/* * Copyright 2002-2008 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. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.beans.factory.support; import java.util.ArrayList; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.Set; import org.springframework.beans.BeansException; import org.springframework.beans.FatalBeanException; import org.springframework.beans.TypeConverter; import org.springframework.beans.factory.BeanCreationException; import org.springframework.beans.factory.BeanCurrentlyInCreationException; 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.NoSuchBeanDefinitionException; import org.springframework.beans.factory.ObjectFactory; import org.springframework.beans.factory.SmartFactoryBean; import org.springframework.beans.factory.config.BeanDefinition; import org.springframework.beans.factory.config.BeanDefinitionHolder; import org.springframework.beans.factory.config.ConfigurableBeanFactory; import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; import org.springframework.beans.factory.config.DependencyDescriptor; import org.springframework.core.CollectionFactory; import org.springframework.util.Assert; import org.springframework.util.ObjectUtils; import org.springframework.util.StringUtils; /** * Default implementation of the * {@link org.springframework.beans.factory.ListableBeanFactory} and * {@link BeanDefinitionRegistry} interfaces: a full-fledged bean factory * based on bean definition objects. * * <p>Typical usage is registering all bean definitions first (possibly read * from a bean definition file), before accessing beans. Bean definition lookup * is therefore an inexpensive operation in a local bean definition table, * operating on pre-built bean definition metadata objects. * * <p>Can be used as a standalone bean factory, or as a superclass for custom * bean factories. Note that readers for specific bean definition formats are * typically implemented separately rather than as bean factory subclasses: * see for example {@link PropertiesBeanDefinitionReader} and * {@link org.springframework.beans.factory.xml.XmlBeanDefinitionReader}. * * <p>For an alternative implementation of the * {@link org.springframework.beans.factory.ListableBeanFactory} interface, * have a look at {@link StaticListableBeanFactory}, which manages existing * bean instances rather than creating new ones based on bean definitions. * * @author Rod Johnson * @author Juergen Hoeller * @author Sam Brannen * @since 16 April 2001 * @see StaticListableBeanFactory * @see PropertiesBeanDefinitionReader * @see org.springframework.beans.factory.xml.XmlBeanDefinitionReader */ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory implements ConfigurableListableBeanFactory, BeanDefinitionRegistry { /** Whether to allow re-registration of a different definition with the same name */ private boolean allowBeanDefinitionOverriding = true; /** Whether to allow eager class loading even for lazy-init beans */ private boolean allowEagerClassLoading = true; /** Whether bean definition metadata may be cached for all beans */ private boolean configurationFrozen = false; /** Map of bean definition objects, keyed by bean name */ private final Map beanDefinitionMap = CollectionFactory.createConcurrentMapIfPossible(16); /** List of bean definition names, in registration order */ private final List beanDefinitionNames = new ArrayList(); /** Cached array of bean definition names in case of frozen configuration */ private String[] frozenBeanDefinitionNames; /** Resolver to use for checking if a bean definition is an autowire candidate */ private AutowireCandidateResolver autowireCandidateResolver = AutowireUtils.createAutowireCandidateResolver(); /** Map from dependency type to corresponding autowired value */ private final Map resolvableDependencies = new HashMap(); /** * Create a new DefaultListableBeanFactory. */ public DefaultListableBeanFactory() { super(); } /** * Create a new DefaultListableBeanFactory with the given parent. * @param parentBeanFactory the parent BeanFactory */ public DefaultListableBeanFactory(BeanFactory parentBeanFactory) { super(parentBeanFactory); } /** * Set a custom autowire candidate resolver for this BeanFactory to use * when deciding whether a bean definition should be considered as a * candidate for autowiring. */ public void setAutowireCandidateResolver(AutowireCandidateResolver autowireCandidateResolver) { Assert.notNull(autowireCandidateResolver, "AutowireCandidateResolver must not be null"); this.autowireCandidateResolver = autowireCandidateResolver; } /** * Return the autowire candidate resolver for this BeanFactory (never <code>null</code>). */ public AutowireCandidateResolver getAutowireCandidateResolver() { return this.autowireCandidateResolver; } /** * Set whether it should be allowed to override bean definitions by registering * a different definition with the same name, automatically replacing the former. * If not, an exception will be thrown. This also applies to overriding aliases. * <p>Default is "true". * @see #registerBeanDefinition */ public void setAllowBeanDefinitionOverriding(boolean allowBeanDefinitionOverriding) { this.allowBeanDefinitionOverriding = allowBeanDefinitionOverriding; } /** * Set whether the factory is allowed to eagerly load bean classes * even for bean definitions that are marked as "lazy-init". * <p>Default is "true". Turn this flag off to suppress class loading * for lazy-init beans unless such a bean is explicitly requested. * In particular, by-type lookups will then simply ignore bean definitions * without resolved class name, instead of loading the bean classes on * demand just to perform a type check. * @see AbstractBeanDefinition#setLazyInit */ public void setAllowEagerClassLoading(boolean allowEagerClassLoading) { this.allowEagerClassLoading = allowEagerClassLoading; } public void copyConfigurationFrom(ConfigurableBeanFactory otherFactory) { super.copyConfigurationFrom(otherFactory); if (otherFactory instanceof DefaultListableBeanFactory) { DefaultListableBeanFactory otherListableFactory = (DefaultListableBeanFactory) otherFactory; this.allowBeanDefinitionOverriding = otherListableFactory.allowBeanDefinitionOverriding; this.allowEagerClassLoading = otherListableFactory.allowEagerClassLoading; } } //--------------------------------------------------------------------- // Implementation of ListableBeanFactory interface //--------------------------------------------------------------------- public boolean containsBeanDefinition(String beanName) { return this.beanDefinitionMap.containsKey(beanName); } public int getBeanDefinitionCount() { return this.beanDefinitionMap.size(); } public String[] getBeanDefinitionNames() { synchronized (this.beanDefinitionMap) { if (this.frozenBeanDefinitionNames != null) { return this.frozenBeanDefinitionNames; } else { return StringUtils.toStringArray(this.beanDefinitionNames); } } } public String[] getBeanNamesForType(Class type) { return getBeanNamesForType(type, true, true); } public String[] getBeanNamesForType(Class type, boolean includeNonSingletons, boolean allowEagerInit) { List result = new ArrayList(); // Check all bean definitions. String[] beanDefinitionNames = getBeanDefinitionNames(); for (int i = 0; i < beanDefinitionNames.length; i++) { String beanName = beanDefinitionNames[i]; // Only consider bean as eligible if the bean name // is not defined as alias for some other bean. if (!isAlias(beanName)) { try { RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName); // Only check bean definition if it is complete. if (!mbd.isAbstract() && (allowEagerInit || ((mbd.hasBeanClass() || !mbd.isLazyInit() || this.allowEagerClassLoading)) && !requiresEagerInitForType(mbd.getFactoryBeanName()))) { // In case of FactoryBean, match object created by FactoryBean. boolean isFactoryBean = isFactoryBean(beanName, mbd); boolean matchFound = (allowEagerInit || !isFactoryBean || containsSingleton(beanName)) && (includeNonSingletons || isSingleton(beanName)) && isTypeMatch(beanName, type); if (!matchFound && isFactoryBean) { // In case of FactoryBean, try to match FactoryBean instance itself next. beanName = FACTORY_BEAN_PREFIX + beanName; matchFound = (includeNonSingletons || mbd.isSingleton()) && isTypeMatch(beanName, type); } if (matchFound) { result.add(beanName); } } } catch (CannotLoadBeanClassException ex) { if (allowEagerInit) { throw ex; } // Probably contains a placeholder: let's ignore it for type matching purposes. if (this.logger.isDebugEnabled()) { this.logger.debug("Ignoring bean class loading failure for bean '" + beanName + "'", ex); } onSuppressedException(ex); } catch (BeanDefinitionStoreException ex) { if (allowEagerInit) { throw ex; } // Probably contains a placeholder: let's ignore it for type matching purposes. if (this.logger.isDebugEnabled()) { this.logger.debug("Ignoring unresolvable metadata in bean definition '" + beanName + "'", ex); } onSuppressedException(ex); } } } // Check singletons too, to catch manually registered singletons. String[] singletonNames = getSingletonNames(); for (int i = 0; i < singletonNames.length; i++) { String beanName = singletonNames[i]; // Only check if manually registered. if (!containsBeanDefinition(beanName)) { // In case of FactoryBean, match object created by FactoryBean. if (isFactoryBean(beanName)) { if ((includeNonSingletons || isSingleton(beanName)) && isTypeMatch(beanName, type)) { result.add(beanName); // Match found for this bean: do not match FactoryBean itself anymore. continue; } // In case of FactoryBean, try to match FactoryBean itself next. beanName = FACTORY_BEAN_PREFIX + beanName; } // Match raw bean instance (might be raw FactoryBean). if (isTypeMatch(beanName, type)) { result.add(beanName); } } } return StringUtils.toStringArray(result); } /** * Check whether the specified bean would need to be eagerly initialized * in order to determine its type. * @param factoryBeanName a factory-bean reference that the bean definition * defines a factory method for * @return whether eager initialization is necessary */ private boolean requiresEagerInitForType(String factoryBeanName) { return (factoryBeanName != null && isFactoryBean(factoryBeanName) && !containsSingleton(factoryBeanName)); } public Map getBeansOfType(Class type) throws BeansException { return getBeansOfType(type, true, true); } public Map getBeansOfType(Class type, boolean includeNonSingletons, boolean allowEagerInit) throws BeansException { String[] beanNames = getBeanNamesForType(type, includeNonSingletons, allowEagerInit); Map result = new LinkedHashMap(beanNames.length); for (int i = 0; i < beanNames.length; i++) { String beanName = beanNames[i]; try { result.put(beanName, getBean(beanName)); } catch (BeanCreationException ex) { Throwable rootCause = ex.getMostSpecificCause(); if (rootCause instanceof BeanCurrentlyInCreationException) { BeanCreationException bce = (BeanCreationException) rootCause; if (isCurrentlyInCreation(bce.getBeanName())) { if (this.logger.isDebugEnabled()) { this.logger.debug("Ignoring match to currently created bean '" + beanName + "': " + ex.getMessage()); } onSuppressedException(ex); // Ignore: indicates a circular reference when autowiring constructors. // We want to find matches other than the currently created bean itself. continue; } } throw ex; } } return result; } //--------------------------------------------------------------------- // Implementation of ConfigurableListableBeanFactory interface //--------------------------------------------------------------------- public void registerResolvableDependency(Class dependencyType, Object autowiredValue) { Assert.notNull(dependencyType, "Type must not be null"); if (autowiredValue != null) { Assert.isTrue((autowiredValue instanceof ObjectFactory || dependencyType.isInstance(autowiredValue)), "Value [" + autowiredValue + "] does not implement specified type [" + dependencyType.getName() + "]"); this.resolvableDependencies.put(dependencyType, autowiredValue); } } public boolean isAutowireCandidate(String beanName, DependencyDescriptor descriptor) throws NoSuchBeanDefinitionException { // Consider FactoryBeans as autowiring candidates. boolean isFactoryBean = (descriptor != null && descriptor.getDependencyType() != null && FactoryBean.class.isAssignableFrom(descriptor.getDependencyType())); if (isFactoryBean) { beanName = BeanFactoryUtils.transformedBeanName(beanName); } if (!containsBeanDefinition(beanName)) { if (containsSingleton(beanName)) { return true; } else if (getParentBeanFactory() instanceof ConfigurableListableBeanFactory) { // No bean definition found in this factory -> delegate to parent. return ((ConfigurableListableBeanFactory) getParentBeanFactory()).isAutowireCandidate(beanName, descriptor); } } return isAutowireCandidate(beanName, getMergedLocalBeanDefinition(beanName), descriptor); } /** * Determine whether the specified bean definition qualifies as an autowire