/*
 * 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.context.support;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.support.ResourceEditorRegistrar;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.HierarchicalMessageSource;
import org.springframework.context.Lifecycle;
import org.springframework.context.MessageSource;
import org.springframework.context.MessageSourceAware;
import org.springframework.context.MessageSourceResolvable;
import org.springframework.context.NoSuchMessageException;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.context.event.ApplicationEventMulticaster;
import org.springframework.context.event.ContextClosedEvent;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.context.event.ContextStartedEvent;
import org.springframework.context.event.ContextStoppedEvent;
import org.springframework.context.event.SimpleApplicationEventMulticaster;
import org.springframework.core.JdkVersion;
import org.springframework.core.OrderComparator;
import org.springframework.core.Ordered;
import org.springframework.core.PriorityOrdered;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;

/**
 * Abstract implementation of the {@link org.springframework.context.ApplicationContext}
 * interface. Doesn't mandate the type of storage used for configuration; simply
 * implements common context functionality. Uses the Template Method design pattern,
 * requiring concrete subclasses to implement abstract methods.
 *
 * <p>In contrast to a plain BeanFactory, an ApplicationContext is supposed
 * to detect special beans defined in its internal bean factory:
 * Therefore, this class automatically registers
 * {@link org.springframework.beans.factory.config.BeanFactoryPostProcessor BeanFactoryPostProcessors},
 * {@link org.springframework.beans.factory.config.BeanPostProcessor BeanPostProcessors}
 * and {@link org.springframework.context.ApplicationListener ApplicationListeners}
 * which are defined as beans in the context.
 *
 * <p>A {@link org.springframework.context.MessageSource} may also be supplied
 * as a bean in the context, with the name "messageSource"; otherwise, message
 * resolution is delegated to the parent context. Furthermore, a multicaster
 * for application events can be supplied as "applicationEventMulticaster" bean
 * of type {@link org.springframework.context.event.ApplicationEventMulticaster}
 * in the context; otherwise, a default multicaster of type
 * {@link org.springframework.context.event.SimpleApplicationEventMulticaster} will be used.
 *
 * <p>Implements resource loading through extending
 * {@link org.springframework.core.io.DefaultResourceLoader}.
 * Consequently treats non-URL resource paths as class path resources
 * (supporting full class path resource names that include the package path,
 * e.g. "mypackage/myresource.dat"), unless the {@link #getResourceByPath}
 * method is overwritten in a subclass.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Mark Fisher
 * @since January 21, 2001
 * @see #refreshBeanFactory
 * @see #getBeanFactory
 * @see org.springframework.beans.factory.config.BeanFactoryPostProcessor
 * @see org.springframework.beans.factory.config.BeanPostProcessor
 * @see org.springframework.context.event.ApplicationEventMulticaster
 * @see org.springframework.context.ApplicationListener
 * @see org.springframework.context.MessageSource
 */
public abstract class AbstractApplicationContext extends DefaultResourceLoader
		implements ConfigurableApplicationContext, DisposableBean {

	/**
	 * Name of the MessageSource bean in the factory.
	 * If none is supplied, message resolution is delegated to the parent.
	 * @see MessageSource
	 */
	public static final String MESSAGE_SOURCE_BEAN_NAME = "messageSource";

	/**
	 * Name of the ApplicationEventMulticaster bean in the factory.
	 * If none is supplied, a default SimpleApplicationEventMulticaster is used.
	 * @see org.springframework.context.event.ApplicationEventMulticaster
	 * @see org.springframework.context.event.SimpleApplicationEventMulticaster
	 */
	public static final String APPLICATION_EVENT_MULTICASTER_BEAN_NAME = "applicationEventMulticaster";


	static {
		// Eagerly load the ContextClosedEvent class to avoid weird classloader issues
		// on application shutdown in WebLogic 8.1. (Reported by Dustin Woods.)
		ContextClosedEvent.class.getName();
	}


	/** Logger used by this class. Available to subclasses. */
	protected final Log logger = LogFactory.getLog(getClass());

	/** Unique id for this context, if any */
	private String id = ObjectUtils.identityToString(this);

	/** Parent context */
	private ApplicationContext parent;

	/** BeanFactoryPostProcessors to apply on refresh */
	private final List beanFactoryPostProcessors = new ArrayList();

	/** Display name */
	private String displayName;

	/** System time in milliseconds when this context started */
	private long startupDate;

	/** Flag that indicates whether this context is currently active */
	private boolean active = false;

	/** Synchronization monitor for the "active" flag */
	private final Object activeMonitor = new Object();

	/** Synchronization monitor for the "refresh" and "destroy" */
	private final Object startupShutdownMonitor = new Object();

	/** Reference to the JVM shutdown hook, if registered */
	private Thread shutdownHook;

	/** ResourcePatternResolver used by this context */
	private ResourcePatternResolver resourcePatternResolver;

	/** MessageSource we delegate our implementation of this interface to */
	private MessageSource messageSource;

