From 8a326a871399c8bbf7dea575e5076e513e21f9bb Mon Sep 17 00:00:00 2001
From: Andy Wilkinson <awilkinson@pivotal.io>
Date: Wed, 1 Mar 2017 14:36:26 +0000
Subject: [PATCH] Simplify BeanTypeRegistry by requiring a
 DefaultListableBeanFactory

Closes gh-8439
---
 .../condition/BeanTypeRegistry.java           | 295 +++++++-----------
 .../condition/OnBeanCondition.java            |   2 +-
 2 files changed, 114 insertions(+), 183 deletions(-)

diff --git a/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/BeanTypeRegistry.java b/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/BeanTypeRegistry.java
index 1e57dd3f74d..fc6ee6d46c6 100644
--- a/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/BeanTypeRegistry.java
+++ b/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/BeanTypeRegistry.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -29,7 +29,6 @@ import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.BeanDefinitionStoreException;
 import org.springframework.beans.factory.BeanFactory;
-import org.springframework.beans.factory.BeanFactoryUtils;
 import org.springframework.beans.factory.CannotLoadBeanClassException;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.ListableBeanFactory;
@@ -43,13 +42,14 @@ import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.type.MethodMetadata;
 import org.springframework.core.type.StandardMethodMetadata;
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
 
 /**
- * A registry of the bean types that are contained in a {@link ListableBeanFactory}.
- * Provides similar functionality to
+ * A registry of the bean types that are contained in a
+ * {@link DefaultListableBeanFactory}. Provides similar functionality to
  * {@link ListableBeanFactory#getBeanNamesForType(Class, boolean, boolean)} but is
  * optimized for use by {@link OnBeanCondition} based on the following assumptions:
  * <ul>
@@ -62,12 +62,43 @@ import org.springframework.util.StringUtils;
  * @author Andy Wilkinson
  * @since 1.2.0
  */
-abstract class BeanTypeRegistry {
+final class BeanTypeRegistry implements SmartInitializingSingleton {
 
 	private static final Log logger = LogFactory.getLog(BeanTypeRegistry.class);
 
 	static final String FACTORY_BEAN_OBJECT_TYPE = "factoryBeanObjectType";
 
