Spring源码学习-4.IoC器皿其他特征分析

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()));
		}
	}

	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;
			}
		}
	}

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();
<span style="white-space:pre">				</span>//在这里对lazy-init属性进行处理
				// 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;
			}
		}
	}

	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();
<span style="white-space:pre">		</span>//在这里开始处理
		// Instantiate all remaining (non-lazy-init) singletons.
		beanFactory.preInstantiateSingletons();
	}

	public void preInstantiateSingletons() throws BeansException {
		if (this.logger.isInfoEnabled()) {
			this.logger.info("Pre-instantiating singletons in " + this);
		}
		//检测BeanDefinition需要提前依赖注入的对象
		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()) {
						//实现依赖注入
							getBean(beanName);
						}
					}
					else {
					//实现依赖注入
						getBean(beanName);
					}
				}
			}
		}
	}

	protected Object getObjectForBeanInstance(
			Object beanInstance, String name, String beanName, RootBeanDefinition mbd) {

			//如果不是对FactoryBean的调用,那么结束
		// Don't let calling code try to dereference the factory if the bean isn't a factory.
		if (BeanFactoryUtils.isFactoryDereference(name) && !(beanInstance instanceof FactoryBean)) {
			throw new BeanIsNotAFactoryException(transformedBeanName(name), beanInstance.getClass());
		}

		// Now we have the bean instance, which may be a normal bean or a FactoryBean.
		// If it's a FactoryBean, we use it to create a bean instance, unless the
		// caller actually wants a reference to the factory.
		if (!(beanInstance instanceof FactoryBean) || BeanFactoryUtils.isFactoryDereference(name)) {
			return beanInstance;
		}

		Object object = null;
		if (mbd == null) {
			object = getCachedObjectForFactoryBean(beanName);
		}
		if (object == null) {
			// Return bean instance from factory.
			FactoryBean factory = (FactoryBean) beanInstance;
			// Caches object obtained from FactoryBean if it is a singleton.
			if (mbd == null && containsBeanDefinition(beanName)) {
				mbd = getMergedLocalBeanDefinition(beanName);
			}
			boolean synthetic = (mbd != null && mbd.isSynthetic());
			//从FactoryBean中得到Bean
			object = getObjectFromFactoryBean(factory, beanName, !synthetic);
		}
		return object;
	}

protected Object getObjectFromFactoryBean(FactoryBean factory, String beanName, boolean shouldPostProcess) {
		if (factory.isSingleton() && containsSingleton(beanName)) {
			synchronized (getSingletonMutex()) {
				Object object = this.factoryBeanObjectCache.get(beanName);
				if (object == null) {
					object = doGetObjectFromFactoryBean(factory, beanName, shouldPostProcess);
					this.factoryBeanObjectCache.put(beanName, (object != null ? object : NULL_OBJECT));
				}
				return (object != NULL_OBJECT ? object : null);
			}
		}
		else {
			return doGetObjectFromFactoryBean(factory, beanName, shouldPostProcess);
		}
	}

	private Object doGetObjectFromFactoryBean(
			final FactoryBean factory, final String beanName, final boolean shouldPostProcess)
			throws BeanCreationException {

		AccessControlContext acc = AccessController.getContext();
		return AccessController.doPrivileged(new PrivilegedAction() {
			public Object run() {
				Object object;

				try {
				//从Factory的getBean从FactoryBean中获取Bean
					object = factory.getObject();
				}
				catch (FactoryBeanNotInitializedException ex) {
					throw new BeanCurrentlyInCreationException(beanName, ex.toString());
				}
				catch (Throwable ex) {
					throw new BeanCreationException(beanName, "FactoryBean threw exception on object creation", ex);
				}

				// Do not accept a null value for a FactoryBean that's not fully
				// initialized yet: Many FactoryBeans just return null then.
				if (object == null && isSingletonCurrentlyInCreation(beanName)) {
					throw new BeanCurrentlyInCreationException(
							beanName, "FactoryBean which is currently in creation returned null from getObject");
				}

				if (object != null && shouldPostProcess) {
					try {
						object = postProcessObjectFromFactoryBean(object, beanName);
					}
					catch (Throwable ex) {
						throw new BeanCreationException(beanName, "Post-processing of the FactoryBean's object failed", ex);
					}
				}

				return object;
			}
		}, acc);
	}

//通过nama自动完成依赖注入
protected void autowireByName(
			String beanName, AbstractBeanDefinition mbd, BeanWrapper bw, MutablePropertyValues pvs) {

		String[] propertyNames = unsatisfiedNonSimpleProperties(mbd, bw);
		for (int i = 0; i < propertyNames.length; i++) {
			String propertyName = propertyNames[i];
			if (containsBean(propertyName)) {
				Object bean = getBean(propertyName);
				pvs.addPropertyValue(propertyName, bean);
				registerDependentBean(propertyName, beanName);
				if (logger.isDebugEnabled()) {
					logger.debug("Added autowiring by name from bean name '" + beanName +
						"' via property '" + propertyName + "' to bean named '" + propertyName + "'");
				}
			}
			else {
				if (logger.isTraceEnabled()) {
					logger.trace("Not autowiring property '" + propertyName + "' of bean '" + beanName +
							"' by name: no matching bean found");
				}
			}
		}
	}

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