MOOC清华《面向对象程序设计》第7章：负载监视器的设计v2.0（采用基于模板的策略模式）

在第6章程序的基础上，按照本章要求做了改进。

Debug经验：采用模板定义类时，含有模板形参的函数必须在类里面定义，不能放到类的外面，不能另外放到实现文件中。

//main.cpp

#include <iostream>
#include <windows.h>
#include "Monitor.h"
#include "LoadStrategy.h"
#include "MemoryStrategy.h"
#include "LatencyStrategy.h"
#include "Display.h"
using namespace std;

int main() {
Monitor<Load, Memory, Latency, Display> monitor;

while(1){
monitor.getLoad();
monitor.getTotalMemory();
monitor.getUsedMemory();
monitor.getNetworkLatency();

monitor.show();
}
return 0;
}

//Monitor.h

#ifndef Monitor_h
#define Monitor_h

#include "LoadStrategy.h"
#include "MemoryStrategy.h"
#include "LatencyStrategy.h"
#include "Display.h"

template <class _load, class _memory, class _latency, class _display>
class Monitor:public _load, public _memory, public _latency, public _display{
public:
Monitor(){}
~Monitor(){}

void getLoad(){
load = _load::getCPULoad();
}

void getTotalMemory(){
totalMemory = _memory::getTotal();
}

void getUsedMemory(){
usedMemory = _memory::getUsed();
}

void getNetworkLatency(){
latency = _latency::getLatency();
}

void show(){
_display::show(load, totalMemory, usedMemory, latency);
}

private:
LoadStrategy *m_loadStrategy;
MemoryStrategy *m_memStrategy;
LatencyStrategy *m_latencyStrategy;
Display *m_display;
float load, latency;
long totalMemory, usedMemory;
};

#endif

//LoadStrategy.h

#ifndef LoadStrategy_h
#define LoadStrategy_h

#include <iostream>
#include <windows.h>
using namespace std;

class LoadStrategy{
public:
virtual ~LoadStrategy(){}
virtual float getLoad() = 0;
};

class LoadStrategyImpl_1:public LoadStrategy{
public:
~LoadStrategyImpl_1(){}

__int64 CompareFileTime(FILETIME time1, FILETIME time2);
float getLoad();
};

class LoadStrategyImpl_2:public LoadStrategy{
public:
~LoadStrategyImpl_2(){}

float getLoad(){
//get load here
float load = 0.0;
return load;
}
};

class Load{
public:
float getCPULoad(){
LoadStrategyImpl_1 obj;
float CPU_LOAD = obj.getLoad();
return CPU_LOAD;
}
};

#endif

//LoadStrategy.cpp

#include <iostream>
#include <windows.h>
#include "LoadStrategy.h"
using namespace std;

__int64 LoadStrategyImpl_1::CompareFileTime(FILETIME time1, FILETIME time2)
{
__int64 a = time1.dwHighDateTime << 32 | time1.dwLowDateTime ;
__int64 b = time2.dwHighDateTime << 32 | time2.dwLowDateTime ;
return (b - a);
}

float LoadStrategyImpl_1::getLoad(){
float load = 0.0;
FILETIME idleTime;//空闲时间
FILETIME kernelTime;//核心态时间
FILETIME userTime;//用户态时间

GetSystemTimes(&idleTime, &kernelTime, &userTime );
//这里务必调用GetSystemTimes函数一次

HANDLE hEvent;
FILETIME pre_idleTime;
FILETIME pre_kernelTime;
FILETIME pre_userTime;

pre_idleTime = idleTime;
pre_kernelTime = kernelTime;
pre_userTime = userTime;

hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
//初始值为nonsignaled，并且每次触发后自动设置为nonsignaled

