C++ Poco - 如何向特定线程发送通知/消息?

我在下面有这段代码。

我有两个不同的线程：Foo和Bar。 在main()，我想向Foo线程发送消息。为此，我使用的是POCO库中的NotificationQueue。

#include <iostream>
#include "Poco/Notification.h"
#include "Poco/NotificationQueue.h"
#include "Poco/ThreadPool.h"
#include "Poco/Runnable.h"
#include "Poco/AutoPtr.h"
using Poco::Notification;
using Poco::NotificationQueue;
using Poco::ThreadPool;
using Poco::Runnable;
using Poco::AutoPtr;
class Message : public Notification
{
public:
Message(std::string msg) 
: mMsg(msg) 
{
}
std::string getMsg() const
{
return mMsg;
}
private:
std::string mMsg;
};
class Foo: public Runnable
{
public:
Foo(NotificationQueue& queue) : mQueue(queue) {}
void run()
{
AutoPtr<Notification> notification(mQueue.waitDequeueNotification());
while (notification)
{
Message* msg = dynamic_cast<Message*>(notification.get());
if (msg)
{
std::cout << "received from Foo: " << msg->getMsg() << std::endl;
}
notification = mQueue.waitDequeueNotification();
}
}
private:
NotificationQueue & mQueue;
};
class Bar: public Runnable
{
public:
Bar(NotificationQueue& queue) : mQueue(queue) {}
void run()
{
AutoPtr<Notification> notification(mQueue.waitDequeueNotification());
while (notification)
{
Message* msg = dynamic_cast<Message*>(notification.get());
if (msg)
{
std::cout << "received from Bar: " << msg->getMsg() << std::endl;
}
notification = mQueue.waitDequeueNotification();
}
}
private:
NotificationQueue & mQueue;
};
int main(int argc, char** argv)
{
NotificationQueue queue;
Foo foo(queue);
Bar bar(queue);
ThreadPool::defaultPool().start(foo);
ThreadPool::defaultPool().start(bar);
queue.enqueueNotification(new Message(std::string("start"))); //I want to send this message to Foo!!!
while (!queue.empty())
{
Poco::Thread::sleep(100);
}
queue.wakeUpAll();
ThreadPool::defaultPool().joinAll();
return 0;
}

我已经运行了几次代码，我可以看到有时线程Foo首先捕获消息，但有时它是Bar线程。

运行5次后输出：

received from Foo: start
received from Foo: start
received from Bar: start
received from Bar: start
received from Foo: start

我知道我可以像过滤器一样在message class上创建一个source和destination。 但这给我带来了两个问题：

1 - 如果我需要为邮件创建自己的过滤，如何只查看邮件而不将其从队列中删除？例如：Thread A需要向Thread B发送消息，但Thread C首先捕获它。所以Thread C只需要偷看目的地......如果不是针对他们，则不会从队列中删除消息。

2 -POCO上没有办法自动执行此操作吗？就像告诉通知仅适用于该特定线程一样？