package com.yunshouhu;

import java.util.concurrent.*;

//java簡單實現非同步佇列:使用生產者與消費者模型
public class MyAsynQueue {

	// http://www.importnew.com/22519.html
	// 模擬訊息佇列訂閱者 同時4個執行緒處理，任務提交者
	private static final ThreadPoolExecutor THREAD_POOL = (ThreadPoolExecutor) Executors.newFixedThreadPool(4);
	// 模擬訊息佇列生產者,單一執行緒， 處理者
	private static final ScheduledExecutorService SCHEDULED_EXECUTOR_SERVICE = Executors.newSingleThreadScheduledExecutor();
	
	// 用於判斷是否關閉訂閱
	private static volatile boolean isClose = false;
	static int taskId=0;
	public static void main(String[] args) throws InterruptedException {
		//儲存任務佇列
		BlockingQueue<String> queue = new ArrayBlockingQueue<String>(100);
		producer(queue);
		consumer(queue);
		exitALl();
		System.out.println("all finish!");
	}
	

	private static boolean exitALl() {
		if(taskId>10)
		{
			
			THREAD_POOL.shutdown();
			SCHEDULED_EXECUTOR_SERVICE.shutdown();
			return true;
		}else{
			return false;
		}
	}


	// 模擬訊息佇列生產者
	private static void producer(final BlockingQueue queue) {

		// 每200毫秒向佇列中放入一個訊息
		SCHEDULED_EXECUTOR_SERVICE.scheduleAtFixedRate(new Runnable() {
			public void run() {
				taskId++;
				queue.offer("taskId="+taskId);
				//exitALl();
				
			}
		}, 0L, 200L, TimeUnit.MILLISECONDS);
	}

	// 模擬訊息佇列消費者 生產者每秒生產5個 消費者4個執行緒消費1個1秒 每秒積壓1個
	private static void consumer(final BlockingQueue queue) throws InterruptedException {
		//while (!isClose) 
		while(true)
		{
			
			// 從佇列中拿到訊息
			final String msg = (String) queue.take();
			// 放入執行緒池處理
			if (!THREAD_POOL.isShutdown()) {
				THREAD_POOL.execute(new Runnable() {
					public void run() {
						try {
							
							TimeUnit.MILLISECONDS.sleep(500L);
							System.out.println(msg+" 任務處理完畢！");
							
							
						} catch (InterruptedException e) {
							e.printStackTrace();
						}
					}
				});
			}
			getPoolBacklogSize();
			if(exitALl())
			{
				break;
			}
			
		}
	}

	// 檢視執行緒池堆積訊息個數
	private static long getPoolBacklogSize() {
		long backlog = THREAD_POOL.getTaskCount() - THREAD_POOL.getCompletedTaskCount();
		System.out.println(String.format("[%s]THREAD_POOL 積壓的任務:%s", System.currentTimeMillis(), backlog));
		return backlog;
	}

	
}