnTypeForFactoryMethod(dbd, descriptor);
+				cacheType = true;
+				// First, check factory method return type, if applicable
+				targetType = getReturnTypeForFactoryMethod(rbd, descriptor);
+				if (targetType == null) {
+					RootBeanDefinition dbd = getResolvedDecoratedDefinition(rbd);
+					if (dbd != null) {
+						targetType = dbd.targetType;
+						if (targetType == null) {
+							targetType = getReturnTypeForFactoryMethod(dbd, descriptor);
+						}
+					}
 				}
 			}
 		}
+
 		if (targetType == null) {
 			// Regular case: straight bean instance, with BeanFactory available.
 			if (this.beanFactory != null) {
@@ -106,7 +116,14 @@ public class GenericTypeAwareAutowireCandidateResolver implements AutowireCandid
 				}
 			}
 		}
-		if (targetType == null || (descriptor.fallbackMatchAllowed() && targetType.hasUnresolvableGenerics())) {
+
+		if (targetType == null) {
+			return true;
+		}
+		if (cacheType) {
+			rbd.targetType = targetType;
+		}
+		if (descriptor.fallbackMatchAllowed() && targetType.hasUnresolvableGenerics()) {
 			return true;
 		}
 		// Full check for complex generic type match...

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

@@ -26,6 +26,7 @@ import org.springframework.beans.MutablePropertyValues;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinitionHolder;
 import org.springframework.beans.factory.config.ConstructorArgumentValues;
+import org.springframework.core.ResolvableType;
 import org.springframework.util.Assert;
 
 /**
@@ -49,22 +50,26 @@ import org.springframework.util.Assert;
 @SuppressWarnings("serial")
 public class RootBeanDefinition extends AbstractBeanDefinition {
 
-	boolean allowCaching = true;
-
 	private BeanDefinitionHolder decoratedDefinition;
 
-	private volatile Class<?> targetType;
+	boolean allowCaching = true;
+
+	volatile ResolvableType targetType;
 
 	boolean isFactoryMethodUnique = false;
 
+	/** Package-visible field for caching the determined Class of a given bean definition */
+	volatile Class<?> resolvedTargetType;
+
+	/** Package-visible field for caching the return type of a generically typed factory method */
+	volatile Class<?> resolvedFactoryMethodReturnType;
+
+	/** Common lock for the four constructor fields below */
 	final Object constructorArgumentLock = new Object();
 
 	/** Package-visible field for caching the resolved constructor or factory method */
 	Executable resolvedConstructorOrFactoryMethod;
 
-	/** Package-visible field for caching the return type of a generically typed factory method */
-	volatile Class<?> resolvedFactoryMethodReturnType;
-
 	/** Package-visible field that marks the constructor arguments as resolved */
 	boolean constructorArgumentsResolved = false;
 
@@ -74,6 +79,7 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 	/** Package-visible field for caching partly prepared constructor arguments */
 	Object[] preparedConstructorArguments;
 
+	/** Common lock for the two post-processing fields below */
 	final Object postProcessingLock = new Object();
 
 	/** Package-visible field that indicates MergedBeanDefinitionPostProcessor having been applied */
@@ -172,8 +178,8 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 	 */
 	public RootBeanDefinition(RootBeanDefinition original) {
 		super(original);
-		this.allowCaching = original.allowCaching;
 		this.decoratedDefinition = original.decoratedDefinition;
+		this.allowCaching = original.allowCaching;
 		this.targetType = original.targetType;
 		this.isFactoryMethodUnique = original.isFactoryMethodUnique;
 	}
@@ -214,19 +220,32 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 		return this.decoratedDefinition;
 	}
 
+	/**
+	 * Specify a generics-containing target type of this bean definition, if known in advance.
+	 * @since 4.3.3
+	 */
+	public void setTargetType(ResolvableType targetType) {
+		this.targetType = targetType;
+	}
+
 	/**
 	 * Specify the target type of this bean definition, if known in advance.
+	 * @since 3.2.2
 	 */
 	public void setTargetType(Class<?> targetType) {
-		this.targetType = targetType;
+		this.targetType = (targetType != null ? ResolvableType.forClass(targetType) : null);
 	}
 
 	/**
 	 * Return the target type of this bean definition, if known
 	 * (either specified in advance or resolved on first instantiation).
+	 * @since 3.2.2
 	 */
 	public Class<?> getTargetType() {
-		return this.targetType;
+		if (this.resolvedTargetType != null) {
+			return this.resolvedTargetType;
+		}
+		return (this.targetType != null ? this.targetType.resolve() : null);
 	}
 
 	/**

spring-beans/src/test/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessorTests.java

@@ -41,6 +41,7 @@ import org.mockito.Mockito;
 
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanNameAware;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.beans.factory.NoUniqueBeanDefinitionException;
@@ -2047,6 +2048,24 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 		assertSame(bean2, bean1.gi2);
 	}
 
+	@Test
+	public void testGenericsBasedInjectionWithBeanDefinitionTargetResolvableType() throws Exception {
+		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
+		bf.setAutowireCandidateResolver(new QualifierAnnotationAutowireCandidateResolver());
+		AutowiredAnnotationBeanPostProcessor bpp = new AutowiredAnnotationBeanPostProcessor();
+		bpp.setBeanFactory(bf);
+		bf.addBeanPostProcessor(bpp);
+		RootBeanDefinition bd1 = new RootBeanDefinition(GenericInterface2Bean.class);
+		bd1.setTargetType(ResolvableType.forClassWithGenerics(GenericInterface2Bean.class, String.class));
+		bf.registerBeanDefinition("bean1", bd1);
+		RootBeanDefinition bd2 = new RootBeanDefinition(GenericInterface2Bean.class);
+		bd2.setTargetType(ResolvableType.forClassWithGenerics(GenericInterface2Bean.class, Integer.class));
+		bf.registerBeanDefinition("bean2", bd2);
+		bf.registerBeanDefinition("bean3", new RootBeanDefinition(MultiGenericFieldInjection.class));
+
+		assertEquals("bean1 a bean2 123", bf.getBean("bean3").toString());
+	}
+
 	@Test
 	public void testCircularTypeReference() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
@@ -3139,6 +3158,37 @@ public class AutowiredAnnotationBeanPostProcessorTests {
 	}
 
 
+	public static class GenericInterface2Bean<K> implements GenericInterface2<K>, BeanNameAware {
+
+		private String name;
+
+		@Override
+		public void setBeanName(String name) {
+			this.name = name;
+		}
+
+		@Override
+		public String doSomethingMoreGeneric(K o) {
+			return this.name + " " + o;
+		}
+	}
+
+
+	public static class MultiGenericFieldInjection {
+
+		@Autowired
+		private GenericInterface2<String> stringBean;
+
+		@Autowired
+		private GenericInterface2<Integer> integerBean;
+
+		@Override
+		public String toString() {
+			return this.stringBean.doSomethingMoreGeneric("a") + " " + this.integerBean.doSomethingMoreGeneric(123);
+		}
+	}
+
+
 	@SuppressWarnings("rawtypes")
 	public static class PlainGenericInterface2Impl implements GenericInterface2 {