	/** Helper class used in event publishing */
	private ApplicationEventMulticaster applicationEventMulticaster;

	/** Statically specified listeners */
	private List applicationListeners = new ArrayList();


	/**
	 * Create a new AbstractApplicationContext with no parent.
	 */
	public AbstractApplicationContext() {
		this(null);
	}

	/**
	 * Create a new AbstractApplicationContext with the given parent context.
	 * @param parent the parent context
	 */
	public AbstractApplicationContext(ApplicationContext parent) {
		this.parent = parent;
		this.resourcePatternResolver = getResourcePatternResolver();
	}


	//---------------------------------------------------------------------
	// Implementation of ApplicationContext interface
	//---------------------------------------------------------------------

	/**
	 * Set the unique id of this application context.
	 * <p>Default is the object id of the context instance, or the name
	 * of the context bean if the context is itself defined as a bean.
	 * @param id the unique id of the context
	 */
	public void setId(String id) {
		this.id = id;
	}

	public String getId() {
		return this.id;
	}

	/**
	 * Return the parent context, or <code>null</code> if there is no parent
	 * (that is, this context is the root of the context hierarchy).
	 */
	public ApplicationContext getParent() {
		return this.parent;
	}

	/**
	 * Return this context's internal bean factory as AutowireCapableBeanFactory,
	 * if already available.
	 * @see #getBeanFactory()
	 */
	public AutowireCapableBeanFactory getAutowireCapableBeanFactory() throws IllegalStateException {
		return getBeanFactory();
	}

	/**
	 * Set a friendly name for this context.
	 * Typically done during initialization of concrete context implementations.
	 */
	public void setDisplayName(String displayName) {
		this.displayName = displayName;
	}

	/**
	 * Return a friendly name for this context.
	 */
	public String getDisplayName() {
		return (this.displayName != null ? this.displayName : getId());
	}

	/**
	 * Return the timestamp (ms) when this context was first loaded.
	 */
	public long getStartupDate() {
		return this.startupDate;
	}

	/**
	 * Publish the given event to all listeners.
	 * <p>Note: Listeners get initialized after the MessageSource, to be able
	 * to access it within listener implementations. Thus, MessageSource
	 * implementations cannot publish events.
	 * @param event the event to publish (may be application-specific or a
	 * standard framework event)
	 */
	public void publishEvent(ApplicationEvent event) {
		Assert.notNull(event, "Event must not be null");
		if (logger.isTraceEnabled()) {
			logger.trace("Publishing event in context [" + getId() + "]: " + event);
		}
		getApplicationEventMulticaster().multicastEvent(event);
		if (this.parent != null) {
			this.parent.publishEvent(event);
		}
	}

	/**
	 * Return the internal MessageSource used by the context.
	 * @return the internal MessageSource (never <code>null</code>)
	 * @throws IllegalStateException if the context has not been initialized yet
	 */
	private ApplicationEventMulticaster getApplicationEventMulticaster() throws IllegalStateException {
		if (this.applicationEventMulticaster == null) {
			throw new IllegalStateException("ApplicationEventMulticaster not initialized - " +
					"call 'refresh' before multicasting events via the context: " + this);
		}
		return this.applicationEventMulticaster;
	}

	/**
	 * Return the ResourcePatternResolver to use for resolving location patterns
	 * into Resource instances. Default is a
	 * {@link org.springframework.core.io.support.PathMatchingResourcePatternResolver},
	 * supporting Ant-style location patterns.
	 * <p>Can be overridden in subclasses, for extended resolution strategies,
	 * for example in a web environment.
	 * <p><b>Do not call this when needing to resolve a location pattern.</b>
	 * Call the context's <code>getResources</code> method instead, which
	 * will delegate to the ResourcePatternResolver.
	 * @return the ResourcePatternResolver for this context
	 * @see #getResources
	 * @see org.springframework.core.io.support.PathMatchingResourcePatternResolver
	 */
	protected ResourcePatternResolver getResourcePatternResolver() {
		return new PathMatchingResourcePatternResolver(this);
	}


	//---------------------------------------------------------------------
	// Implementation of ConfigurableApplicationContext interface
	//---------------------------------------------------------------------

	public void setParent(ApplicationContext parent) {
		this.parent = parent;
	}

	public void addBeanFactoryPostProcessor(BeanFactoryPostProcessor beanFactoryPostProcessor) {
		this.beanFactoryPostProcessors.add(beanFactoryPostProcessor);
	}

	/**
	 * Return the list of BeanFactoryPostProcessors that will get applied
	 * to the internal BeanFactory.
	 * @see org.springframework.beans.factory.config.BeanFactoryPostProcessor
	 */
	public List getBeanFactoryPostProcessors() {
		return this.beanFactoryPostProcessors;
	}

	public void addApplicationListener(ApplicationListener listener) {
		this.applicationListeners.add(listener);
	}

