随想 2018052202

继续学习事件驱动编程：

 

1. 方法论中的： Observer 设计模式， Pub-Sub MQ设计模式

2. 业务之间的解耦，必须引入一个额外的一个组件来。还是那句话： add addtional indirecation layer for flexible or discompose.

3. Zookeeper 中 watch 机制也可以用来解耦（分布式），作为事件驱动执行器，FileWatch也是可以的

4. 事件、事件源、发布事件、消费事件、事件处理器 Executor

5. Spring: ApplicationContext, ApplicationEvent, ApplicationEventListner, @EventListener,  事件处理器的 并发处理需要配置 @Configuration

6. ApplicationEvent:  startup, refresh, shutdown 

7. @Async 可以使方法异步执行

 

publish<event> ----->  executor (ThreadPool)   <------- handler<event>

可获取结果的异步 PubSub 模式

1.  Publish event

2.  Tranlate event to internal bucket with id for exchange the information between producer & consumer

3.  Create Future<?> and save map container with bucket id

4.  Save internal bucket to local memory waiting for executor to send

5.  Way 1: directly create new FutureTask<?> with Callable<?> executing body and submit it to executor, after event is done by handler, Future<?> can be get 

6.  Way 2: Using ArrayBlockingQueue<?> with only 1 element inside subclass of Future<?>, and create a connetion between Future<?> and bucket id, after registering the 

     listener to executor for waiting for the event is done by handler. If done, set ArrayBlockingQueue<?> by finding object the subclass of Future<?> from container with bucket id