This article mainly introduces some problems of timers in Java with examples. Friends in need can refer to it
Timer problems
Timers It is a basic basic component. Whether it is program development in user space or kernel space, timers are often needed as support as a basic component. The implementation of a timer needs to have the following four basic behaviors: adding timer, canceling timer, timer check, and expiration execution.
Please design a timer and implement the following three basic behaviors. The function prototype has been given. You can use any programming language to design the data structure and implementation, and support a large number of timers as efficiently as possible:
// Add a timer: perform the target operation after a specific time interval
//Input 1: Interval timer time, unit ms
/ / Input 2: ExpiryAction target operation
// Return: TimerId
StartTimer(Interval, ExpiryAction) -> TimerId
// Cancel timer
// Input: Timer Id
StopTimer(TimerId)
// Timer check
// The system will call this function every 10ms
PerTickBookkeeping()
Without further ado, let’s go straight to the code:
1)Timer.java:
import java.util.ArrayList; public class Timer { private long interval; // 定时器时间,单位 ms private String expiryAction; // 目标操作 private int timerId; // 定时器Id private long waitTime; // 定时器等待时间 // 构造函数 public Timer(){ this.waitTime = 0; } // 添加定时器 public int StartTimer(long interval, String expiryAction, int id){ this.interval = interval; this.expiryAction = expiryAction; this.timerId = id; return timerId; } // 取消定时器 public void StopTimer(int timerId, ArrayList<Timer> timer){ timer.remove(timerId); } // 定时器检查 public void PerTickBookkeeping(){ if (this.interval > this.waitTime) this.waitTime += 10; else{ System.out.println("定时器"+this.timerId+":"+this.expiryAction); this.waitTime = 0; } } public long getInterval() { return interval; } public void setInterval(long interval) { this.interval = interval; } public String getExpiryAction() { return expiryAction; } public void setExpiryAction(String expiryAction) { this.expiryAction = expiryAction; } public int getTimerId() { return timerId; } public void setTimerId(int timerId) { this.timerId = timerId; } public long getWaitTime() { return waitTime; } public void setWaitTime(long waitTime) { this.waitTime = waitTime; } }
2)DoTimer.java:
import java.util.ArrayList; import java.util.Iterator; public class DoTimer extends Thread { private static ArrayList<Timer> timerList; public static void main(String[] args){ timerList = new ArrayList<Timer>(); Timer timer1 = new Timer(); timer1.StartTimer(3000, "我是第一个定时器,等待3秒", 0); Timer timer2 = new Timer(); timer2.StartTimer(4000, "我是第二个定时器,等待4秒", 1); timerList.add(timer1); timerList.add(timer2); //public void run(){} new Thread(){ @Override public void run() { while(true){ Iterator<Timer> it = timerList.iterator(); while(it.hasNext()){ it.next().PerTickBookkeeping(); } try { sleep(10); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }.start(); timer1.StopTimer(timer1.getTimerId(), timerList); } }
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