java利用delayedQueue实现本地的延迟队列

import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

/**
 * <p>
 * [任务调度系统]
 * <br>
 * [队列中要执行的任务]
 * </p>
 *
 * @author wangguangdong
 * @version 1.0
 * @Date 2015年11月22日19:46:39
 */
public class Task<T extends Runnable> implements Delayed {
 /**
  * 到期时间
  */
 private final long time;

 /**
  * 问题对象
  */
 private final T task;
 private static final AtomicLong atomic = new AtomicLong(0);

 private final long n;

 public Task(long timeout, T t) {
  this.time = System.nanoTime() + timeout;
  this.task = t;
  this.n = atomic.getAndIncrement();
 }

 /**
  * 返回与此对象相关的剩余延迟时间，以给定的时间单位表示
  */
 @Override
 public long getDelay(TimeUnit unit) {
  return unit.convert(this.time - System.nanoTime(), TimeUnit.NANOSECONDS);
 }

 @Override
 public int compareTo(Delayed other) {
  // TODO Auto-generated method stub
  if (other == this) // compare zero ONLY if same object
   return 0;
  if (other instanceof Task) {
   Task x = (Task) other;
   long diff = time - x.time;
   if (diff < 0)
    return -1;
   else if (diff > 0)
    return 1;
   else if (n < x.n)
    return -1;
   else
    return 1;
  }
  long d = (getDelay(TimeUnit.NANOSECONDS) - other.getDelay(TimeUnit.NANOSECONDS));
  return (d == 0) ? 0 : ((d < 0) ? -1 : 1);
 }

 public T getTask() {
  return this.task;
 }

 @Override
 public int hashCode() {
  return task.hashCode();
 }

 @Override
 public boolean equals(Object object) {
  if (object instanceof Task) {
   return object.hashCode() == hashCode() ? true : false;
  }
  return false;
 }


}

import org.apache.log4j.Logger;

import java.util.concurrent.DelayQueue;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

/**
 * <p>
 * [任务调度系统]
 * <br>
 * [后台守护线程不断的执行检测工作]
 * </p>
 *
 * @author wangguangdong
 * @version 1.0
 * @Date 2015年11月23日14:19:40
 */
public class TaskQueueDaemonThread {

 private static final Logger LOG = Logger.getLogger(TaskQueueDaemonThread.class);

 private TaskQueueDaemonThread() {
 }

 private static class LazyHolder {
  private static TaskQueueDaemonThread taskQueueDaemonThread = new TaskQueueDaemonThread();
 }

 public static TaskQueueDaemonThread getInstance() {
  return LazyHolder.taskQueueDaemonThread;
 }

 Executor executor = Executors.newFixedThreadPool(20);
 /**
  * 守护线程
  */
 private Thread daemonThread;

 /**
  * 初始化守护线程
  */
 public void init() {
  daemonThread = new Thread(() -> execute());
  daemonThread.setDaemon(true);
  daemonThread.setName("Task Queue Daemon Thread");
  daemonThread.start();
 }

 private void execute() {
  System.out.println("start:" + System.currentTimeMillis());
  while (true) {
   try {
    //从延迟队列中取值,如果没有对象过期则队列一直等待，
    Task t1 = t.take();
    if (t1 != null) {
     //修改问题的状态
     Runnable task = t1.getTask();
     if (task == null) {
      continue;
     }
     executor.execute(task);
     LOG.info("[at task:" + task + "] [Time:" + System.currentTimeMillis() + "]");
    }
   } catch (Exception e) {
    e.printStackTrace();
    break;
   }
  }
 }

 /**
  * 创建一个最初为空的新 DelayQueue
  */
 private DelayQueue<Task> t = new DelayQueue<>();

 /**
  * 添加任务，
  * time 延迟时间
  * task 任务
  * 用户为问题设置延迟时间
  */
 public void put(long time, Runnable task) {
  //转换成ns
  long nanoTime = TimeUnit.NANOSECONDS.convert(time, TimeUnit.MILLISECONDS);
  //创建一个任务
  Task k = new Task(nanoTime, task);
  //将任务放在延迟的队列中
  t.put(k);
 }

 /**
  * 结束订单
  * @param task
  */
 public boolean endTask(Task<Runnable> task){
  return t.remove(task);
 }
}