package com.jayfulmath.designpattern.command;import java.util.concurrent.Semaphore;/*    P(S)：        ①将信号量S的值减1，即S=S-1；        ②如果S>=0，则该进程继续执行；否则该进程置为等待状态。        V(S)：        ①将信号量S的值加1，即S=S+1；        ②该进程继续执行；如果该信号的等待队列中有等待进程就唤醒一等待进程。 *  * */public class PVObject {        private Semaphore mSemaphore =null;    private int Max_size = 0xff;    private String name = null;    public PVObject(int size,String name)    {        if(size>0)        {            Max_size = size;            mSemaphore = new Semaphore(size);        }        this.name = name;    }        public PVObject(String name)    {        Max_size = 1;        mSemaphore = new Semaphore(1);        this.name = name;    }        public void Init(int status)    {        if(status<0 || status>Max_size)        {            System.out.println("[PVObject][Init]"+name+" wrong,status:"+status);            return;        }                if(status == Max_size)        {            return;        }                try {            mSemaphore.release(Max_size);            mSemaphore.acquire(Max_size-status);        } catch (InterruptedException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        }        public void P()    {        try {            //            mSemaphore.acquire();        } catch (InterruptedException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }            }        public void V()    {        mSemaphore.release();            }}