candidate, * to be injected into other beans which declare a dependency of matching type. * @param beanName the name of the bean definition to check * @param mbd the merged bean definition to check * @param descriptor the descriptor of the dependency to resolve * @return whether the bean should be considered as autowire candidate */ protected boolean isAutowireCandidate(String beanName, RootBeanDefinition mbd, DependencyDescriptor descriptor) { resolveBeanClass(mbd, beanName); return getAutowireCandidateResolver().isAutowireCandidate( new BeanDefinitionHolder(mbd, beanName, getAliases(beanName)), descriptor); } public BeanDefinition getBeanDefinition(String beanName) throws NoSuchBeanDefinitionException { BeanDefinition bd = (BeanDefinition) this.beanDefinitionMap.get(beanName); if (bd == null) { if (this.logger.isTraceEnabled()) { this.logger.trace("No bean named '" + beanName + "' found in " + this); } throw new NoSuchBeanDefinitionException(beanName); } return bd; } public void freezeConfiguration() { this.configurationFrozen = true; synchronized (this.beanDefinitionMap) { this.frozenBeanDefinitionNames = StringUtils.toStringArray(this.beanDefinitionNames); } } public boolean isConfigurationFrozen() { return this.configurationFrozen; } /** * Considers all beans as eligible for metdata caching * if the factory's configuration has been marked as frozen. * @see #freezeConfiguration() */ protected boolean isBeanEligibleForMetadataCaching(String beanName) { return (this.configurationFrozen || super.isBeanEligibleForMetadataCaching(beanName)); } public void preInstantiateSingletons() throws BeansException { if (this.logger.isInfoEnabled()) { this.logger.info("Pre-instantiating singletons in " + this); } synchronized (this.beanDefinitionMap) { for (Iterator it = this.beanDefinitionNames.iterator(); it.hasNext();) { String beanName = (String) it.next(); RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName); if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) { if (isFactoryBean(beanName)) { FactoryBean factory = (FactoryBean) getBean(FACTORY_BEAN_PREFIX + beanName); if (factory instanceof SmartFactoryBean && ((SmartFactoryBean) factory).isEagerInit()) { getBean(beanName); } } else { getBean(beanName); } } } } } //--------------------------------------------------------------------- // Implementation of BeanDefinitionRegistry interface //--------------------------------------------------------------------- public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition) throws BeanDefinitionStoreException { Assert.hasText(beanName, "'beanName' must not be empty"); Assert.notNull(beanDefinition, "BeanDefinition must not be null"); if (beanDefinition instanceof AbstractBeanDefinition) { try { ((AbstractBeanDefinition) beanDefinition).validate(); } catch (BeanDefinitionValidationException ex) { throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName, "Validation of bean definition failed", ex); } } synchronized (this.beanDefinitionMap) { Object oldBeanDefinition = this.beanDefinitionMap.get(beanName); if (oldBeanDefinition != null) { if (!this.allowBeanDefinitionOverriding) { throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName, "Cannot register bean definition [" + beanDefinition + "] for bean '" + beanName + "': There is already [" + oldBeanDefinition + "] bound."); } else { if (this.logger.isInfoEnabled()) { this.logger.info("Overriding bean definition for bean '" + beanName + "': replacing [" + oldBeanDefinition + "] with [" + beanDefinition + "]"); } } } else { this.beanDefinitionNames.add(beanName); this.frozenBeanDefinitionNames = null; } this.beanDefinitionMap.put(beanName, beanDefinition); resetBeanDefinition(beanName); } } public void removeBeanDefinition(String beanName) throws NoSuchBeanDefinitionException { Assert.hasText(beanName, "'beanName' must not be empty"); synchronized (this.beanDefinitionMap) { BeanDefinition bd = (BeanDefinition) this.beanDefinitionMap.remove(beanName); if (bd == null) { if (this.logger.isTraceEnabled()) { this.logger.trace("No bean named '" + beanName + "' found in " + this); } throw new NoSuchBeanDefinitionException(beanName); } this.beanDefinitionNames.remove(beanName); this.frozenBeanDefinitionNames = null; resetBeanDefinition(beanName); } } /** * Reset all bean definition