package com.zehong.common.utils;

import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 线程相关工具类.
 * 
 * @author zehong
 */
public class Threads
{
    private static final Logger logger = LoggerFactory.getLogger(Threads.class);

    /**
     * sleep等待,单位为毫秒
     */
    public static void sleep(long milliseconds)
    {
        try
        {
            Thread.sleep(milliseconds);
        }
        catch (InterruptedException e)
        {
            return;
        }
    }

    /**
     * 停止线程池
     * 先使用shutdown, 停止接收新任务并尝试完成所有已存在任务.
     * 如果超时, 则调用shutdownNow, 取消在workQueue中Pending的任务,并中断所有阻塞函数.
     * 如果仍人超時，則強制退出.
     * 另对在shutdown时线程本身被调用中断做了处理.
     */
    public static void shutdownAndAwaitTermination(ExecutorService pool)
    {
        if (pool != null && !pool.isShutdown())
        {
            pool.shutdown();
            try
            {
                if (!pool.awaitTermination(120, TimeUnit.SECONDS))
                {
                    pool.shutdownNow();
                    if (!pool.awaitTermination(120, TimeUnit.SECONDS))
                    {
                        logger.info("Pool did not terminate");
                    }
                }
            }
            catch (InterruptedException ie)
            {
                pool.shutdownNow();
                Thread.currentThread().interrupt();
            }
        }
    }

    /**
     * 打印线程异常信息
     */
    public static void printException(Runnable r, Throwable t)
    {
        if (t == null && r instanceof Future<?>)
        {
            try
            {
                Future<?> future = (Future<?>) r;
                if (future.isDone())
                {
                    future.get();
                }
            }
            catch (CancellationException ce)
            {
                t = ce;
            }
            catch (ExecutionException ee)
            {
                t = ee.getCause();
            }
            catch (InterruptedException ie)
            {
                Thread.currentThread().interrupt();
            }
        }
        if (t != null)
        {
            logger.error(t.getMessage(), t);
        }
    }
}
