DelayQueue的简单使用

我最近想用一个数据结构，可以定时从它里面取出数据，发现java提供了DelayQueue，使用DelayQueue需要实现Delayed这个接口，而实现Delayed这个接口主要就是实现它的getDelay()和compareTo()这两个方法，示例代码如下：

import java.util.ArrayList;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

class TestString implements Delayed{
	private String str;
	private long   timeout;
	TestString(String str,long timeout){
		this.str = str;
		this.timeout = timeout + System.nanoTime();
	}
	//返回距离你自定义的超时时间还有多少
	public long getDelay(TimeUnit unit){
		return unit.convert(timeout-System.nanoTime(), TimeUnit.NANOSECONDS);
	}
	//比较getDelay()函数的返回值
	public int compareTo(Delayed other){
		 if (other == this) // compare zero ONLY if same object
             return 0;
         
		 TestString t = (TestString)other;
		 long d = (getDelay(TimeUnit.NANOSECONDS) - t.getDelay(TimeUnit.NANOSECONDS));
	     return (d == 0) ? 0 : ((d < 0) ? -1 : 1);
	}
	void print(){
		System.out.println(str);
	}
}
public class TestCode {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ArrayList<String> list = new ArrayList<String>();
		list.add("string 1");
		list.add("string 2");
		list.add("string 3");
		list.add("string 4");
		list.add("string 5");
		list.add("string 6");
		list.add("string 7");
		list.add("string 8");
		list.add("string 9");
		list.add("string 10");
		
        DelayQueue<TestString> queue = new DelayQueue<TestString>();
        
        long start = System.currentTimeMillis();
        for(int i = 0;i<10;i++){
        	queue.put(new TestString(list.get(i),
        			TimeUnit.NANOSECONDS.convert(1, TimeUnit.SECONDS)));
	        	try {
	    			 queue.take().print();
	    			 System.out.println("After " + 
	    					 (System.currentTimeMillis()-start) + " MilliSeconds");
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
        }
	}
}

运行结果：

string 1
After 1012 MilliSeconds
string 2
After 2023 MilliSeconds
string 3
After 3026 MilliSeconds
string 4
After 4030 MilliSeconds
string 5
After 5033 MilliSeconds
string 6
After 6037 MilliSeconds
string 7
After 7040 MilliSeconds
string 8
After 8043 MilliSeconds
string 9
After 9046 MilliSeconds
string 10
After 10050 MilliSeconds