caches for the given bean, * including the caches of beans that are derived from it. * @param beanName the name of the bean to reset */ protected void resetBeanDefinition(String beanName) { // Remove the merged bean definition for the given bean, if already created. clearMergedBeanDefinition(beanName); // Remove corresponding bean from singleton cache, if any. Shouldn't usually // be necessary, rather just meant for overriding a context's default beans // (e.g. the default StaticMessageSource in a StaticApplicationContext). synchronized (getSingletonMutex()) { destroySingleton(beanName); } // Reset all bean definitions that have the given bean as parent // (recursively). for (Iterator it = this.beanDefinitionNames.iterator(); it.hasNext();) { String bdName = (String) it.next(); if (!beanName.equals(bdName)) { BeanDefinition bd = (BeanDefinition) this.beanDefinitionMap.get(bdName); if (beanName.equals(bd.getParentName())) { resetBeanDefinition(bdName); } } } } /** * Only allows alias overriding if bean definition overriding is allowed. */ protected boolean allowAliasOverriding() { return this.allowBeanDefinitionOverriding; } //--------------------------------------------------------------------- // Implementation of superclass abstract methods //--------------------------------------------------------------------- public Object resolveDependency(DependencyDescriptor descriptor, String beanName, Set autowiredBeanNames, TypeConverter typeConverter) throws BeansException { Class type = descriptor.getDependencyType(); if (type.isArray()) { Class componentType = type.getComponentType(); Map matchingBeans = findAutowireCandidates(beanName, componentType, descriptor); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(componentType, "array of " + componentType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); return converter.convertIfNecessary(matchingBeans.values(), type); } else if (Collection.class.isAssignableFrom(type) && type.isInterface()) { Class elementType = descriptor.getCollectionType(); if (elementType == null) { if (descriptor.isRequired()) { throw new FatalBeanException("No element type declared for collection [" + type.getName() + "]"); } return null; } Map matchingBeans = findAutowireCandidates(beanName, elementType, descriptor); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(elementType, "collection of " + elementType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } TypeConverter converter = (typeConverter != null ? typeConverter : getTypeConverter()); return converter.convertIfNecessary(matchingBeans.values(), type); } else if (Map.class.isAssignableFrom(type) && type.isInterface()) { Class keyType = descriptor.getMapKeyType(); if (keyType == null || !String.class.isAssignableFrom(keyType)) { if (descriptor.isRequired()) { throw new FatalBeanException("Key type [" + keyType + "] of map [" + type.getName() + "] must be assignable to [java.lang.String]"); } return null; } Class valueType = descriptor.getMapValueType(); if (valueType == null) { if (descriptor.isRequired()) { throw new FatalBeanException("No value type declared for map [" + type.getName() + "]"); } return null; } Map matchingBeans = findAutowireCandidates(beanName, valueType, descriptor); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { raiseNoSuchBeanDefinitionException(valueType, "map with value type " + valueType.getName(), descriptor); } return null; } if (autowiredBeanNames != null) { autowiredBeanNames.addAll(matchingBeans.keySet()); } return matchingBeans; } else { Map matchingBeans = findAutowireCandidates(beanName, type, descriptor); if (matchingBeans.isEmpty()) { if (descriptor.isRequired()) { throw new NoSuchBeanDefinitionException(type, "Unsatisfied dependency of type [" + type + "]: expected at least 1 matching bean"); } return null; } if (matchingBeans.size() > 1) { String primaryBeanName = determinePrimaryCandidate(matchingBeans, type); if (primaryBeanName == null) { throw new NoSuchBeanDefinitionException(type, "expected single matching bean but found " + matchingBeans.size() + ": " + matchingBeans.keySet()); } if (autowiredBeanNames != null) { autowiredBeanNames.add(primaryBeanName); } return matchingBeans.get(primaryBeanName); } // We have exactly one match. Map.Entry entry = (Map.Entry) matchingBeans.entrySet().iterator().next(); if (autowiredBeanNames != null) { autowiredBeanNames.add(entry.getKey()); } return entry.getValue(); } } /** * Find bean instances that match the required type. * Called during autowiring for the specified bean. * @param beanName the name of the bean that is about to be wired * @param requiredType the actual type of bean to look for * (may be an array component type or collection element type) * @param descriptor the descriptor of the dependency to resolve * @return a Map of candidate names and candidate instances that match * the required type (never <code>null</code>) * @throws BeansException in case of errors * @see #autowireByType * @see #autowireConstructor */ protected Map findAutowireCandidates(String beanName, Class requiredType, DependencyDescriptor descriptor) { String[] candidateNames = BeanFactoryUtils.beanNamesForTypeIncludingAncestors( this, requiredType, true, descriptor.isEager()); Map result = new LinkedHashMap(candidateNames.length); for (Iterator it = this.resolvableDependencies.keySet().iterator(); it.hasNext();) { Class autowiringType = (Class) it.next(); if (autowiringType.isAssignableFrom(requiredType)) { Object autowiringValue = this.resolvableDependencies.get(autowiringType); if (autowiringValue instanceof ObjectFactory && !requiredType.isInstance(autowiringValue)) { autowiringValue = ((ObjectFactory) autowiringValue).getObject(); } if (requiredType.isInstance(autowiringValue)) { result.put(ObjectUtils.identityToString(autowiringValue), autowiringValue); break; } } } for (int i = 0; i < candidateNames.length; i++) { String candidateName = candidateNames[i]; if (!candidateName.equals(beanName) && isAutowireCandidate(candidateName, descriptor)) { result.put(candidateName, getBean(candidateName)); } } return result; } /** * Determine the primary autowire candidate in the given set of beans. * @param candidateBeans a Map of candidate names and candidate instances * that match the required type, as returned by {@link #findAutowireCandidates} * @param type the required type * @return the name of the primary candidate, or <code>null</code> if none found */ protected String determinePrimaryCandidate(Map candidateBeans, Class type) { String primaryBeanName = null; for (Iterator it = candidateBeans.entrySet().iterator(); it.hasNext();) { Map.Entry entry = (Map.Entry) it.next(); String candidateBeanName = (String) entry.getKey(); if (isPrimary(candidateBeanName, entry.getValue())) { if (primaryBeanName != null) { throw new NoSuchBeanDefinitionException(type, "more than one 'primary' bean found among candidates: " + candidateBeans.keySet()); } primaryBeanName = candidateBeanName; } } return primaryBeanName; } /** * Return whether the bean definition for the given bean name has been * marked as a primary bean. * @param beanName the name of the bean * @param beanInstance the corresponding bean instance * @return whether the given bean qualifies as primary */ protected boolean isPrimary(String beanName, Object beanInstance) { if (containsBeanDefinition(beanName)) { return getMergedLocalBeanDefinition(beanName).isPrimary(); } if (this.resolvableDependencies.values().contains(beanInstance)) { return true; } BeanFactory parentFactory = getParentBeanFactory(); return (parentFactory instanceof DefaultListableBeanFactory && ((DefaultListableBeanFactory) parentFactory).isPrimary(beanName, beanInstance)); } /** * Raise a NoSuchBeanDefinitionException for an unresolvable dependency. */ private void raiseNoSuchBeanDefinitionException( Class type, String dependencyDescription, DependencyDescriptor descriptor) throws NoSuchBeanDefinitionException { throw new NoSuchBeanDefinitionException(type, dependencyDescription, "expected at least 1 bean which qualifies as autowire candidate for this dependency. " + "Dependency annotations: " + ObjectUtils.nullSafeToString(descriptor.getAnnotations())); } public String toString() { StringBuffer sb = new StringBuffer(ObjectUtils.identityToString(this)); sb.append(": defining beans ["); sb.append(StringUtils.arrayToCommaDelimitedString(getBeanDefinitionNames())); sb.append("]; "); BeanFactory parent = getParentBeanFactory(); if (parent == null) { sb.append("root of factory hierarchy"); } else { sb.append("parent: " + ObjectUtils.identityToString(parent)); } return sb.toString(); } }