前言
DefaultListableBeanFactory是beanFactory体系里面最后一个子类，也是唯一的操作类，唯一的实现。DefaultListableBeanFactory继承了AbstractAutowireCapableBeanFactory，实现了ConfigurableListableBeanFactory接口。
解读变量
allowBeanDefinitionOverriding变量
allowBeanDefinitionOverriding是一个坑，DefaultListableBeanFactory重写了父类SimpleAliasRegistry的allowAliasOverriding方法。重写的allowAliasOverriding方法就是使用的allowBeanDefinitionOverriding。如果要修改allowBeanDefinitionOverriding变量，需要深入的考虑SimpleAliasRegistry的行为。
private boolean allowBeanDefinitionOverriding = true;
public boolean isAllowBeanDefinitionOverriding() {
return this.allowBeanDefinitionOverriding;
}
protected boolean allowAliasOverriding() {
return isAllowBeanDefinitionOverriding();
}
public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition) throws BeanDefinitionStoreException {
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.");
}
}
......
}
解读
- 修改allowBeanDefinitionOverriding，注意SimpleAliasRegistry的行为
- allowBeanDefinitionOverriding的作用是是否允许一个name有多个BeanDefinition
dependencyComparator变量
private Comparator<Object> dependencyComparator;
解读
resolvableDependencies
private final Map<Class<?>, Object> resolvableDependencies = new ConcurrentHashMap<Class<?>, Object>(16);
public void registerResolvableDependency(Class<?> dependencyType, Object autowiredValue) {
Assert.notNull(dependencyType, "Dependency type must not be null");
if (autowiredValue != null) {
if (!(autowiredValue instanceof ObjectFactory || dependencyType.isInstance(autowiredValue))) {
throw new IllegalArgumentException("Value [" + autowiredValue +"] does not implement specified dependency type [" + dependencyType.getName() + "]");
}
this.resolvableDependencies.put(dependencyType, autowiredValue);
}
}
AbstractApplicationContext
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// 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);
}
解读
resolvableDependencies用来保存spring中自己的bean。这样隔离系统bean与业务bean，好像spring，没有做得彻底。
beanDefinitionMap属性
private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<String, BeanDefinition>(256);
保存BeanDefinition的实现类，
allBeanNamesByType属性 与 singletonBeanNamesByType变量
private final Map<Class<?>, String[]> allBeanNamesByType = new ConcurrentHashMap<Class<?>, String[]>(64);
private final Map<Class<?>, String[]> singletonBeanNamesByType = new ConcurrentHashMap<Class<?>, String[]>(64);
public String[] getBeanNamesForType(Class<?> type, boolean includeNonSingletons, boolean allowEagerInit) {
if (!isConfigurationFrozen() || type == null || !allowEagerInit) {
return doGetBeanNamesForType(ResolvableType.forRawClass(type), includeNonSingletons, allowEagerInit);
}
Map<Class<?>, String[]> cache =
(includeNonSingletons ? this.allBeanNamesByType : this.singletonBeanNamesByType);
String[] resolvedBeanNames = cache.get(type);
if (resolvedBeanNames != null) {
return resolvedBeanNames;
}
resolvedBeanNames = doGetBeanNamesForType(ResolvableType.forRawClass(type), includeNonSingletons, true);
if (ClassUtils.isCacheSafe(type, getBeanClassLoader())) {
cache.put(type, resolvedBeanNames);
}
return resolvedBeanNames;
}
当getBeanNamesForType方法被调用的时候，会把结果缓存到allBeanNamesByType或singletonBeanNamesByType里面。getBeanNamesForType参数type对应class类型的所有beanName
beanDefinitionNames与manualSingletonNames变量
private volatile List<String> beanDefinitionNames = new ArrayList<String>(256);
private volatile Set<String> manualSingletonNames = new LinkedHashSet<String>(16);
public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition) throws BeanDefinitionStoreException {
if (hasBeanCreationStarted()) {
// 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)) {// beanDefinitionNames 存在的beanName，就不能在manualSingletonNames存在
Set<String> updatedSingletons = new LinkedHashSet<String>(this.manualSingletonNames);
updatedSingletons.remove(beanName);
this.manualSingletonNames = updatedSingletons;
}
}
}
}
public void registerSingleton(String beanName, Object singletonObject) throws IllegalStateException {
super.registerSingleton(beanName, singletonObject);
if (hasBeanCreationStarted()) {
// Cannot modify startup-time collection elements anymore (for stable iteration)
synchronized (this.beanDefinitionMap) {
if (!this.beanDefinitionMap.containsKey(beanName)) {
Set<String> updatedSingletons = new LinkedHashSet<String>(this.manualSingletonNames.size() + 1);
updatedSingletons.addAll(this.manualSingletonNames);
updatedSingletons.add(beanName);
this.manualSingletonNames = updatedSingletons;
}
}
}
else {
// Still in startup registration phase
if (!this.beanDefinitionMap.containsKey(beanName)) {
this.manualSingletonNames.add(beanName);
}
}
clearByTypeCache();
}
beanDefinitionNames保存所有BeanDefinition的名字，manualSingletonNames保存了所有singleton的BeanDefinitionName。注意beanDefinitionNames声明了 volatile