	/**
	 * Return the list of statically specified ApplicationListeners.
	 * @see org.springframework.context.ApplicationListener
	 */
	public List getApplicationListeners() {
		return this.applicationListeners;
	}


	public void refresh() throws BeansException, IllegalStateException {
		synchronized (this.startupShutdownMonitor) {
			// Prepare this context for refreshing.
			prepareRefresh();

			// Tell the subclass to refresh the internal bean factory.
			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

			// Prepare the bean factory for use in this context.
			prepareBeanFactory(beanFactory);

			try {
				// Allows post-processing of the bean factory in context subclasses.
				postProcessBeanFactory(beanFactory);

				// Invoke factory processors registered as beans in the context.
				invokeBeanFactoryPostProcessors(beanFactory);

				// Register bean processors that intercept bean creation.
				registerBeanPostProcessors(beanFactory);

				// Initialize message source for this context.
				initMessageSource();

				// Initialize event multicaster for this context.
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
				onRefresh();

				// Check for listener beans and register them.
				registerListeners();

				// Instantiate all remaining (non-lazy-init) singletons.
				finishBeanFactoryInitialization(beanFactory);

				// Last step: publish corresponding event.
				finishRefresh();
			}

			catch (BeansException ex) {
				// Destroy already created singletons to avoid dangling resources.
				beanFactory.destroySingletons();

				// Reset 'active' flag.
				cancelRefresh(ex);

				// Propagate exception to caller.
				throw ex;
			}
		}
	}

	/**
	 * Prepare this context for refreshing, setting its startup date and
	 * active flag.
	 */
	protected void prepareRefresh() {
		this.startupDate = System.currentTimeMillis();

		synchronized (this.activeMonitor) {
			this.active = true;
		}

		if (logger.isInfoEnabled()) {
			logger.info("Refreshing " + this);
		}
	}

	/**
	 * Tell the subclass to refresh the internal bean factory.
	 * @return the fresh BeanFactory instance
	 * @see #refreshBeanFactory()
	 * @see #getBeanFactory()
	 */
	protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
		refreshBeanFactory();
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();

		if (logger.isInfoEnabled()) {
			logger.info("Bean factory for application context [" + getId() + "]: " +
					ObjectUtils.identityToString(beanFactory));
		}
		if (logger.isDebugEnabled()) {
			logger.debug(beanFactory.getBeanDefinitionCount() + " beans defined in " + this);
		}

		return beanFactory;
	}

	/**
	 * Configure the factory's standard context characteristics,
	 * such as the context's ClassLoader and post-processors.
	 * @param beanFactory the BeanFactory to configure
	 */
	protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
		// Tell the internal bean factory to use the context's class loader.
		beanFactory.setBeanClassLoader(getClassLoader());

		// Populate the bean factory with context-specific resource editors.
		beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this));

		// Configure the bean factory with context callbacks.
		beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
		beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
		beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
		beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
		beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);

		// BeanFactory interface not registered as resolvable type in a plain factory.
		// MessageSource registered (and found for autowiring) as a bean.
		beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
		beanFactory.registerResolvableDependency(ResourceLoader.class, this);
		beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
		beanFactory.registerResolvableDependency(ApplicationContext.class, this);

		// Detect a LoadTimeWeaver and prepare for weaving, if found.
		if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME) && JdkVersion.isAtLeastJava15()) {
			// Register the (JDK 1.5 specific) LoadTimeWeaverAwareProcessor.
			try {
				Class ltwapClass = ClassUtils.forName(
						"org.springframework.context.weaving.LoadTimeWeaverAwareProcessor",
						AbstractApplicationContext.class.getClassLoader());
				BeanPostProcessor ltwap = (BeanPostProcessor) BeanUtils.instantiateClass(ltwapClass);
				((BeanFactoryAware) ltwap).setBeanFactory(beanFactory);
				beanFactory.addBeanPostProcessor(ltwap);
			}
			catch (ClassNotFoundException ex) {
				throw new IllegalStateException("Spring's LoadTimeWeaverAwareProcessor class is not available");
			}
			// Set a temporary ClassLoader for type matching.
			beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
		}
	}

	/**
	 * Modify the application context's internal bean factory after its standard
	 * initialization. All bean definitions will have been loaded, but no beans
	 * will have been instantiated yet. This allows for registering special
	 * BeanPostProcessors etc in certain ApplicationContext implementations.
	 * @param beanFactory the bean factory used by the application context
	 */
	protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
	}

	/**
	 * Instantiate and invoke all registered BeanFactoryPostProcessor beans,
	 * respecting explicit order if given.
	 * <p>Must be called before singleton instantiation.
	 */
	protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
		// Invoke factory processors registered with the context instance.
		for (Iterator it = getBeanFactoryPostProcessors().iterator(); it.hasNext();) {
			BeanFactoryPostProcessor factoryProcessor = (BeanFactoryPostProcessor) it.next();
			factoryProcessor.postProcessBeanFactory(beanFactory);
		}

