windows 读者写者实现[c++ & java]

c++初步实现：

// 读者写者.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <iostream>
#include <Windows.h>
using namespace std;

const int readerNum=5;
const int writerNum=5;
const int readerSleep=100;
const int writerSleep=100;
const int waittime=100;
static int nr=0;
static int nw=0;
static int readerCount=0;
HANDLE mutex;
HANDLE db;

void acquireReadLock(){
    WaitForSingleObject(mutex,waittime);
    ++readerCount;

    if(readerCount==1)
        WaitForSingleObject(db,waittime);

    ReleaseMutex(mutex);
}

void releaseReadLock(){
    WaitForSingleObject(mutex,waittime);
    --readerCount;

    if(readerCount==0)
        ReleaseSemaphore(db,1,NULL);

    ReleaseMutex(mutex);
}

void acquireWriteLock(){
    WaitForSingleObject(db,waittime);
}

void releaseWriteLock(){
    ReleaseSemaphore(db,1,NULL);
}

DWORD WINAPI readerFun(LPVOID lparam)
{
    Sleep(readerSleep);
    acquireReadLock();

    cout<<"reader:"<<nr++<<endl;

    Sleep(readerSleep);
    releaseReadLock();
    return(0);
}

DWORD WINAPI writerFun(LPVOID lparam)
{
    Sleep(writerSleep);
    acquireWriteLock();

    cout<<"writer:"<<nw++<<endl;

    Sleep(writerSleep);
    releaseWriteLock();
    return(0);
}

int _tmain(int argc, _TCHAR* argv[])
{
    int i;
    HANDLE rThread[readerNum];
    HANDLE wThread[writerNum];

    mutex=CreateMutex(NULL,FALSE,NULL);
    db=CreateSemaphore(NULL,1,1,NULL);

    for(i=0 ; i<readerNum ;i++){
        rThread[i]=CreateThread(NULL,0,readerFun,&db,NULL,NULL);
        if(rThread[i]==NULL)
            return -1;
    }

    for(i=0 ; i<writerNum ; i++){
        wThread[i]=CreateThread(NULL,0,writerFun,&db,NULL,NULL);
        if(wThread[i]==NULL)
            return -1;
    }

    bool isContinue=true;
    while(isContinue){
        if(getchar())
            isContinue=false;
    }

    for(i=0 ;i<readerNum ; i++){
        CloseHandle(rThread[i]);
    }

    for(i=0 ; i<writerNum ; i++){
        CloseHandle(wThread[i]);
    }

    return 0;
}

java初步实现：

import java.util.concurrent.Semaphore;


interface RWLock
{
    public abstract void acquireReadLock();
    public abstract void releaseReadLock();
    public abstract void acquireWriteLock();
    public abstract void releaseWriteLock();
}

class Database implements RWLock
{
    private int readerCount;
    private Semaphore mutex;
    private Semaphore db;

    public Database(){
        readerCount=0;
        mutex=new Semaphore(1);
        db=new Semaphore(1);
    }

    public void acquireReadLock(){
        try {
            mutex.acquire();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        ++readerCount;

        if(readerCount==1)
            try {
                db.acquire();
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        mutex.release();
    }

    public void releaseReadLock(){
        try {
            mutex.acquire();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        --readerCount;

        if(readerCount==0)
            db.release();

        mutex.release();
    }

    public void acquireWriteLock(){
        try {
            db.acquire();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    public void releaseWriteLock(){
        db.release();
    }
}

class Reader implements Runnable
{
    private RWLock db;
    private int readerNum=5;
    private long sleeptime=50;

    public Reader(RWLock db){
        this.db=db;
    }

    public void run(){
        for(int i=0 ; i<readerNum ; i++){
            try {
                Thread.sleep(sleeptime);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            db.acquireReadLock();

            System.out.println("reader:"+i);

            try {
                Thread.sleep(sleeptime);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            db.releaseReadLock();
        }
    }
}

class Writer implements Runnable
{
    private RWLock db;
    private int writeNum=5;
    private long sleeptime=100;

    public Writer(RWLock db){
        this.db=db;
    }

    public void run(){
        for(int i=0 ; i<writeNum ; i++){
            try {
                Thread.sleep(sleeptime);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            db.acquireWriteLock();

            System.out.println("writer:"+i);

            try {
                Thread.sleep(sleeptime);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            db.releaseWriteLock();
        }
    }
}

public class 读者写者
{
    public static void main(String[] args){
        RWLock db=new Database();

        Thread reader=new Thread(new Reader(db));
        Thread writer=new Thread(new Writer(db));

        reader.start();
        writer.start();
    }
}

 菜鸟学习中，求路过大神指点。