EventBus - 10 源码解析-8：发送事件post

/** Posts the given event to the event bus. */
    public void post(Object event) {
        // PostingThreadState : 发送事件的一个线程状态的封装类    duanran
        // currentPostingThreadState 作用：线程独有的，不会让其他线程共享当前线程数据
        PostingThreadState postingState = currentPostingThreadState.get();
        // 获取到事件的队列
        List<Object> eventQueue = postingState.eventQueue;
        eventQueue.add(event);
         // 判断是否在进行发送
        if (!postingState.isPosting) {
            postingState.isMainThread = isMainThread();
            // 表示事件已正在分发了，其他事件先阻塞在这里，等会再走
            postingState.isPosting = true;
            // 如果标志位取消的话
            if (postingState.canceled) {
                throw new EventBusException("Internal error. Abort state was not reset");
            }
            try {
                // 循环，直到整个队列都为空
                while (!eventQueue.isEmpty()) {
                    postSingleEvent(eventQueue.remove(0), postingState);
                }
            } finally {
                postingState.isPosting = false;
                postingState.isMainThread = false;
            }
        }
    }

/** For ThreadLocal, much faster to set (and get multiple values). */
    final static class PostingThreadState {
        // 事件队列集合
        final List<Object> eventQueue = new ArrayList<>();
        // 是否正在发送事件的标志位
        boolean isPosting;
        // 是否在主线程判断的标志位
        boolean isMainThread;
        // 将订阅者和订阅方法，封装起来的封装类
        Subscription subscription;
        // 事件
        Object event;
        // 取消标志位
        boolean canceled;
    }

private void postSingleEvent(Object event, PostingThreadState postingState) throws Error {
        Class<?> eventClass = event.getClass();
        boolean subscriptionFound = false;
        // 判断 是否查看 这个事件有关的 所有的继承关系
        if (eventInheritance) {
            // 通过 lookupAllEventTypes 查找到所有继承关系的事件类型
            List<Class<?>> eventTypes = lookupAllEventTypes(eventClass);
            int countTypes = eventTypes.size();
            for (int h = 0; h < countTypes; h++) {
                Class<?> clazz = eventTypes.get(h);
                subscriptionFound |= postSingleEventForEventType(event, postingState, clazz);
            }
        } else {
            subscriptionFound = postSingleEventForEventType(event, postingState, eventClass);
        }
        if (!subscriptionFound) { // 如果没有事件
            if (logNoSubscriberMessages) {
                logger.log(Level.FINE, "No subscribers registered for event " + eventClass);
            }
            if (sendNoSubscriberEvent && eventClass != NoSubscriberEvent.class &&
                    eventClass != SubscriberExceptionEvent.class) {
                // NoSubscriberEvent 表示没有订阅者订阅该事件
                post(new NoSubscriberEvent(this, event));
            }
        }
    }