接口实现public void addListener(Object listener) {//interface 1synchronized (lock) {if (allListeners.add(listener)) {for (BroadcastDispatch<?> broadcaster : dispatchers.values()) {maybeAddToDispatcher(broadcaster, listener);}}}}——————————————————————————public void useLogger(Object logger) {//interface 2synchronized (lock) {if (allLoggers.add(logger)) {for (LoggerDispatch dispatch : loggers.values()) {dispatch.maybeSetLogger(logger);}}}}——————————————————————————–public <T> T getBroadcaster(Class<T> listenerClass) {//interface 3return getBroadcasterInternal(listenerClass).getSource();}private <T> ListenerBroadcast<T> getBroadcasterInternal(Class<T> listenerClass) {synchronized (lock) {ListenerBroadcast<T> broadcaster = broadcasters.get(listenerClass);if (broadcaster == null) {broadcaster = new ListenerBroadcast<T>(listenerClass);//Add dispatch object into broadcaster's handlers queue.broadcaster.add(getLogger(listenerClass));broadcaster.add(getDispatcher(listenerClass));if (parent != null) {broadcaster.add(parent.getDispatcher(listenerClass));}broadcasters.put(listenerClass, broadcaster);}return broadcaster;}}private LoggerDispatch getLogger(Class<?> listenerClass) {synchronized (lock) {LoggerDispatch dispatch = loggers.get(listenerClass);if (dispatch == null) {dispatch = new LoggerDispatch(listenerClass, parent == null ? null : parent.getLogger(listenerClass));for (Object logger : allLoggers) {dispatch.maybeSetLogger(logger);}loggers.put(listenerClass, dispatch);}return dispatch;}}private LoggerDispatch(Class<?> type, LoggerDispatch parentDispatch) {this.type = type;this.dispatch = parentDispatch;}//1.In org.gradle.initialization DefaultGradleLauncherFactory.java//The constructor of DefaultGradleLauncherFactory// Register default loggersListenerManager listenerManager = sharedServices.get(ListenerManager.class);buildProgressLogger = new BuildProgressLogger(sharedServices.get(ProgressLoggerFactory.class));//interface 1, 'allListeners' is empty, and only add item to Set<>, do nothing else.listenerManager.addListener(new BuildProgressFilter(buildProgressLogger));//interface 2, 'allLoggers' is empty, and only add item to Set<>, do nothing elselistenerManager.useLogger(new DependencyResolutionLogger(sharedServices.get(ProgressLoggerFactory.class)));//2. Same package, DefaultGradleLauncherFactory.java//doNewInstance function//小插曲，，调用了一下函数 from BuildScopeServies::createListenerManager/*public ListenerManager createChild() {return new DefaultListenerManager(this);}*///Then the 'listenerManager' is a totally new object, //and the one before becomes its 'parent'ListenerManager listenerManager = serviceRegistry.get(ListenerManager.class);//this hooks up the ListenerManager and LoggingConfigurer so you can call Gradle.addListener() with a StandardOutputListener.//Interface 3, 'broadcasters' map is empty , then new an ListenerBroadcast object 'broadcaster'//In 'getLogger', the 'loggers' is empty, //in new LoggerDispatch, it will call parent.getLogger first (递归), parent's loggers is empty //so parent listenerManager will return a LoggerDispatch object, with 'dispatch' null, and put it into parent's loggers queue.//To son's turn, the new LoggerDispatch will be an object with 'dispatch' point to the object returned from parent.//Parent.loggers.values constains a value of DefaultListenerManager$LoggerDispatch (id=196), its dispatch is null//this.loggers.values constains value of DefaultListenerManager$LoggerDispatch, it's dispatch var member is also a DefaultListenerManager$LoggerDispatch//with id=196, so the parent/child chain is madeloggingManager.addStandardOutputListener(listenerManager.getBroadcaster(StandardOutputListener.class));
生命不在长而在于好，只要每一次尽力的演示，都值得鼓励与喝采。
