package com.victor.thread;

/**
 * volatile 關鍵字，使一個變數在多個執行緒間可見 volatile並不能保證多個執行緒共同修改running變數時所帶來的不一致問題，
 * 也就是說volatile不能替代synchronized synchronized可以保證可見性和原子性，volatile只能保證可見性
 * 
 * 原理比較複雜，需要了解java記憶體模型JMM
 * 
 * @author Victor
 */
public class VolatileThread_010 extends Thread {

    // 不加volatile 程式會出現死迴圈
 

    private volatile boolean running;

    public void run() {
        System.out.println("m start");
        while (!running) {
        }
        System.out.println("m end!");
    }

    public void stopIt() {
        running = true;
    }

    public boolean getStop() {
        return running;
    }

    /**
     * @param
 
 args
     * @throws InterruptedException
     */
    public static void main(String[] args) throws InterruptedException {
        VolatileThread_010 a = new VolatileThread_010();
        a.start();
        Thread.sleep(1000);
        a.stopIt();
        Thread.sleep(2000);
        System.out.println("finish main"
 
);
        System.out.println(a.getStop());
    }

}