（48）21.4.4 检查中断---Java编程思想之并发笔记

21.4.4 检查中断

1.中断状态的设置

     通过用interrupted()来检查中断状态，这个不仅可以告诉你interrupt()是否被调用过，而且可以清除中断状态。清除中断状态可以确保并发结构不会就某个任务被中断这个问题通知你两次，你可以经由单一的InterruptedException或单一的成功的Thread.interrupted()测试来得到这种通知。

2.例子

package jiangning.c21;

import java.util.concurrent.TimeUnit;

class NeedsCleanUp{

       private final int id;

       public NeedsCleanUp(int ident){

             this.id = ident;

            System. out.println("NeedsCleanUp " + id);

      }

       public void cleanUp(){

            System. out.println("cleanUp " + id);

      }

}

class Block3 implements Runnable{

       private volatile double d = 0.0;

       public void run(){

             try {

                   while(!Thread.interrupted()){

                         //point1

                        NeedsCleanUp n1 = new NeedsCleanUp(1);

                         try{

                              System. out.println("Sleeping" );

                              TimeUnit. SECONDS.sleep(1);

                               //point2

                              NeedsCleanUp n2 = new NeedsCleanUp(2);

                               try {

                                    System. out.println("Calculating" );

                                     for(int i=0;i<2500000;i++){

                                           d = d + (Math. PI + Math.E)/d;

                                    }

                                    System. out.println("Finished time-consuming opration");

                              } finally {

                                    n2.cleanUp();

                              }

                        } finally{

                              n1.cleanUp();

                        }

                  }

                  System. out.println("Exiting while() test" );

            } catch (InterruptedException e) {

                  System. out.println("Exiting via InterruptedException");

            }

      }

}

public class InterruptingIdiom {

       public static void main(String[] args) throws Exception {

             if(args.length != 1){

                  System. out.println("usage: java InterruptingIdiom delay-in-mS");

                  System. exit(1);

            }

            Thread t = new Thread(new Block3());

            t.start();

            TimeUnit. MILLISECONDS.sleep(new Integer(args[0]));

            t.interrupt();

      }

}