		// Do not initialize FactoryBeans here: We need to leave all regular beans
		// uninitialized to let the bean factory post-processors apply to them!
		String[] postProcessorNames =
				beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);

		// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
		// Ordered, and the rest.
		List priorityOrderedPostProcessors = new ArrayList();
		List orderedPostProcessorNames = new ArrayList();
		List nonOrderedPostProcessorNames = new ArrayList();
		for (int i = 0; i < postProcessorNames.length; i++) {
			if (isTypeMatch(postProcessorNames[i], PriorityOrdered.class)) {
				priorityOrderedPostProcessors.add(beanFactory.getBean(postProcessorNames[i]));
			}
			else if (isTypeMatch(postProcessorNames[i], Ordered.class)) {
				orderedPostProcessorNames.add(postProcessorNames[i]);
			}
			else {
				nonOrderedPostProcessorNames.add(postProcessorNames[i]);
			}
		}

		// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
		Collections.sort(priorityOrderedPostProcessors, new OrderComparator());
		invokeBeanFactoryPostProcessors(beanFactory, priorityOrderedPostProcessors);

		// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
		List orderedPostProcessors = new ArrayList();
		for (Iterator it = orderedPostProcessorNames.iterator(); it.hasNext();) {
			String postProcessorName = (String) it.next();
			orderedPostProcessors.add(getBean(postProcessorName));
		}
		Collections.sort(orderedPostProcessors, new OrderComparator());
		invokeBeanFactoryPostProcessors(beanFactory, orderedPostProcessors);

		// Finally, invoke all other BeanFactoryPostProcessors.
		List nonOrderedPostProcessors = new ArrayList();
		for (Iterator it = nonOrderedPostProcessorNames.iterator(); it.hasNext();) {
			String postProcessorName = (String) it.next();
			nonOrderedPostProcessors.add(getBean(postProcessorName));
		}
		invokeBeanFactoryPostProcessors(beanFactory, nonOrderedPostProcessors);
	}

	/**
	 * Invoke the given BeanFactoryPostProcessor beans.
	 */
	private void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List postProcessors) {
		for (Iterator it = postProcessors.iterator(); it.hasNext();) {
			BeanFactoryPostProcessor postProcessor = (BeanFactoryPostProcessor) it.next();
			postProcessor.postProcessBeanFactory(beanFactory);
		}
	}

	/**
	 * Instantiate and invoke all registered BeanPostProcessor beans,
	 * respecting explicit order if given.
	 * <p>Must be called before any instantiation of application beans.
	 */
	protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
		String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);

		// Register BeanPostProcessorChecker that logs an info message when
		// a bean is created during BeanPostProcessor instantiation, i.e. when
		// a bean is not eligible for getting processed by all BeanPostProcessors.
		int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

		// Separate between BeanPostProcessors that implement PriorityOrdered,
		// Ordered, and the rest.
		List priorityOrderedPostProcessors = new ArrayList();
		List orderedPostProcessorNames = new ArrayList();
		List nonOrderedPostProcessorNames = new ArrayList();
		for (int i = 0; i < postProcessorNames.length; i++) {
			if (isTypeMatch(postProcessorNames[i], PriorityOrdered.class)) {
				priorityOrderedPostProcessors.add(beanFactory.getBean(postProcessorNames[i]));
			}
			else if (isTypeMatch(postProcessorNames[i], Ordered.class)) {
				orderedPostProcessorNames.add(postProcessorNames[i]);
			}
			else {
				nonOrderedPostProcessorNames.add(postProcessorNames[i]);
			}
		}

		// First, register the BeanPostProcessors that implement PriorityOrdered.
		Collections.sort(priorityOrderedPostProcessors, new OrderComparator());
		registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

		// Next, register the BeanPostProcessors that implement Ordered.
		List orderedPostProcessors = new ArrayList();
		for (Iterator it = orderedPostProcessorNames.iterator(); it.hasNext();) {
			String postProcessorName = (String) it.next();
			orderedPostProcessors.add(getBean(postProcessorName));
		}
		Collections.sort(orderedPostProcessors, new OrderComparator());
		registerBeanPostProcessors(beanFactory, orderedPostProcessors);

		// Finally, register all other BeanPostProcessors.
		List nonOrderedPostProcessors = new ArrayList();
		for (Iterator it = nonOrderedPostProcessorNames.iterator(); it.hasNext();) {
			String postProcessorName = (String) it.next();
			nonOrderedPostProcessors.add(getBean(postProcessorName));
		}
		registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
	}

	/**
	 * Register the given BeanPostProcessor beans.
	 */
	private void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory, List postProcessors) {
		for (Iterator it = postProcessors.iterator(); it.hasNext();) {
			BeanPostProcessor postProcessor = (BeanPostProcessor) it.next();
			beanFactory.addBeanPostProcessor(postProcessor);
		}
	}

