Java并发编程中的join()与interrupt()函数

      刚刚写了下Java的并发程序，在此做个笔记。对于线程a和b，在线程b中调用a.join()，那么此时线程b将会被挂起，直至线程a执行完才会有线程b执行的机会，若想打破这种机制，可以调用a.interrupt()，这时，线程b可以不必受刚才的约束。

 

import java.util.concurrent.*;

class Sleeper extends Thread {
    //private String name;
    private int duration;
    
    public Sleeper(String name, int duration){
        super(name);
        this.duration = duration;
        start();
    }
    public void run(){
        try{
            System.out.println(getName() + " before sleep.");
            TimeUnit.MILLISECONDS.sleep(duration);
            System.out.println(getName() + " is asleep.");
        }catch(InterruptedException e){
            System.out.println(getName() + " was interrupted. " + " isInterrupted(): " + isInterrupted());
            return;
        }
        System.out.println(getName() + " has awakened.");
    }
}

class Joiner extends Thread{
    private Sleeper sleeper;
    public Joiner(String name, Sleeper sleeper){
        super(name);
        this.sleeper = sleeper;
        start();
    }
    
    public void run(){
        try{
            System.out.println(getName() + " before join.");
            sleeper.join();
            System.out.println(getName() + " after join.");
        }catch (InterruptedException e) {
            System.out.println(getName() + " was interrupted.");
        }
        System.out.println(getName() + " join completed.");
    }
}
public class ConcurrentBasic {
    public static void main(String args[]){
        Sleeper sleepy = new Sleeper("Sleepy", 3000);
        Sleeper grumpy = new Sleeper("Grumpy", 3000);
        Joiner dopey = new Joiner("Dopey", sleepy);
        Joiner doc = new Joiner("Doc", grumpy);
        
        grumpy.interrupt();

    }
}

      grumpy在这被打断了，那么和它join的doc将会被唤醒，从而导致doc线程的执行，这里可以把grumpy.interrupt()改为doc.interrupt()，运行情况与预想差不多。