江苏龙网

  1. 主页 > 生活百科 > >

Spring三级缓存解决循环依赖( 五 )

spring


DefaultSingletonBeanRegistry.java 三级缓存
public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements SingletonBeanRegistry {/** Cache of singleton objects: bean name to bean instance. 一级缓存 */private final Map<String, Object> singletonObjects = new ConcurrentHashMap<>(256);/** Cache of singleton factories: bean name to ObjectFactory. 三级缓存 */private final Map<String, ObjectFactory<?>> singletonFactories = new HashMap<>(16);/** Cache of early singleton objects: bean name to bean instance. 二级缓存 */private final Map<String, Object> earlySingletonObjects = new ConcurrentHashMap<>(16);.../*** Return the (raw) singleton object registered under the given name.* <p>Checks already instantiated singletons and also allows for an early* reference to a currently created singleton (resolving a circular reference).* @param beanName the name of the bean to look for* @param allowEarlyReference whether early references should be created or not* @return the registered singleton object, or {@code null} if none found*/@Nullableprotected Object getSingleton(String beanName, boolean allowEarlyReference) {// Quick check for existing instance without full singleton lockObject singletonObject = this.singletonObjects.get(beanName);if (singletonObject == null && isSingletonCurrentlyInCreation(beanName)) {singletonObject = this.earlySingletonObjects.get(beanName);if (singletonObject == null && allowEarlyReference) {synchronized (this.singletonObjects) {// Consistent creation of early reference within full singleton locksingletonObject = this.singletonObjects.get(beanName);if (singletonObject == null) {singletonObject = this.earlySingletonObjects.get(beanName);if (singletonObject == null) {ObjectFactory<?> singletonFactory = this.singletonFactories.get(beanName);if (singletonFactory != null) {singletonObject = singletonFactory.getObject();this.earlySingletonObjects.put(beanName, singletonObject);this.singletonFactories.remove(beanName);}}}}}}return singletonObject;}} 


原文作者：小丸子的呆地
原文链接：
https://www.jianshu.com/p/d17795a605de




推荐阅读


上一篇：四年级作文我战胜了恐惧?四年级作文我战胜了恐惧400字

下一篇：庞统跟诸葛亮谁更聪明?庞统和诸葛亮被称为什么