	/**
	 * Initialize the MessageSource.
	 * Use parent's if none defined in this context.
	 */
	protected void initMessageSource() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {
			this.messageSource = (MessageSource) beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);
			// Make MessageSource aware of parent MessageSource.
			if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {
				HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;
				if (hms.getParentMessageSource() == null) {
					// Only set parent context as parent MessageSource if no parent MessageSource
					// registered already.
					hms.setParentMessageSource(getInternalParentMessageSource());
				}
			}
			if (logger.isDebugEnabled()) {
				logger.debug("Using MessageSource [" + this.messageSource + "]");
			}
		}
		else {
			// Use empty MessageSource to be able to accept getMessage calls.
			DelegatingMessageSource dms = new DelegatingMessageSource();
			dms.setParentMessageSource(getInternalParentMessageSource());
			this.messageSource = dms;
			beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);
			if (logger.isDebugEnabled()) {
				logger.debug("Unable to locate MessageSource with name '" + MESSAGE_SOURCE_BEAN_NAME +
						"': using default [" + this.messageSource + "]");
			}
		}
	}

	/**
	 * Initialize the ApplicationEventMulticaster.
	 * Uses SimpleApplicationEventMulticaster if none defined in the context.
	 * @see org.springframework.context.event.SimpleApplicationEventMulticaster
	 */
	protected void initApplicationEventMulticaster() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
			this.applicationEventMulticaster = (ApplicationEventMulticaster)
					beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
			}
		}
		else {
			this.applicationEventMulticaster = new SimpleApplicationEventMulticaster();
			beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
			if (logger.isDebugEnabled()) {
				logger.debug("Unable to locate ApplicationEventMulticaster with name '" +
						APPLICATION_EVENT_MULTICASTER_BEAN_NAME +
						"': using default [" + this.applicationEventMulticaster + "]");
			}
		}
	}

	/**
	 * Template method which can be overridden to add context-specific refresh work.
	 * Called on initialization of special beans, before instantiation of singletons.
	 * <p>This implementation is empty.
	 * @throws BeansException in case of errors
	 * @see #refresh()
	 */
	protected void onRefresh() throws BeansException {
		// For subclasses: do nothing by default.
	}

	/**
	 * Add beans that implement ApplicationListener as listeners.
	 * Doesn't affect other listeners, which can be added without being beans.
	 */
	protected void registerListeners() {
		// Register statically specified listeners first.
		for (Iterator it = getApplicationListeners().iterator(); it.hasNext();) {
			addListener((ApplicationListener) it.next());
		}
		// Do not initialize FactoryBeans here: We need to leave all regular beans
		// uninitialized to let post-processors apply to them!
		Collection listenerBeans = getBeansOfType(ApplicationListener.class, true, false).values();
		for (Iterator it = listenerBeans.iterator(); it.hasNext();) {
			addListener((ApplicationListener) it.next());
		}
	}

	/**
	 * Subclasses can invoke this method to register a listener.
	 * Any beans in the context that are listeners are automatically added.
	 * @param listener the listener to register
	 */
	protected void addListener(ApplicationListener listener) {
		getApplicationEventMulticaster().addApplicationListener(listener);
	}

	/**
	 * Finish the initialization of this context's bean factory,
	 * initializing all remaining singleton beans.
	 */
	protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
		// Stop using the temporary ClassLoader for type matching.
		beanFactory.setTempClassLoader(null);

		// Allow for caching all bean definition metadata, not expecting further changes.
		beanFactory.freezeConfiguration();

		// Instantiate all remaining (non-lazy-init) singletons.
		beanFactory.preInstantiateSingletons();
	}

	/**
	 * Finish the refresh of this context, publishing the
	 * {@link org.springframework.context.event.ContextRefreshedEvent}.
	 */
	protected void finishRefresh() {
		publishEvent(new ContextRefreshedEvent(this));
	}

	/**
	 * Cancel this context's refresh attempt, resetting the <code>active</code> flag
	 * after an exception got thrown.
	 * @param ex the exception that led to the cancellation
	 */
	protected void cancelRefresh(BeansException ex) {
		synchronized (this.activeMonitor) {
			this.active = false;
		}
	}


	/**
	 * Register a shutdown hook with the JVM runtime, closing this context
	 * on JVM shutdown unless it has already been closed at that time.
	 * <p>Delegates to <code>doClose()</code> for the actual closing procedure.
	 * @see java.lang.Runtime#addShutdownHook
	 * @see #close()
	 * @see #doClose()
	 */
	public void registerShutdownHook() {
		if (this.shutdownHook == null) {
			// No shutdown hook registered yet.
			this.shutdownHook = new Thread() {
				public void run() {
					doClose();
				}
			};
			Runtime.getRuntime().addShutdownHook(this.shutdownHook);
		}
	}