+	private static final String BEAN_NAME = BeanTypeRegistry.class.getName();
+
+	private final DefaultListableBeanFactory beanFactory;
+
+	private final Map<String, Class<?>> beanTypes = new HashMap<String, Class<?>>();
+
+	private int lastBeanDefinitionCount = 0;
+
+	private BeanTypeRegistry(DefaultListableBeanFactory beanFactory) {
+		this.beanFactory = beanFactory;
+	}
+
+	/**
+	 * Factory method to get the {@link BeanTypeRegistry} for a given {@link BeanFactory}.
+	 * @param beanFactory the source bean factory
+	 * @return the {@link BeanTypeRegistry} for the given bean factory
+	 */
+	public static BeanTypeRegistry create(ListableBeanFactory beanFactory) {
+		Assert.isInstanceOf(DefaultListableBeanFactory.class, beanFactory);
+		DefaultListableBeanFactory listableBeanFactory = (DefaultListableBeanFactory) beanFactory;
+		Assert.isTrue(listableBeanFactory.isAllowEagerClassLoading(),
+				"Bean factory must allow eager class loading");
+		if (!listableBeanFactory.containsLocalBean(BEAN_NAME)) {
+			BeanDefinition bd = new RootBeanDefinition(BeanTypeRegistry.class);
+			bd.getConstructorArgumentValues().addIndexedArgumentValue(0, beanFactory);
+			listableBeanFactory.registerBeanDefinition(BEAN_NAME, bd);
+
+		}
+		return listableBeanFactory.getBean(BEAN_NAME, BeanTypeRegistry.class);
+	}
+
 	/**
 	 * Return the names of beans matching the given type (including subclasses), judging
 	 * from either bean definitions or the value of {@code getObjectType} in the case of
@@ -76,7 +107,81 @@ abstract class BeanTypeRegistry {
 	 * @return the names of beans (or objects created by FactoryBeans) matching the given
 	 * object type (including subclasses), or an empty set if none
 	 */
-	public abstract Set<String> getNamesForType(Class<?> type);
+	Set<String> getNamesForType(Class<?> type) {
+		if (this.lastBeanDefinitionCount != this.beanFactory.getBeanDefinitionCount()) {
+			Iterator<String> names = this.beanFactory.getBeanNamesIterator();
+			while (names.hasNext()) {
+				String name = names.next();
+				if (!this.beanTypes.containsKey(name)) {
+					addBeanType(name);
+				}
+			}
+			this.lastBeanDefinitionCount = this.beanFactory.getBeanDefinitionCount();
+		}
+		Set<String> matches = new LinkedHashSet<String>();
+		for (Map.Entry<String, Class<?>> entry : this.beanTypes.entrySet()) {
+			if (entry.getValue() != null && type.isAssignableFrom(entry.getValue())) {
+				matches.add(entry.getKey());
+			}
+		}
+		return matches;
+	}
+
+	@Override
+	public void afterSingletonsInstantiated() {
+		// We're done at this point, free up some memory
+		this.beanTypes.clear();
+		this.lastBeanDefinitionCount = 0;
+	}
+
+	private void addBeanType(String name) {
+		if (this.beanFactory.containsSingleton(name)) {
+			this.beanTypes.put(name, this.beanFactory.getType(name));
+		}
+		else if (!this.beanFactory.isAlias(name)) {
+			addBeanTypeForNonAliasDefinition(name);
+		}
+	}
+
+	private void addBeanTypeForNonAliasDefinition(String name) {
+		try {
+			String factoryName = BeanFactory.FACTORY_BEAN_PREFIX + name;
+			RootBeanDefinition beanDefinition = (RootBeanDefinition) this.beanFactory
+					.getMergedBeanDefinition(name);
+			if (!beanDefinition.isAbstract()
+					&& !requiresEagerInit(beanDefinition.getFactoryBeanName())) {
+				if (this.beanFactory.isFactoryBean(factoryName)) {
+					Class<?> factoryBeanGeneric = getFactoryBeanGeneric(this.beanFactory,
+							beanDefinition, name);
+					this.beanTypes.put(name, factoryBeanGeneric);
+					this.beanTypes.put(factoryName,
+							this.beanFactory.getType(factoryName));
+				}
+				else {
+					this.beanTypes.put(name, this.beanFactory.getType(name));
+				}
+			}
+		}
+		catch (CannotLoadBeanClassException ex) {
+			// Probably contains a placeholder
+			logIgnoredError("bean class loading failure for bean", name, ex);
+		}
+		catch (BeanDefinitionStoreException ex) {
+			// Probably contains a placeholder
+			logIgnoredError("unresolvable metadata in bean definition", name, ex);
+		}
+	}
+
+	private void logIgnoredError(String message, String name, Exception ex) {
+		if (BeanTypeRegistry.logger.isDebugEnabled()) {
+			BeanTypeRegistry.logger.debug("Ignoring " + message + " '" + name + "'", ex);
+		}
+	}
+
+	private boolean requiresEagerInit(String factoryBeanName) {
+		return (factoryBeanName != null && this.beanFactory.isFactoryBean(factoryBeanName)
+				&& !this.beanFactory.containsSingleton(factoryBeanName));
+	}
 
 	/**
 	 * Attempt to guess the type that a {@link FactoryBean} will return based on the
@@ -86,9 +191,8 @@ abstract class BeanTypeRegistry {
 	 * @param name the name of the bean
 	 * @return the generic type of the {@link FactoryBean} or {@code null}
 	 */
-	protected final Class<?> getFactoryBeanGeneric(
-			ConfigurableListableBeanFactory beanFactory, BeanDefinition definition,
-			String name) {
+	private Class<?> getFactoryBeanGeneric(ConfigurableListableBeanFactory beanFactory,
+			BeanDefinition definition, String name) {
 		try {
 			return doGetFactoryBeanGeneric(beanFactory, definition, name);
 		}
@@ -198,177 +302,4 @@ abstract class BeanTypeRegistry {
 		return null;
 	}
 
