This sample demonstrates Activity class and synchronisation using FastMutex. There's a Buffer class(thread-safe) that wraps a stack object and a SizeController class to control the size of a Buffer object. When it determines that the size of buffer is less than the threshold value, it calls Buffer object to load data.
If I have wrongs in the code, I appreciate to hear these. Here's the code:
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#include "Poco/ThreadPool.h"
#include "Poco/Thread.h"
#include "Poco/Runnable.h"
#include "Poco/Mutex.h"
#include "Poco/Random.h"
#include "Poco/Activity.h"
#include <stack>
#include <iostream>
using Poco::Thread;
using Poco::FastMutex;
using Poco::Random;
using Poco::Activity;
#define THRESHOLD 3
#define CHUNKSIZE 5
class Buffer
{
public:
Buffer(){}
int getData()
{
int data = 0;
{
FastMutex::ScopedLock lock(_mutex);
data = _elements.top();
_elements.pop();
}
return data;
}
void loadData()
{
Random rnd;
{
FastMutex::ScopedLock lock(_mutex);
for (int i=0;i<CHUNKSIZE;i++)
_elements.push(rnd.next(200));
}
}
int size()
{
return _elements.size();
}
protected:
private:
std::stack<int> _elements;
static FastMutex _mutex;
};
FastMutex Buffer::_mutex;
class SizeController
{
public:
SizeController():
_activity(this, &SizeController::runActivity)
{
}
void setControlObject(Buffer* obj)
{
_obj = obj;
}
void start()
{
_activity.start();
}
void stop()
{
_activity.stop();
_activity.wait();
}
protected:
void runActivity()
{
while (!_activity.isStopped())
{
std::cout<<"--- "<<_obj->size()<<" ---\n";
if (_obj->size()<THRESHOLD)
{
std::cout<<"--- Under Threshold Limit ---\n";
_obj->loadData();
}
Thread::sleep(1000);
}
}
private:
Activity<SizeController> _activity;
Buffer* _obj;
};
int main()
{
Buffer buf;
buf.loadData();
SizeController szcontroller;
szcontroller.setControlObject(&buf);
szcontroller.start();
while(1)
{
std::cout<<buf.getData()<<"\n"<<std::flush;
Thread::sleep(5000);
}
}