PostProcessorRegistrationDelegate 是一个静态工具类,包访问权限,AbstractApplicationContext's post-processor handling 的委托.把BeanFactoryPostProcessor获取与执行 以及BeanPostProcessor的注册.
2.1 registerBeanPostProcessors 方法分析
public static void registerBeanPostProcessors(
ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
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.
//使用PriorityOrdered保证顺序
List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>();
//使用Ordered保证顺序
List<String> orderedPostProcessorNames = new ArrayList<String>();
List<String> nonOrderedPostProcessorNames = new ArrayList<String>();
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, register the BeanPostProcessors that implement PriorityOrdered.
//第一步,注册所有实现PriorityOrdered的BeanPostProcessor
sortPostProcessors(beanFactory, priorityOrderedPostProcessors);
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
//第二部注册所有实现ordered接口
List<BeanPostProcessor> orderedPostProcessors = new ArrayList<BeanPostProcessor>();
for (String ppName : orderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
orderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
sortPostProcessors(beanFactory, orderedPostProcessors);
registerBeanPostProcessors(beanFactory, orderedPostProcessors);
// Now, register all regular BeanPostProcessors.
//第三步注册所有无序的BeanPostProcessor
List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
for (String ppName : nonOrderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
nonOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
// Finally, re-register all internal BeanPostProcessors.
//第四步注册所有MergedBeanDefinitionPostProcessor类型的BeanPostProcessor
sortPostProcessors(beanFactory, internalPostProcessors);
registerBeanPostProcessors(beanFactory, internalPostProcessors);
//添加ApplicationListener 探测器
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}