-	/**
-	 * Factory method to get the {@link BeanTypeRegistry} for a given {@link BeanFactory}.
-	 * @param beanFactory the source bean factory
-	 * @return the {@link BeanTypeRegistry} for the given bean factory
-	 */
-	public static BeanTypeRegistry get(ListableBeanFactory beanFactory) {
-		if (beanFactory instanceof DefaultListableBeanFactory) {
-			DefaultListableBeanFactory listableBeanFactory = (DefaultListableBeanFactory) beanFactory;
-			if (listableBeanFactory.isAllowEagerClassLoading()) {
-				return OptimizedBeanTypeRegistry.getFromFactory(listableBeanFactory);
-			}
-		}
-		return new DefaultBeanTypeRegistry(beanFactory);
-	}
-
-	/**
-	 * Default (non-optimized) {@link BeanTypeRegistry} implementation.
-	 */
-	static class DefaultBeanTypeRegistry extends BeanTypeRegistry {
-
-		private final ListableBeanFactory beanFactory;
-
-		DefaultBeanTypeRegistry(ListableBeanFactory beanFactory) {
-			this.beanFactory = beanFactory;
-		}
-
-		@Override
-		public Set<String> getNamesForType(Class<?> type) {
-			Set<String> result = new LinkedHashSet<String>();
-			result.addAll(Arrays
-					.asList(this.beanFactory.getBeanNamesForType(type, true, false)));
-			if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
-				collectBeanNamesForTypeFromFactoryBeans(result,
-						(ConfigurableListableBeanFactory) this.beanFactory, type);
-			}
-			return result;
-		}
-
-		private void collectBeanNamesForTypeFromFactoryBeans(Set<String> result,
-				ConfigurableListableBeanFactory beanFactory, Class<?> type) {
-			String[] names = beanFactory.getBeanNamesForType(FactoryBean.class, true,
-					false);
-			for (String name : names) {
-				name = BeanFactoryUtils.transformedBeanName(name);
-				BeanDefinition beanDefinition = beanFactory.getBeanDefinition(name);
-				Class<?> generic = getFactoryBeanGeneric(beanFactory, beanDefinition,
-						name);
-				if (generic != null && ClassUtils.isAssignable(type, generic)) {
-					result.add(name);
-				}
-			}
-		}
-
-	}
-
-	/**
-	 * {@link BeanTypeRegistry} optimized for {@link DefaultListableBeanFactory}
-	 * implementations that allow eager class loading.
-	 */
-	static class OptimizedBeanTypeRegistry extends BeanTypeRegistry
-			implements SmartInitializingSingleton {
-
-		private static final String BEAN_NAME = BeanTypeRegistry.class.getName();
-
-		private final DefaultListableBeanFactory beanFactory;
-
-		private final Map<String, Class<?>> beanTypes = new HashMap<String, Class<?>>();
-
-		private int lastBeanDefinitionCount = 0;
-
-		OptimizedBeanTypeRegistry(DefaultListableBeanFactory beanFactory) {
-			this.beanFactory = beanFactory;
-		}
-
-		@Override
-		public void afterSingletonsInstantiated() {
-			// We're done at this point, free up some memory
-			this.beanTypes.clear();
-			this.lastBeanDefinitionCount = 0;
-		}
-
-		@Override
-		public Set<String> getNamesForType(Class<?> type) {
-			if (this.lastBeanDefinitionCount != this.beanFactory
-					.getBeanDefinitionCount()) {
-				Iterator<String> names = this.beanFactory.getBeanNamesIterator();
-				while (names.hasNext()) {
-					String name = names.next();
-					if (!this.beanTypes.containsKey(name)) {
-						addBeanType(name);
-					}
-				}
-				this.lastBeanDefinitionCount = this.beanFactory.getBeanDefinitionCount();
-			}
-			Set<String> matches = new LinkedHashSet<String>();
-			for (Map.Entry<String, Class<?>> entry : this.beanTypes.entrySet()) {
-				if (entry.getValue() != null && type.isAssignableFrom(entry.getValue())) {