	/**
	 * DisposableBean callback for destruction of this instance.
	 * Only called when the ApplicationContext itself is running
	 * as a bean in another BeanFactory or ApplicationContext,
	 * which is rather unusual.
	 * <p>The <code>close</code> method is the native way to
	 * shut down an ApplicationContext.
	 * @see #close()
	 * @see org.springframework.beans.factory.access.SingletonBeanFactoryLocator
	 */
	public void destroy() {
		close();
	}

	/**
	 * Close this application context, destroying all beans in its bean factory.
	 * <p>Delegates to <code>doClose()</code> for the actual closing procedure.
	 * Also removes a JVM shutdown hook, if registered, as it's not needed anymore.
	 * @see #doClose()
	 * @see #registerShutdownHook()
	 */
	public void close() {
		synchronized (this.startupShutdownMonitor) {
			doClose();
			// If we registered a JVM shutdown hook, we don't need it anymore now:
			// We've already explicitly closed the context.
			if (this.shutdownHook != null) {
				Runtime.getRuntime().removeShutdownHook(this.shutdownHook);
			}
		}
	}

	/**
	 * Actually performs context closing: publishes a ContextClosedEvent and
	 * destroys the singletons in the bean factory of this application context.
	 * <p>Called by both <code>close()</code> and a JVM shutdown hook, if any.
	 * @see org.springframework.context.event.ContextClosedEvent
	 * @see org.springframework.beans.factory.config.ConfigurableBeanFactory#destroySingletons()
	 * @see #close()
	 * @see #registerShutdownHook()
	 */
	protected void doClose() {
		if (isActive()) {
			if (logger.isInfoEnabled()) {
				logger.info("Closing " + this);
			}
			try {
				// Publish shutdown event.
				publishEvent(new ContextClosedEvent(this));
			}
			catch (Throwable ex) {
				logger.error("Exception thrown from ApplicationListener handling ContextClosedEvent", ex);
			}
			// Stop all Lifecycle beans, to avoid delays during individual destruction.
			Map lifecycleBeans = getLifecycleBeans();
			for (Iterator it = new LinkedHashSet(lifecycleBeans.keySet()).iterator(); it.hasNext();) {
				String beanName = (String) it.next();
				doStop(lifecycleBeans, beanName);
			}
			// Destroy all cached singletons in the context's BeanFactory.
			destroyBeans();
			// Close the state of this context itself.
			closeBeanFactory();
			onClose();
			synchronized (this.activeMonitor) {
				this.active = false;
			}
		}
	}

	/**
	 * Template method for destroying all beans that this context manages.
	 * The default implementation destroy all cached singletons in this context,
	 * invoking <code>DisposableBean.destroy()</code> and/or the specified
	 * "destroy-method".
	 * <p>Can be overridden to add context-specific bean destruction steps
	 * right before or right after standard singleton destruction,
	 * while the context's BeanFactory is still active.
	 * @see #getBeanFactory()
	 * @see org.springframework.beans.factory.config.ConfigurableBeanFactory#destroySingletons()
	 */
	protected void destroyBeans() {
		getBeanFactory().destroySingletons();
	}

	/**
	 * Template method which can be overridden to add context-specific shutdown work.
	 * The default implementation is empty.
	 * <p>Called at the end of {@link #doClose}'s shutdown procedure, after
	 * this context's BeanFactory has been closed. If custom shutdown logic
	 * needs to execute while the BeanFactory is still active, override
	 * the {@link #destroyBeans()} method instead.
	 */
	protected void onClose() {
		// For subclasses: do nothing by default.
	}

	public boolean isActive() {
		synchronized (this.activeMonitor) {
			return this.active;
		}
	}


	//---------------------------------------------------------------------
	// Implementation of BeanFactory interface
	//---------------------------------------------------------------------

	public Object getBean(String name) throws BeansException {
		return getBeanFactory().getBean(name);
	}

	public Object getBean(String name, Class requiredType) throws BeansException {
		return getBeanFactory().getBean(name, requiredType);
	}

	public Object getBean(String name, Object[] args) throws BeansException {
		return getBeanFactory().getBean(name, args);
	}

	public boolean containsBean(String name) {
		return getBeanFactory().containsBean(name);
	}

	public boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
		return getBeanFactory().isSingleton(name);
	}

	public boolean isPrototype(String name) throws NoSuchBeanDefinitionException {
		return getBeanFactory().isPrototype(name);
	}

	public boolean isTypeMatch(String name, Class targetType) throws NoSuchBeanDefinitionException {
		return getBeanFactory().isTypeMatch(name, targetType);
	}

	public Class getType(String name) throws NoSuchBeanDefinitionException {
		return getBeanFactory().getType(name);
	}

	public String[] getAliases(String name) {
		return getBeanFactory().getAliases(name);
	}