WaitForSingleObject(hEvent, 500);//等待500毫秒

GetSystemTimes(&idleTime, &kernelTime, &userTime );
//这里务必再调用GetSystemTimes函数一次

__int64 idle = CompareFileTime(pre_idleTime, idleTime);
__int64 kernel = CompareFileTime(pre_kernelTime, kernelTime);
__int64 user = CompareFileTime(pre_userTime, userTime);

load = (kernel + user - idle) * 100.0 / (kernel + user);
//（总的时间 - 空闲时间）/ 总的时间 = 占用CPU时间的比率，即占用率

pre_idleTime = idleTime;
pre_kernelTime = kernelTime;
pre_userTime = userTime;

return load;
}

//MemoryStrategy.h

#ifndef MemoryStrategy_h
#define MemoryStrategy_h

#include <iostream>
using namespace std;

class MemoryStrategy{
public:
virtual ~MemoryStrategy(){}
virtual long getTotal() = 0;
virtual long getUsed() = 0;
};

class MemoryStrategyImpl_1:public MemoryStrategy{
public:
~MemoryStrategyImpl_1(){}

long getTotal();

long getUsed();
};

class MemoryStrategyImpl_2:public MemoryStrategy{
public:
~MemoryStrategyImpl_2(){}

long getTotal(){
//get total memory here
long total = 0;
return total;
}

long getUsed(){
//get used memory here
long used = 0;
return used;
}
};

class Memory{
public:
long getTotal(){
MemoryStrategyImpl_1 obj;
long TOTAL_MEMORY = obj.getTotal();
return TOTAL_MEMORY;
}
long getUsed(){
MemoryStrategyImpl_1 obj;
long USED_MEMORY = obj.getUsed();
return USED_MEMORY;
}
};

#endif

//MemoryStrategy.cpp

#include <iostream>
#include <windows.h>
#include "MemoryStrategy.h"
using namespace std;

long MemoryStrategyImpl_1::getTotal(){
//get total memory here
long total = 0;

MEMORYSTATUSEX statex;
statex.dwLength = sizeof (statex);//必须有这一句，否则函数错误！
bool res = GlobalMemoryStatusEx(&statex);

HANDLE hEvent;
hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
//初始值为nonsignaled，并且每次触发后自动设置为nonsignaled

const unsigned long long DIV = 1024;

WaitForSingleObject(hEvent, 500);//等待500毫秒

total = statex.ullTotalPhys / DIV / DIV ;

return total;
}

long MemoryStrategyImpl_1::getUsed(){
//get used memory here
long used = 0;

MEMORYSTATUSEX statex;
statex.dwLength = sizeof (statex);//必须有这一句，否则函数错误！
bool res = GlobalMemoryStatusEx(&statex);

HANDLE hEvent;
hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
//初始值为nonsignaled，并且每次触发后自动设置为nonsignaled

const unsigned long long DIV = 1024;

WaitForSingleObject(hEvent, 500);//等待500毫秒

used = statex.ullTotalPhys / DIV / DIV - statex.ullAvailPhys / DIV / DIV ;

return used;
}

//LatencyStrategy.h

#ifndef LatencyStrategy_h
#define LatencyStrategy_h

#include <iostream>
using namespace std;

class LatencyStrategy{
public:
virtual ~LatencyStrategy(){}
virtual float getLatency() = 0;
};

class LatencyStrategyImpl_1:public LatencyStrategy{
public:
~LatencyStrategyImpl_1(){}

float getLatency(){
//get load here
float latency = 0.0;
return latency;
}
};

class LatencyStrategyImpl_2:public LatencyStrategy{
public:
~LatencyStrategyImpl_2(){}

float getLatency(){
//get load here
float latency = 0.0;
return latency;
}
};

class Latency{
public:
float getLatency(){
//return NETWORK_LATENCY;
}
};

#endif

//Display.h

#ifndef Display_h
#define Display_h

#include <iostream>
#include <iomanip>
using namespace std;

class Display{
public:
void show(float load, long totalMemory, long usedMemory, float latency){
//cout << load << ",  "
//	<< totalMemory << ",  "
//	<< usedMemory << ",  "
//	<< latency << endl;
cout << setw(8) << setiosflags(ios::fixed) << setprecision(2)
<< load << ",  "
<< totalMemory << ",  "
<< usedMemory << endl;
}
};

#endif

上图运行结果中出现了37.21等CPU占用率较高的情况，是因为我在这一刻打开了一个网页。