秒杀多线程第八篇 经典线程同步 信号量Semaphore （续）

package com.multithread.semaphore;

import java.util.concurrent.Semaphore;

import com.multithread.main.ExampleInterface;

/**
 * semaphore 可以控制某个资源被同时使用的个数。
 * 通过 acquire()获得许可，没有就等待。
 * release() 释放一个许可。
 * 
 * */
public class SemaphoreExample extends ExampleInterface{
    
    final Semaphore sema = new Semaphore(1);
    int g_num = 0;
    @Override
    public void startDemo() {

        for(int i=0;i<10;i++)
        {
            Thread se = new SemaMultiThread(i,sema);
            se.start();
        }
        
    }
    
    
    
    
    @Override
    public void startDemo2() {
        final Semaphore _lsema = new Semaphore(10);
        for(int i=0;i<50;i++)
        {
            Thread se = new SemaMultiThread(i,_lsema);
            se.start();
        }
    }




    class SemaMultiThread extends Thread {
        
        int index = -1;
        Semaphore mSema = null;
        public SemaMultiThread(int i,Semaphore se) {
            this.index = i;
            mSema = se;
        }

        @Override
        public void run() {
            try {
                mSema.acquire();
                System.out.println("index:"+this.index);
                Thread.sleep((long) (Math.random()*100));
                mSema.release();
                System.out.println("----------------:"+mSema.availablePermits());
                Thread.sleep((long) (Math.random()*100));
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }
}