DefaultListableBeanFactory 源碼 分析

1.1 public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition) throws BeanDefinitionStoreException

@Override
	public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)
			throws BeanDefinitionStoreException {

		Assert.hasText(beanName, "Bean name must not be empty");
		Assert.notNull(beanDefinition, "BeanDefinition must not be null");

		if (beanDefinition instanceof AbstractBeanDefinition) {
			try {
                                //驗證beanDefinition
				((AbstractBeanDefinition) beanDefinition).validate();
			}
			catch (BeanDefinitionValidationException ex) {
				throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName,
						"Validation of bean definition failed", ex);
			}
		}

		BeanDefinition oldBeanDefinition;

		oldBeanDefinition = this.beanDefinitionMap.get(beanName);
		if (oldBeanDefinition != null) {
			if (!isAllowBeanDefinitionOverriding()) {
				throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName,
						"Cannot register bean definition [" + beanDefinition + "] for bean '" + beanName +
						"': There is already [" + oldBeanDefinition + "] bound.");
			}
			else if (oldBeanDefinition.getRole() < beanDefinition.getRole()) {
				// e.g. was ROLE_APPLICATION, now overriding with ROLE_SUPPORT or ROLE_INFRASTRUCTURE
				if (this.logger.isWarnEnabled()) {
					this.logger.warn("Overriding user-defined bean definition for bean '" + beanName +
							"' with a framework-generated bean definition: replacing [" +
							oldBeanDefinition + "] with [" + beanDefinition + "]");
				}
			}
			else if (!beanDefinition.equals(oldBeanDefinition)) {
				if (this.logger.isInfoEnabled()) {
					this.logger.info("Overriding bean definition for bean '" + beanName +
							"' with a different definition: replacing [" + oldBeanDefinition +
							"] with [" + beanDefinition + "]");
				}
			}
			else {
				if (this.logger.isDebugEnabled()) {
					this.logger.debug("Overriding bean definition for bean '" + beanName +
							"' with an equivalent definition: replacing [" + oldBeanDefinition +
							"] with [" + beanDefinition + "]");
				}
			}
			this.beanDefinitionMap.put(beanName, beanDefinition);
		}
		else {
			if (hasBeanCreationStarted()) {//是否已經開始建立bean
				// Cannot modify startup-time collection elements anymore (for stable iteration)
				synchronized (this.beanDefinitionMap) {
					this.beanDefinitionMap.put(beanName, beanDefinition);
					List<String> updatedDefinitions = new ArrayList<String>(this.beanDefinitionNames.size() + 1);
					updatedDefinitions.addAll(this.beanDefinitionNames);
					updatedDefinitions.add(beanName);
					this.beanDefinitionNames = updatedDefinitions;
					if (this.manualSingletonNames.contains(beanName)) {
						Set<String> updatedSingletons = new LinkedHashSet<String>(this.manualSingletonNames);
						updatedSingletons.remove(beanName);
						this.manualSingletonNames = updatedSingletons;
					}
				}
			}
			else {
				// Still in startup registration phase
				this.beanDefinitionMap.put(beanName, beanDefinition);
				this.beanDefinitionNames.add(beanName);
				this.manualSingletonNames.remove(beanName);
			}
			this.frozenBeanDefinitionNames = null;
		}

		if (oldBeanDefinition != null || containsSingleton(beanName)) {
			resetBeanDefinition(beanName);
		}
	}