-					matches.add(entry.getKey());
-				}
-			}
-			return matches;
-		}
-
-		private void addBeanType(String name) {
-			if (this.beanFactory.containsSingleton(name)) {
-				this.beanTypes.put(name, this.beanFactory.getType(name));
-			}
-			else if (!this.beanFactory.isAlias(name)) {
-				addBeanTypeForNonAliasDefinition(name);
-			}
-		}
-
-		private void addBeanTypeForNonAliasDefinition(String name) {
-			try {
-				String factoryName = BeanFactory.FACTORY_BEAN_PREFIX + name;
-				RootBeanDefinition beanDefinition = (RootBeanDefinition) this.beanFactory
-						.getMergedBeanDefinition(name);
-				if (!beanDefinition.isAbstract()
-						&& !requiresEagerInit(beanDefinition.getFactoryBeanName())) {
-					if (this.beanFactory.isFactoryBean(factoryName)) {
-						Class<?> factoryBeanGeneric = getFactoryBeanGeneric(
-								this.beanFactory, beanDefinition, name);
-						this.beanTypes.put(name, factoryBeanGeneric);
-						this.beanTypes.put(factoryName,
-								this.beanFactory.getType(factoryName));
-					}
-					else {
-						this.beanTypes.put(name, this.beanFactory.getType(name));
-					}
-				}
-			}
-			catch (CannotLoadBeanClassException ex) {
-				// Probably contains a placeholder
-				logIgnoredError("bean class loading failure for bean", name, ex);
-			}
-			catch (BeanDefinitionStoreException ex) {
-				// Probably contains a placeholder
-				logIgnoredError("unresolvable metadata in bean definition", name, ex);
-			}
-		}
-
-		private void logIgnoredError(String message, String name, Exception ex) {
-			if (BeanTypeRegistry.logger.isDebugEnabled()) {
-				BeanTypeRegistry.logger.debug("Ignoring " + message + " '" + name + "'",
-						ex);
-			}
-		}
-
-		private boolean requiresEagerInit(String factoryBeanName) {
-			return (factoryBeanName != null
-					&& this.beanFactory.isFactoryBean(factoryBeanName)
-					&& !this.beanFactory.containsSingleton(factoryBeanName));
-		}
-
-		/**
-		 * Returns the {@link OptimizedBeanTypeRegistry} for the given bean factory.
-		 * @param factory the source {@link BeanFactory}
-		 * @return the {@link OptimizedBeanTypeRegistry}
-		 */
-		public static OptimizedBeanTypeRegistry getFromFactory(
-				DefaultListableBeanFactory factory) {
-			if (!factory.containsLocalBean(BEAN_NAME)) {
-				BeanDefinition bd = new RootBeanDefinition(
-						OptimizedBeanTypeRegistry.class);
-				bd.getConstructorArgumentValues().addIndexedArgumentValue(0, factory);
-				factory.registerBeanDefinition(BEAN_NAME, bd);
-
-			}
-			return factory.getBean(BEAN_NAME, OptimizedBeanTypeRegistry.class);
-		}
-
-	}
-
 }
diff --git a/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java b/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java
index 99c828412a6..33a90b440d9 100644
--- a/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java
+++ b/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java
@@ -184,7 +184,7 @@ class OnBeanCondition extends SpringBootCondition implements ConfigurationCondit
 
 	private void collectBeanNamesForType(Set<String> result,
 			ListableBeanFactory beanFactory, Class<?> type, boolean considerHierarchy) {
-		result.addAll(BeanTypeRegistry.get(beanFactory).getNamesForType(type));
+		result.addAll(BeanTypeRegistry.create(beanFactory).getNamesForType(type));
 		if (considerHierarchy && beanFactory instanceof HierarchicalBeanFactory) {
 			BeanFactory parent = ((HierarchicalBeanFactory) beanFactory)
 					.getParentBeanFactory();