	//---------------------------------------------------------------------
	// Implementation of ListableBeanFactory interface
	//---------------------------------------------------------------------

	public boolean containsBeanDefinition(String name) {
		return getBeanFactory().containsBeanDefinition(name);
	}

	public int getBeanDefinitionCount() {
		return getBeanFactory().getBeanDefinitionCount();
	}

	public String[] getBeanDefinitionNames() {
		return getBeanFactory().getBeanDefinitionNames();
	}

	public String[] getBeanNamesForType(Class type) {
		return getBeanFactory().getBeanNamesForType(type);
	}

	public String[] getBeanNamesForType(Class type, boolean includePrototypes, boolean allowEagerInit) {
		return getBeanFactory().getBeanNamesForType(type, includePrototypes, allowEagerInit);
	}

	public Map getBeansOfType(Class type) throws BeansException {
		return getBeanFactory().getBeansOfType(type);
	}

	public Map getBeansOfType(Class type, boolean includePrototypes, boolean allowEagerInit)
			throws BeansException {

		return getBeanFactory().getBeansOfType(type, includePrototypes, allowEagerInit);
	}


	//---------------------------------------------------------------------
	// Implementation of HierarchicalBeanFactory interface
	//---------------------------------------------------------------------

	public BeanFactory getParentBeanFactory() {
		return getParent();
	}

	public boolean containsLocalBean(String name) {
		return getBeanFactory().containsLocalBean(name);
	}

	/**
	 * Return the internal bean factory of the parent context if it implements
	 * ConfigurableApplicationContext; else, return the parent context itself.
	 * @see org.springframework.context.ConfigurableApplicationContext#getBeanFactory
	 */
	protected BeanFactory getInternalParentBeanFactory() {
		return (getParent() instanceof ConfigurableApplicationContext) ?
				((ConfigurableApplicationContext) getParent()).getBeanFactory() : (BeanFactory) getParent();
	}


	//---------------------------------------------------------------------
	// Implementation of MessageSource interface
	//---------------------------------------------------------------------

	public String getMessage(String code, Object args[], String defaultMessage, Locale locale) {
		return getMessageSource().getMessage(code, args, defaultMessage, locale);
	}

	public String getMessage(String code, Object args[], Locale locale) throws NoSuchMessageException {
		return getMessageSource().getMessage(code, args, locale);
	}

	public String getMessage(MessageSourceResolvable resolvable, Locale locale) throws NoSuchMessageException {
		return getMessageSource().getMessage(resolvable, locale);
	}

	/**
	 * Return the internal MessageSource used by the context.
	 * @return the internal MessageSource (never <code>null</code>)
	 * @throws IllegalStateException if the context has not been initialized yet
	 */
	private MessageSource getMessageSource() throws IllegalStateException {
		if (this.messageSource == null) {
			throw new IllegalStateException("MessageSource not initialized - " +
					"call 'refresh' before accessing messages via the context: " + this);
		}
		return this.messageSource;
	}

	/**
	 * Return the internal message source of the parent context if it is an
	 * AbstractApplicationContext too; else, return the parent context itself.
	 */
	protected MessageSource getInternalParentMessageSource() {
		return (getParent() instanceof AbstractApplicationContext) ?
		    ((AbstractApplicationContext) getParent()).messageSource : getParent();
	}


	//---------------------------------------------------------------------
	// Implementation of ResourcePatternResolver interface
	//---------------------------------------------------------------------

	public Resource[] getResources(String locationPattern) throws IOException {
		return this.resourcePatternResolver.getResources(locationPattern);
	}


	//---------------------------------------------------------------------
	// Implementation of Lifecycle interface
	//---------------------------------------------------------------------

	public void start() {
		Map lifecycleBeans = getLifecycleBeans();
		for (Iterator it = new LinkedHashSet(lifecycleBeans.keySet()).iterator(); it.hasNext();) {
			String beanName = (String) it.next();
			doStart(lifecycleBeans, beanName);
		}
		publishEvent(new ContextStartedEvent(this));
	}

	public void stop() {
		Map lifecycleBeans = getLifecycleBeans();
		for (Iterator it = new LinkedHashSet(lifecycleBeans.keySet()).iterator(); it.hasNext();) {
			String beanName = (String) it.next();
			doStop(lifecycleBeans, beanName);
		}
		publishEvent(new ContextStoppedEvent(this));
	}

	public boolean isRunning() {
		Iterator it = getLifecycleBeans().values().iterator();
		while (it.hasNext()) {
			Lifecycle lifecycle = (Lifecycle) it.next();
			if (!lifecycle.isRunning()) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Return a Map of all singleton beans that implement the
	 * Lifecycle interface in this context.
	 * @return Map of Lifecycle beans with bean name as key
	 */
	private Map getLifecycleBeans() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		String[] beanNames = beanFactory.getSingletonNames();
		Map beans = new LinkedHashMap();
		for (int i = 0; i < beanNames.length; i++) {
			Object bean = beanFactory.getSingleton(beanNames[i]);
			if (bean instanceof Lifecycle) {
				beans.put(beanNames[i], bean);
			}
		}
		return beans;
	}

