DefaultListableBeanFactory efficiently accesses current bean names and exposes them via getBeanNamesIterator()

Issue: SPR-12404

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/config/ConfigurableListableBeanFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.beans.factory.config;
 
+import java.util.Iterator;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
@@ -105,6 +107,20 @@ boolean isAutowireCandidate(String beanName, DependencyDescriptor descriptor)
 	 */
 	BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException;
 
+	/**
+	 * Return a unified view over all bean names managed by this factory.
+	 * <p>Includes bean definition names as well as names of manually registered
+	 * singleton instances, with bean definition names consistently coming first,
+	 * analogous to how type/annotation specific retrieval of bean names works.
+	 * @return the composite iterator for the bean names view
+	 * @since 4.1.2
+	 * @see #containsBeanDefinition
+	 * @see #registerSingleton
+	 * @see #getBeanNamesForType
+	 * @see #getBeanNamesForAnnotation
+	 */
+	Iterator<String> getBeanNamesIterator();
+
 	/**
 	 * Freeze all bean definitions, signalling that the registered bean definitions
 	 * will not be modified or post-processed any further.