/*******************************************************************************
 * Copyright (c) 2005, 2014 springside.github.io
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 *******************************************************************************/
package com.cjs.site.util.redis;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 线程相关工具类.
 * 
 * @author calvin
 */
public class Threads {

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

    /**
     * sleep等待.
     */
    public static void sleep(long duration, TimeUnit unit) {
        try {
            Thread.sleep(unit.toMillis(duration));
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }

    /**
     * 按照ExecutorService JavaDoc示例代码编写的Graceful Shutdown方法.
     * 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.
     * 如果仍然超時，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 gracefulShutdown(ExecutorService pool, int shutdownTimeout,
                                        int shutdownNowTimeout, TimeUnit timeUnit) {
        pool.shutdown(); // Disable new tasks from being submitted
        try {
            // Wait a while for existing tasks to terminate
            if (!pool.awaitTermination(shutdownTimeout, timeUnit)) {
                pool.shutdownNow(); // Cancel currently executing tasks
                // Wait a while for tasks to respond to being cancelled
                if (!pool.awaitTermination(shutdownNowTimeout, timeUnit)) {
                    System.err.println("Pool did not terminated");
                }
            }
        } catch (InterruptedException ie) {
            // (Re-)Cancel if current thread also interrupted
            pool.shutdownNow();
            // Preserve interrupt status
            Thread.currentThread().interrupt();
        }
    }

    /**
     * 直接调用shutdownNow的方法, 有timeout控制.取消在workQueue中Pending的任务,并中断所有阻塞函数.
     */
    public static void normalShutdown(ExecutorService pool, int timeout, TimeUnit timeUnit) {
        try {
            pool.shutdownNow();
            if (!pool.awaitTermination(timeout, timeUnit)) {
                System.err.println("Pool did not terminated");
            }
        } catch (InterruptedException ie) {
            Thread.currentThread().interrupt();
        }
    }

    /**
     * 保证不会有Exception抛出到线程池的Runnable，防止用户没有捕捉异常导致中断了线程池中的线程。
     */
    public static class WrapExceptionRunnable implements Runnable {

        private static Logger logger = LoggerFactory.getLogger(WrapExceptionRunnable.class);

        private Runnable      runnable;

        public WrapExceptionRunnable(Runnable runnable) {
            this.runnable = runnable;
        }

        @Override
        public void run() {
            try {
                runnable.run();
            } catch (Exception e) {
                // catch any exception, because the scheduled thread will break if the exception thrown outside.
                logger.error("Unexpected error occurred in task", e);
            }
        }
    }

}