	/**
	 * Start the specified bean as part of the given set of Lifecycle beans,
	 * making sure that any beans that it depends on are started first.
	 * @param lifecycleBeans Map with bean name as key and Lifecycle instance as value
	 * @param beanName the name of the bean to start
	 */
	private void doStart(Map lifecycleBeans, String beanName) {
		Lifecycle bean = (Lifecycle) lifecycleBeans.get(beanName);
		if (bean != null) {
			String[] dependenciesForBean = getBeanFactory().getDependenciesForBean(beanName);
			for (int i = 0; i < dependenciesForBean.length; i++) {
				doStart(lifecycleBeans, dependenciesForBean[i]);
			}
			if (!bean.isRunning()) {
				bean.start();
			}
			lifecycleBeans.remove(beanName);
		}
	}

	/**
	 * Stop the specified bean as part of the given set of Lifecycle beans,
	 * making sure that any beans that depends on it are stopped first.
	 * @param lifecycleBeans Map with bean name as key and Lifecycle instance as value
	 * @param beanName the name of the bean to stop
	 */
	private void doStop(Map lifecycleBeans, String beanName) {
		Lifecycle bean = (Lifecycle) lifecycleBeans.get(beanName);
		if (bean != null) {
			String[] dependentBeans = getBeanFactory().getDependentBeans(beanName);
			for (int i = 0; i < dependentBeans.length; i++) {
				doStop(lifecycleBeans, dependentBeans[i]);
			}
			if (bean.isRunning()) {
				bean.stop();
			}
			lifecycleBeans.remove(beanName);
		}
	}


	//---------------------------------------------------------------------
	// Abstract methods that must be implemented by subclasses
	//---------------------------------------------------------------------

	/**
	 * Subclasses must implement this method to perform the actual configuration load.
	 * The method is invoked by {@link #refresh()} before any other initialization work.
	 * <p>A subclass will either create a new bean factory and hold a reference to it,
	 * or return a single BeanFactory instance that it holds. In the latter case, it will
	 * usually throw an IllegalStateException if refreshing the context more than once.
	 * @throws BeansException if initialization of the bean factory failed
	 * @throws IllegalStateException if already initialized and multiple refresh
	 * attempts are not supported
	 */
	protected abstract void refreshBeanFactory() throws BeansException, IllegalStateException;

	/**
	 * Subclasses must implement this method to release their internal bean factory.
	 * This method gets invoked by {@link #close()} after all other shutdown work.
	 * <p>Should never throw an exception but rather log shutdown failures.
	 */
	protected abstract void closeBeanFactory();

	/**
	 * Subclasses must return their internal bean factory here. They should implement the
	 * lookup efficiently, so that it can be called repeatedly without a performance penalty.
	 * <p>Note: Subclasses should check whether the context is still active before
	 * returning the internal bean factory. The internal factory should generally be
	 * considered unavailable once the context has been closed.
	 * @return this application context's internal bean factory (never <code>null</code>)
	 * @throws IllegalStateException if the context does not hold an internal bean factory yet
	 * (usually if {@link #refresh()} has never been called) or if the context has been
	 * closed already
	 * @see #refreshBeanFactory()
	 * @see #closeBeanFactory()
	 */
	public abstract ConfigurableListableBeanFactory getBeanFactory() throws IllegalStateException;


	/**
	 * Return information about this context.
	 */
	public String toString() {
		StringBuffer sb = new StringBuffer(getId());
		sb.append(": display name [").append(getDisplayName());
		sb.append("]; startup date [").append(new Date(getStartupDate()));
		sb.append("]; ");
		ApplicationContext parent = getParent();
		if (parent == null) {
			sb.append("root of context hierarchy");
		}
		else {
			sb.append("parent: ").append(parent.getId());
		}
		return sb.toString();
	}


	/**
	 * BeanPostProcessor that logs an info message when a bean is created during
	 * BeanPostProcessor instantiation, i.e. when a bean is not eligible for
	 * getting processed by all BeanPostProcessors.
	 */
	private class BeanPostProcessorChecker implements BeanPostProcessor {

		private final ConfigurableListableBeanFactory beanFactory;

		private final int beanPostProcessorTargetCount;

		public BeanPostProcessorChecker(ConfigurableListableBeanFactory beanFactory, int beanPostProcessorTargetCount) {
			this.beanFactory = beanFactory;
			this.beanPostProcessorTargetCount = beanPostProcessorTargetCount;
		}

		public Object postProcessBeforeInitialization(Object bean, String beanName) {
			return bean;
		}

		public Object postProcessAfterInitialization(Object bean, String beanName) {
			if (!(bean instanceof BeanPostProcessor) &&
					this.beanFactory.getBeanPostProcessorCount() < this.beanPostProcessorTargetCount) {
				if (logger.isInfoEnabled()) {
					logger.info("Bean '" + beanName + "' is not eligible for getting processed by all " +
							"BeanPostProcessors (for example: not eligible for auto-proxying)");
				}
			}
			return bean;
		}
	}

}