[原创]C#编写的多生产者多消费者同步问题

// 多个生产者和多个消费者，能生产n个产品的情况

using System;
using System.Threading;

public class HoldIntegerSynchronized{

private int[] buffer; //缓冲区

private int occupiedBufferCount = 0;

private int readPosition = 0 , writePosition = 0;
//下一个读到的位置和写到的位置

public HoldIntegerSynchronized(int capacity){
buffer = new int[capacity];
}

public int BufferSize{
get{
return buffer.Length;
}
}

public int Buffer{
get{
int bufferCopy;
// 加锁
lock(this){
while(occupiedBufferCount == 0){ //多个消费者，所以此处改用while
Console.WriteLine(Thread.CurrentThread.Name + " tries to read. ");
DisplayState("Buffer Empty. " + Thread.CurrentThread.Name + " waits.");
Monitor.Wait(this);
// 为临界区之外等待的生产者放行，让他来"生产"
// 一直到生产者生产结束，调用了Monitor.PauseAll()
// 才能继续执行下去,此时，消费者自动重新获得this的锁
}

--occupiedBufferCount;

bufferCopy = buffer[readPosition];

readPosition = (readPosition + 1) % buffer.Length;

DisplayState(Thread.CurrentThread.Name + " reads " + bufferCopy);

// 通知，让等待的 生产者线程 进入Started状态,如果生产者处于临界区之外，这句话执行完后他仍然在临界区之外
Monitor.PulseAll(this);

// 释放锁
}//lock
return bufferCopy;
}

set{
// 加锁
lock(this){
while(occupiedBufferCount == buffer.Length){
Console.WriteLine(Thread.CurrentThread.Name + " tries to write. ");
DisplayState("Buffer Full. " + Thread.CurrentThread.Name + " waits.");
Monitor.Wait(this);
// 为临界区之外等待消费者放行，让他来"消费"
// 一直到消费者调用了Monitor.Pause()
// 才能继续执行下去，此时，生产者自动重新获得this的锁
}

buffer[writePosition] = value;

++occupiedBufferCount;

writePosition = (writePosition + 1) % buffer.Length;

DisplayState(Thread.CurrentThread.Name + " writes " + value);

// 通知，让Wait状态的 消费者 进入Started状态,如果消费者处于临界区之外，这句话执行完后他仍然在临界区之外
Monitor.PulseAll(this);

// 释放锁
}
}
}

public void DisplayState(string operation){
Console.Write("{0,-35}",operation);
for(int i = 0; i < BufferSize; i++ ){
int a = readPosition;
int b = writePosition;

if( a <= i && i < b) {
Console.Write("{0,-9}",buffer[i]);
}else if( b < a && !( b <= i && i < a ) ){
Console.Write("{0,-9}",buffer[i]);
}else if( occupiedBufferCount == BufferSize){
Console.Write("{0,-9}",buffer[i]);
}else{
Console.Write("{0,-9}","");
}

}
Console.WriteLine("{0}/r/n",occupiedBufferCount);
}
}

class Producer{
private HoldIntegerSynchronized sharedLocation;
private Random randomSleepTime;

public Producer(HoldIntegerSynchronized shared,Random random){
sharedLocation = shared;
randomSleepTime = random;
}

public void Produce(){
for (int count=0; count<3; count++) {
Thread.Sleep(randomSleepTime.Next(1,2000));
sharedLocation.Buffer = randomSleepTime.Next(5,10);
}
Console.WriteLine(Thread.CurrentThread.Name + " done producing./r/nTerminating " + Thread.CurrentThread.Name + "./r/n");
}
}

class Consumer{
private HoldIntegerSynchronized sharedLocation;
private Random randomSleepTime;

public Consumer(HoldIntegerSynchronized shared,Random random){
sharedLocation = shared;
randomSleepTime = random;
}

public void Consume(){
int sum = 0;
for (int count=0; count<4; count++) {
Thread.Sleep(randomSleepTime.Next(1,2000));
sum += sharedLocation.Buffer;
}
Console.WriteLine(Thread.CurrentThread.Name + " read values totaling:" + sum + "/r/nTerminating " + Thread.CurrentThread.Name + ".");
}
}

class SharedCell{
static void Main(string[] args){
HoldIntegerSynchronized holdInteger = new HoldIntegerSynchronized(5);
Random random = new Random();

Thread[] producerThreads = new Thread[4];
Thread[] consumerThreads = new Thread[3];

Console.Write("{0,-35}","Operation");
for(int i = 0;i < holdInteger.BufferSize;i++){
Console.Write("{0,-9}","Elem " + i);
}
Console.WriteLine("Occupied Count/r/n");

for(int i = 0; i < producerThreads.Length;i++){
Producer producer = new Producer(holdInteger,random);
producerThreads[i] = new Thread(new ThreadStart(producer.Produce));
producerThreads[i].Name = "Producer No." + i;
}

for(int i = 0; i < consumerThreads.Length;i++){
Consumer consumer = new Consumer(holdInteger,random);
consumerThreads[i] = new Thread(new ThreadStart(consumer.Consume));
consumerThreads[i].Name = "Consumer No." + i;
}

for(int i = 0; i < producerThreads.Length;i++){
producerThreads[i].Start();
}

for(int i = 0; i < consumerThreads.Length;i++){
consumerThreads[i].Start();
}
}
}